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/*
 * Copyright (c) 2016-2022 VMware Inc. or its affiliates, All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package reactor.core.publisher;

import java.time.Duration;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Objects;
import java.util.Queue;
import java.util.Set;
import java.util.Spliterator;
import java.util.concurrent.Callable;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.function.BiConsumer;
import java.util.function.BiFunction;
import java.util.function.BiPredicate;
import java.util.function.BooleanSupplier;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.function.LongConsumer;
import java.util.function.Predicate;
import java.util.function.Supplier;
import java.util.logging.Level;
import java.util.stream.Collector;
import java.util.stream.Stream;

import io.micrometer.core.instrument.MeterRegistry;
import org.reactivestreams.Publisher;
import org.reactivestreams.Subscriber;
import org.reactivestreams.Subscription;

import reactor.core.CorePublisher;
import reactor.core.CoreSubscriber;
import reactor.core.Disposable;
import reactor.core.Exceptions;
import reactor.core.Fuseable;
import reactor.core.Scannable;
import reactor.core.publisher.FluxOnAssembly.CheckpointHeavySnapshot;
import reactor.core.publisher.FluxOnAssembly.CheckpointLightSnapshot;
import reactor.core.publisher.FluxOnAssembly.AssemblySnapshot;
import reactor.core.publisher.FluxSink.OverflowStrategy;
import reactor.core.scheduler.Scheduler;
import reactor.core.scheduler.Scheduler.Worker;
import reactor.core.scheduler.Schedulers;
import reactor.util.Logger;
import reactor.util.Metrics;
import reactor.util.annotation.Nullable;
import reactor.util.concurrent.Queues;
import reactor.util.context.Context;
import reactor.util.context.ContextView;
import reactor.util.function.Tuple2;
import reactor.util.function.Tuple3;
import reactor.util.function.Tuple4;
import reactor.util.function.Tuple5;
import reactor.util.function.Tuple6;
import reactor.util.function.Tuple7;
import reactor.util.function.Tuple8;
import reactor.util.function.Tuples;
import reactor.util.retry.Retry;

/**
 * A Reactive Streams {@link Publisher} with rx operators that emits 0 to N elements, and then completes
 * (successfully or with an error).
 * 

* The recommended way to learn about the {@link Flux} API and discover new operators is * through the reference documentation, rather than through this javadoc (as opposed to * learning more about individual operators). See the * "which operator do I need?" appendix. * *

* * *

It is intended to be used in implementations and return types. Input parameters should keep using raw * {@link Publisher} as much as possible. * *

If it is known that the underlying {@link Publisher} will emit 0 or 1 element, {@link Mono} should be used * instead. * *

Note that using state in the {@code java.util.function} / lambdas used within Flux operators * should be avoided, as these may be shared between several {@link Subscriber Subscribers}. * *

{@link #subscribe(CoreSubscriber)} is an internal extension to * {@link #subscribe(Subscriber)} used internally for {@link Context} passing. User * provided {@link Subscriber} may * be passed to this "subscribe" extension but will loose the available * per-subscribe {@link Hooks#onLastOperator}. * * @param the element type of this Reactive Streams {@link Publisher} * * @author Sebastien Deleuze * @author Stephane Maldini * @author David Karnok * @author Simon Baslé * * @see Mono */ public abstract class Flux implements CorePublisher { // ============================================================================================================== // Static Generators // ============================================================================================================== /** * Build a {@link Flux} whose data are generated by the combination of the * most recently published value from each of the {@link Publisher} sources. *

* * *

Discard Support: This operator is NOT suited for types that need guaranteed discard of unpropagated elements, as * it doesn't track which elements have been used by the combinator and which haven't. Furthermore, elements can and * will be passed to the combinator multiple times. * * @param sources The {@link Publisher} sources to combine values from * @param combinator The aggregate function that will receive the latest value from each upstream and return the value * to signal downstream * @param type of the value from sources * @param The produced output after transformation by the given combinator * * @return a {@link Flux} based on the produced combinations */ @SafeVarargs public static Flux combineLatest(Function combinator, Publisher... sources) { return combineLatest(combinator, Queues.XS_BUFFER_SIZE, sources); } /** * Build a {@link Flux} whose data are generated by the combination of the * most recently published value from each of the {@link Publisher} sources. *

* * *

Discard Support: This operator is NOT suited for types that need guaranteed discard of unpropagated elements, as * it doesn't track which elements have been used by the combinator and which haven't. Furthermore, elements can and * will be passed to the combinator multiple times. * * @param sources The {@link Publisher} sources to combine values from * @param prefetch The demand sent to each combined source {@link Publisher} * @param combinator The aggregate function that will receive the latest value from each upstream and return the value * to signal downstream * @param type of the value from sources * @param The produced output after transformation by the given combinator * * @return a {@link Flux} based on the produced combinations */ @SafeVarargs public static Flux combineLatest(Function combinator, int prefetch, Publisher... sources) { if (sources.length == 0) { return empty(); } if (sources.length == 1) { Publisher source = sources[0]; if (source instanceof Fuseable) { return onAssembly(new FluxMapFuseable<>(from(source), v -> combinator.apply(new Object[]{v}))); } return onAssembly(new FluxMap<>(from(source), v -> combinator.apply(new Object[]{v}))); } return onAssembly(new FluxCombineLatest<>(sources, combinator, Queues.get(prefetch), prefetch)); } /** * Build a {@link Flux} whose data are generated by the combination of the * most recently published value from each of two {@link Publisher} sources. *

* * *

Discard Support: This operator is NOT suited for types that need guaranteed discard of unpropagated elements, as * it doesn't track which elements have been used by the combinator and which haven't. Furthermore, elements can and * will be passed to the combinator multiple times. * * @param source1 The first {@link Publisher} source to combine values from * @param source2 The second {@link Publisher} source to combine values from * @param combinator The aggregate function that will receive the latest value from each upstream and return the value * to signal downstream * @param type of the value from source1 * @param type of the value from source2 * @param The produced output after transformation by the given combinator * * @return a {@link Flux} based on the produced combinations */ @SuppressWarnings("unchecked") public static Flux combineLatest(Publisher source1, Publisher source2, BiFunction combinator) { return combineLatest(tuple -> combinator.apply((T1)tuple[0], (T2)tuple[1]), source1, source2); } /** * Build a {@link Flux} whose data are generated by the combination of the * most recently published value from each of three {@link Publisher} sources. *

* * *

Discard Support: This operator is NOT suited for types that need guaranteed discard of unpropagated elements, as * it doesn't track which elements have been used by the combinator and which haven't. Furthermore, elements can and * will be passed to the combinator multiple times. * * @param source1 The first {@link Publisher} source to combine values from * @param source2 The second {@link Publisher} source to combine values from * @param source3 The third {@link Publisher} source to combine values from * @param combinator The aggregate function that will receive the latest value from each upstream and return the value * to signal downstream * @param type of the value from source1 * @param type of the value from source2 * @param type of the value from source3 * @param The produced output after transformation by the given combinator * * @return a {@link Flux} based on the produced combinations */ public static Flux combineLatest(Publisher source1, Publisher source2, Publisher source3, Function combinator) { return combineLatest(combinator, source1, source2, source3); } /** * Build a {@link Flux} whose data are generated by the combination of the * most recently published value from each of four {@link Publisher} sources. *

* * *

Discard Support: This operator is NOT suited for types that need guaranteed discard of unpropagated elements, as * it doesn't track which elements have been used by the combinator and which haven't. Furthermore, elements can and * will be passed to the combinator multiple times. * * @param source1 The first {@link Publisher} source to combine values from * @param source2 The second {@link Publisher} source to combine values from * @param source3 The third {@link Publisher} source to combine values from * @param source4 The fourth {@link Publisher} source to combine values from * @param combinator The aggregate function that will receive the latest value from each upstream and return the value * to signal downstream * @param type of the value from source1 * @param type of the value from source2 * @param type of the value from source3 * @param type of the value from source4 * @param The produced output after transformation by the given combinator * * @return a {@link Flux} based on the produced combinations */ public static Flux combineLatest(Publisher source1, Publisher source2, Publisher source3, Publisher source4, Function combinator) { return combineLatest(combinator, source1, source2, source3, source4); } /** * Build a {@link Flux} whose data are generated by the combination of the * most recently published value from each of five {@link Publisher} sources. *

* * *

Discard Support: This operator is NOT suited for types that need guaranteed discard of unpropagated elements, as * it doesn't track which elements have been used by the combinator and which haven't. Furthermore, elements can and * will be passed to the combinator multiple times. * * @param source1 The first {@link Publisher} source to combine values from * @param source2 The second {@link Publisher} source to combine values from * @param source3 The third {@link Publisher} source to combine values from * @param source4 The fourth {@link Publisher} source to combine values from * @param source5 The fifth {@link Publisher} source to combine values from * @param combinator The aggregate function that will receive the latest value from each upstream and return the value * to signal downstream * @param type of the value from source1 * @param type of the value from source2 * @param type of the value from source3 * @param type of the value from source4 * @param type of the value from source5 * @param The produced output after transformation by the given combinator * * @return a {@link Flux} based on the produced combinations */ public static Flux combineLatest(Publisher source1, Publisher source2, Publisher source3, Publisher source4, Publisher source5, Function combinator) { return combineLatest(combinator, source1, source2, source3, source4, source5); } /** * Build a {@link Flux} whose data are generated by the combination of the * most recently published value from each of six {@link Publisher} sources. *

* * *

Discard Support: This operator is NOT suited for types that need guaranteed discard of unpropagated elements, as * it doesn't track which elements have been used by the combinator and which haven't. Furthermore, elements can and * will be passed to the combinator multiple times. * * @param source1 The first {@link Publisher} source to combine values from * @param source2 The second {@link Publisher} source to combine values from * @param source3 The third {@link Publisher} source to combine values from * @param source4 The fourth {@link Publisher} source to combine values from * @param source5 The fifth {@link Publisher} source to combine values from * @param source6 The sixth {@link Publisher} source to combine values from * @param combinator The aggregate function that will receive the latest value from each upstream and return the value * to signal downstream * @param type of the value from source1 * @param type of the value from source2 * @param type of the value from source3 * @param type of the value from source4 * @param type of the value from source5 * @param type of the value from source6 * @param The produced output after transformation by the given combinator * * @return a {@link Flux} based on the produced combinations */ public static Flux combineLatest(Publisher source1, Publisher source2, Publisher source3, Publisher source4, Publisher source5, Publisher source6, Function combinator) { return combineLatest(combinator, source1, source2, source3, source4, source5, source6); } /** * Build a {@link Flux} whose data are generated by the combination of the * most recently published value from each * of the {@link Publisher} sources provided in an {@link Iterable}. *

* * *

Discard Support: This operator is NOT suited for types that need guaranteed discard of unpropagated elements, as * it doesn't track which elements have been used by the combinator and which haven't. Furthermore, elements can and * will be passed to the combinator multiple times. * * @param sources The list of {@link Publisher} sources to combine values from * @param combinator The aggregate function that will receive the latest value from each upstream and return the value * to signal downstream * @param The common base type of the values from sources * @param The produced output after transformation by the given combinator * * @return a {@link Flux} based on the produced combinations */ public static Flux combineLatest(Iterable> sources, Function combinator) { return combineLatest(sources, Queues.XS_BUFFER_SIZE, combinator); } /** * Build a {@link Flux} whose data are generated by the combination of the * most recently published value from each * of the {@link Publisher} sources provided in an {@link Iterable}. *

* * *

Discard Support: This operator is NOT suited for types that need guaranteed discard of unpropagated elements, as * it doesn't track which elements have been used by the combinator and which haven't. Furthermore, elements can and * will be passed to the combinator multiple times. * * @param sources The list of {@link Publisher} sources to combine values from * @param prefetch demand produced to each combined source {@link Publisher} * @param combinator The aggregate function that will receive the latest value from each upstream and return the value * to signal downstream * @param The common base type of the values from sources * @param The produced output after transformation by the given combinator * * @return a {@link Flux} based on the produced combinations */ public static Flux combineLatest(Iterable> sources, int prefetch, Function combinator) { return onAssembly(new FluxCombineLatest(sources, combinator, Queues.get(prefetch), prefetch)); } /** * Concatenate all sources provided in an {@link Iterable}, forwarding elements * emitted by the sources downstream. *

* Concatenation is achieved by sequentially subscribing to the first source then * waiting for it to complete before subscribing to the next, and so on until the * last source completes. Any error interrupts the sequence immediately and is * forwarded downstream. *

* * * @param sources The {@link Iterable} of {@link Publisher} to concatenate * @param The type of values in both source and output sequences * * @return a new {@link Flux} concatenating all source sequences */ public static Flux concat(Iterable> sources) { return onAssembly(new FluxConcatIterable<>(sources)); } /** * Concatenates the values to the end of the {@link Flux} *

* * * @param values The values to concatenate * * @return a new {@link Flux} concatenating all source sequences */ @SafeVarargs public final Flux concatWithValues(T... values) { return concatWith(Flux.fromArray(values)); } /** * Concatenate all sources emitted as an onNext signal from a parent {@link Publisher}, * forwarding elements emitted by the sources downstream. *

* Concatenation is achieved by sequentially subscribing to the first source then * waiting for it to complete before subscribing to the next, and so on until the * last source completes. Any error interrupts the sequence immediately and is * forwarded downstream. *

* * *

Discard Support: This operator discards elements it internally queued for backpressure upon cancellation. * * @param sources The {@link Publisher} of {@link Publisher} to concatenate * @param The type of values in both source and output sequences * * @return a new {@link Flux} concatenating all inner sources sequences */ public static Flux concat(Publisher> sources) { return concat(sources, Queues.XS_BUFFER_SIZE); } /** * Concatenate all sources emitted as an onNext signal from a parent {@link Publisher}, * forwarding elements emitted by the sources downstream. *

* Concatenation is achieved by sequentially subscribing to the first source then * waiting for it to complete before subscribing to the next, and so on until the * last source completes. Any error interrupts the sequence immediately and is * forwarded downstream. *

* * *

Discard Support: This operator discards elements it internally queued for backpressure upon cancellation. * * @param sources The {@link Publisher} of {@link Publisher} to concatenate * @param prefetch the number of Publishers to prefetch from the outer {@link Publisher} * @param The type of values in both source and output sequences * * @return a new {@link Flux} concatenating all inner sources sequences */ public static Flux concat(Publisher> sources, int prefetch) { return from(sources).concatMap(identityFunction(), prefetch); } /** * Concatenate all sources provided as a vararg, forwarding elements emitted by the * sources downstream. *

* Concatenation is achieved by sequentially subscribing to the first source then * waiting for it to complete before subscribing to the next, and so on until the * last source completes. Any error interrupts the sequence immediately and is * forwarded downstream. *

* * * @param sources The {@link Publisher} of {@link Publisher} to concat * @param The type of values in both source and output sequences * * @return a new {@link Flux} concatenating all source sequences */ @SafeVarargs public static Flux concat(Publisher... sources) { return onAssembly(new FluxConcatArray<>(false, sources)); } /** * Concatenate all sources emitted as an onNext signal from a parent {@link Publisher}, * forwarding elements emitted by the sources downstream. *

* Concatenation is achieved by sequentially subscribing to the first source then * waiting for it to complete before subscribing to the next, and so on until the * last source completes. Errors do not interrupt the main sequence but are propagated * after the rest of the sources have had a chance to be concatenated. *

* * * *

Discard Support: This operator discards elements it internally queued for backpressure upon cancellation. * * @param sources The {@link Publisher} of {@link Publisher} to concatenate * @param The type of values in both source and output sequences * * @return a new {@link Flux} concatenating all inner sources sequences, delaying errors */ public static Flux concatDelayError(Publisher> sources) { return concatDelayError(sources, Queues.XS_BUFFER_SIZE); } /** * Concatenate all sources emitted as an onNext signal from a parent {@link Publisher}, * forwarding elements emitted by the sources downstream. *

* Concatenation is achieved by sequentially subscribing to the first source then * waiting for it to complete before subscribing to the next, and so on until the * last source completes. Errors do not interrupt the main sequence but are propagated * after the rest of the sources have had a chance to be concatenated. *

* *

*

Discard Support: This operator discards elements it internally queued for backpressure upon cancellation. * * @param sources The {@link Publisher} of {@link Publisher} to concatenate * @param prefetch number of elements to prefetch from the source, to be turned into inner Publishers * @param The type of values in both source and output sequences * * @return a new {@link Flux} concatenating all inner sources sequences until complete or error */ public static Flux concatDelayError(Publisher> sources, int prefetch) { return from(sources).concatMapDelayError(identityFunction(), prefetch); } /** * Concatenate all sources emitted as an onNext signal from a parent {@link Publisher}, * forwarding elements emitted by the sources downstream. *

* Concatenation is achieved by sequentially subscribing to the first source then * waiting for it to complete before subscribing to the next, and so on until the * last source completes. *

* Errors do not interrupt the main sequence but are propagated after the current * concat backlog if {@code delayUntilEnd} is {@literal false} or after all sources * have had a chance to be concatenated if {@code delayUntilEnd} is {@literal true}. *

* *

* *

Discard Support: This operator discards elements it internally queued for backpressure upon cancellation. * * @param sources The {@link Publisher} of {@link Publisher} to concatenate * @param delayUntilEnd delay error until all sources have been consumed instead of * after the current source * @param prefetch the number of Publishers to prefetch from the outer {@link Publisher} * @param The type of values in both source and output sequences * * @return a new {@link Flux} concatenating all inner sources sequences until complete or error */ public static Flux concatDelayError(Publisher> sources, boolean delayUntilEnd, int prefetch) { return from(sources).concatMapDelayError(identityFunction(), delayUntilEnd, prefetch); } /** * Concatenate all sources provided as a vararg, forwarding elements emitted by the * sources downstream. *

* Concatenation is achieved by sequentially subscribing to the first source then * waiting for it to complete before subscribing to the next, and so on until the * last source completes. Errors do not interrupt the main sequence but are propagated * after the rest of the sources have had a chance to be concatenated. *

* *

* *

Discard Support: This operator discards elements it internally queued for backpressure upon cancellation. * * @param sources The {@link Publisher} of {@link Publisher} to concat * @param The type of values in both source and output sequences * * @return a new {@link Flux} concatenating all source sequences */ @SafeVarargs public static Flux concatDelayError(Publisher... sources) { return onAssembly(new FluxConcatArray<>(true, sources)); } /** * Programmatically create a {@link Flux} with the capability of emitting multiple * elements in a synchronous or asynchronous manner through the {@link FluxSink} API. * This includes emitting elements from multiple threads. *

* *

* This Flux factory is useful if one wants to adapt some other multi-valued async API * and not worry about cancellation and backpressure (which is handled by buffering * all signals if the downstream can't keep up). *

* For example: * *


	 * Flux.<String>create(emitter -> {
	 *
	 *     ActionListener al = e -> {
	 *         emitter.next(textField.getText());
	 *     };
	 *     // without cleanup support:
	 *
	 *     button.addActionListener(al);
	 *
	 *     // with cleanup support:
	 *
	 *     button.addActionListener(al);
	 *     emitter.onDispose(() -> {
	 *         button.removeListener(al);
	 *     });
	 * });
	 * 
* *

Discard Support: The {@link FluxSink} exposed by this operator buffers in case of * overflow. The buffer is discarded when the main sequence is cancelled. * * @param The type of values in the sequence * @param emitter Consume the {@link FluxSink} provided per-subscriber by Reactor to generate signals. * @return a {@link Flux} * @see #push(Consumer) */ public static Flux create(Consumer> emitter) { return create(emitter, OverflowStrategy.BUFFER); } /** * Programmatically create a {@link Flux} with the capability of emitting multiple * elements in a synchronous or asynchronous manner through the {@link FluxSink} API. * This includes emitting elements from multiple threads. *

* *

* This Flux factory is useful if one wants to adapt some other multi-valued async API * and not worry about cancellation and backpressure (which is handled by buffering * all signals if the downstream can't keep up). *

* For example: * *


	 * Flux.<String>create(emitter -> {
	 *
	 *     ActionListener al = e -> {
	 *         emitter.next(textField.getText());
	 *     };
	 *     // without cleanup support:
	 *
	 *     button.addActionListener(al);
	 *
	 *     // with cleanup support:
	 *
	 *     button.addActionListener(al);
	 *     emitter.onDispose(() -> {
	 *         button.removeListener(al);
	 *     });
	 * }, FluxSink.OverflowStrategy.LATEST);
	 * 
* *

Discard Support: The {@link FluxSink} exposed by this operator discards elements * as relevant to the chosen {@link OverflowStrategy}. For example, the {@link OverflowStrategy#DROP} * discards each items as they are being dropped, while {@link OverflowStrategy#BUFFER} * will discard the buffer upon cancellation. * * @param The type of values in the sequence * @param backpressure the backpressure mode, see {@link OverflowStrategy} for the * available backpressure modes * @param emitter Consume the {@link FluxSink} provided per-subscriber by Reactor to generate signals. * @return a {@link Flux} * @see #push(Consumer, reactor.core.publisher.FluxSink.OverflowStrategy) */ public static Flux create(Consumer> emitter, OverflowStrategy backpressure) { return onAssembly(new FluxCreate<>(emitter, backpressure, FluxCreate.CreateMode.PUSH_PULL)); } /** * Programmatically create a {@link Flux} with the capability of emitting multiple * elements from a single-threaded producer through the {@link FluxSink} API. For * a multi-threaded capable alternative, see {@link #create(Consumer)}. *

* *

* This Flux factory is useful if one wants to adapt some other single-threaded * multi-valued async API and not worry about cancellation and backpressure (which is * handled by buffering all signals if the downstream can't keep up). *

* For example: * *


	 * Flux.<String>push(emitter -> {
	 *
	 *	 ActionListener al = e -> {
	 *		 emitter.next(textField.getText());
	 *	 };
	 *	 // without cleanup support:
	 *
	 *	 button.addActionListener(al);
	 *
	 *	 // with cleanup support:
	 *
	 *	 button.addActionListener(al);
	 *	 emitter.onDispose(() -> {
	 *		 button.removeListener(al);
	 *	 });
	 * });
	 * 
* *

Discard Support: The {@link FluxSink} exposed by this operator buffers in case of * overflow. The buffer is discarded when the main sequence is cancelled. * * @param The type of values in the sequence * @param emitter Consume the {@link FluxSink} provided per-subscriber by Reactor to generate signals. * @return a {@link Flux} * @see #create(Consumer) */ public static Flux push(Consumer> emitter) { return push(emitter, OverflowStrategy.BUFFER); } /** * Programmatically create a {@link Flux} with the capability of emitting multiple * elements from a single-threaded producer through the {@link FluxSink} API. For * a multi-threaded capable alternative, see {@link #create(Consumer, reactor.core.publisher.FluxSink.OverflowStrategy)}. *

* *

* This Flux factory is useful if one wants to adapt some other single-threaded * multi-valued async API and not worry about cancellation and backpressure (which is * handled by buffering all signals if the downstream can't keep up). *

* For example: * *


	 * Flux.<String>push(emitter -> {
	 *
	 *	 ActionListener al = e -> {
	 *		 emitter.next(textField.getText());
	 *	 };
	 *	 // without cleanup support:
	 *
	 *	 button.addActionListener(al);
	 *
	 *	 // with cleanup support:
	 *
	 *	 button.addActionListener(al);
	 *	 emitter.onDispose(() -> {
	 *		 button.removeListener(al);
	 *	 });
	 * }, FluxSink.OverflowStrategy.LATEST);
	 * 
* *

Discard Support: The {@link FluxSink} exposed by this operator discards elements * as relevant to the chosen {@link OverflowStrategy}. For example, the {@link OverflowStrategy#DROP} * discards each items as they are being dropped, while {@link OverflowStrategy#BUFFER} * will discard the buffer upon cancellation. * * @param The type of values in the sequence * @param backpressure the backpressure mode, see {@link OverflowStrategy} for the * available backpressure modes * @param emitter Consume the {@link FluxSink} provided per-subscriber by Reactor to generate signals. * @return a {@link Flux} * @see #create(Consumer, reactor.core.publisher.FluxSink.OverflowStrategy) */ public static Flux push(Consumer> emitter, OverflowStrategy backpressure) { return onAssembly(new FluxCreate<>(emitter, backpressure, FluxCreate.CreateMode.PUSH_ONLY)); } /** * Lazily supply a {@link Publisher} every time a {@link Subscription} is made on the * resulting {@link Flux}, so the actual source instantiation is deferred until each * subscribe and the {@link Supplier} can create a subscriber-specific instance. * If the supplier doesn't generate a new instance however, this operator will * effectively behave like {@link #from(Publisher)}. * *

* * * @param supplier the {@link Publisher} {@link Supplier} to call on subscribe * @param the type of values passing through the {@link Flux} * * @return a deferred {@link Flux} * @see #deferContextual(Function) */ public static Flux defer(Supplier> supplier) { return onAssembly(new FluxDefer<>(supplier)); } /** * Lazily supply a {@link Publisher} every time a {@link Subscription} is made on the * resulting {@link Flux}, so the actual source instantiation is deferred until each * subscribe and the {@link Function} can create a subscriber-specific instance. * This operator behaves the same way as {@link #defer(Supplier)}, * but accepts a {@link Function} that will receive the current {@link Context} as an argument. * If the supplier doesn't generate a new instance however, this operator will * effectively behave like {@link #from(Publisher)}. * *

* * * @param contextualPublisherFactory the {@link Publisher} {@link Function} to call on subscribe * @param the type of values passing through the {@link Flux} * @return a deferred {@link Flux} deriving actual {@link Flux} from context values for each subscription * @deprecated use {@link #deferContextual(Function)} */ @Deprecated public static Flux deferWithContext(Function> contextualPublisherFactory) { return deferContextual(view -> contextualPublisherFactory.apply(Context.of(view))); } /** * Lazily supply a {@link Publisher} every time a {@link Subscription} is made on the * resulting {@link Flux}, so the actual source instantiation is deferred until each * subscribe and the {@link Function} can create a subscriber-specific instance. * This operator behaves the same way as {@link #defer(Supplier)}, * but accepts a {@link Function} that will receive the current {@link ContextView} as an argument. * If the function doesn't generate a new instance however, this operator will * effectively behave like {@link #from(Publisher)}. * *

* * * @param contextualPublisherFactory the {@link Publisher} {@link Function} to call on subscribe * @param the type of values passing through the {@link Flux} * @return a deferred {@link Flux} deriving actual {@link Flux} from context values for each subscription */ public static Flux deferContextual(Function> contextualPublisherFactory) { return onAssembly(new FluxDeferContextual<>(contextualPublisherFactory)); } /** * Create a {@link Flux} that completes without emitting any item. *

* * * @param the reified type of the target {@link Subscriber} * * @return an empty {@link Flux} */ public static Flux empty() { return FluxEmpty.instance(); } /** * Create a {@link Flux} that terminates with the specified error immediately after * being subscribed to. *

* * * @param error the error to signal to each {@link Subscriber} * @param the reified type of the target {@link Subscriber} * * @return a new failing {@link Flux} */ public static Flux error(Throwable error) { return error(error, false); } /** * Create a {@link Flux} that terminates with an error immediately after being * subscribed to. The {@link Throwable} is generated by a {@link Supplier}, invoked * each time there is a subscription and allowing for lazy instantiation. *

* * * @param errorSupplier the error signal {@link Supplier} to invoke for each {@link Subscriber} * @param the reified type of the target {@link Subscriber} * * @return a new failing {@link Flux} */ public static Flux error(Supplier errorSupplier) { return onAssembly(new FluxErrorSupplied<>(errorSupplier)); } /** * Create a {@link Flux} that terminates with the specified error, either immediately * after being subscribed to or after being first requested. * *

* * * @param throwable the error to signal to each {@link Subscriber} * @param whenRequested if true, will onError on the first request instead of subscribe(). * @param the reified type of the target {@link Subscriber} * * @return a new failing {@link Flux} */ public static Flux error(Throwable throwable, boolean whenRequested) { if (whenRequested) { return onAssembly(new FluxErrorOnRequest<>(throwable)); } else { return onAssembly(new FluxError<>(throwable)); } } /** * Pick the first {@link Publisher} to emit any signal (onNext/onError/onComplete) and * replay all signals from that {@link Publisher}, effectively behaving like the * fastest of these competing sources. * *

* * * @param sources The competing source publishers * @param The type of values in both source and output sequences * * @return a new {@link Flux} behaving like the fastest of its sources * @deprecated use {@link #firstWithSignal(Publisher[])}. To be removed in reactor 3.5. */ @SafeVarargs @Deprecated public static Flux first(Publisher... sources) { return firstWithSignal(sources); } /** * Pick the first {@link Publisher} to emit any signal (onNext/onError/onComplete) and * replay all signals from that {@link Publisher}, effectively behaving like the * fastest of these competing sources. * *

* * * @param sources The competing source publishers * @param The type of values in both source and output sequences * * @return a new {@link Flux} behaving like the fastest of its sources * @deprecated use {@link #firstWithSignal(Iterable)}. To be removed in reactor 3.5. */ @Deprecated public static Flux first(Iterable> sources) { return firstWithSignal(sources); } /** * Pick the first {@link Publisher} to emit any signal (onNext/onError/onComplete) and * replay all signals from that {@link Publisher}, effectively behaving like the * fastest of these competing sources. * *

* * * @param sources The competing source publishers * @param The type of values in both source and output sequences * * @return a new {@link Flux} behaving like the fastest of its sources */ @SafeVarargs public static Flux firstWithSignal(Publisher... sources) { return onAssembly(new FluxFirstWithSignal<>(sources)); } /** * Pick the first {@link Publisher} to emit any signal (onNext/onError/onComplete) and * replay all signals from that {@link Publisher}, effectively behaving like the * fastest of these competing sources. * *

* * * @param sources The competing source publishers * @param The type of values in both source and output sequences * * @return a new {@link Flux} behaving like the fastest of its sources */ public static Flux firstWithSignal(Iterable> sources) { return onAssembly(new FluxFirstWithSignal<>(sources)); } /** * Pick the first {@link Publisher} to emit any value and replay all values * from that {@link Publisher}, effectively behaving like the source that first * emits an {@link Subscriber#onNext(Object) onNext}. * *

* Sources with values always "win" over empty sources (ones that only emit onComplete) * or failing sources (ones that only emit onError). *

* When no source can provide a value, this operator fails with a {@link NoSuchElementException} * (provided there are at least two sources). This exception has a {@link Exceptions#multiple(Throwable...) composite} * as its {@link Throwable#getCause() cause} that can be used to inspect what went wrong with each source * (so the composite has as many elements as there are sources). *

* Exceptions from failing sources are directly reflected in the composite at the index of the failing source. * For empty sources, a {@link NoSuchElementException} is added at their respective index. * One can use {@link Exceptions#unwrapMultiple(Throwable) Exceptions.unwrapMultiple(topLevel.getCause())} * to easily inspect these errors as a {@link List}. *

* Note that like in {@link #firstWithSignal(Iterable)}, an infinite source can be problematic * if no other source emits onNext. *

* * * @param sources An {@link Iterable} of the competing source publishers * @param The type of values in both source and output sequences * * @return a new {@link Flux} behaving like the fastest of its sources */ public static Flux firstWithValue(Iterable> sources) { return onAssembly(new FluxFirstWithValue<>(sources)); } /** * Pick the first {@link Publisher} to emit any value and replay all values * from that {@link Publisher}, effectively behaving like the source that first * emits an {@link Subscriber#onNext(Object) onNext}. *

* Sources with values always "win" over an empty source (ones that only emit onComplete) * or failing sources (ones that only emit onError). *

* When no source can provide a value, this operator fails with a {@link NoSuchElementException} * (provided there are at least two sources). This exception has a {@link Exceptions#multiple(Throwable...) composite} * as its {@link Throwable#getCause() cause} that can be used to inspect what went wrong with each source * (so the composite has as many elements as there are sources). *

* Exceptions from failing sources are directly reflected in the composite at the index of the failing source. * For empty sources, a {@link NoSuchElementException} is added at their respective index. * One can use {@link Exceptions#unwrapMultiple(Throwable) Exceptions.unwrapMultiple(topLevel.getCause())} * to easily inspect these errors as a {@link List}. *

* Note that like in {@link #firstWithSignal(Publisher[])}, an infinite source can be problematic * if no other source emits onNext. * In case the {@code first} source is already an array-based {@link #firstWithValue(Publisher, Publisher[])} * instance, nesting is avoided: a single new array-based instance is created with all the * sources from {@code first} plus all the {@code others} sources at the same level. *

* * * @param first The first competing source publisher * @param others The other competing source publishers * @param The type of values in both source and output sequences * * @return a new {@link Flux} behaving like the fastest of its sources */ @SafeVarargs public static Flux firstWithValue(Publisher first, Publisher... others) { if (first instanceof FluxFirstWithValue) { @SuppressWarnings("unchecked") FluxFirstWithValue orPublisher = (FluxFirstWithValue) first; FluxFirstWithValue result = orPublisher.firstValuedAdditionalSources(others); if (result != null) { return result; } } return onAssembly(new FluxFirstWithValue<>(first, others)); } /** * Decorate the specified {@link Publisher} with the {@link Flux} API. *

* *

* {@link Hooks#onEachOperator(String, Function)} and similar assembly hooks are applied * unless the source is already a {@link Flux}. * * @param source the source to decorate * @param The type of values in both source and output sequences * * @return a new {@link Flux} */ public static Flux from(Publisher source) { //duplicated in wrap, but necessary to detect early and thus avoid applying assembly if (source instanceof Flux) { @SuppressWarnings("unchecked") Flux casted = (Flux) source; return casted; } //all other cases (including ScalarCallable) are managed without assembly in wrap //let onAssembly point to Flux.from: return onAssembly(wrap(source)); } /** * Create a {@link Flux} that emits the items contained in the provided array. *

* * * @param array the array to read data from * @param The type of values in the source array and resulting Flux * * @return a new {@link Flux} */ public static Flux fromArray(T[] array) { if (array.length == 0) { return empty(); } if (array.length == 1) { return just(array[0]); } return onAssembly(new FluxArray<>(array)); } /** * Create a {@link Flux} that emits the items contained in the provided {@link Iterable}. * The {@link Iterable#iterator()} method will be invoked at least once and at most twice * for each subscriber. *

* *

* This operator inspects the {@link Iterable}'s {@link Spliterator} to assess if the iteration * can be guaranteed to be finite (see {@link Operators#onDiscardMultiple(Iterator, boolean, Context)}). * Since the default Spliterator wraps the Iterator we can have two {@link Iterable#iterator()} * calls. This second invocation is skipped on a {@link Collection} however, a type which is * assumed to be always finite. * *

Discard Support: Upon cancellation, this operator attempts to discard the remainder of the * {@link Iterable} if it can safely ensure the iterator is finite. * Note that this means the {@link Iterable#iterator()} method could be invoked twice. * * @param it the {@link Iterable} to read data from * @param The type of values in the source {@link Iterable} and resulting Flux * * @return a new {@link Flux} */ public static Flux fromIterable(Iterable it) { return onAssembly(new FluxIterable<>(it)); } /** * Create a {@link Flux} that emits the items contained in the provided {@link Stream}. * Keep in mind that a {@link Stream} cannot be re-used, which can be problematic in * case of multiple subscriptions or re-subscription (like with {@link #repeat()} or * {@link #retry()}). The {@link Stream} is {@link Stream#close() closed} automatically * by the operator on cancellation, error or completion. *

* * *

Discard Support: Upon cancellation, this operator attempts to discard remainder of the * {@link Stream} through its open {@link Spliterator}, if it can safely ensure it is finite * (see {@link Operators#onDiscardMultiple(Iterator, boolean, Context)}). * * @param s the {@link Stream} to read data from * @param The type of values in the source {@link Stream} and resulting Flux * * @return a new {@link Flux} */ public static Flux fromStream(Stream s) { Objects.requireNonNull(s, "Stream s must be provided"); return onAssembly(new FluxStream<>(() -> s)); } /** * Create a {@link Flux} that emits the items contained in a {@link Stream} created by * the provided {@link Supplier} for each subscription. The {@link Stream} is * {@link Stream#close() closed} automatically by the operator on cancellation, error * or completion. *

* * *

Discard Support: Upon cancellation, this operator attempts to discard remainder of the * {@link Stream} through its open {@link Spliterator}, if it can safely ensure it is finite * (see {@link Operators#onDiscardMultiple(Iterator, boolean, Context)}). * * @param streamSupplier the {@link Supplier} that generates the {@link Stream} from * which to read data * @param The type of values in the source {@link Stream} and resulting Flux * * @return a new {@link Flux} */ public static Flux fromStream(Supplier> streamSupplier) { return onAssembly(new FluxStream<>(streamSupplier)); } /** * Programmatically create a {@link Flux} by generating signals one-by-one via a * consumer callback. *

* * * @param the value type emitted * @param generator Consume the {@link SynchronousSink} provided per-subscriber by Reactor * to generate a single signal on each pass. * * @return a {@link Flux} */ public static Flux generate(Consumer> generator) { Objects.requireNonNull(generator, "generator"); return onAssembly(new FluxGenerate<>(generator)); } /** * Programmatically create a {@link Flux} by generating signals one-by-one via a * consumer callback and some state. The {@code stateSupplier} may return {@literal null}. *

* * * @param the value type emitted * @param the per-subscriber custom state type * @param stateSupplier called for each incoming Subscriber to provide the initial state for the generator bifunction * @param generator Consume the {@link SynchronousSink} provided per-subscriber by Reactor * as well as the current state to generate a single signal on each pass * and return a (new) state. * @return a {@link Flux} */ public static Flux generate(Callable stateSupplier, BiFunction, S> generator) { return onAssembly(new FluxGenerate<>(stateSupplier, generator)); } /** * Programmatically create a {@link Flux} by generating signals one-by-one via a * consumer callback and some state, with a final cleanup callback. The * {@code stateSupplier} may return {@literal null} but your cleanup {@code stateConsumer} * will need to handle the null case. *

* * * @param the value type emitted * @param the per-subscriber custom state type * @param stateSupplier called for each incoming Subscriber to provide the initial state for the generator bifunction * @param generator Consume the {@link SynchronousSink} provided per-subscriber by Reactor * as well as the current state to generate a single signal on each pass * and return a (new) state. * @param stateConsumer called after the generator has terminated or the downstream cancelled, receiving the last * state to be handled (i.e., release resources or do other cleanup). * * @return a {@link Flux} */ public static Flux generate(Callable stateSupplier, BiFunction, S> generator, Consumer stateConsumer) { return onAssembly(new FluxGenerate<>(stateSupplier, generator, stateConsumer)); } /** * Create a {@link Flux} that emits long values starting with 0 and incrementing at * specified time intervals on the global timer. The first element is emitted after * an initial delay equal to the {@code period}. If demand is not produced in time, * an onError will be signalled with an {@link Exceptions#isOverflow(Throwable) overflow} * {@code IllegalStateException} detailing the tick that couldn't be emitted. * In normal conditions, the {@link Flux} will never complete. *

* Runs on the {@link Schedulers#parallel()} Scheduler. *

* * * @param period the period {@link Duration} between each increment * @return a new {@link Flux} emitting increasing numbers at regular intervals */ public static Flux interval(Duration period) { return interval(period, Schedulers.parallel()); } /** * Create a {@link Flux} that emits long values starting with 0 and incrementing at * specified time intervals, after an initial delay, on the global timer. If demand is * not produced in time, an onError will be signalled with an * {@link Exceptions#isOverflow(Throwable) overflow} {@code IllegalStateException} * detailing the tick that couldn't be emitted. In normal conditions, the {@link Flux} * will never complete. *

* Runs on the {@link Schedulers#parallel()} Scheduler. *

* * * @param delay the {@link Duration} to wait before emitting 0l * @param period the period {@link Duration} before each following increment * * @return a new {@link Flux} emitting increasing numbers at regular intervals */ public static Flux interval(Duration delay, Duration period) { return interval(delay, period, Schedulers.parallel()); } /** * Create a {@link Flux} that emits long values starting with 0 and incrementing at * specified time intervals, on the specified {@link Scheduler}. The first element is * emitted after an initial delay equal to the {@code period}. If demand is not * produced in time, an onError will be signalled with an {@link Exceptions#isOverflow(Throwable) overflow} * {@code IllegalStateException} detailing the tick that couldn't be emitted. * In normal conditions, the {@link Flux} will never complete. *

* * * @param period the period {@link Duration} between each increment * @param timer a time-capable {@link Scheduler} instance to run on * * @return a new {@link Flux} emitting increasing numbers at regular intervals */ public static Flux interval(Duration period, Scheduler timer) { return interval(period, period, timer); } /** * Create a {@link Flux} that emits long values starting with 0 and incrementing at * specified time intervals, after an initial delay, on the specified {@link Scheduler}. * If demand is not produced in time, an onError will be signalled with an * {@link Exceptions#isOverflow(Throwable) overflow} {@code IllegalStateException} * detailing the tick that couldn't be emitted. In normal conditions, the {@link Flux} * will never complete. *

* * * @param delay the {@link Duration} to wait before emitting 0l * @param period the period {@link Duration} before each following increment * @param timer a time-capable {@link Scheduler} instance to run on * * @return a new {@link Flux} emitting increasing numbers at regular intervals */ public static Flux interval(Duration delay, Duration period, Scheduler timer) { return onAssembly(new FluxInterval(delay.toNanos(), period.toNanos(), TimeUnit.NANOSECONDS, timer)); } /** * Create a {@link Flux} that emits the provided elements and then completes. *

* * * @param data the elements to emit, as a vararg * @param the emitted data type * * @return a new {@link Flux} */ @SafeVarargs public static Flux just(T... data) { return fromArray(data); } /** * Create a new {@link Flux} that will only emit a single element then onComplete. *

* * * @param data the single element to emit * @param the emitted data type * * @return a new {@link Flux} */ public static Flux just(T data) { return onAssembly(new FluxJust<>(data)); } /** * Merge data from {@link Publisher} sequences emitted by the passed {@link Publisher} * into an interleaved merged sequence. Unlike {@link #concat(Publisher) concat}, inner * sources are subscribed to eagerly. *

* * *

* Note that merge is tailored to work with asynchronous sources or finite sources. When dealing with * an infinite source that doesn't already publish on a dedicated Scheduler, you must isolate that source * in its own Scheduler, as merge would otherwise attempt to drain it before subscribing to * another source. * * @param source a {@link Publisher} of {@link Publisher} sources to merge * @param the merged type * * @return a merged {@link Flux} */ public static Flux merge(Publisher> source) { return merge(source, Queues.SMALL_BUFFER_SIZE, Queues.XS_BUFFER_SIZE); } /** * Merge data from {@link Publisher} sequences emitted by the passed {@link Publisher} * into an interleaved merged sequence. Unlike {@link #concat(Publisher) concat}, inner * sources are subscribed to eagerly (but at most {@code concurrency} sources are * subscribed to at the same time). *

* *

* Note that merge is tailored to work with asynchronous sources or finite sources. When dealing with * an infinite source that doesn't already publish on a dedicated Scheduler, you must isolate that source * in its own Scheduler, as merge would otherwise attempt to drain it before subscribing to * another source. * * @param source a {@link Publisher} of {@link Publisher} sources to merge * @param concurrency the request produced to the main source thus limiting concurrent merge backlog * @param the merged type * * @return a merged {@link Flux} */ public static Flux merge(Publisher> source, int concurrency) { return merge(source, concurrency, Queues.XS_BUFFER_SIZE); } /** * Merge data from {@link Publisher} sequences emitted by the passed {@link Publisher} * into an interleaved merged sequence. Unlike {@link #concat(Publisher) concat}, inner * sources are subscribed to eagerly (but at most {@code concurrency} sources are * subscribed to at the same time). *

* *

* Note that merge is tailored to work with asynchronous sources or finite sources. When dealing with * an infinite source that doesn't already publish on a dedicated Scheduler, you must isolate that source * in its own Scheduler, as merge would otherwise attempt to drain it before subscribing to * another source. * * @param source a {@link Publisher} of {@link Publisher} sources to merge * @param concurrency the request produced to the main source thus limiting concurrent merge backlog * @param prefetch the inner source request size * @param the merged type * * @return a merged {@link Flux} */ public static Flux merge(Publisher> source, int concurrency, int prefetch) { return onAssembly(new FluxFlatMap<>( from(source), identityFunction(), false, concurrency, Queues.get(concurrency), prefetch, Queues.get(prefetch))); } /** * Merge data from {@link Publisher} sequences contained in an {@link Iterable} * into an interleaved merged sequence. Unlike {@link #concat(Publisher) concat}, inner * sources are subscribed to eagerly. * A new {@link Iterator} will be created for each subscriber. *

* *

* Note that merge is tailored to work with asynchronous sources or finite sources. When dealing with * an infinite source that doesn't already publish on a dedicated Scheduler, you must isolate that source * in its own Scheduler, as merge would otherwise attempt to drain it before subscribing to * another source. * * @param sources the {@link Iterable} of sources to merge (will be lazily iterated on subscribe) * @param The source type of the data sequence * * @return a merged {@link Flux} */ public static Flux merge(Iterable> sources) { return merge(fromIterable(sources)); } /** * Merge data from {@link Publisher} sequences contained in an array / vararg * into an interleaved merged sequence. Unlike {@link #concat(Publisher) concat}, * sources are subscribed to eagerly. *

* *

* Note that merge is tailored to work with asynchronous sources or finite sources. When dealing with * an infinite source that doesn't already publish on a dedicated Scheduler, you must isolate that source * in its own Scheduler, as merge would otherwise attempt to drain it before subscribing to * another source. * * @param sources the array of {@link Publisher} sources to merge * @param The source type of the data sequence * * @return a merged {@link Flux} */ @SafeVarargs public static Flux merge(Publisher... sources) { return merge(Queues.XS_BUFFER_SIZE, sources); } /** * Merge data from {@link Publisher} sequences contained in an array / vararg * into an interleaved merged sequence. Unlike {@link #concat(Publisher) concat}, * sources are subscribed to eagerly. *

* *

* Note that merge is tailored to work with asynchronous sources or finite sources. When dealing with * an infinite source that doesn't already publish on a dedicated Scheduler, you must isolate that source * in its own Scheduler, as merge would otherwise attempt to drain it before subscribing to * another source. * * @param sources the array of {@link Publisher} sources to merge * @param prefetch the inner source request size * @param The source type of the data sequence * * @return a fresh Reactive {@link Flux} publisher ready to be subscribed */ @SafeVarargs public static Flux merge(int prefetch, Publisher... sources) { return merge(prefetch, false, sources); } /** * Merge data from {@link Publisher} sequences contained in an array / vararg * into an interleaved merged sequence. Unlike {@link #concat(Publisher) concat}, * sources are subscribed to eagerly. * This variant will delay any error until after the rest of the merge backlog has been processed. *

* *

* Note that merge is tailored to work with asynchronous sources or finite sources. When dealing with * an infinite source that doesn't already publish on a dedicated Scheduler, you must isolate that source * in its own Scheduler, as merge would otherwise attempt to drain it before subscribing to * another source. * * @param sources the array of {@link Publisher} sources to merge * @param prefetch the inner source request size * @param The source type of the data sequence * * @return a fresh Reactive {@link Flux} publisher ready to be subscribed */ @SafeVarargs public static Flux mergeDelayError(int prefetch, Publisher... sources) { return merge(prefetch, true, sources); } /** * Merge data from provided {@link Publisher} sequences into an ordered merged sequence, * by picking the smallest values from each source (as defined by their natural order). * This is not a {@link #sort()}, as it doesn't consider the whole of each sequences. *

* Instead, this operator considers only one value from each source and picks the * smallest of all these values, then replenishes the slot for that picked source. *

* * * @param sources {@link Publisher} sources of {@link Comparable} to merge * @param a {@link Comparable} merged type that has a {@link Comparator#naturalOrder() natural order} * @return a merged {@link Flux} that , subscribing early but keeping the original ordering */ @SafeVarargs public static > Flux mergeComparing(Publisher... sources) { return mergeComparing(Queues.SMALL_BUFFER_SIZE, Comparator.naturalOrder(), sources); } /** * Merge data from provided {@link Publisher} sequences into an ordered merged sequence, * by picking the smallest values from each source (as defined by the provided * {@link Comparator}). This is not a {@link #sort(Comparator)}, as it doesn't consider * the whole of each sequences. *

* Instead, this operator considers only one value from each source and picks the * smallest of all these values, then replenishes the slot for that picked source. *

* * * @param comparator the {@link Comparator} to use to find the smallest value * @param sources {@link Publisher} sources to merge * @param the merged type * @return a merged {@link Flux} that compares latest values from each source, using the * smallest value and replenishing the source that produced it */ @SafeVarargs public static Flux mergeComparing(Comparator comparator, Publisher... sources) { return mergeComparing(Queues.SMALL_BUFFER_SIZE, comparator, sources); } /** * Merge data from provided {@link Publisher} sequences into an ordered merged sequence, * by picking the smallest values from each source (as defined by the provided * {@link Comparator}). This is not a {@link #sort(Comparator)}, as it doesn't consider * the whole of each sequences. *

* Instead, this operator considers only one value from each source and picks the * smallest of all these values, then replenishes the slot for that picked source. *

* * * @param prefetch the number of elements to prefetch from each source (avoiding too * many small requests to the source when picking) * @param comparator the {@link Comparator} to use to find the smallest value * @param sources {@link Publisher} sources to merge * @param the merged type * @return a merged {@link Flux} that compares latest values from each source, using the * smallest value and replenishing the source that produced it */ @SafeVarargs public static Flux mergeComparing(int prefetch, Comparator comparator, Publisher... sources) { if (sources.length == 0) { return empty(); } if (sources.length == 1) { return from(sources[0]); } return onAssembly(new FluxMergeComparing<>(prefetch, comparator, false, sources)); } /** * Merge data from provided {@link Publisher} sequences into an ordered merged sequence, * by picking the smallest values from each source (as defined by the provided * {@link Comparator}). This is not a {@link #sort(Comparator)}, as it doesn't consider * the whole of each sequences. *

* Instead, this operator considers only one value from each source and picks the * smallest of all these values, then replenishes the slot for that picked source. *

* Note that it is delaying errors until all data is consumed. *

* * * @param prefetch the number of elements to prefetch from each source (avoiding too * many small requests to the source when picking) * @param comparator the {@link Comparator} to use to find the smallest value * @param sources {@link Publisher} sources to merge * @param the merged type * @return a merged {@link Flux} that compares latest values from each source, using the * smallest value and replenishing the source that produced it */ @SafeVarargs public static Flux mergeComparingDelayError(int prefetch, Comparator comparator, Publisher... sources) { if (sources.length == 0) { return empty(); } if (sources.length == 1) { return from(sources[0]); } return onAssembly(new FluxMergeComparing<>(prefetch, comparator, true, sources)); } /** * Merge data from provided {@link Publisher} sequences into an ordered merged sequence, * by picking the smallest values from each source (as defined by their natural order). * This is not a {@link #sort()}, as it doesn't consider the whole of each sequences. *

* Instead, this operator considers only one value from each source and picks the * smallest of all these values, then replenishes the slot for that picked source. *

* Note that it is delaying errors until all data is consumed. *

* * * @param sources {@link Publisher} sources of {@link Comparable} to merge * @param a {@link Comparable} merged type that has a {@link Comparator#naturalOrder() natural order} * @return a merged {@link Flux} that compares latest values from each source, using the * smallest value and replenishing the source that produced it * @deprecated Use {@link #mergeComparingDelayError(int, Comparator, Publisher[])} instead * (as {@link #mergeComparing(Publisher[])} don't have this operator's delayError behavior). * To be removed in 3.6.0 at the earliest. */ @SafeVarargs @Deprecated public static > Flux mergeOrdered(Publisher... sources) { return mergeOrdered(Queues.SMALL_BUFFER_SIZE, Comparator.naturalOrder(), sources); } /** * Merge data from provided {@link Publisher} sequences into an ordered merged sequence, * by picking the smallest values from each source (as defined by the provided * {@link Comparator}). This is not a {@link #sort(Comparator)}, as it doesn't consider * the whole of each sequences. *

* Instead, this operator considers only one value from each source and picks the * smallest of all these values, then replenishes the slot for that picked source. *

* Note that it is delaying errors until all data is consumed. *

* * * @param comparator the {@link Comparator} to use to find the smallest value * @param sources {@link Publisher} sources to merge * @param the merged type * @return a merged {@link Flux} that compares latest values from each source, using the * smallest value and replenishing the source that produced it * @deprecated Use {@link #mergeComparingDelayError(int, Comparator, Publisher[])} instead * (as {@link #mergeComparing(Publisher[])} don't have this operator's delayError behavior). * To be removed in 3.6.0 at the earliest. */ @SafeVarargs @Deprecated public static Flux mergeOrdered(Comparator comparator, Publisher... sources) { return mergeOrdered(Queues.SMALL_BUFFER_SIZE, comparator, sources); } /** * Merge data from provided {@link Publisher} sequences into an ordered merged sequence, * by picking the smallest values from each source (as defined by the provided * {@link Comparator}). This is not a {@link #sort(Comparator)}, as it doesn't consider * the whole of each sequences. *

* Instead, this operator considers only one value from each source and picks the * smallest of all these values, then replenishes the slot for that picked source. *

* Note that it is delaying errors until all data is consumed. *

* * * @param prefetch the number of elements to prefetch from each source (avoiding too * many small requests to the source when picking) * @param comparator the {@link Comparator} to use to find the smallest value * @param sources {@link Publisher} sources to merge * @param the merged type * @return a merged {@link Flux} that compares latest values from each source, using the * smallest value and replenishing the source that produced it * @deprecated Use {@link #mergeComparingDelayError(int, Comparator, Publisher[])} instead * (as {@link #mergeComparing(Publisher[])} don't have this operator's delayError behavior). * To be removed in 3.6.0 at the earliest. */ @SafeVarargs @Deprecated public static Flux mergeOrdered(int prefetch, Comparator comparator, Publisher... sources) { if (sources.length == 0) { return empty(); } if (sources.length == 1) { return from(sources[0]); } return onAssembly(new FluxMergeComparing<>(prefetch, comparator, true, sources)); } /** * Merge data from {@link Publisher} sequences emitted by the passed {@link Publisher} * into an ordered merged sequence. Unlike concat, the inner publishers are subscribed to * eagerly. Unlike merge, their emitted values are merged into the final sequence in * subscription order. *

* * * @param sources a {@link Publisher} of {@link Publisher} sources to merge * @param the merged type * * @return a merged {@link Flux}, subscribing early but keeping the original ordering */ public static Flux mergeSequential(Publisher> sources) { return mergeSequential(sources, false, Queues.SMALL_BUFFER_SIZE, Queues.XS_BUFFER_SIZE); } /** * Merge data from {@link Publisher} sequences emitted by the passed {@link Publisher} * into an ordered merged sequence. Unlike concat, the inner publishers are subscribed to * eagerly (but at most {@code maxConcurrency} sources at a time). Unlike merge, their * emitted values are merged into the final sequence in subscription order. *

* * * @param sources a {@link Publisher} of {@link Publisher} sources to merge * @param prefetch the inner source request size * @param maxConcurrency the request produced to the main source thus limiting concurrent merge backlog * @param the merged type * * @return a merged {@link Flux}, subscribing early but keeping the original ordering */ public static Flux mergeSequential(Publisher> sources, int maxConcurrency, int prefetch) { return mergeSequential(sources, false, maxConcurrency, prefetch); } /** * Merge data from {@link Publisher} sequences emitted by the passed {@link Publisher} * into an ordered merged sequence. Unlike concat, the inner publishers are subscribed to * eagerly (but at most {@code maxConcurrency} sources at a time). Unlike merge, their * emitted values are merged into the final sequence in subscription order. * This variant will delay any error until after the rest of the mergeSequential backlog has been processed. *

* * * @param sources a {@link Publisher} of {@link Publisher} sources to merge * @param prefetch the inner source request size * @param maxConcurrency the request produced to the main source thus limiting concurrent merge backlog * @param the merged type * * @return a merged {@link Flux}, subscribing early but keeping the original ordering */ public static Flux mergeSequentialDelayError(Publisher> sources, int maxConcurrency, int prefetch) { return mergeSequential(sources, true, maxConcurrency, prefetch); } /** * Merge data from {@link Publisher} sequences provided in an array/vararg * into an ordered merged sequence. Unlike concat, sources are subscribed to * eagerly. Unlike merge, their emitted values are merged into the final sequence in subscription order. *

* * * @param sources a number of {@link Publisher} sequences to merge * @param the merged type * * @return a merged {@link Flux}, subscribing early but keeping the original ordering */ @SafeVarargs public static Flux mergeSequential(Publisher... sources) { return mergeSequential(Queues.XS_BUFFER_SIZE, false, sources); } /** * Merge data from {@link Publisher} sequences provided in an array/vararg * into an ordered merged sequence. Unlike concat, sources are subscribed to * eagerly. Unlike merge, their emitted values are merged into the final sequence in subscription order. *

* * * @param prefetch the inner source request size * @param sources a number of {@link Publisher} sequences to merge * @param the merged type * * @return a merged {@link Flux}, subscribing early but keeping the original ordering */ @SafeVarargs public static Flux mergeSequential(int prefetch, Publisher... sources) { return mergeSequential(prefetch, false, sources); } /** * Merge data from {@link Publisher} sequences provided in an array/vararg * into an ordered merged sequence. Unlike concat, sources are subscribed to * eagerly. Unlike merge, their emitted values are merged into the final sequence in subscription order. * This variant will delay any error until after the rest of the mergeSequential backlog * has been processed. *

* * * @param prefetch the inner source request size * @param sources a number of {@link Publisher} sequences to merge * @param the merged type * * @return a merged {@link Flux}, subscribing early but keeping the original ordering */ @SafeVarargs public static Flux mergeSequentialDelayError(int prefetch, Publisher... sources) { return mergeSequential(prefetch, true, sources); } /** * Merge data from {@link Publisher} sequences provided in an {@link Iterable} * into an ordered merged sequence. Unlike concat, sources are subscribed to * eagerly. Unlike merge, their emitted values are merged into the final sequence in subscription order. *

* * * @param sources an {@link Iterable} of {@link Publisher} sequences to merge * @param the merged type * * @return a merged {@link Flux}, subscribing early but keeping the original ordering */ public static Flux mergeSequential(Iterable> sources) { return mergeSequential(sources, false, Queues.SMALL_BUFFER_SIZE, Queues.XS_BUFFER_SIZE); } /** * Merge data from {@link Publisher} sequences provided in an {@link Iterable} * into an ordered merged sequence. Unlike concat, sources are subscribed to * eagerly (but at most {@code maxConcurrency} sources at a time). Unlike merge, their * emitted values are merged into the final sequence in subscription order. *

* * * @param sources an {@link Iterable} of {@link Publisher} sequences to merge * @param maxConcurrency the request produced to the main source thus limiting concurrent merge backlog * @param prefetch the inner source request size * @param the merged type * * @return a merged {@link Flux}, subscribing early but keeping the original ordering */ public static Flux mergeSequential(Iterable> sources, int maxConcurrency, int prefetch) { return mergeSequential(sources, false, maxConcurrency, prefetch); } /** * Merge data from {@link Publisher} sequences provided in an {@link Iterable} * into an ordered merged sequence. Unlike concat, sources are subscribed to * eagerly (but at most {@code maxConcurrency} sources at a time). Unlike merge, their * emitted values are merged into the final sequence in subscription order. * This variant will delay any error until after the rest of the mergeSequential backlog * has been processed. *

* * * @param sources an {@link Iterable} of {@link Publisher} sequences to merge * @param maxConcurrency the request produced to the main source thus limiting concurrent merge backlog * @param prefetch the inner source request size * @param the merged type * * @return a merged {@link Flux}, subscribing early but keeping the original ordering */ public static Flux mergeSequentialDelayError(Iterable> sources, int maxConcurrency, int prefetch) { return mergeSequential(sources, true, maxConcurrency, prefetch); } /** * Create a {@link Flux} that will never signal any data, error or completion signal. *

* * * @param the {@link Subscriber} type target * * @return a never completing {@link Flux} */ public static Flux never() { return FluxNever.instance(); } /** * Build a {@link Flux} that will only emit a sequence of {@code count} incrementing integers, * starting from {@code start}. That is, emit integers between {@code start} (included) * and {@code start + count} (excluded) then complete. * *

* * * @param start the first integer to be emit * @param count the total number of incrementing values to emit, including the first value * @return a ranged {@link Flux} */ public static Flux range(int start, int count) { if (count == 1) { return just(start); } if (count == 0) { return empty(); } return onAssembly(new FluxRange(start, count)); } /** * Creates a {@link Flux} that mirrors the most recently emitted {@link Publisher}, * forwarding its data until a new {@link Publisher} comes in the source. *

* The resulting {@link Flux} will complete once there are no new {@link Publisher} in * the source (source has completed) and the last mirrored {@link Publisher} has also * completed. *

* * * @param mergedPublishers The {@link Publisher} of {@link Publisher} to switch on and mirror. * @param the produced type * * @return a {@link FluxProcessor} accepting publishers and producing T */ public static Flux switchOnNext(Publisher> mergedPublishers) { return switchOnNext(mergedPublishers, Queues.XS_BUFFER_SIZE); } /** * Creates a {@link Flux} that mirrors the most recently emitted {@link Publisher}, * forwarding its data until a new {@link Publisher} comes in the source. *

* The resulting {@link Flux} will complete once there are no new {@link Publisher} in * the source (source has completed) and the last mirrored {@link Publisher} has also * completed. *

* * * @param mergedPublishers The {@link Publisher} of {@link Publisher} to switch on and mirror. * @param prefetch the inner source request size * @param the produced type * * @return a {@link FluxProcessor} accepting publishers and producing T * * @deprecated to be removed in 3.6.0 at the earliest. In 3.5.0, you should replace * calls with prefetch=0 with calls to switchOnNext(mergedPublishers), as the default * behavior of the single-parameter variant will then change to prefetch=0. */ @Deprecated public static Flux switchOnNext(Publisher> mergedPublishers, int prefetch) { if (prefetch == 0) { return onAssembly(new FluxSwitchMapNoPrefetch<>(from(mergedPublishers), identityFunction())); } return onAssembly(new FluxSwitchMap<>(from(mergedPublishers), identityFunction(), Queues.unbounded(prefetch), prefetch)); } /** * Uses a resource, generated by a supplier for each individual Subscriber, while streaming the values from a * Publisher derived from the same resource and makes sure the resource is released if the sequence terminates or * the Subscriber cancels. *

* Eager resource cleanup happens just before the source termination and exceptions raised by the cleanup Consumer * may override the terminal event. *

* *

* For an asynchronous version of the cleanup, with distinct path for onComplete, onError * and cancel terminations, see {@link #usingWhen(Publisher, Function, Function, BiFunction, Function)}. * * @param resourceSupplier a {@link Callable} that is called on subscribe to generate the resource * @param sourceSupplier a factory to derive a {@link Publisher} from the supplied resource * @param resourceCleanup a resource cleanup callback invoked on completion * @param emitted type * @param resource type * * @return a new {@link Flux} built around a disposable resource * @see #usingWhen(Publisher, Function, Function, BiFunction, Function) * @see #usingWhen(Publisher, Function, Function) */ public static Flux using(Callable resourceSupplier, Function> sourceSupplier, Consumer resourceCleanup) { return using(resourceSupplier, sourceSupplier, resourceCleanup, true); } /** * Uses a resource, generated by a supplier for each individual Subscriber, while streaming the values from a * Publisher derived from the same resource and makes sure the resource is released if the sequence terminates or * the Subscriber cancels. *

*

  • Eager resource cleanup happens just before the source termination and exceptions raised by the cleanup * Consumer may override the terminal event.
  • Non-eager cleanup will drop any exception.
*

* *

* For an asynchronous version of the cleanup, with distinct path for onComplete, onError * and cancel terminations, see {@link #usingWhen(Publisher, Function, Function, BiFunction, Function)}. * * @param resourceSupplier a {@link Callable} that is called on subscribe to generate the resource * @param sourceSupplier a factory to derive a {@link Publisher} from the supplied resource * @param resourceCleanup a resource cleanup callback invoked on completion * @param eager true to clean before terminating downstream subscribers * @param emitted type * @param resource type * * @return a new {@link Flux} built around a disposable resource * @see #usingWhen(Publisher, Function, Function, BiFunction, Function) * @see #usingWhen(Publisher, Function, Function) */ public static Flux using(Callable resourceSupplier, Function> sourceSupplier, Consumer resourceCleanup, boolean eager) { return onAssembly(new FluxUsing<>(resourceSupplier, sourceSupplier, resourceCleanup, eager)); } /** * Uses a resource, generated by a {@link Publisher} for each individual {@link Subscriber}, * while streaming the values from a {@link Publisher} derived from the same resource. * Whenever the resulting sequence terminates, a provided {@link Function} generates * a "cleanup" {@link Publisher} that is invoked but doesn't change the content of the * main sequence. Instead it just defers the termination (unless it errors, in which case * the error suppresses the original termination signal). *

* Note that if the resource supplying {@link Publisher} emits more than one resource, the * subsequent resources are dropped ({@link Operators#onNextDropped(Object, Context)}). If * the publisher errors AFTER having emitted one resource, the error is also silently dropped * ({@link Operators#onErrorDropped(Throwable, Context)}). * An empty completion or error without at least one onNext signal triggers a short-circuit * of the main sequence with the same terminal signal (no resource is established, no * cleanup is invoked). * *

* * * @param resourceSupplier a {@link Publisher} that "generates" the resource, * subscribed for each subscription to the main sequence * @param resourceClosure a factory to derive a {@link Publisher} from the supplied resource * @param asyncCleanup an asynchronous resource cleanup invoked when the resource * closure terminates (with onComplete, onError or cancel) * @param the type of elements emitted by the resource closure, and thus the main sequence * @param the type of the resource object * @return a new {@link Flux} built around a "transactional" resource, with asynchronous * cleanup on all terminations (onComplete, onError, cancel) */ public static Flux usingWhen(Publisher resourceSupplier, Function> resourceClosure, Function> asyncCleanup) { return usingWhen(resourceSupplier, resourceClosure, asyncCleanup, (resource, error) -> asyncCleanup.apply(resource), asyncCleanup); } /** * Uses a resource, generated by a {@link Publisher} for each individual {@link Subscriber}, * while streaming the values from a {@link Publisher} derived from the same resource. * Note that all steps of the operator chain that would need the resource to be in an open * stable state need to be described inside the {@code resourceClosure} {@link Function}. *

* Whenever the resulting sequence terminates, the relevant {@link Function} generates * a "cleanup" {@link Publisher} that is invoked but doesn't change the content of the * main sequence. Instead it just defers the termination (unless it errors, in which case * the error suppresses the original termination signal). * *

* *

* Individual cleanups can also be associated with main sequence cancellation and * error terminations: *

* *

* Note that if the resource supplying {@link Publisher} emits more than one resource, the * subsequent resources are dropped ({@link Operators#onNextDropped(Object, Context)}). If * the publisher errors AFTER having emitted one resource, the error is also silently dropped * ({@link Operators#onErrorDropped(Throwable, Context)}). * An empty completion or error without at least one onNext signal triggers a short-circuit * of the main sequence with the same terminal signal (no resource is established, no * cleanup is invoked). *

* Additionally, the terminal signal is replaced by any error that might have happened * in the terminating {@link Publisher}: *

* *

* Finally, early cancellations will cancel the resource supplying {@link Publisher}: *

* * * @param resourceSupplier a {@link Publisher} that "generates" the resource, * subscribed for each subscription to the main sequence * @param resourceClosure a factory to derive a {@link Publisher} from the supplied resource * @param asyncComplete an asynchronous resource cleanup invoked if the resource closure terminates with onComplete * @param asyncError an asynchronous resource cleanup invoked if the resource closure terminates with onError. * The terminating error is provided to the {@link BiFunction} * @param asyncCancel an asynchronous resource cleanup invoked if the resource closure is cancelled. * When {@code null}, the {@code asyncComplete} path is used instead. * @param the type of elements emitted by the resource closure, and thus the main sequence * @param the type of the resource object * @return a new {@link Flux} built around a "transactional" resource, with several * termination path triggering asynchronous cleanup sequences * @see #usingWhen(Publisher, Function, Function) */ public static Flux usingWhen(Publisher resourceSupplier, Function> resourceClosure, Function> asyncComplete, BiFunction> asyncError, //the operator itself accepts null for asyncCancel, but we won't in the public API Function> asyncCancel) { return onAssembly(new FluxUsingWhen<>(resourceSupplier, resourceClosure, asyncComplete, asyncError, asyncCancel)); } /** * Zip two sources together, that is to say wait for all the sources to emit one * element and combine these elements once into an output value (constructed by the provided * combinator). The operator will continue doing so until any of the sources completes. * Errors will immediately be forwarded. * This "Step-Merge" processing is especially useful in Scatter-Gather scenarios. *

* * * @param source1 The first {@link Publisher} source to zip. * @param source2 The second {@link Publisher} source to zip. * @param combinator The aggregate function that will receive a unique value from each upstream and return the * value to signal downstream * @param type of the value from source1 * @param type of the value from source2 * @param The produced output after transformation by the combinator * * @return a zipped {@link Flux} */ public static Flux zip(Publisher source1, Publisher source2, final BiFunction combinator) { return onAssembly(new FluxZip(source1, source2, combinator, Queues.xs(), Queues.XS_BUFFER_SIZE)); } /** * Zip two sources together, that is to say wait for all the sources to emit one * element and combine these elements once into a {@link Tuple2}. * The operator will continue doing so until any of the sources completes. * Errors will immediately be forwarded. * This "Step-Merge" processing is especially useful in Scatter-Gather scenarios. *

* * * @param source1 The first {@link Publisher} source to zip. * @param source2 The second {@link Publisher} source to zip. * @param type of the value from source1 * @param type of the value from source2 * * @return a zipped {@link Flux} */ public static Flux> zip(Publisher source1, Publisher source2) { return zip(source1, source2, tuple2Function()); } /** * Zip three sources together, that is to say wait for all the sources to emit one * element and combine these elements once into a {@link Tuple3}. * The operator will continue doing so until any of the sources completes. * Errors will immediately be forwarded. * This "Step-Merge" processing is especially useful in Scatter-Gather scenarios. *

* * * @param source1 The first upstream {@link Publisher} to subscribe to. * @param source2 The second upstream {@link Publisher} to subscribe to. * @param source3 The third upstream {@link Publisher} to subscribe to. * @param type of the value from source1 * @param type of the value from source2 * @param type of the value from source3 * * @return a zipped {@link Flux} */ public static Flux> zip(Publisher source1, Publisher source2, Publisher source3) { return zip(Tuples.fn3(), source1, source2, source3); } /** * Zip four sources together, that is to say wait for all the sources to emit one * element and combine these elements once into a {@link Tuple4}. * The operator will continue doing so until any of the sources completes. * Errors will immediately be forwarded. * This "Step-Merge" processing is especially useful in Scatter-Gather scenarios. *

* * * @param source1 The first upstream {@link Publisher} to subscribe to. * @param source2 The second upstream {@link Publisher} to subscribe to. * @param source3 The third upstream {@link Publisher} to subscribe to. * @param source4 The fourth upstream {@link Publisher} to subscribe to. * @param type of the value from source1 * @param type of the value from source2 * @param type of the value from source3 * @param type of the value from source4 * * @return a zipped {@link Flux} */ public static Flux> zip(Publisher source1, Publisher source2, Publisher source3, Publisher source4) { return zip(Tuples.fn4(), source1, source2, source3, source4); } /** * Zip five sources together, that is to say wait for all the sources to emit one * element and combine these elements once into a {@link Tuple5}. * The operator will continue doing so until any of the sources completes. * Errors will immediately be forwarded. * This "Step-Merge" processing is especially useful in Scatter-Gather scenarios. *

* * * @param source1 The first upstream {@link Publisher} to subscribe to. * @param source2 The second upstream {@link Publisher} to subscribe to. * @param source3 The third upstream {@link Publisher} to subscribe to. * @param source4 The fourth upstream {@link Publisher} to subscribe to. * @param source5 The fifth upstream {@link Publisher} to subscribe to. * @param type of the value from source1 * @param type of the value from source2 * @param type of the value from source3 * @param type of the value from source4 * @param type of the value from source5 * * @return a zipped {@link Flux} */ public static Flux> zip(Publisher source1, Publisher source2, Publisher source3, Publisher source4, Publisher source5) { return zip(Tuples.fn5(), source1, source2, source3, source4, source5); } /** * Zip six sources together, that is to say wait for all the sources to emit one * element and combine these elements once into a {@link Tuple6}. * The operator will continue doing so until any of the sources completes. * Errors will immediately be forwarded. * This "Step-Merge" processing is especially useful in Scatter-Gather scenarios. *

* * * @param source1 The first upstream {@link Publisher} to subscribe to. * @param source2 The second upstream {@link Publisher} to subscribe to. * @param source3 The third upstream {@link Publisher} to subscribe to. * @param source4 The fourth upstream {@link Publisher} to subscribe to. * @param source5 The fifth upstream {@link Publisher} to subscribe to. * @param source6 The sixth upstream {@link Publisher} to subscribe to. * @param type of the value from source1 * @param type of the value from source2 * @param type of the value from source3 * @param type of the value from source4 * @param type of the value from source5 * @param type of the value from source6 * * @return a zipped {@link Flux} */ public static Flux> zip(Publisher source1, Publisher source2, Publisher source3, Publisher source4, Publisher source5, Publisher source6) { return zip(Tuples.fn6(), source1, source2, source3, source4, source5, source6); } /** * Zip seven sources together, that is to say wait for all the sources to emit one * element and combine these elements once into a {@link Tuple7}. * The operator will continue doing so until any of the sources completes. * Errors will immediately be forwarded. * This "Step-Merge" processing is especially useful in Scatter-Gather scenarios. *

* * * @param source1 The first upstream {@link Publisher} to subscribe to. * @param source2 The second upstream {@link Publisher} to subscribe to. * @param source3 The third upstream {@link Publisher} to subscribe to. * @param source4 The fourth upstream {@link Publisher} to subscribe to. * @param source5 The fifth upstream {@link Publisher} to subscribe to. * @param source6 The sixth upstream {@link Publisher} to subscribe to. * @param source7 The seventh upstream {@link Publisher} to subscribe to. * @param type of the value from source1 * @param type of the value from source2 * @param type of the value from source3 * @param type of the value from source4 * @param type of the value from source5 * @param type of the value from source6 * @param type of the value from source7 * * @return a zipped {@link Flux} */ public static Flux> zip(Publisher source1, Publisher source2, Publisher source3, Publisher source4, Publisher source5, Publisher source6, Publisher source7) { return zip(Tuples.fn7(), source1, source2, source3, source4, source5, source6, source7); } /** * Zip eight sources together, that is to say wait for all the sources to emit one * element and combine these elements once into a {@link Tuple8}. * The operator will continue doing so until any of the sources completes. * Errors will immediately be forwarded. * This "Step-Merge" processing is especially useful in Scatter-Gather scenarios. *

* * * @param source1 The first upstream {@link Publisher} to subscribe to. * @param source2 The second upstream {@link Publisher} to subscribe to. * @param source3 The third upstream {@link Publisher} to subscribe to. * @param source4 The fourth upstream {@link Publisher} to subscribe to. * @param source5 The fifth upstream {@link Publisher} to subscribe to. * @param source6 The sixth upstream {@link Publisher} to subscribe to. * @param source7 The seventh upstream {@link Publisher} to subscribe to. * @param source8 The eight upstream {@link Publisher} to subscribe to. * @param type of the value from source1 * @param type of the value from source2 * @param type of the value from source3 * @param type of the value from source4 * @param type of the value from source5 * @param type of the value from source6 * @param type of the value from source7 * @param type of the value from source8 * * @return a zipped {@link Flux} */ public static Flux> zip(Publisher source1, Publisher source2, Publisher source3, Publisher source4, Publisher source5, Publisher source6, Publisher source7, Publisher source8) { return zip(Tuples.fn8(), source1, source2, source3, source4, source5, source6, source7, source8); } /** * Zip multiple sources together, that is to say wait for all the sources to emit one * element and combine these elements once into an output value (constructed by the provided * combinator). * The operator will continue doing so until any of the sources completes. * Errors will immediately be forwarded. * This "Step-Merge" processing is especially useful in Scatter-Gather scenarios. * * The {@link Iterable#iterator()} will be called on each {@link Publisher#subscribe(Subscriber)}. * *

* * * @param sources the {@link Iterable} providing sources to zip * @param combinator The aggregate function that will receive a unique value from each upstream and return the value * to signal downstream * @param the combined produced type * * @return a zipped {@link Flux} */ public static Flux zip(Iterable> sources, final Function combinator) { return zip(sources, Queues.XS_BUFFER_SIZE, combinator); } /** * Zip multiple sources together, that is to say wait for all the sources to emit one * element and combine these elements once into an output value (constructed by the provided * combinator). * The operator will continue doing so until any of the sources completes. * Errors will immediately be forwarded. * This "Step-Merge" processing is especially useful in Scatter-Gather scenarios. * * The {@link Iterable#iterator()} will be called on each {@link Publisher#subscribe(Subscriber)}. * *

* * * @param sources the {@link Iterable} providing sources to zip * @param prefetch the inner source request size * @param combinator The aggregate function that will receive a unique value from each upstream and return the value * to signal downstream * @param the combined produced type * * @return a zipped {@link Flux} */ public static Flux zip(Iterable> sources, int prefetch, final Function combinator) { return onAssembly(new FluxZip(sources, combinator, Queues.get(prefetch), prefetch)); } /** * Zip multiple sources together, that is to say wait for all the sources to emit one * element and combine these elements once into an output value (constructed by the provided * combinator). * The operator will continue doing so until any of the sources completes. * Errors will immediately be forwarded. * This "Step-Merge" processing is especially useful in Scatter-Gather scenarios. *

* * * @param combinator The aggregate function that will receive a unique value from each upstream and return the * value to signal downstream * @param sources the array providing sources to zip * @param the type of the input sources * @param the combined produced type * * @return a zipped {@link Flux} */ @SafeVarargs public static Flux zip( final Function combinator, Publisher... sources) { return zip(combinator, Queues.XS_BUFFER_SIZE, sources); } /** * Zip multiple sources together, that is to say wait for all the sources to emit one * element and combine these elements once into an output value (constructed by the provided * combinator). * The operator will continue doing so until any of the sources completes. * Errors will immediately be forwarded. * This "Step-Merge" processing is especially useful in Scatter-Gather scenarios. *

* * * @param combinator The aggregate function that will receive a unique value from each upstream and return the * value to signal downstream * @param prefetch individual source request size * @param sources the array providing sources to zip * @param the type of the input sources * @param the combined produced type * * @return a zipped {@link Flux} */ @SafeVarargs public static Flux zip(final Function combinator, int prefetch, Publisher... sources) { if (sources.length == 0) { return empty(); } if (sources.length == 1) { Publisher source = sources[0]; if (source instanceof Fuseable) { return onAssembly(new FluxMapFuseable<>(from(source), v -> combinator.apply(new Object[]{v}))); } return onAssembly(new FluxMap<>(from(source), v -> combinator.apply(new Object[]{v}))); } return onAssembly(new FluxZip<>(sources, combinator, Queues.get(prefetch), prefetch)); } /** * Zip multiple sources together, that is to say wait for all the sources to emit one * element and combine these elements once into an output value (constructed by the provided * combinator). * The operator will continue doing so until any of the sources completes. * Errors will immediately be forwarded. * This "Step-Merge" processing is especially useful in Scatter-Gather scenarios. *

* Note that the {@link Publisher} sources from the outer {@link Publisher} will * accumulate into an exhaustive list before starting zip operation. *

* * * @param sources The {@link Publisher} of {@link Publisher} sources to zip. A finite publisher is required. * @param combinator The aggregate function that will receive a unique value from each upstream and return the value * to signal downstream * @param the raw tuple type * @param The produced output after transformation by the given combinator * * @return a {@link Flux} based on the produced value */ @SuppressWarnings({ "rawtypes", "unchecked" }) public static Flux zip(Publisher> sources, final Function combinator) { return onAssembly(new FluxBuffer<>(from(sources), Integer.MAX_VALUE, listSupplier()) .flatMap(new Function>, Publisher>() { @Override public Publisher apply(List> publishers) { return zip(Tuples.fnAny((Function) combinator), publishers.toArray(new Publisher[publishers .size()])); } })); } /** * * Emit a single boolean true if all values of this sequence match * the {@link Predicate}. *

* The implementation uses short-circuit logic and completes with false if * the predicate doesn't match a value. * *

* * * @param predicate the {@link Predicate} that needs to apply to all emitted items * * @return a new {@link Mono} with true if all values satisfies a predicate and false * otherwise */ public final Mono all(Predicate predicate) { return Mono.onAssembly(new MonoAll<>(this, predicate)); } /** * Emit a single boolean true if any of the values of this {@link Flux} sequence match * the predicate. *

* The implementation uses short-circuit logic and completes with true if * the predicate matches a value. * *

* * * @param predicate the {@link Predicate} that needs to apply to at least one emitted item * * @return a new {@link Mono} with true if any value satisfies a predicate and false * otherwise */ public final Mono any(Predicate predicate) { return Mono.onAssembly(new MonoAny<>(this, predicate)); } /** * Transform this {@link Flux} into a target type. *

	 * {@code flux.as(Mono::from).subscribe() }
	 * 
* * @param transformer the {@link Function} to immediately map this {@link Flux} * into a target type instance. * @param

the returned instance type * * @return the {@link Flux} transformed to an instance of P * @see #transformDeferred(Function) transformDeferred(Function) for a lazy transformation of Flux */ public final

P as(Function, P> transformer) { return transformer.apply(this); } /** * Subscribe to this {@link Flux} and block indefinitely * until the upstream signals its first value or completes. Returns that value, * or null if the Flux completes empty. In case the Flux errors, the original * exception is thrown (wrapped in a {@link RuntimeException} if it was a checked * exception). *

* Note that each blockFirst() will trigger a new subscription: in other words, * the result might miss signal from hot publishers. * *

* * * @return the first value or null */ @Nullable public final T blockFirst() { BlockingFirstSubscriber subscriber = new BlockingFirstSubscriber<>(); subscribe((Subscriber) subscriber); return subscriber.blockingGet(); } /** * Subscribe to this {@link Flux} and block until the upstream * signals its first value, completes or a timeout expires. Returns that value, * or null if the Flux completes empty. In case the Flux errors, the original * exception is thrown (wrapped in a {@link RuntimeException} if it was a checked * exception). If the provided timeout expires, a {@link RuntimeException} is thrown. *

* Note that each blockFirst() will trigger a new subscription: in other words, * the result might miss signal from hot publishers. * *

* * * @param timeout maximum time period to wait for before raising a {@link RuntimeException} * @return the first value or null */ @Nullable public final T blockFirst(Duration timeout) { BlockingFirstSubscriber subscriber = new BlockingFirstSubscriber<>(); subscribe((Subscriber) subscriber); return subscriber.blockingGet(timeout.toNanos(), TimeUnit.NANOSECONDS); } /** * Subscribe to this {@link Flux} and block indefinitely * until the upstream signals its last value or completes. Returns that value, * or null if the Flux completes empty. In case the Flux errors, the original * exception is thrown (wrapped in a {@link RuntimeException} if it was a checked * exception). *

* Note that each blockLast() will trigger a new subscription: in other words, * the result might miss signal from hot publishers. * *

* * * @return the last value or null */ @Nullable public final T blockLast() { BlockingLastSubscriber subscriber = new BlockingLastSubscriber<>(); subscribe((Subscriber) subscriber); return subscriber.blockingGet(); } /** * Subscribe to this {@link Flux} and block until the upstream * signals its last value, completes or a timeout expires. Returns that value, * or null if the Flux completes empty. In case the Flux errors, the original * exception is thrown (wrapped in a {@link RuntimeException} if it was a checked * exception). If the provided timeout expires, a {@link RuntimeException} is thrown. *

* Note that each blockLast() will trigger a new subscription: in other words, * the result might miss signal from hot publishers. * *

* * * @param timeout maximum time period to wait for before raising a {@link RuntimeException} * @return the last value or null */ @Nullable public final T blockLast(Duration timeout) { BlockingLastSubscriber subscriber = new BlockingLastSubscriber<>(); subscribe((Subscriber) subscriber); return subscriber.blockingGet(timeout.toNanos(), TimeUnit.NANOSECONDS); } /** * Collect all incoming values into a single {@link List} buffer that will be emitted * by the returned {@link Flux} once this Flux completes. *

* * *

Discard Support: This operator discards the buffer upon cancellation or error triggered by a data signal. * * @return a buffered {@link Flux} of at most one {@link List} * @see #collectList() for an alternative collecting algorithm returning {@link Mono} */ public final Flux> buffer() { return buffer(Integer.MAX_VALUE); } /** * Collect incoming values into multiple {@link List} buffers that will be emitted * by the returned {@link Flux} each time the given max size is reached or once this * Flux completes. *

* * *

Discard Support: This operator discards the currently open buffer upon cancellation or error triggered by a data signal. * * @param maxSize the maximum collected size * * @return a microbatched {@link Flux} of {@link List} */ public final Flux> buffer(int maxSize) { return buffer(maxSize, listSupplier()); } /** * Collect incoming values into multiple user-defined {@link Collection} buffers that * will be emitted by the returned {@link Flux} each time the given max size is reached * or once this Flux completes. *

* * *

Discard Support: This operator discards the currently open buffer upon cancellation or error triggered by a data signal, * as well as latest unbuffered element if the bufferSupplier fails. * * @param maxSize the maximum collected size * @param bufferSupplier a {@link Supplier} of the concrete {@link Collection} to use for each buffer * @param the {@link Collection} buffer type * * @return a microbatched {@link Flux} of {@link Collection} */ public final > Flux buffer(int maxSize, Supplier bufferSupplier) { return onAssembly(new FluxBuffer<>(this, maxSize, bufferSupplier)); } /** * Collect incoming values into multiple {@link List} buffers that will be emitted * by the returned {@link Flux} each time the given max size is reached or once this * Flux completes. Buffers can be created with gaps, as a new buffer will be created * every time {@code skip} values have been emitted by the source. *

* When maxSize < skip : dropping buffers *

* *

* When maxSize > skip : overlapping buffers *

* *

* When maxSize == skip : exact buffers *

* * *

Discard Support: This operator discards elements in between buffers (in the case of * dropping buffers). It also discards the currently open buffer upon cancellation or error triggered by a data signal. * Note however that overlapping buffer variant DOES NOT discard, as this might result in an element * being discarded from an early buffer while it is still valid in a more recent buffer. * * @param skip the number of items to count before creating a new buffer * @param maxSize the max collected size * * @return a microbatched {@link Flux} of possibly overlapped or gapped {@link List} */ public final Flux> buffer(int maxSize, int skip) { return buffer(maxSize, skip, listSupplier()); } /** * Collect incoming values into multiple user-defined {@link Collection} buffers that * will be emitted by the returned {@link Flux} each time the given max size is reached * or once this Flux completes. Buffers can be created with gaps, as a new buffer will * be created every time {@code skip} values have been emitted by the source *

* When maxSize < skip : dropping buffers *

* *

* When maxSize > skip : overlapping buffers *

* *

* When maxSize == skip : exact buffers *

* * *

Discard Support: This operator discards elements in between buffers (in the case of * dropping buffers). It also discards the currently open buffer upon cancellation or error triggered by a data signal. * Note however that overlapping buffer variant DOES NOT discard, as this might result in an element * being discarded from an early buffer while it is still valid in a more recent buffer. * * @param skip the number of items to count before creating a new buffer * @param maxSize the max collected size * @param bufferSupplier a {@link Supplier} of the concrete {@link Collection} to use for each buffer * @param the {@link Collection} buffer type * * @return a microbatched {@link Flux} of possibly overlapped or gapped * {@link Collection} */ public final > Flux buffer(int maxSize, int skip, Supplier bufferSupplier) { return onAssembly(new FluxBuffer<>(this, maxSize, skip, bufferSupplier)); } /** * Collect incoming values into multiple {@link List} buffers, as delimited by the * signals of a companion {@link Publisher} this operator will subscribe to. *

* * *

Discard Support: This operator discards the currently open buffer upon cancellation or error triggered by a data signal. * * @param other the companion {@link Publisher} whose signals trigger new buffers * * @return a microbatched {@link Flux} of {@link List} delimited by signals from a {@link Publisher} */ public final Flux> buffer(Publisher other) { return buffer(other, listSupplier()); } /** * Collect incoming values into multiple user-defined {@link Collection} buffers, as * delimited by the signals of a companion {@link Publisher} this operator will * subscribe to. *

* * *

Discard Support: This operator discards the currently open buffer upon cancellation or error triggered by a data signal, * and the last received element when the bufferSupplier fails. * * @param other the companion {@link Publisher} whose signals trigger new buffers * @param bufferSupplier a {@link Supplier} of the concrete {@link Collection} to use for each buffer * @param the {@link Collection} buffer type * * @return a microbatched {@link Flux} of {@link Collection} delimited by signals from a {@link Publisher} */ public final > Flux buffer(Publisher other, Supplier bufferSupplier) { return onAssembly(new FluxBufferBoundary<>(this, other, bufferSupplier)); } /** * Collect incoming values into multiple {@link List} buffers that will be emitted by * the returned {@link Flux} every {@code bufferingTimespan}. *

* * *

Discard Support: This operator discards the currently open buffer upon cancellation or error triggered by a data signal. * * @param bufferingTimespan the duration from buffer creation until a buffer is closed and emitted * * @return a microbatched {@link Flux} of {@link List} delimited by the given time span */ public final Flux> buffer(Duration bufferingTimespan) { return buffer(bufferingTimespan, Schedulers.parallel()); } /** * Collect incoming values into multiple {@link List} buffers created at a given * {@code openBufferEvery} period. Each buffer will last until the {@code bufferingTimespan} has elapsed, * thus emitting the bucket in the resulting {@link Flux}. *

* When bufferingTimespan < openBufferEvery : dropping buffers *

* *

* When bufferingTimespan > openBufferEvery : overlapping buffers *

* *

* When bufferingTimespan == openBufferEvery : exact buffers *

* * *

Discard Support: This operator discards the currently open buffer upon cancellation or error triggered by a data signal. * It DOES NOT provide strong guarantees in the case of overlapping buffers, as elements * might get discarded too early (from the first of two overlapping buffers for instance). * * @param bufferingTimespan the duration from buffer creation until a buffer is closed and emitted * @param openBufferEvery the interval at which to create a new buffer * * @return a microbatched {@link Flux} of {@link List} delimited by the given period openBufferEvery and sized by bufferingTimespan */ public final Flux> buffer(Duration bufferingTimespan, Duration openBufferEvery) { return buffer(bufferingTimespan, openBufferEvery, Schedulers.parallel()); } /** * Collect incoming values into multiple {@link List} buffers that will be emitted by * the returned {@link Flux} every {@code bufferingTimespan}, as measured on the provided {@link Scheduler}. *

* * *

Discard Support: This operator discards the currently open buffer upon cancellation or error triggered by a data signal. * * @param bufferingTimespan the duration from buffer creation until a buffer is closed and emitted * @param timer a time-capable {@link Scheduler} instance to run on * * @return a microbatched {@link Flux} of {@link List} delimited by the given period */ public final Flux> buffer(Duration bufferingTimespan, Scheduler timer) { return buffer(interval(bufferingTimespan, timer)); } /** * Collect incoming values into multiple {@link List} buffers created at a given * {@code openBufferEvery} period, as measured on the provided {@link Scheduler}. Each * buffer will last until the {@code bufferingTimespan} has elapsed (also measured on the scheduler), * thus emitting the bucket in the resulting {@link Flux}. *

* When bufferingTimespan < openBufferEvery : dropping buffers *

* *

* When bufferingTimespan > openBufferEvery : overlapping buffers *

* *

* When bufferingTimespan == openBufferEvery : exact buffers *

* * *

Discard Support: This operator discards the currently open buffer upon cancellation or error triggered by a data signal. * It DOES NOT provide strong guarantees in the case of overlapping buffers, as elements * might get discarded too early (from the first of two overlapping buffers for instance). * * @param bufferingTimespan the duration from buffer creation until a buffer is closed and emitted * @param openBufferEvery the interval at which to create a new buffer * @param timer a time-capable {@link Scheduler} instance to run on * * @return a microbatched {@link Flux} of {@link List} delimited by the given period openBufferEvery and sized by bufferingTimespan */ public final Flux> buffer(Duration bufferingTimespan, Duration openBufferEvery, Scheduler timer) { if (bufferingTimespan.equals(openBufferEvery)) { return buffer(bufferingTimespan, timer); } return bufferWhen(interval(Duration.ZERO, openBufferEvery, timer), aLong -> Mono .delay(bufferingTimespan, timer)); } /** * Collect incoming values into multiple {@link List} buffers that will be emitted * by the returned {@link Flux} each time the buffer reaches a maximum size OR the * maxTime {@link Duration} elapses. *

* * *

Discard Support: This operator discards the currently open buffer upon cancellation or error triggered by a data signal. * * @param maxSize the max collected size * @param maxTime the timeout enforcing the release of a partial buffer * * @return a microbatched {@link Flux} of {@link List} delimited by given size or a given period timeout */ public final Flux> bufferTimeout(int maxSize, Duration maxTime) { return bufferTimeout(maxSize, maxTime, listSupplier()); } /** * Collect incoming values into multiple user-defined {@link Collection} buffers that * will be emitted by the returned {@link Flux} each time the buffer reaches a maximum * size OR the maxTime {@link Duration} elapses. *

* * *

Discard Support: This operator discards the currently open buffer upon cancellation or error triggered by a data signal. * * @param maxSize the max collected size * @param maxTime the timeout enforcing the release of a partial buffer * @param bufferSupplier a {@link Supplier} of the concrete {@link Collection} to use for each buffer * @param the {@link Collection} buffer type * * @return a microbatched {@link Flux} of {@link Collection} delimited by given size or a given period timeout */ public final > Flux bufferTimeout(int maxSize, Duration maxTime, Supplier bufferSupplier) { return bufferTimeout(maxSize, maxTime, Schedulers.parallel(), bufferSupplier); } /** * Collect incoming values into multiple {@link List} buffers that will be emitted * by the returned {@link Flux} each time the buffer reaches a maximum size OR the * maxTime {@link Duration} elapses, as measured on the provided {@link Scheduler}. *

* * *

Discard Support: This operator discards the currently open buffer upon cancellation or error triggered by a data signal. * * @param maxSize the max collected size * @param maxTime the timeout enforcing the release of a partial buffer * @param timer a time-capable {@link Scheduler} instance to run on * * @return a microbatched {@link Flux} of {@link List} delimited by given size or a given period timeout */ public final Flux> bufferTimeout(int maxSize, Duration maxTime, Scheduler timer) { return bufferTimeout(maxSize, maxTime, timer, listSupplier()); } /** * Collect incoming values into multiple user-defined {@link Collection} buffers that * will be emitted by the returned {@link Flux} each time the buffer reaches a maximum * size OR the maxTime {@link Duration} elapses, as measured on the provided {@link Scheduler}. *

* * *

Discard Support: This operator discards the currently open buffer upon cancellation or error triggered by a data signal. * * @param maxSize the max collected size * @param maxTime the timeout enforcing the release of a partial buffer * @param timer a time-capable {@link Scheduler} instance to run on * @param bufferSupplier a {@link Supplier} of the concrete {@link Collection} to use for each buffer * @param the {@link Collection} buffer type * * @return a microbatched {@link Flux} of {@link Collection} delimited by given size or a given period timeout */ public final > Flux bufferTimeout(int maxSize, Duration maxTime, Scheduler timer, Supplier bufferSupplier) { return onAssembly(new FluxBufferTimeout<>(this, maxSize, maxTime.toNanos(), TimeUnit.NANOSECONDS, timer, bufferSupplier)); } /** * Collect incoming values into multiple {@link List} buffers that will be emitted by * the resulting {@link Flux} each time the given predicate returns true. Note that * the element that triggers the predicate to return true (and thus closes a buffer) * is included as last element in the emitted buffer. *

* *

* On completion, if the latest buffer is non-empty and has not been closed it is * emitted. However, such a "partial" buffer isn't emitted in case of onError * termination. * *

Discard Support: This operator discards the currently open buffer upon cancellation or error triggered by a data signal. * * @param predicate a predicate that triggers the next buffer when it becomes true. * * @return a microbatched {@link Flux} of {@link List} */ public final Flux> bufferUntil(Predicate predicate) { return onAssembly(new FluxBufferPredicate<>(this, predicate, listSupplier(), FluxBufferPredicate.Mode.UNTIL)); } /** * Collect incoming values into multiple {@link List} buffers that will be emitted by * the resulting {@link Flux} each time the given predicate returns true. Note that * the buffer into which the element that triggers the predicate to return true * (and thus closes a buffer) is included depends on the {@code cutBefore} parameter: * set it to true to include the boundary element in the newly opened buffer, false to * include it in the closed buffer (as in {@link #bufferUntil(Predicate)}). *

* *

* On completion, if the latest buffer is non-empty and has not been closed it is * emitted. However, such a "partial" buffer isn't emitted in case of onError * termination. * *

Discard Support: This operator discards the currently open buffer upon cancellation or error triggered by a data signal. * * @param predicate a predicate that triggers the next buffer when it becomes true. * @param cutBefore set to true to include the triggering element in the new buffer rather than the old. * * @return a microbatched {@link Flux} of {@link List} */ public final Flux> bufferUntil(Predicate predicate, boolean cutBefore) { return onAssembly(new FluxBufferPredicate<>(this, predicate, listSupplier(), cutBefore ? FluxBufferPredicate.Mode.UNTIL_CUT_BEFORE : FluxBufferPredicate.Mode.UNTIL)); } /** * Collect subsequent repetitions of an element (that is, if they arrive right after * one another) into multiple {@link List} buffers that will be emitted by the * resulting {@link Flux}. * *

* *

* * @return a microbatched {@link Flux} of {@link List} */ public final Flux> bufferUntilChanged() { return bufferUntilChanged(identityFunction()); } /** * Collect subsequent repetitions of an element (that is, if they arrive right after * one another), as compared by a key extracted through the user provided {@link * Function}, into multiple {@link List} buffers that will be emitted by the * resulting {@link Flux}. * *

* *

* * @param keySelector function to compute comparison key for each element * @return a microbatched {@link Flux} of {@link List} */ public final Flux> bufferUntilChanged(Function keySelector) { return bufferUntilChanged(keySelector, equalPredicate()); } /** * Collect subsequent repetitions of an element (that is, if they arrive right after * one another), as compared by a key extracted through the user provided {@link * Function} and compared using a supplied {@link BiPredicate}, into multiple * {@link List} buffers that will be emitted by the resulting {@link Flux}. * *

* *

* * @param keySelector function to compute comparison key for each element * @param keyComparator predicate used to compare keys * @return a microbatched {@link Flux} of {@link List} */ public final Flux> bufferUntilChanged(Function keySelector, BiPredicate keyComparator) { return Flux.defer(() -> bufferUntil(new FluxBufferPredicate.ChangedPredicate(keySelector, keyComparator), true)); } /** * Collect incoming values into multiple {@link List} buffers that will be emitted by * the resulting {@link Flux}. Each buffer continues aggregating values while the * given predicate returns true, and a new buffer is created as soon as the * predicate returns false... Note that the element that triggers the predicate * to return false (and thus closes a buffer) is NOT included in any emitted buffer. *

* *

* On completion, if the latest buffer is non-empty and has not been closed it is * emitted. However, such a "partial" buffer isn't emitted in case of onError * termination. * *

Discard Support: This operator discards the currently open buffer upon cancellation or error triggered by a data signal, * as well as the buffer-triggering element. * * @param predicate a predicate that triggers the next buffer when it becomes false. * * @return a microbatched {@link Flux} of {@link List} */ public final Flux> bufferWhile(Predicate predicate) { return onAssembly(new FluxBufferPredicate<>(this, predicate, listSupplier(), FluxBufferPredicate.Mode.WHILE)); } /** * Collect incoming values into multiple {@link List} buffers started each time an opening * companion {@link Publisher} emits. Each buffer will last until the corresponding * closing companion {@link Publisher} emits, thus releasing the buffer to the resulting {@link Flux}. *

* When Open signal is strictly not overlapping Close signal : dropping buffers (see green marbles in diagram below). *

* When Open signal is strictly more frequent than Close signal : overlapping buffers (see second and third buffers in diagram below). *

* When Open signal is exactly coordinated with Close signal : exact buffers *

* * *

Discard Support: This operator discards the currently open buffer upon cancellation or error triggered by a data signal. * It DOES NOT provide strong guarantees in the case of overlapping buffers, as elements * might get discarded too early (from the first of two overlapping buffers for instance). * * @param bucketOpening a companion {@link Publisher} to subscribe for buffer creation signals. * @param closeSelector a factory that, given a buffer opening signal, returns a companion * {@link Publisher} to subscribe to for buffer closure and emission signals. * @param the element type of the buffer-opening sequence * @param the element type of the buffer-closing sequence * * @return a microbatched {@link Flux} of {@link List} delimited by an opening {@link Publisher} and a relative * closing {@link Publisher} */ public final Flux> bufferWhen(Publisher bucketOpening, Function> closeSelector) { return bufferWhen(bucketOpening, closeSelector, listSupplier()); } /** * Collect incoming values into multiple user-defined {@link Collection} buffers started each time an opening * companion {@link Publisher} emits. Each buffer will last until the corresponding * closing companion {@link Publisher} emits, thus releasing the buffer to the resulting {@link Flux}. *

* When Open signal is strictly not overlapping Close signal : dropping buffers (see green marbles in diagram below). *

* When Open signal is strictly more frequent than Close signal : overlapping buffers (see second and third buffers in diagram below). *

* * *

Discard Support: This operator discards the currently open buffer upon cancellation or error triggered by a data signal. * It DOES NOT provide strong guarantees in the case of overlapping buffers, as elements * might get discarded too early (from the first of two overlapping buffers for instance). * * @param bucketOpening a companion {@link Publisher} to subscribe for buffer creation signals. * @param closeSelector a factory that, given a buffer opening signal, returns a companion * {@link Publisher} to subscribe to for buffer closure and emission signals. * @param bufferSupplier a {@link Supplier} of the concrete {@link Collection} to use for each buffer * @param the element type of the buffer-opening sequence * @param the element type of the buffer-closing sequence * @param the {@link Collection} buffer type * * @return a microbatched {@link Flux} of {@link Collection} delimited by an opening {@link Publisher} and a relative * closing {@link Publisher} */ public final > Flux bufferWhen(Publisher bucketOpening, Function> closeSelector, Supplier bufferSupplier) { return onAssembly(new FluxBufferWhen<>(this, bucketOpening, closeSelector, bufferSupplier, Queues.unbounded(Queues.XS_BUFFER_SIZE))); } /** * Turn this {@link Flux} into a hot source and cache last emitted signals for further {@link Subscriber}. Will * retain an unbounded volume of onNext signals. Completion and Error will also be * replayed. *

* * * @return a replaying {@link Flux} */ public final Flux cache() { return cache(Integer.MAX_VALUE); } /** * Turn this {@link Flux} into a hot source and cache last emitted signals for further {@link Subscriber}. * Will retain up to the given history size onNext signals. Completion and Error will also be * replayed. *

* Note that {@code cache(0)} will only cache the terminal signal without * expiration. *

* * * @param history number of elements retained in cache * * @return a replaying {@link Flux} * */ public final Flux cache(int history) { return replay(history).autoConnect(); } /** * Turn this {@link Flux} into a hot source and cache last emitted signals for further * {@link Subscriber}. Will retain an unbounded history but apply a per-item expiry timeout *

* Completion and Error will also be replayed until {@code ttl} triggers in which case * the next {@link Subscriber} will start over a new subscription. *

* * * @param ttl Time-to-live for each cached item and post termination. * * @return a replaying {@link Flux} */ public final Flux cache(Duration ttl) { return cache(ttl, Schedulers.parallel()); } /** * Turn this {@link Flux} into a hot source and cache last emitted signals for further * {@link Subscriber}. Will retain an unbounded history but apply a per-item expiry timeout *

* Completion and Error will also be replayed until {@code ttl} triggers in which case * the next {@link Subscriber} will start over a new subscription. *

* * * @param ttl Time-to-live for each cached item and post termination. * @param timer the {@link Scheduler} on which to measure the duration. * * @return a replaying {@link Flux} */ public final Flux cache(Duration ttl, Scheduler timer) { return cache(Integer.MAX_VALUE, ttl, timer); } /** * Turn this {@link Flux} into a hot source and cache last emitted signals for further * {@link Subscriber}. Will retain up to the given history size and apply a per-item expiry * timeout. *

* Completion and Error will also be replayed until {@code ttl} triggers in which case * the next {@link Subscriber} will start over a new subscription. *

* * * @param history number of elements retained in cache * @param ttl Time-to-live for each cached item and post termination. * * @return a replaying {@link Flux} */ public final Flux cache(int history, Duration ttl) { return cache(history, ttl, Schedulers.parallel()); } /** * Turn this {@link Flux} into a hot source and cache last emitted signals for further * {@link Subscriber}. Will retain up to the given history size and apply a per-item expiry * timeout. *

* Completion and Error will also be replayed until {@code ttl} triggers in which case * the next {@link Subscriber} will start over a new subscription. *

* * * @param history number of elements retained in cache * @param ttl Time-to-live for each cached item and post termination. * @param timer the {@link Scheduler} on which to measure the duration. * * @return a replaying {@link Flux} */ public final Flux cache(int history, Duration ttl, Scheduler timer) { return replay(history, ttl, timer).autoConnect(); } /** * Cast the current {@link Flux} produced type into a target produced type. * *

* * * @param the {@link Flux} output type * @param clazz the target class to cast to * * @return a casted {@link Flux} */ public final Flux cast(Class clazz) { Objects.requireNonNull(clazz, "clazz"); return map(clazz::cast); } /** * Prepare this {@link Flux} so that subscribers will cancel from it on a * specified * {@link Scheduler}. * *

* * * @param scheduler the {@link Scheduler} to signal cancel on * * @return a scheduled cancel {@link Flux} */ public final Flux cancelOn(Scheduler scheduler) { return onAssembly(new FluxCancelOn<>(this, scheduler)); } /** * Activate traceback (full assembly tracing) for this particular {@link Flux}, in case of an error * upstream of the checkpoint. Tracing incurs the cost of an exception stack trace * creation. *

* It should be placed towards the end of the reactive chain, as errors * triggered downstream of it cannot be observed and augmented with the traceback. *

* The traceback is attached to the error as a {@link Throwable#getSuppressed() suppressed exception}. * As such, if the error is a {@link Exceptions#isMultiple(Throwable) composite one}, the traceback * would appear as a component of the composite. In any case, the traceback nature can be detected via * {@link Exceptions#isTraceback(Throwable)}. * * @return the assembly tracing {@link Flux}. */ public final Flux checkpoint() { return checkpoint(null, true); } /** * Activate traceback (assembly marker) for this particular {@link Flux} by giving it a description that * will be reflected in the assembly traceback in case of an error upstream of the * checkpoint. Note that unlike {@link #checkpoint()}, this doesn't create a * filled stack trace, avoiding the main cost of the operator. * However, as a trade-off the description must be unique enough for the user to find * out where this Flux was assembled. If you only want a generic description, and * still rely on the stack trace to find the assembly site, use the * {@link #checkpoint(String, boolean)} variant. *

* It should be placed towards the end of the reactive chain, as errors * triggered downstream of it cannot be observed and augmented with assembly trace. *

* The traceback is attached to the error as a {@link Throwable#getSuppressed() suppressed exception}. * As such, if the error is a {@link Exceptions#isMultiple(Throwable) composite one}, the traceback * would appear as a component of the composite. In any case, the traceback nature can be detected via * {@link Exceptions#isTraceback(Throwable)}. * * @param description a unique enough description to include in the light assembly traceback. * @return the assembly marked {@link Flux} */ public final Flux checkpoint(String description) { return checkpoint(Objects.requireNonNull(description), false); } /** * Activate traceback (full assembly tracing or the lighter assembly marking depending on the * {@code forceStackTrace} option). *

* By setting the {@code forceStackTrace} parameter to {@literal true}, activate assembly * tracing for this particular {@link Flux} and give it a description that * will be reflected in the assembly traceback in case of an error upstream of the * checkpoint. Note that unlike {@link #checkpoint(String)}, this will incur * the cost of an exception stack trace creation. The description could for * example be a meaningful name for the assembled flux or a wider correlation ID, * since the stack trace will always provide enough information to locate where this * Flux was assembled. *

* By setting {@code forceStackTrace} to {@literal false}, behaves like * {@link #checkpoint(String)} and is subject to the same caveat in choosing the * description. *

* It should be placed towards the end of the reactive chain, as errors * triggered downstream of it cannot be observed and augmented with assembly marker. *

* The traceback is attached to the error as a {@link Throwable#getSuppressed() suppressed exception}. * As such, if the error is a {@link Exceptions#isMultiple(Throwable) composite one}, the traceback * would appear as a component of the composite. In any case, the traceback nature can be detected via * {@link Exceptions#isTraceback(Throwable)}. * * @param description a description (must be unique enough if forceStackTrace is set * to false). * @param forceStackTrace false to make a light checkpoint without a stacktrace, true * to use a stack trace. * @return the assembly marked {@link Flux}. */ public final Flux checkpoint(@Nullable String description, boolean forceStackTrace) { final AssemblySnapshot stacktrace; if (!forceStackTrace) { stacktrace = new CheckpointLightSnapshot(description); } else { stacktrace = new CheckpointHeavySnapshot(description, Traces.callSiteSupplierFactory.get()); } return new FluxOnAssembly<>(this, stacktrace); } /** * Collect all elements emitted by this {@link Flux} into a user-defined container, * by applying a collector {@link BiConsumer} taking the container and each element. * The collected result will be emitted when this sequence completes, emitting the * empty container if the sequence was empty. * *

* * *

Discard Support: This operator discards the container upon cancellation or error triggered by a data signal. * Either the container type is a {@link Collection} (in which case individual elements are discarded) * or not (in which case the entire container is discarded). In case the collector {@link BiConsumer} fails * to accumulate an element, the container is discarded as above and the triggering element is also discarded. * * @param the container type * @param containerSupplier the supplier of the container instance for each Subscriber * @param collector a consumer of both the container instance and the value being currently collected * * @return a {@link Mono} of the collected container on complete * */ public final Mono collect(Supplier containerSupplier, BiConsumer collector) { return Mono.onAssembly(new MonoCollect<>(this, containerSupplier, collector)); } /** * Collect all elements emitted by this {@link Flux} into a container, * by applying a Java 8 Stream API {@link Collector} * The collected result will be emitted when this sequence completes, emitting * the empty container if the sequence was empty. * *

* * *

Discard Support: This operator discards the intermediate container (see {@link Collector#supplier()}) upon * cancellation, error or exception while applying the {@link Collector#finisher()}. Either the container type * is a {@link Collection} (in which case individual elements are discarded) or not (in which case the entire * container is discarded). In case the accumulator {@link BiConsumer} of the collector fails to accumulate * an element into the intermediate container, the container is discarded as above and the triggering element * is also discarded. * * @param collector the {@link Collector} * @param The mutable accumulation type * @param the container type * * @return a {@link Mono} of the collected container on complete * */ public final Mono collect(Collector collector) { return Mono.onAssembly(new MonoStreamCollector<>(this, collector)); } /** * Collect all elements emitted by this {@link Flux} into a {@link List} that is * emitted by the resulting {@link Mono} when this sequence completes, emitting the * empty {@link List} if the sequence was empty. * *

* * *

Discard Support: This operator discards the elements in the {@link List} upon * cancellation or error triggered by a data signal. * * @return a {@link Mono} of a {@link List} of all values from this {@link Flux} */ public final Mono> collectList() { if (this instanceof Callable) { if (this instanceof Fuseable.ScalarCallable) { @SuppressWarnings("unchecked") Fuseable.ScalarCallable scalarCallable = (Fuseable.ScalarCallable) this; T v; try { v = scalarCallable.call(); } catch (Exception e) { return Mono.error(Exceptions.unwrap(e)); } return Mono.onAssembly(new MonoCallable<>(() -> { List list = Flux.listSupplier().get(); if (v != null) { list.add(v); } return list; })); } @SuppressWarnings("unchecked") Callable thiz = (Callable)this; return Mono.onAssembly(new MonoCallable<>(() -> { List list = Flux.listSupplier().get(); T u = thiz.call(); if (u != null) { list.add(u); } return list; })); } return Mono.onAssembly(new MonoCollectList<>(this)); } /** * Collect all elements emitted by this {@link Flux} into a hashed {@link Map} that is * emitted by the resulting {@link Mono} when this sequence completes, emitting the * empty {@link Map} if the sequence was empty. * The key is extracted from each element by applying the {@code keyExtractor} * {@link Function}. In case several elements map to the same key, the associated value * will be the most recently emitted element. * *

* * *

Discard Support: This operator discards the whole {@link Map} upon cancellation or error * triggered by a data signal, so discard handlers will have to unpack the map. * * @param keyExtractor a {@link Function} to map elements to a key for the {@link Map} * @param the type of the key extracted from each source element * * @return a {@link Mono} of a {@link Map} of key-element pairs (only including latest * element in case of key conflicts) */ public final Mono> collectMap(Function keyExtractor) { return collectMap(keyExtractor, identityFunction()); } /** * Collect all elements emitted by this {@link Flux} into a hashed {@link Map} that is * emitted by the resulting {@link Mono} when this sequence completes, emitting the * empty {@link Map} if the sequence was empty. * The key is extracted from each element by applying the {@code keyExtractor} * {@link Function}, and the value is extracted by the {@code valueExtractor} Function. * In case several elements map to the same key, the associated value will be derived * from the most recently emitted element. * *

* * *

Discard Support: This operator discards the whole {@link Map} upon cancellation or error * triggered by a data signal, so discard handlers will have to unpack the map. * * @param keyExtractor a {@link Function} to map elements to a key for the {@link Map} * @param valueExtractor a {@link Function} to map elements to a value for the {@link Map} * * @param the type of the key extracted from each source element * @param the type of the value extracted from each source element * * @return a {@link Mono} of a {@link Map} of key-element pairs (only including latest * element's value in case of key conflicts) */ public final Mono> collectMap(Function keyExtractor, Function valueExtractor) { return collectMap(keyExtractor, valueExtractor, () -> new HashMap<>()); } /** * Collect all elements emitted by this {@link Flux} into a user-defined {@link Map} that is * emitted by the resulting {@link Mono} when this sequence completes, emitting the * empty {@link Map} if the sequence was empty. * The key is extracted from each element by applying the {@code keyExtractor} * {@link Function}, and the value is extracted by the {@code valueExtractor} Function. * In case several elements map to the same key, the associated value will be derived * from the most recently emitted element. * *

* * *

Discard Support: This operator discards the whole {@link Map} upon cancellation or error * triggered by a data signal, so discard handlers will have to unpack the map. * * @param keyExtractor a {@link Function} to map elements to a key for the {@link Map} * @param valueExtractor a {@link Function} to map elements to a value for the {@link Map} * @param mapSupplier a {@link Map} factory called for each {@link Subscriber} * * @param the type of the key extracted from each source element * @param the type of the value extracted from each source element * * @return a {@link Mono} of a {@link Map} of key-value pairs (only including latest * element's value in case of key conflicts) */ public final Mono> collectMap( final Function keyExtractor, final Function valueExtractor, Supplier> mapSupplier) { Objects.requireNonNull(keyExtractor, "Key extractor is null"); Objects.requireNonNull(valueExtractor, "Value extractor is null"); Objects.requireNonNull(mapSupplier, "Map supplier is null"); return collect(mapSupplier, (m, d) -> m.put(keyExtractor.apply(d), valueExtractor.apply(d))); } /** * Collect all elements emitted by this {@link Flux} into a {@link Map multimap} that is * emitted by the resulting {@link Mono} when this sequence completes, emitting the * empty {@link Map multimap} if the sequence was empty. * The key is extracted from each element by applying the {@code keyExtractor} * {@link Function}, and every element mapping to the same key is stored in the {@link List} * associated to said key. * *

* * *

Discard Support: This operator discards the whole {@link Map} upon cancellation or error * triggered by a data signal, so discard handlers will have to unpack the list values in the map. * * @param keyExtractor a {@link Function} to map elements to a key for the {@link Map} * * @param the type of the key extracted from each source element * * @return a {@link Mono} of a {@link Map} of key-List(elements) pairs */ public final Mono>> collectMultimap(Function keyExtractor) { return collectMultimap(keyExtractor, identityFunction()); } /** * Collect all elements emitted by this {@link Flux} into a {@link Map multimap} that is * emitted by the resulting {@link Mono} when this sequence completes, emitting the * empty {@link Map multimap} if the sequence was empty. * The key is extracted from each element by applying the {@code keyExtractor} * {@link Function}, and every element mapping to the same key is converted by the * {@code valueExtractor} Function to a value stored in the {@link List} associated to * said key. * *

* * *

Discard Support: This operator discards the whole {@link Map} upon cancellation or error * triggered by a data signal, so discard handlers will have to unpack the list values in the map. * * @param keyExtractor a {@link Function} to map elements to a key for the {@link Map} * @param valueExtractor a {@link Function} to map elements to a value for the {@link Map} * * @param the type of the key extracted from each source element * @param the type of the value extracted from each source element * * @return a {@link Mono} of a {@link Map} of key-List(values) pairs */ public final Mono>> collectMultimap(Function keyExtractor, Function valueExtractor) { return collectMultimap(keyExtractor, valueExtractor, () -> new HashMap<>()); } /** * Collect all elements emitted by this {@link Flux} into a user-defined {@link Map multimap} that is * emitted by the resulting {@link Mono} when this sequence completes, emitting the * empty {@link Map multimap} if the sequence was empty. * The key is extracted from each element by applying the {@code keyExtractor} * {@link Function}, and every element mapping to the same key is converted by the * {@code valueExtractor} Function to a value stored in the {@link Collection} associated to * said key. * *

* * *

Discard Support: This operator discards the whole {@link Map} upon cancellation or error * triggered by a data signal, so discard handlers will have to unpack the list values in the map. * * @param keyExtractor a {@link Function} to map elements to a key for the {@link Map} * @param valueExtractor a {@link Function} to map elements to a value for the {@link Map} * @param mapSupplier a multimap ({@link Map} of {@link Collection}) factory called * for each {@link Subscriber} * * @param the type of the key extracted from each source element * @param the type of the value extracted from each source element * * @return a {@link Mono} of a {@link Map} of key-Collection(values) pairs * */ public final Mono>> collectMultimap( final Function keyExtractor, final Function valueExtractor, Supplier>> mapSupplier) { Objects.requireNonNull(keyExtractor, "Key extractor is null"); Objects.requireNonNull(valueExtractor, "Value extractor is null"); Objects.requireNonNull(mapSupplier, "Map supplier is null"); return collect(mapSupplier, (m, d) -> { K key = keyExtractor.apply(d); Collection values = m.computeIfAbsent(key, k -> new ArrayList<>()); values.add(valueExtractor.apply(d)); }); } /** * Collect all elements emitted by this {@link Flux} until this sequence completes, * and then sort them in natural order into a {@link List} that is emitted by the * resulting {@link Mono}. If the sequence was empty, empty {@link List} will be emitted. * *

* * *

Discard Support: This operator is based on {@link #collectList()}, and as such discards the * elements in the {@link List} individually upon cancellation or error triggered by a data signal. * * @return a {@link Mono} of a sorted {@link List} of all values from this {@link Flux}, in natural order */ public final Mono> collectSortedList() { return collectSortedList(null); } /** * Collect all elements emitted by this {@link Flux} until this sequence completes, * and then sort them using a {@link Comparator} into a {@link List} that is emitted * by the resulting {@link Mono}. If the sequence was empty, empty {@link List} will be emitted. * *

* * *

Discard Support: This operator is based on {@link #collectList()}, and as such discards the * elements in the {@link List} individually upon cancellation or error triggered by a data signal. * * @param comparator a {@link Comparator} to sort the items of this sequences * * @return a {@link Mono} of a sorted {@link List} of all values from this {@link Flux} */ @SuppressWarnings({ "unchecked", "rawtypes" }) public final Mono> collectSortedList(@Nullable Comparator comparator) { return collectList().doOnNext(list -> { // Note: this assumes the list emitted by buffer() is mutable list.sort(comparator); }); } /** * Transform the elements emitted by this {@link Flux} asynchronously into Publishers, * then flatten these inner publishers into a single {@link Flux}, sequentially and * preserving order using concatenation. *

* There are three dimensions to this operator that can be compared with * {@link #flatMap(Function) flatMap} and {@link #flatMapSequential(Function) flatMapSequential}: *

* *

* Errors will immediately short circuit current concat backlog. * *

* * *

Discard Support: This operator discards elements it internally queued for backpressure upon cancellation. * * @param mapper the function to transform this sequence of T into concatenated sequences of V * @param the produced concatenated type * * @return a concatenated {@link Flux} */ public final Flux concatMap(Function> mapper) { return concatMap(mapper, Queues.XS_BUFFER_SIZE); } /** * Transform the elements emitted by this {@link Flux} asynchronously into Publishers, * then flatten these inner publishers into a single {@link Flux}, sequentially and * preserving order using concatenation. *

* There are three dimensions to this operator that can be compared with * {@link #flatMap(Function) flatMap} and {@link #flatMapSequential(Function) flatMapSequential}: *

    *
  • Generation of inners and subscription: this operator waits for one * inner to complete before generating the next one and subscribing to it.
  • *
  • Ordering of the flattened values: this operator naturally preserves * the same order as the source elements, concatenating the inners from each source * element sequentially.
  • *
  • Interleaving: this operator does not let values from different inners * interleave (concatenation).
  • *
* *

* Errors will immediately short circuit current concat backlog. The prefetch argument * allows to give an arbitrary prefetch size to the upstream source. * *

* * *

Discard Support: This operator discards elements it internally queued for backpressure upon cancellation. * * @param mapper the function to transform this sequence of T into concatenated sequences of V * @param prefetch the number of values to prefetch from upstream source (set it to 0 if you don't want it to prefetch) * @param the produced concatenated type * * @return a concatenated {@link Flux} */ public final Flux concatMap(Function> mapper, int prefetch) { if (prefetch == 0) { return onAssembly(new FluxConcatMapNoPrefetch<>(this, mapper, FluxConcatMap.ErrorMode.IMMEDIATE)); } return onAssembly(new FluxConcatMap<>(this, mapper, Queues.get(prefetch), prefetch, FluxConcatMap.ErrorMode.IMMEDIATE)); } /** * Transform the elements emitted by this {@link Flux} asynchronously into Publishers, * then flatten these inner publishers into a single {@link Flux}, sequentially and * preserving order using concatenation. *

* There are three dimensions to this operator that can be compared with * {@link #flatMap(Function) flatMap} and {@link #flatMapSequential(Function) flatMapSequential}: *

    *
  • Generation of inners and subscription: this operator waits for one * inner to complete before generating the next one and subscribing to it.
  • *
  • Ordering of the flattened values: this operator naturally preserves * the same order as the source elements, concatenating the inners from each source * element sequentially.
  • *
  • Interleaving: this operator does not let values from different inners * interleave (concatenation).
  • *
* *

* Errors in the individual publishers will be delayed at the end of the whole concat * sequence (possibly getting combined into a {@link Exceptions#isMultiple(Throwable) composite}) * if several sources error. * *

* * *

Discard Support: This operator discards elements it internally queued for backpressure upon cancellation. * * @param mapper the function to transform this sequence of T into concatenated sequences of V * @param the produced concatenated type * * @return a concatenated {@link Flux} * */ public final Flux concatMapDelayError(Function> mapper) { return concatMapDelayError(mapper, Queues.XS_BUFFER_SIZE); } /** * Transform the elements emitted by this {@link Flux} asynchronously into Publishers, * then flatten these inner publishers into a single {@link Flux}, sequentially and * preserving order using concatenation. *

* There are three dimensions to this operator that can be compared with * {@link #flatMap(Function) flatMap} and {@link #flatMapSequential(Function) flatMapSequential}: *

    *
  • Generation of inners and subscription: this operator waits for one * inner to complete before generating the next one and subscribing to it.
  • *
  • Ordering of the flattened values: this operator naturally preserves * the same order as the source elements, concatenating the inners from each source * element sequentially.
  • *
  • Interleaving: this operator does not let values from different inners * interleave (concatenation).
  • *
* *

* Errors in the individual publishers will be delayed at the end of the whole concat * sequence (possibly getting combined into a {@link Exceptions#isMultiple(Throwable) composite}) * if several sources error. * The prefetch argument allows to give an arbitrary prefetch size to the upstream source. * *

* * *

Discard Support: This operator discards elements it internally queued for backpressure upon cancellation. * * @param mapper the function to transform this sequence of T into concatenated sequences of V * @param prefetch the number of values to prefetch from upstream source * @param the produced concatenated type * * @return a concatenated {@link Flux} * */ public final Flux concatMapDelayError(Function> mapper, int prefetch) { return concatMapDelayError(mapper, true, prefetch); } /** * Transform the elements emitted by this {@link Flux} asynchronously into Publishers, * then flatten these inner publishers into a single {@link Flux}, sequentially and * preserving order using concatenation. *

* There are three dimensions to this operator that can be compared with * {@link #flatMap(Function) flatMap} and {@link #flatMapSequential(Function) flatMapSequential}: *

    *
  • Generation of inners and subscription: this operator waits for one * inner to complete before generating the next one and subscribing to it.
  • *
  • Ordering of the flattened values: this operator naturally preserves * the same order as the source elements, concatenating the inners from each source * element sequentially.
  • *
  • Interleaving: this operator does not let values from different inners * interleave (concatenation).
  • *
* *

* Errors in the individual publishers will be delayed after the current concat * backlog if delayUntilEnd is false or after all sources if delayUntilEnd is true. * The prefetch argument allows to give an arbitrary prefetch size to the upstream source. * *

* * *

Discard Support: This operator discards elements it internally queued for backpressure upon cancellation. * * @param mapper the function to transform this sequence of T into concatenated sequences of V * @param delayUntilEnd delay error until all sources have been consumed instead of * after the current source * @param prefetch the number of values to prefetch from upstream source * @param the produced concatenated type * * @return a concatenated {@link Flux} * */ public final Flux concatMapDelayError(Function> mapper, boolean delayUntilEnd, int prefetch) { FluxConcatMap.ErrorMode errorMode = delayUntilEnd ? FluxConcatMap.ErrorMode.END : FluxConcatMap.ErrorMode.BOUNDARY; if (prefetch == 0) { return onAssembly(new FluxConcatMapNoPrefetch<>(this, mapper, errorMode)); } return onAssembly(new FluxConcatMap<>(this, mapper, Queues.get(prefetch), prefetch, errorMode)); } /** * Transform the items emitted by this {@link Flux} into {@link Iterable}, then flatten the elements from those by * concatenating them into a single {@link Flux}. For each iterable, {@link Iterable#iterator()} will be called * at least once and at most twice. * *

* *

* This operator inspects each {@link Iterable}'s {@link Spliterator} to assess if the iteration * can be guaranteed to be finite (see {@link Operators#onDiscardMultiple(Iterator, boolean, Context)}). * Since the default Spliterator wraps the Iterator we can have two {@link Iterable#iterator()} * calls per iterable. This second invocation is skipped on a {@link Collection} however, a type which is * assumed to be always finite. *

* Note that unlike {@link #flatMap(Function)} and {@link #concatMap(Function)}, with Iterable there is * no notion of eager vs lazy inner subscription. The content of the Iterables are all played sequentially. * Thus {@code flatMapIterable} and {@code concatMapIterable} are equivalent offered as a discoverability * improvement for users that explore the API with the concat vs flatMap expectation. * *

Discard Support: Upon cancellation, this operator discards {@code T} elements it prefetched and, in * some cases, attempts to discard remainder of the currently processed {@link Iterable} (if it can * safely ensure the iterator is finite). Note that this means each {@link Iterable}'s {@link Iterable#iterator()} * method could be invoked twice. * *

Error Mode Support: This operator supports {@link #onErrorContinue(BiConsumer) resuming on errors} * (including when fusion is enabled). Exceptions thrown by the consumer are passed to * the {@link #onErrorContinue(BiConsumer)} error consumer (the value consumer * is not invoked, as the source element will be part of the sequence). The onNext * signal is then propagated as normal. * * @param mapper the {@link Function} to transform input sequence into N {@link Iterable} * @param the merged output sequence type * * @return a concatenation of the values from the Iterables obtained from each element in this {@link Flux} */ public final Flux concatMapIterable(Function> mapper) { return concatMapIterable(mapper, Queues.XS_BUFFER_SIZE); } /** * Transform the items emitted by this {@link Flux} into {@link Iterable}, then flatten the emissions from those by * concatenating them into a single {@link Flux}. * The prefetch argument allows to give an arbitrary prefetch size to the upstream source. * For each iterable, {@link Iterable#iterator()} will be called at least once and at most twice. * *

* *

* This operator inspects each {@link Iterable}'s {@link Spliterator} to assess if the iteration * can be guaranteed to be finite (see {@link Operators#onDiscardMultiple(Iterator, boolean, Context)}). * Since the default Spliterator wraps the Iterator we can have two {@link Iterable#iterator()} * calls per iterable. This second invocation is skipped on a {@link Collection} however, a type which is * assumed to be always finite. *

* Note that unlike {@link #flatMap(Function)} and {@link #concatMap(Function)}, with Iterable there is * no notion of eager vs lazy inner subscription. The content of the Iterables are all played sequentially. * Thus {@code flatMapIterable} and {@code concatMapIterable} are equivalent offered as a discoverability * improvement for users that explore the API with the concat vs flatMap expectation. * *

Discard Support: Upon cancellation, this operator discards {@code T} elements it prefetched and, in * some cases, attempts to discard remainder of the currently processed {@link Iterable} (if it can * safely ensure the iterator is finite). Note that this means each {@link Iterable}'s {@link Iterable#iterator()} * method could be invoked twice. * *

Error Mode Support: This operator supports {@link #onErrorContinue(BiConsumer) resuming on errors} * (including when fusion is enabled). Exceptions thrown by the consumer are passed to * the {@link #onErrorContinue(BiConsumer)} error consumer (the value consumer * is not invoked, as the source element will be part of the sequence). The onNext * signal is then propagated as normal. * * @param mapper the {@link Function} to transform input sequence into N {@link Iterable} * @param prefetch the number of values to request from the source upon subscription, to be transformed to {@link Iterable} * @param the merged output sequence type * * @return a concatenation of the values from the Iterables obtained from each element in this {@link Flux} */ public final Flux concatMapIterable(Function> mapper, int prefetch) { return onAssembly(new FluxFlattenIterable<>(this, mapper, prefetch, Queues.get(prefetch))); } /** * Concatenate emissions of this {@link Flux} with the provided {@link Publisher} (no interleave). *

* * * @param other the {@link Publisher} sequence to concat after this {@link Flux} * * @return a concatenated {@link Flux} */ public final Flux concatWith(Publisher other) { if (this instanceof FluxConcatArray) { @SuppressWarnings({ "unchecked" }) FluxConcatArray fluxConcatArray = (FluxConcatArray) this; return fluxConcatArray.concatAdditionalSourceLast(other); } return concat(this, other); } /** * Enrich the {@link Context} visible from downstream for the benefit of upstream * operators, by making all values from the provided {@link ContextView} visible on top * of pairs from downstream. *

* A {@link Context} (and its {@link ContextView}) is tied to a given subscription * and is read by querying the downstream {@link Subscriber}. {@link Subscriber} that * don't enrich the context instead access their own downstream's context. As a result, * this operator conceptually enriches a {@link Context} coming from under it in the chain * (downstream, by default an empty one) and makes the new enriched {@link Context} * visible to operators above it in the chain. * * @param contextToAppend the {@link ContextView} to merge with the downstream {@link Context}, * resulting in a new more complete {@link Context} that will be visible from upstream. * * @return a contextualized {@link Flux} * @see ContextView */ public final Flux contextWrite(ContextView contextToAppend) { return contextWrite(c -> c.putAll(contextToAppend)); } /** * Enrich the {@link Context} visible from downstream for the benefit of upstream * operators, by applying a {@link Function} to the downstream {@link Context}. *

* The {@link Function} takes a {@link Context} for convenience, allowing to easily * call {@link Context#put(Object, Object) write APIs} to return a new {@link Context}. *

* A {@link Context} (and its {@link ContextView}) is tied to a given subscription * and is read by querying the downstream {@link Subscriber}. {@link Subscriber} that * don't enrich the context instead access their own downstream's context. As a result, * this operator conceptually enriches a {@link Context} coming from under it in the chain * (downstream, by default an empty one) and makes the new enriched {@link Context} * visible to operators above it in the chain. * * @param contextModifier the {@link Function} to apply to the downstream {@link Context}, * resulting in a new more complete {@link Context} that will be visible from upstream. * * @return a contextualized {@link Flux} * @see Context */ public final Flux contextWrite(Function contextModifier) { return onAssembly(new FluxContextWrite<>(this, contextModifier)); } /** * Counts the number of values in this {@link Flux}. * The count will be emitted when onComplete is observed. * *

* * * @return a new {@link Mono} of {@link Long} count */ public final Mono count() { return Mono.onAssembly(new MonoCount<>(this)); } /** * Provide a default unique value if this sequence is completed without any data *

* * * @param defaultV the alternate value if this sequence is empty * * @return a new {@link Flux} */ public final Flux defaultIfEmpty(T defaultV) { return onAssembly(new FluxDefaultIfEmpty<>(this, defaultV)); } /** * Delay each of this {@link Flux} elements ({@link Subscriber#onNext} signals) * by a given {@link Duration}. Signals are delayed and continue on the * {@link Schedulers#parallel() parallel} default Scheduler, but empty sequences or * immediate error signals are not delayed. * *

* * * @param delay duration by which to delay each {@link Subscriber#onNext} signal * @return a delayed {@link Flux} * @see #delaySubscription(Duration) delaySubscription to introduce a delay at the beginning of the sequence only */ public final Flux delayElements(Duration delay) { return delayElements(delay, Schedulers.parallel()); } /** * Delay each of this {@link Flux} elements ({@link Subscriber#onNext} signals) * by a given {@link Duration}. Signals are delayed and continue on a user-specified * {@link Scheduler}, but empty sequences or immediate error signals are not delayed. * *

* * * @param delay period to delay each {@link Subscriber#onNext} signal * @param timer a time-capable {@link Scheduler} instance to delay each signal on * @return a delayed {@link Flux} */ public final Flux delayElements(Duration delay, Scheduler timer) { return delayUntil(d -> Mono.delay(delay, timer)); } /** * Shift this {@link Flux} forward in time by a given {@link Duration}. * Unlike with {@link #delayElements(Duration)}, elements are shifted forward in time * as they are emitted, always resulting in the delay between two elements being * the same as in the source (only the first element is visibly delayed from the * previous event, that is the subscription). * Signals are delayed and continue on the {@link Schedulers#parallel() parallel} * {@link Scheduler}, but empty sequences or immediate error signals are not delayed. *

* With this operator, a source emitting at 10Hz with a delaySequence {@link Duration} * of 1s will still emit at 10Hz, with an initial "hiccup" of 1s. * On the other hand, {@link #delayElements(Duration)} would end up emitting * at 1Hz. *

* This is closer to {@link #delaySubscription(Duration)}, except the source * is subscribed to immediately. * *

* * *

Discard Support: This operator discards elements currently being delayed * * if the sequence is cancelled during the delay. * * @param delay {@link Duration} to shift the sequence by * * @return a shifted {@link Flux} emitting at the same frequency as the source */ public final Flux delaySequence(Duration delay) { return delaySequence(delay, Schedulers.parallel()); } /** * Shift this {@link Flux} forward in time by a given {@link Duration}. * Unlike with {@link #delayElements(Duration, Scheduler)}, elements are shifted forward in time * as they are emitted, always resulting in the delay between two elements being * the same as in the source (only the first element is visibly delayed from the * previous event, that is the subscription). * Signals are delayed and continue on a user-specified {@link Scheduler}, but empty * sequences or immediate error signals are not delayed. *

* With this operator, a source emitting at 10Hz with a delaySequence {@link Duration} * of 1s will still emit at 10Hz, with an initial "hiccup" of 1s. * On the other hand, {@link #delayElements(Duration, Scheduler)} would end up emitting * at 1Hz. *

* This is closer to {@link #delaySubscription(Duration, Scheduler)}, except the source * is subscribed to immediately. * *

* * *

Discard Support: This operator discards elements currently being delayed * if the sequence is cancelled during the delay. * * @param delay {@link Duration} to shift the sequence by * @param timer a time-capable {@link Scheduler} instance to delay signals on * * @return a shifted {@link Flux} emitting at the same frequency as the source */ public final Flux delaySequence(Duration delay, Scheduler timer) { return onAssembly(new FluxDelaySequence<>(this, delay, timer)); } /** * Subscribe to this {@link Flux} and generate a {@link Publisher} from each of this * Flux elements, each acting as a trigger for relaying said element. *

* That is to say, the resulting {@link Flux} delays each of its emission until the * associated trigger Publisher terminates. *

* In case of an error either in the source or in a trigger, that error is propagated * immediately downstream. * Note that unlike with the {@link Mono#delayUntil(Function) Mono variant} there is * no fusion of subsequent calls. *

* * * @param triggerProvider a {@link Function} that maps each element into a * {@link Publisher} whose termination will trigger relaying the value. * * @return this Flux, but with elements delayed until their derived publisher terminates. */ public final Flux delayUntil(Function> triggerProvider) { return concatMap(v -> Mono.just(v) .delayUntil(triggerProvider)); } /** * Delay the {@link Flux#subscribe(Subscriber) subscription} to this {@link Flux} source until the given * period elapses. The delay is introduced through the {@link Schedulers#parallel() parallel} default Scheduler. * *

* * * @param delay duration before subscribing this {@link Flux} * * @return a delayed {@link Flux} * */ public final Flux delaySubscription(Duration delay) { return delaySubscription(delay, Schedulers.parallel()); } /** * Delay the {@link Flux#subscribe(Subscriber) subscription} to this {@link Flux} source until the given * period elapses, as measured on the user-provided {@link Scheduler}. * *

* * * @param delay {@link Duration} before subscribing this {@link Flux} * @param timer a time-capable {@link Scheduler} instance to run on * * @return a delayed {@link Flux} */ public final Flux delaySubscription(Duration delay, Scheduler timer) { return delaySubscription(Mono.delay(delay, timer)); } /** * Delay the {@link Flux#subscribe(Subscriber) subscription} to this {@link Flux} * source until another {@link Publisher} signals a value or completes. * *

* * * @param subscriptionDelay a companion {@link Publisher} whose onNext/onComplete signal will trigger the {@link Flux#subscribe(Subscriber) subscription} * @param the other source type * * @return a delayed {@link Flux} * */ public final Flux delaySubscription(Publisher subscriptionDelay) { return onAssembly(new FluxDelaySubscription<>(this, subscriptionDelay)); } /** * An operator working only if this {@link Flux} emits onNext, onError or onComplete {@link Signal} * instances, transforming these {@link #materialize() materialized} signals into * real signals on the {@link Subscriber}. * The error {@link Signal} will trigger onError and complete {@link Signal} will trigger * onComplete. * *

* * * @param the dematerialized type * * @return a dematerialized {@link Flux} * @see #materialize() */ public final Flux dematerialize() { @SuppressWarnings("unchecked") Flux> thiz = (Flux>) this; return onAssembly(new FluxDematerialize<>(thiz)); } /** * For each {@link Subscriber}, track elements from this {@link Flux} that have been * seen and filter out duplicates. *

* The values themselves are recorded into a {@link HashSet} for distinct detection. * Use {@code distinct(Object::hashcode)} if you want a more lightweight approach that * doesn't retain all the objects, but is more susceptible to falsely considering two * elements as distinct due to a hashcode collision. * *

* * *

Discard Support: This operator discards elements that don't match the distinct predicate, * but you should use the version with a cleanup if you need discarding of keys * categorized by the operator as "seen". See {@link #distinct(Function, Supplier, BiPredicate, Consumer)}. * * @return a filtering {@link Flux} only emitting distinct values */ public final Flux distinct() { return distinct(identityFunction()); } /** * For each {@link Subscriber}, track elements from this {@link Flux} that have been * seen and filter out duplicates, as compared by a key extracted through the user * provided {@link Function}. * *

* * *

Discard Support: This operator discards elements that don't match the distinct predicate, * but you should use the version with a cleanup if you need discarding of keys * categorized by the operator as "seen". See {@link #distinct(Function, Supplier, BiPredicate, Consumer)}. * * @param keySelector function to compute comparison key for each element * @param the type of the key extracted from each value in this sequence * * @return a filtering {@link Flux} only emitting values with distinct keys */ public final Flux distinct(Function keySelector) { return distinct(keySelector, hashSetSupplier()); } /** * For each {@link Subscriber}, track elements from this {@link Flux} that have been * seen and filter out duplicates, as compared by a key extracted through the user * provided {@link Function} and by the {@link Collection#add(Object) add method} * of the {@link Collection} supplied (typically a {@link Set}). * *

* * *

Discard Support: This operator discards elements that don't match the distinct predicate, * but you should use the version with a cleanup if you need discarding of keys * categorized by the operator as "seen". See {@link #distinct(Function, Supplier, BiPredicate, Consumer)}. * * @param keySelector function to compute comparison key for each element * @param distinctCollectionSupplier supplier of the {@link Collection} used for distinct * check through {@link Collection#add(Object) add} of the key. * * @param the type of the key extracted from each value in this sequence * @param the type of Collection used for distinct checking of keys * * @return a filtering {@link Flux} only emitting values with distinct keys */ public final > Flux distinct( Function keySelector, Supplier distinctCollectionSupplier) { return this.distinct(keySelector, distinctCollectionSupplier, Collection::add, Collection::clear); } /** * For each {@link Subscriber}, track elements from this {@link Flux} that have been * seen and filter out duplicates, as compared by applying a {@link BiPredicate} on * an arbitrary user-supplied {@code } store and a key extracted through the user * provided {@link Function}. The BiPredicate should typically add the key to the * arbitrary store for further comparison. A cleanup callback is also invoked on the * store upon termination of the sequence. * *

* * *

Discard Support: This operator discards elements that don't match the distinct predicate, * but you should use the {@code cleanup} as well if you need discarding of keys * categorized by the operator as "seen". * * @param keySelector function to compute comparison key for each element * @param distinctStoreSupplier supplier of the arbitrary store object used in distinct * checks along the extracted key. * @param distinctPredicate the {@link BiPredicate} to apply to the arbitrary store + * extracted key to perform a distinct check. Since nothing is assumed of the store, * this predicate should also add the key to the store as necessary. * @param cleanup the cleanup callback to invoke on the store upon termination. * * @param the type of the key extracted from each value in this sequence * @param the type of store backing the {@link BiPredicate} * * @return a filtering {@link Flux} only emitting values with distinct keys */ public final Flux distinct( Function keySelector, Supplier distinctStoreSupplier, BiPredicate distinctPredicate, Consumer cleanup) { if (this instanceof Fuseable) { return onAssembly(new FluxDistinctFuseable<>(this, keySelector, distinctStoreSupplier, distinctPredicate, cleanup)); } return onAssembly(new FluxDistinct<>(this, keySelector, distinctStoreSupplier, distinctPredicate, cleanup)); } /** * Filter out subsequent repetitions of an element (that is, if they arrive right after * one another). * *

* *

* The last distinct value seen is retained for further comparison, which is done * on the values themselves using {@link Object#equals(Object) the equals method}. * Use {@code distinctUntilChanged(Object::hashcode)} if you want a more lightweight approach that * doesn't retain all the objects, but is more susceptible to falsely considering two * elements as distinct due to a hashcode collision. * *

Discard Support: Although this operator discards elements that are considered as "already seen", * it is not recommended for cases where discarding is needed as the operator doesn't * discard the "key" (in this context, the distinct instance that was last seen). * * @return a filtering {@link Flux} with only one occurrence in a row of each element * (yet elements can repeat in the overall sequence) */ public final Flux distinctUntilChanged() { return distinctUntilChanged(identityFunction()); } /** * Filter out subsequent repetitions of an element (that is, if they arrive right after * one another), as compared by a key extracted through the user provided {@link Function} * using equality. * *

* * *

Discard Support: This operator discards elements that are considered as "already seen". * The keys themselves are not discarded. * * @param keySelector function to compute comparison key for each element * @param the type of the key extracted from each value in this sequence * * @return a filtering {@link Flux} with only one occurrence in a row of each element of * the same key (yet element keys can repeat in the overall sequence) */ public final Flux distinctUntilChanged(Function keySelector) { return distinctUntilChanged(keySelector, equalPredicate()); } /** * Filter out subsequent repetitions of an element (that is, if they arrive right * after one another), as compared by a key extracted through the user provided {@link * Function} and then comparing keys with the supplied {@link BiPredicate}. *

* * *

Discard Support: This operator discards elements that are considered as "already seen" * (for which the {@code keyComparator} returns {@literal true}). The keys themselves * are not discarded. * * @param keySelector function to compute comparison key for each element * @param keyComparator predicate used to compare keys. * @param the type of the key extracted from each value in this sequence * * @return a filtering {@link Flux} with only one occurrence in a row of each element * of the same key for which the predicate returns true (yet element keys can repeat * in the overall sequence) */ public final Flux distinctUntilChanged(Function keySelector, BiPredicate keyComparator) { return onAssembly(new FluxDistinctUntilChanged<>(this, keySelector, keyComparator)); } /** * Add behavior (side-effect) triggered after the {@link Flux} terminates, either by completing downstream successfully or with an error. *

* *

* The relevant signal is propagated downstream, then the {@link Runnable} is executed. * * @param afterTerminate the callback to call after {@link Subscriber#onComplete} or {@link Subscriber#onError} * * @return an observed {@link Flux} */ public final Flux doAfterTerminate(Runnable afterTerminate) { Objects.requireNonNull(afterTerminate, "afterTerminate"); return doOnSignal(this, null, null, null, null, afterTerminate, null, null); } /** * Add behavior (side-effect) triggered when the {@link Flux} is cancelled. *

* *

* The handler is executed first, then the cancel signal is propagated upstream * to the source. * * @param onCancel the callback to call on {@link Subscription#cancel} * * @return an observed {@link Flux} */ public final Flux doOnCancel(Runnable onCancel) { Objects.requireNonNull(onCancel, "onCancel"); return doOnSignal(this, null, null, null, null, null, null, onCancel); } /** * Add behavior (side-effect) triggered when the {@link Flux} completes successfully. *

* *

* The {@link Runnable} is executed first, then the onComplete signal is propagated * downstream. * * @param onComplete the callback to call on {@link Subscriber#onComplete} * * @return an observed {@link Flux} */ public final Flux doOnComplete(Runnable onComplete) { Objects.requireNonNull(onComplete, "onComplete"); return doOnSignal(this, null, null, null, onComplete, null, null, null); } /** * Potentially modify the behavior of the whole chain of operators upstream of this one to * conditionally clean up elements that get discarded by these operators. *

* The {@code discardHook} MUST be idempotent and safe to use on any instance of the desired * type. * Calls to this method are additive, and the order of invocation of the {@code discardHook} * is the same as the order of declaration (calling {@code .filter(...).doOnDiscard(first).doOnDiscard(second)} * will let the filter invoke {@code first} then {@code second} handlers). *

* Two main categories of discarding operators exist: *

    *
  • filtering operators, dropping some source elements as part of their designed behavior
  • *
  • operators that prefetch a few elements and keep them around pending a request, but get cancelled/in error
  • *
* WARNING: Not all operators support this instruction. The ones that do are identified in the javadoc by * the presence of a Discard Support section. * * @param type the {@link Class} of elements in the upstream chain of operators that * this cleanup hook should take into account. * @param discardHook a {@link Consumer} of elements in the upstream chain of operators * that performs the cleanup. * @return a {@link Flux} that cleans up matching elements that get discarded upstream of it. */ public final Flux doOnDiscard(final Class type, final Consumer discardHook) { return subscriberContext(Operators.discardLocalAdapter(type, discardHook)); } /** * Add behavior (side-effects) triggered when the {@link Flux} emits an item, fails with an error * or completes successfully. All these events are represented as a {@link Signal} * that is passed to the side-effect callback. Note that this is an advanced operator, * typically used for monitoring of a Flux. These {@link Signal} have a {@link Context} * associated to them. *

* *

* The {@link Consumer} is executed first, then the relevant signal is propagated * downstream. * * @param signalConsumer the mandatory callback to call on * {@link Subscriber#onNext(Object)}, {@link Subscriber#onError(Throwable)} and * {@link Subscriber#onComplete()} * @return an observed {@link Flux} * @see #doOnNext(Consumer) * @see #doOnError(Consumer) * @see #doOnComplete(Runnable) * @see #materialize() * @see Signal */ public final Flux doOnEach(Consumer> signalConsumer) { if (this instanceof Fuseable) { return onAssembly(new FluxDoOnEachFuseable<>(this, signalConsumer)); } return onAssembly(new FluxDoOnEach<>(this, signalConsumer)); } /** * Add behavior (side-effect) triggered when the {@link Flux} completes with an error. *

* *

* The {@link Consumer} is executed first, then the onError signal is propagated * downstream. * * @param onError the callback to call on {@link Subscriber#onError} * * @return an observed {@link Flux} */ public final Flux doOnError(Consumer onError) { Objects.requireNonNull(onError, "onError"); return doOnSignal(this, null, null, onError, null, null, null, null); } /** * Add behavior (side-effect) triggered when the {@link Flux} completes with an error matching the given exception type. *

* *

* The {@link Consumer} is executed first, then the onError signal is propagated * downstream. * * @param exceptionType the type of exceptions to handle * @param onError the error handler for each error * @param type of the error to handle * * @return an observed {@link Flux} * */ public final Flux doOnError(Class exceptionType, final Consumer onError) { Objects.requireNonNull(exceptionType, "type"); @SuppressWarnings("unchecked") Consumer handler = (Consumer)onError; return doOnError(exceptionType::isInstance, (handler)); } /** * Add behavior (side-effect) triggered when the {@link Flux} completes with an error matching the given exception. *

* *

* The {@link Consumer} is executed first, then the onError signal is propagated * downstream. * * @param predicate the matcher for exceptions to handle * @param onError the error handler for each error * * @return an observed {@link Flux} * */ public final Flux doOnError(Predicate predicate, final Consumer onError) { Objects.requireNonNull(predicate, "predicate"); return doOnError(t -> { if (predicate.test(t)) { onError.accept(t); } }); } /** * Add behavior (side-effect) triggered when the {@link Flux} emits an item. *

* *

* The {@link Consumer} is executed first, then the onNext signal is propagated * downstream. * *

Error Mode Support: This operator supports {@link #onErrorContinue(BiConsumer) resuming on errors} * (including when fusion is enabled). Exceptions thrown by the consumer are passed to * the {@link #onErrorContinue(BiConsumer)} error consumer (the value consumer * is not invoked, as the source element will be part of the sequence). The onNext * signal is then propagated as normal. * * @param onNext the callback to call on {@link Subscriber#onNext} * * @return an observed {@link Flux} */ public final Flux doOnNext(Consumer onNext) { Objects.requireNonNull(onNext, "onNext"); return doOnSignal(this, null, onNext, null, null, null, null, null); } /** * Add behavior (side-effect) triggering a {@link LongConsumer} when this {@link Flux} * receives any request. *

* Note that non fatal error raised in the callback will not be propagated and * will simply trigger {@link Operators#onOperatorError(Throwable, Context)}. * *

* *

* The {@link LongConsumer} is executed first, then the request signal is propagated * upstream to the parent. * * @param consumer the consumer to invoke on each request * * @return an observed {@link Flux} */ public final Flux doOnRequest(LongConsumer consumer) { Objects.requireNonNull(consumer, "consumer"); return doOnSignal(this, null, null, null, null, null, consumer, null); } /** * Add behavior (side-effect) triggered when the {@link Flux} is being subscribed, * that is to say when a {@link Subscription} has been produced by the {@link Publisher} * and is being passed to the {@link Subscriber#onSubscribe(Subscription)}. *

* This method is not intended for capturing the subscription and calling its methods, * but for side effects like monitoring. For instance, the correct way to cancel a subscription is * to call {@link Disposable#dispose()} on the Disposable returned by {@link Flux#subscribe()}. *

* *

* The {@link Consumer} is executed first, then the {@link Subscription} is propagated * downstream to the next subscriber in the chain that is being established. * * @param onSubscribe the callback to call on {@link Subscriber#onSubscribe} * * @return an observed {@link Flux} * @see #doFirst(Runnable) */ public final Flux doOnSubscribe(Consumer onSubscribe) { Objects.requireNonNull(onSubscribe, "onSubscribe"); return doOnSignal(this, onSubscribe, null, null, null, null, null, null); } /** * Add behavior (side-effect) triggered when the {@link Flux} terminates, either by * completing successfully or failing with an error. *

* *

* The {@link Runnable} is executed first, then the onComplete/onError signal is propagated * downstream. * * @param onTerminate the callback to call on {@link Subscriber#onComplete} or {@link Subscriber#onError} * * @return an observed {@link Flux} */ public final Flux doOnTerminate(Runnable onTerminate) { Objects.requireNonNull(onTerminate, "onTerminate"); return doOnSignal(this, null, null, e -> onTerminate.run(), onTerminate, null, null, null); } /** * Add behavior (side-effect) triggered before the {@link Flux} is * subscribed to, which should be the first event after assembly time. *

* *

* Note that when several {@link #doFirst(Runnable)} operators are used anywhere in a * chain of operators, their order of execution is reversed compared to the declaration * order (as subscribe signal flows backward, from the ultimate subscriber to the source * publisher): *


	 * Flux.just(1, 2)
	 *     .doFirst(() -> System.out.println("three"))
	 *     .doFirst(() -> System.out.println("two"))
	 *     .doFirst(() -> System.out.println("one"));
	 * //would print one two three
	 * 
	 * 
*

* In case the {@link Runnable} throws an exception, said exception will be directly * propagated to the subscribing {@link Subscriber} along with a no-op {@link Subscription}, * similarly to what {@link #error(Throwable)} does. Otherwise, after the handler has * executed, the {@link Subscriber} is directly subscribed to the original source * {@link Flux} ({@code this}). *

* This side-effect method provides stronger first guarantees compared to * {@link #doOnSubscribe(Consumer)}, which is triggered once the {@link Subscription} * has been set up and passed to the {@link Subscriber}. * * @param onFirst the callback to execute before the {@link Flux} is subscribed to * @return an observed {@link Flux} */ public final Flux doFirst(Runnable onFirst) { Objects.requireNonNull(onFirst, "onFirst"); if (this instanceof Fuseable) { return onAssembly(new FluxDoFirstFuseable<>(this, onFirst)); } return onAssembly(new FluxDoFirst<>(this, onFirst)); } /** * Add behavior (side-effect) triggered after the {@link Flux} terminates for any reason, * including cancellation. The terminating event ({@link SignalType#ON_COMPLETE}, * {@link SignalType#ON_ERROR} and {@link SignalType#CANCEL}) is passed to the consumer, * which is executed after the signal has been passed downstream. *

* Note that the fact that the signal is propagated downstream before the callback is * executed means that several doFinally in a row will be executed in * reverse order. If you want to assert the execution of the callback * please keep in mind that the Flux will complete before it is executed, so its * effect might not be visible immediately after eg. a {@link #blockLast()}. *

* * * @param onFinally the callback to execute after a terminal signal (complete, error * or cancel) * @return an observed {@link Flux} */ public final Flux doFinally(Consumer onFinally) { Objects.requireNonNull(onFinally, "onFinally"); return onAssembly(new FluxDoFinally<>(this, onFinally)); } /** * Map this {@link Flux} into {@link reactor.util.function.Tuple2 Tuple2<Long, T>} * of timemillis and source data. The timemillis corresponds to the elapsed time * between each signal as measured by the {@link Schedulers#parallel() parallel} scheduler. * First duration is measured between the subscription and the first element. * *

* * * @return a new {@link Flux} that emits a tuple of time elapsed in milliseconds and matching data * @see #timed() * @see Timed#elapsed() */ public final Flux> elapsed() { return elapsed(Schedulers.parallel()); } /** * Map this {@link Flux} into {@link reactor.util.function.Tuple2 Tuple2<Long, T>} * of timemillis and source data. The timemillis corresponds to the elapsed time * between each signal as measured by the provided {@link Scheduler}. * First duration is measured between the subscription and the first element. *

* * * @param scheduler a {@link Scheduler} instance to {@link Scheduler#now(TimeUnit) read time from} * * @return a new {@link Flux} that emits tuples of time elapsed in milliseconds and matching data * @see #timed(Scheduler) * @see Timed#elapsed() */ public final Flux> elapsed(Scheduler scheduler) { Objects.requireNonNull(scheduler, "scheduler"); return onAssembly(new FluxElapsed<>(this, scheduler)); } /** * Emit only the element at the given index position or {@link IndexOutOfBoundsException} * if the sequence is shorter. * *

* * *

Discard Support: This operator discards elements that appear before the requested index. * * @param index zero-based index of the only item to emit * * @return a {@link Mono} of the item at the specified zero-based index */ public final Mono elementAt(int index) { return Mono.onAssembly(new MonoElementAt<>(this, index)); } /** * Emit only the element at the given index position or fall back to a * default value if the sequence is shorter. * *

* * *

Discard Support: This operator discards elements that appear before the requested index. * * @param index zero-based index of the only item to emit * @param defaultValue a default value to emit if the sequence is shorter * * @return a {@link Mono} of the item at the specified zero-based index or a default value */ public final Mono elementAt(int index, T defaultValue) { return Mono.onAssembly(new MonoElementAt<>(this, index, defaultValue)); } /** * Recursively expand elements into a graph and emit all the resulting element, * in a depth-first traversal order. *

* That is: emit one value from this {@link Flux}, expand it and emit the first value * at this first level of recursion, and so on... When no more recursion is possible, * backtrack to the previous level and re-apply the strategy. *

* For example, given the hierarchical structure *

	 *  A
	 *   - AA
	 *     - aa1
	 *  B
	 *   - BB
	 *     - bb1
	 * 
* * Expands {@code Flux.just(A, B)} into *
	 *  A
	 *  AA
	 *  aa1
	 *  B
	 *  BB
	 *  bb1
	 * 
* * @param expander the {@link Function} applied at each level of recursion to expand * values into a {@link Publisher}, producing a graph. * @param capacityHint a capacity hint to prepare the inner queues to accommodate n * elements per level of recursion. * * @return a {@link Flux} expanded depth-first */ public final Flux expandDeep(Function> expander, int capacityHint) { return onAssembly(new FluxExpand<>(this, expander, false, capacityHint)); } /** * Recursively expand elements into a graph and emit all the resulting element, * in a depth-first traversal order. *

* That is: emit one value from this {@link Flux}, expand it and emit the first value * at this first level of recursion, and so on... When no more recursion is possible, * backtrack to the previous level and re-apply the strategy. *

* For example, given the hierarchical structure *

	 *  A
	 *   - AA
	 *     - aa1
	 *  B
	 *   - BB
	 *     - bb1
	 * 
* * Expands {@code Flux.just(A, B)} into *
	 *  A
	 *  AA
	 *  aa1
	 *  B
	 *  BB
	 *  bb1
	 * 
* * @param expander the {@link Function} applied at each level of recursion to expand * values into a {@link Publisher}, producing a graph. * * @return a {@link Flux} expanded depth-first */ public final Flux expandDeep(Function> expander) { return expandDeep(expander, Queues.SMALL_BUFFER_SIZE); } /** * Recursively expand elements into a graph and emit all the resulting element using * a breadth-first traversal strategy. *

* That is: emit the values from this {@link Flux} first, then expand each at a first level of * recursion and emit all of the resulting values, then expand all of these at a second * level and so on. *

* For example, given the hierarchical structure *

	 *  A
	 *   - AA
	 *     - aa1
	 *  B
	 *   - BB
	 *     - bb1
	 * 
* * Expands {@code Flux.just(A, B)} into *
	 *  A
	 *  B
	 *  AA
	 *  BB
	 *  aa1
	 *  bb1
	 * 
* * @param expander the {@link Function} applied at each level of recursion to expand * values into a {@link Publisher}, producing a graph. * @param capacityHint a capacity hint to prepare the inner queues to accommodate n * elements per level of recursion. * * @return a breadth-first expanded {@link Flux} */ public final Flux expand(Function> expander, int capacityHint) { return Flux.onAssembly(new FluxExpand<>(this, expander, true, capacityHint)); } /** * Recursively expand elements into a graph and emit all the resulting element using * a breadth-first traversal strategy. *

* That is: emit the values from this {@link Flux} first, then expand each at a first level of * recursion and emit all of the resulting values, then expand all of these at a second * level and so on.. *

* For example, given the hierarchical structure *

	 *  A
	 *   - AA
	 *     - aa1
	 *  B
	 *   - BB
	 *     - bb1
	 * 
* * Expands {@code Flux.just(A, B)} into *
	 *  A
	 *  B
	 *  AA
	 *  BB
	 *  aa1
	 *  bb1
	 * 
* * @param expander the {@link Function} applied at each level of recursion to expand * values into a {@link Publisher}, producing a graph. * * @return a breadth-first expanded {@link Flux} */ public final Flux expand(Function> expander) { return expand(expander, Queues.SMALL_BUFFER_SIZE); } /** * Evaluate each source value against the given {@link Predicate}. If the predicate test succeeds, the value is * emitted. If the predicate test fails, the value is ignored and a request of 1 is made upstream. * *

* * *

Discard Support: This operator discards elements that do not match the filter. It * also discards elements internally queued for backpressure upon cancellation or error triggered by a data signal. * *

Error Mode Support: This operator supports {@link #onErrorContinue(BiConsumer) resuming on errors} * (including when fusion is enabled). Exceptions thrown by the predicate are * considered as if the predicate returned false: they cause the source value to be * dropped and a new element ({@code request(1)}) being requested from upstream. * * @param p the {@link Predicate} to test values against * * @return a new {@link Flux} containing only values that pass the predicate test */ public final Flux filter(Predicate p) { if (this instanceof Fuseable) { return onAssembly(new FluxFilterFuseable<>(this, p)); } return onAssembly(new FluxFilter<>(this, p)); } /** * Test each value emitted by this {@link Flux} asynchronously using a generated * {@code Publisher} test. A value is replayed if the first item emitted * by its corresponding test is {@literal true}. It is dropped if its test is either * empty or its first emitted value is {@literal false}. *

* Note that only the first value of the test publisher is considered, and unless it * is a {@link Mono}, test will be cancelled after receiving that first value. Test * publishers are generated and subscribed to in sequence. * *

* * *

Discard Support: This operator discards elements that do not match the filter. It * also discards elements internally queued for backpressure upon cancellation or error triggered by a data signal. * * @param asyncPredicate the function generating a {@link Publisher} of {@link Boolean} * for each value, to filter the Flux with * * @return a filtered {@link Flux} */ public final Flux filterWhen(Function> asyncPredicate) { return filterWhen(asyncPredicate, Queues.SMALL_BUFFER_SIZE); } /** * Test each value emitted by this {@link Flux} asynchronously using a generated * {@code Publisher} test. A value is replayed if the first item emitted * by its corresponding test is {@literal true}. It is dropped if its test is either * empty or its first emitted value is {@literal false}. *

* Note that only the first value of the test publisher is considered, and unless it * is a {@link Mono}, test will be cancelled after receiving that first value. Test * publishers are generated and subscribed to in sequence. * *

* * *

Discard Support: This operator discards elements that do not match the filter. It * also discards elements internally queued for backpressure upon cancellation or error triggered by a data signal. * * @param asyncPredicate the function generating a {@link Publisher} of {@link Boolean} * for each value, to filter the Flux with * @param bufferSize the maximum expected number of values to hold pending a result of * their respective asynchronous predicates, rounded to the next power of two. This is * capped depending on the size of the heap and the JVM limits, so be careful with * large values (although eg. {@literal 65536} should still be fine). Also serves as * the initial request size for the source. * * @return a filtered {@link Flux} */ public final Flux filterWhen(Function> asyncPredicate, int bufferSize) { return onAssembly(new FluxFilterWhen<>(this, asyncPredicate, bufferSize)); } /** * Transform the elements emitted by this {@link Flux} asynchronously into Publishers, * then flatten these inner publishers into a single {@link Flux} through merging, * which allow them to interleave. *

* There are three dimensions to this operator that can be compared with * {@link #flatMapSequential(Function) flatMapSequential} and {@link #concatMap(Function) concatMap}: *

    *
  • Generation of inners and subscription: this operator is eagerly * subscribing to its inners.
  • *
  • Ordering of the flattened values: this operator does not necessarily preserve * original ordering, as inner element are flattened as they arrive.
  • *
  • Interleaving: this operator lets values from different inners interleave * (similar to merging the inner sequences).
  • *
*

* *

* *

Discard Support: This operator discards elements internally queued for backpressure upon cancellation or error triggered by a data signal. * *

Error Mode Support: This operator supports {@link #onErrorContinue(BiConsumer) resuming on errors} * in the mapper {@link Function}. Exceptions thrown by the mapper then behave as if * it had mapped the value to an empty publisher. If the mapper does map to a scalar * publisher (an optimization in which the value can be resolved immediately without * subscribing to the publisher, e.g. a {@link Mono#fromCallable(Callable)}) but said * publisher throws, this can be resumed from in the same manner. * * @param mapper the {@link Function} to transform input sequence into N sequences {@link Publisher} * @param the merged output sequence type * * @return a new {@link Flux} */ public final Flux flatMap(Function> mapper) { return flatMap(mapper, Queues.SMALL_BUFFER_SIZE, Queues .XS_BUFFER_SIZE); } /** * Transform the elements emitted by this {@link Flux} asynchronously into Publishers, * then flatten these inner publishers into a single {@link Flux} through merging, * which allow them to interleave. *

* There are three dimensions to this operator that can be compared with * {@link #flatMapSequential(Function) flatMapSequential} and {@link #concatMap(Function) concatMap}: *

    *
  • Generation of inners and subscription: this operator is eagerly * subscribing to its inners.
  • *
  • Ordering of the flattened values: this operator does not necessarily preserve * original ordering, as inner element are flattened as they arrive.
  • *
  • Interleaving: this operator lets values from different inners interleave * (similar to merging the inner sequences).
  • *
* The concurrency argument allows to control how many {@link Publisher} can be * subscribed to and merged in parallel. In turn, that argument shows the size of * the first {@link Subscription#request} to the upstream. * *

* * *

Discard Support: This operator discards elements internally queued for backpressure upon cancellation or error triggered by a data signal. * *

Error Mode Support: This operator supports {@link #onErrorContinue(BiConsumer) resuming on errors} * in the mapper {@link Function}. Exceptions thrown by the mapper then behave as if * it had mapped the value to an empty publisher. If the mapper does map to a scalar * publisher (an optimization in which the value can be resolved immediately without * subscribing to the publisher, e.g. a {@link Mono#fromCallable(Callable)}) but said * publisher throws, this can be resumed from in the same manner. * * @param mapper the {@link Function} to transform input sequence into N sequences {@link Publisher} * @param concurrency the maximum number of in-flight inner sequences * * @param the merged output sequence type * * @return a new {@link Flux} */ public final Flux flatMap(Function> mapper, int concurrency) { return flatMap(mapper, concurrency, Queues.XS_BUFFER_SIZE); } /** * Transform the elements emitted by this {@link Flux} asynchronously into Publishers, * then flatten these inner publishers into a single {@link Flux} through merging, * which allow them to interleave. *

* There are three dimensions to this operator that can be compared with * {@link #flatMapSequential(Function) flatMapSequential} and {@link #concatMap(Function) concatMap}: *

    *
  • Generation of inners and subscription: this operator is eagerly * subscribing to its inners.
  • *
  • Ordering of the flattened values: this operator does not necessarily preserve * original ordering, as inner element are flattened as they arrive.
  • *
  • Interleaving: this operator lets values from different inners interleave * (similar to merging the inner sequences).
  • *
* The concurrency argument allows to control how many {@link Publisher} can be * subscribed to and merged in parallel. In turn, that argument shows the size of * the first {@link Subscription#request} to the upstream. * The prefetch argument allows to give an arbitrary prefetch size to the merged * {@link Publisher} (in other words prefetch size means the size of the first * {@link Subscription#request} to the merged {@link Publisher}). * *

* * *

Discard Support: This operator discards elements internally queued for backpressure upon cancellation or error triggered by a data signal. * *

Error Mode Support: This operator supports {@link #onErrorContinue(BiConsumer) resuming on errors} * in the mapper {@link Function}. Exceptions thrown by the mapper then behave as if * it had mapped the value to an empty publisher. If the mapper does map to a scalar * publisher (an optimization in which the value can be resolved immediately without * subscribing to the publisher, e.g. a {@link Mono#fromCallable(Callable)}) but said * publisher throws, this can be resumed from in the same manner. * * @param mapper the {@link Function} to transform input sequence into N sequences {@link Publisher} * @param concurrency the maximum number of in-flight inner sequences * @param prefetch the maximum in-flight elements from each inner {@link Publisher} sequence * * @param the merged output sequence type * * @return a merged {@link Flux} */ public final Flux flatMap(Function> mapper, int concurrency, int prefetch) { return flatMap(mapper, false, concurrency, prefetch); } /** * Transform the elements emitted by this {@link Flux} asynchronously into Publishers, * then flatten these inner publishers into a single {@link Flux} through merging, * which allow them to interleave. *

* There are three dimensions to this operator that can be compared with * {@link #flatMapSequential(Function) flatMapSequential} and {@link #concatMap(Function) concatMap}: *

    *
  • Generation of inners and subscription: this operator is eagerly * subscribing to its inners.
  • *
  • Ordering of the flattened values: this operator does not necessarily preserve * original ordering, as inner element are flattened as they arrive.
  • *
  • Interleaving: this operator lets values from different inners interleave * (similar to merging the inner sequences).
  • *
* The concurrency argument allows to control how many {@link Publisher} can be * subscribed to and merged in parallel. The prefetch argument allows to give an * arbitrary prefetch size to the merged {@link Publisher}. This variant will delay * any error until after the rest of the flatMap backlog has been processed. * *

* * *

Discard Support: This operator discards elements internally queued for backpressure upon cancellation or error triggered by a data signal. * *

Error Mode Support: This operator supports {@link #onErrorContinue(BiConsumer) resuming on errors} * in the mapper {@link Function}. Exceptions thrown by the mapper then behave as if * it had mapped the value to an empty publisher. If the mapper does map to a scalar * publisher (an optimization in which the value can be resolved immediately without * subscribing to the publisher, e.g. a {@link Mono#fromCallable(Callable)}) but said * publisher throws, this can be resumed from in the same manner. * * @param mapper the {@link Function} to transform input sequence into N sequences {@link Publisher} * @param concurrency the maximum number of in-flight inner sequences * @param prefetch the maximum in-flight elements from each inner {@link Publisher} sequence * * @param the merged output sequence type * * @return a merged {@link Flux} */ public final Flux flatMapDelayError(Function> mapper, int concurrency, int prefetch) { return flatMap(mapper, true, concurrency, prefetch); } /** * Transform the signals emitted by this {@link Flux} asynchronously into Publishers, * then flatten these inner publishers into a single {@link Flux} through merging, * which allow them to interleave. Note that at least one of the signal mappers must * be provided, and all provided mappers must produce a publisher. *

* There are three dimensions to this operator that can be compared with * {@link #flatMapSequential(Function) flatMapSequential} and {@link #concatMap(Function) concatMap}: *

    *
  • Generation of inners and subscription: this operator is eagerly * subscribing to its inners.
  • *
  • Ordering of the flattened values: this operator does not necessarily preserve * original ordering, as inner element are flattened as they arrive.
  • *
  • Interleaving: this operator lets values from different inners interleave * (similar to merging the inner sequences).
  • *
*

* OnError will be transformed into completion signal after its mapping callback has been applied. *

* * * @param mapperOnNext the {@link Function} to call on next data and returning a sequence to merge. * Use {@literal null} to ignore (provided at least one other mapper is specified). * @param mapperOnError the {@link Function} to call on error signal and returning a sequence to merge. * Use {@literal null} to ignore (provided at least one other mapper is specified). * @param mapperOnComplete the {@link Function} to call on complete signal and returning a sequence to merge. * Use {@literal null} to ignore (provided at least one other mapper is specified). * @param the output {@link Publisher} type target * * @return a new {@link Flux} */ public final Flux flatMap( @Nullable Function> mapperOnNext, @Nullable Function> mapperOnError, @Nullable Supplier> mapperOnComplete) { return onAssembly(new FluxFlatMap<>( new FluxMapSignal<>(this, mapperOnNext, mapperOnError, mapperOnComplete), identityFunction(), false, Queues.XS_BUFFER_SIZE, Queues.xs(), Queues.XS_BUFFER_SIZE, Queues.xs() )); } /** * Transform the items emitted by this {@link Flux} into {@link Iterable}, then flatten the elements from those by * merging them into a single {@link Flux}. For each iterable, {@link Iterable#iterator()} will be called at least * once and at most twice. * *

* *

* This operator inspects each {@link Iterable}'s {@link Spliterator} to assess if the iteration * can be guaranteed to be finite (see {@link Operators#onDiscardMultiple(Iterator, boolean, Context)}). * Since the default Spliterator wraps the Iterator we can have two {@link Iterable#iterator()} * calls per iterable. This second invocation is skipped on a {@link Collection} however, a type which is * assumed to be always finite. *

* Note that unlike {@link #flatMap(Function)} and {@link #concatMap(Function)}, with Iterable there is * no notion of eager vs lazy inner subscription. The content of the Iterables are all played sequentially. * Thus {@code flatMapIterable} and {@code concatMapIterable} are equivalent offered as a discoverability * improvement for users that explore the API with the concat vs flatMap expectation. * *

Discard Support: Upon cancellation, this operator discards {@code T} elements it prefetched and, in * some cases, attempts to discard remainder of the currently processed {@link Iterable} (if it can * safely ensure the iterator is finite). Note that this means each {@link Iterable}'s {@link Iterable#iterator()} * method could be invoked twice. * *

Error Mode Support: This operator supports {@link #onErrorContinue(BiConsumer) resuming on errors} * (including when fusion is enabled). Exceptions thrown by the consumer are passed to * the {@link #onErrorContinue(BiConsumer)} error consumer (the value consumer * is not invoked, as the source element will be part of the sequence). The onNext * signal is then propagated as normal. * * @param mapper the {@link Function} to transform input sequence into N {@link Iterable} * * @param the merged output sequence type * * @return a concatenation of the values from the Iterables obtained from each element in this {@link Flux} */ public final Flux flatMapIterable(Function> mapper) { return flatMapIterable(mapper, Queues.SMALL_BUFFER_SIZE); } /** * Transform the items emitted by this {@link Flux} into {@link Iterable}, then flatten the emissions from those by * merging them into a single {@link Flux}. The prefetch argument allows to give an * arbitrary prefetch size to the upstream source. * For each iterable, {@link Iterable#iterator()} will be called at least once and at most twice. * *

* *

* This operator inspects each {@link Iterable}'s {@link Spliterator} to assess if the iteration * can be guaranteed to be finite (see {@link Operators#onDiscardMultiple(Iterator, boolean, Context)}). * Since the default Spliterator wraps the Iterator we can have two {@link Iterable#iterator()} * calls per iterable. This second invocation is skipped on a {@link Collection} however, a type which is * assumed to be always finite. *

* Note that unlike {@link #flatMap(Function)} and {@link #concatMap(Function)}, with Iterable there is * no notion of eager vs lazy inner subscription. The content of the Iterables are all played sequentially. * Thus {@code flatMapIterable} and {@code concatMapIterable} are equivalent offered as a discoverability * improvement for users that explore the API with the concat vs flatMap expectation. * *

Discard Support: Upon cancellation, this operator discards {@code T} elements it prefetched and, in * some cases, attempts to discard remainder of the currently processed {@link Iterable} (if it can * safely ensure the iterator is finite). * Note that this means each {@link Iterable}'s {@link Iterable#iterator()} method could be invoked twice. * *

Error Mode Support: This operator supports {@link #onErrorContinue(BiConsumer) resuming on errors} * (including when fusion is enabled). Exceptions thrown by the consumer are passed to * the {@link #onErrorContinue(BiConsumer)} error consumer (the value consumer * is not invoked, as the source element will be part of the sequence). The onNext * signal is then propagated as normal. * * @param mapper the {@link Function} to transform input sequence into N {@link Iterable} * @param prefetch the number of values to request from the source upon subscription, to be transformed to {@link Iterable} * * @param the merged output sequence type * * @return a concatenation of the values from the Iterables obtained from each element in this {@link Flux} */ public final Flux flatMapIterable(Function> mapper, int prefetch) { return onAssembly(new FluxFlattenIterable<>(this, mapper, prefetch, Queues.get(prefetch))); } /** * Transform the elements emitted by this {@link Flux} asynchronously into Publishers, * then flatten these inner publishers into a single {@link Flux}, but merge them in * the order of their source element. *

* There are three dimensions to this operator that can be compared with * {@link #flatMap(Function) flatMap} and {@link #concatMap(Function) concatMap}: *

    *
  • Generation of inners and subscription: this operator is eagerly * subscribing to its inners (like flatMap).
  • *
  • Ordering of the flattened values: this operator queues elements from * late inners until all elements from earlier inners have been emitted, thus emitting * inner sequences as a whole, in an order that matches their source's order.
  • *
  • Interleaving: this operator does not let values from different inners * interleave (similar looking result to concatMap, but due to queueing of values * that would have been interleaved otherwise).
  • *
* *

* That is to say, whenever a source element is emitted it is transformed to an inner * {@link Publisher}. However, if such an early inner takes more time to complete than * subsequent faster inners, the data from these faster inners will be queued until * the earlier inner completes, so as to maintain source ordering. * *

* * * @param mapper the {@link Function} to transform input sequence into N sequences {@link Publisher} * @param the merged output sequence type * * @return a merged {@link Flux}, subscribing early but keeping the original ordering */ public final Flux flatMapSequential(Function> mapper) { return flatMapSequential(mapper, Queues.SMALL_BUFFER_SIZE); } /** * Transform the elements emitted by this {@link Flux} asynchronously into Publishers, * then flatten these inner publishers into a single {@link Flux}, but merge them in * the order of their source element. *

* There are three dimensions to this operator that can be compared with * {@link #flatMap(Function) flatMap} and {@link #concatMap(Function) concatMap}: *

    *
  • Generation of inners and subscription: this operator is eagerly * subscribing to its inners (like flatMap).
  • *
  • Ordering of the flattened values: this operator queues elements from * late inners until all elements from earlier inners have been emitted, thus emitting * inner sequences as a whole, in an order that matches their source's order.
  • *
  • Interleaving: this operator does not let values from different inners * interleave (similar looking result to concatMap, but due to queueing of values * that would have been interleaved otherwise).
  • *
* *

* That is to say, whenever a source element is emitted it is transformed to an inner * {@link Publisher}. However, if such an early inner takes more time to complete than * subsequent faster inners, the data from these faster inners will be queued until * the earlier inner completes, so as to maintain source ordering. * *

* The concurrency argument allows to control how many merged {@link Publisher} can happen in parallel. * *

* * * @param mapper the {@link Function} to transform input sequence into N sequences {@link Publisher} * @param maxConcurrency the maximum number of in-flight inner sequences * @param the merged output sequence type * * @return a merged {@link Flux}, subscribing early but keeping the original ordering */ public final Flux flatMapSequential(Function> mapper, int maxConcurrency) { return flatMapSequential(mapper, maxConcurrency, Queues.XS_BUFFER_SIZE); } /** * Transform the elements emitted by this {@link Flux} asynchronously into Publishers, * then flatten these inner publishers into a single {@link Flux}, but merge them in * the order of their source element. *

* There are three dimensions to this operator that can be compared with * {@link #flatMap(Function) flatMap} and {@link #concatMap(Function) concatMap}: *

    *
  • Generation of inners and subscription: this operator is eagerly * subscribing to its inners (like flatMap).
  • *
  • Ordering of the flattened values: this operator queues elements from * late inners until all elements from earlier inners have been emitted, thus emitting * inner sequences as a whole, in an order that matches their source's order.
  • *
  • Interleaving: this operator does not let values from different inners * interleave (similar looking result to concatMap, but due to queueing of values * that would have been interleaved otherwise).
  • *
* *

* That is to say, whenever a source element is emitted it is transformed to an inner * {@link Publisher}. However, if such an early inner takes more time to complete than * subsequent faster inners, the data from these faster inners will be queued until * the earlier inner completes, so as to maintain source ordering. * *

* The concurrency argument allows to control how many merged {@link Publisher} * can happen in parallel. The prefetch argument allows to give an arbitrary prefetch * size to the merged {@link Publisher}. * *

* * * @param mapper the {@link Function} to transform input sequence into N sequences {@link Publisher} * @param maxConcurrency the maximum number of in-flight inner sequences * @param prefetch the maximum in-flight elements from each inner {@link Publisher} sequence * @param the merged output sequence type * * @return a merged {@link Flux}, subscribing early but keeping the original ordering */ public final Flux flatMapSequential(Function> mapper, int maxConcurrency, int prefetch) { return flatMapSequential(mapper, false, maxConcurrency, prefetch); } /** * Transform the elements emitted by this {@link Flux} asynchronously into Publishers, * then flatten these inner publishers into a single {@link Flux}, but merge them in * the order of their source element. *

* There are three dimensions to this operator that can be compared with * {@link #flatMap(Function) flatMap} and {@link #concatMap(Function) concatMap}: *

    *
  • Generation of inners and subscription: this operator is eagerly * subscribing to its inners (like flatMap).
  • *
  • Ordering of the flattened values: this operator queues elements from * late inners until all elements from earlier inners have been emitted, thus emitting * inner sequences as a whole, in an order that matches their source's order.
  • *
  • Interleaving: this operator does not let values from different inners * interleave (similar looking result to concatMap, but due to queueing of values * that would have been interleaved otherwise).
  • *
* *

* That is to say, whenever a source element is emitted it is transformed to an inner * {@link Publisher}. However, if such an early inner takes more time to complete than * subsequent faster inners, the data from these faster inners will be queued until * the earlier inner completes, so as to maintain source ordering. * *

* The concurrency argument allows to control how many merged {@link Publisher} * can happen in parallel. The prefetch argument allows to give an arbitrary prefetch * size to the merged {@link Publisher}. This variant will delay any error until after the * rest of the flatMap backlog has been processed. * *

* * * @param mapper the {@link Function} to transform input sequence into N sequences {@link Publisher} * @param maxConcurrency the maximum number of in-flight inner sequences * @param prefetch the maximum in-flight elements from each inner {@link Publisher} sequence * @param the merged output sequence type * * @return a merged {@link Flux}, subscribing early but keeping the original ordering */ public final Flux flatMapSequentialDelayError(Function> mapper, int maxConcurrency, int prefetch) { return flatMapSequential(mapper, true, maxConcurrency, prefetch); } /** * The prefetch configuration of the {@link Flux} * @return the prefetch configuration of the {@link Flux}, -1 if unspecified */ public int getPrefetch() { return -1; } /** * Divide this sequence into dynamically created {@link Flux} (or groups) for each * unique key, as produced by the provided keyMapper {@link Function}. Note that * groupBy works best with a low cardinality of groups, so chose your keyMapper * function accordingly. * *

* * *

* The groups need to be drained and consumed downstream for groupBy to work correctly. * Notably when the criteria produces a large amount of groups, it can lead to hanging * if the groups are not suitably consumed downstream (eg. due to a {@code flatMap} * with a {@code maxConcurrency} parameter that is set too low). * *

* Note that groups are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a specific group more than once: groups are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * * @param keyMapper the key mapping {@link Function} that evaluates an incoming data and returns a key. * @param the key type extracted from each value of this sequence * * @return a {@link Flux} of {@link GroupedFlux} grouped sequences */ public final Flux> groupBy(Function keyMapper) { return groupBy(keyMapper, identityFunction()); } /** * Divide this sequence into dynamically created {@link Flux} (or groups) for each * unique key, as produced by the provided keyMapper {@link Function}. Note that * groupBy works best with a low cardinality of groups, so chose your keyMapper * function accordingly. * *

* * *

* The groups need to be drained and consumed downstream for groupBy to work correctly. * Notably when the criteria produces a large amount of groups, it can lead to hanging * if the groups are not suitably consumed downstream (eg. due to a {@code flatMap} * with a {@code maxConcurrency} parameter that is set too low). * *

* Note that groups are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a specific group more than once: groups are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * * @param keyMapper the key mapping {@link Function} that evaluates an incoming data and returns a key. * @param prefetch the number of values to prefetch from the source * @param the key type extracted from each value of this sequence * * @return a {@link Flux} of {@link GroupedFlux} grouped sequences */ public final Flux> groupBy(Function keyMapper, int prefetch) { return groupBy(keyMapper, identityFunction(), prefetch); } /** * Divide this sequence into dynamically created {@link Flux} (or groups) for each * unique key, as produced by the provided keyMapper {@link Function}. Source elements * are also mapped to a different value using the {@code valueMapper}. Note that * groupBy works best with a low cardinality of groups, so chose your keyMapper * function accordingly. * *

* * *

* The groups need to be drained and consumed downstream for groupBy to work correctly. * Notably when the criteria produces a large amount of groups, it can lead to hanging * if the groups are not suitably consumed downstream (eg. due to a {@code flatMap} * with a {@code maxConcurrency} parameter that is set too low). * *

* Note that groups are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a specific group more than once: groups are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * * @param keyMapper the key mapping function that evaluates an incoming data and returns a key. * @param valueMapper the value mapping function that evaluates which data to extract for re-routing. * @param the key type extracted from each value of this sequence * @param the value type extracted from each value of this sequence * * @return a {@link Flux} of {@link GroupedFlux} grouped sequences * */ public final Flux> groupBy(Function keyMapper, Function valueMapper) { return groupBy(keyMapper, valueMapper, Queues.SMALL_BUFFER_SIZE); } /** * Divide this sequence into dynamically created {@link Flux} (or groups) for each * unique key, as produced by the provided keyMapper {@link Function}. Source elements * are also mapped to a different value using the {@code valueMapper}. Note that * groupBy works best with a low cardinality of groups, so chose your keyMapper * function accordingly. * *

* * *

* The groups need to be drained and consumed downstream for groupBy to work correctly. * Notably when the criteria produces a large amount of groups, it can lead to hanging * if the groups are not suitably consumed downstream (eg. due to a {@code flatMap} * with a {@code maxConcurrency} parameter that is set too low). * *

* Note that groups are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a specific group more than once: groups are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * * @param keyMapper the key mapping function that evaluates an incoming data and returns a key. * @param valueMapper the value mapping function that evaluates which data to extract for re-routing. * @param prefetch the number of values to prefetch from the source * * @param the key type extracted from each value of this sequence * @param the value type extracted from each value of this sequence * * @return a {@link Flux} of {@link GroupedFlux} grouped sequences * */ public final Flux> groupBy(Function keyMapper, Function valueMapper, int prefetch) { return onAssembly(new FluxGroupBy<>(this, keyMapper, valueMapper, Queues.unbounded(prefetch), Queues.unbounded(prefetch), prefetch)); } /** * Map values from two Publishers into time windows and emit combination of values * in case their windows overlap. The emitted elements are obtained by passing the * value from this {@link Flux} and a {@link Flux} emitting the value from the other * {@link Publisher} to a {@link BiFunction}. *

* There are no guarantees in what order the items get combined when multiple items from * one or both source Publishers overlap. *

* Unlike {@link Flux#join}, items from the second {@link Publisher} will be provided * as a {@link Flux} to the {@code resultSelector}. * *

* * * @param other the other {@link Publisher} to correlate items with * @param leftEnd a function that returns a Publisher whose emissions indicate the * time window for the source value to be considered * @param rightEnd a function that returns a Publisher whose emissions indicate the * time window for the {@code right} Publisher value to be considered * @param resultSelector a function that takes an item emitted by this {@link Flux} and * a {@link Flux} representation of the overlapping item from the other {@link Publisher} * and returns the value to be emitted by the resulting {@link Flux} * @param the type of the elements from the right {@link Publisher} * @param the type for this {@link Flux} window signals * @param the type for the right {@link Publisher} window signals * @param the combined result type * * @return a joining {@link Flux} * @see #join(Publisher, Function, Function, BiFunction) */ public final Flux groupJoin( Publisher other, Function> leftEnd, Function> rightEnd, BiFunction, ? extends R> resultSelector ) { return onAssembly(new FluxGroupJoin( this, other, leftEnd, rightEnd, resultSelector, Queues.unbounded(Queues.XS_BUFFER_SIZE), Queues.unbounded(Queues.XS_BUFFER_SIZE))); } /** * Handle the items emitted by this {@link Flux} by calling a biconsumer with the * output sink for each onNext. At most one {@link SynchronousSink#next(Object)} * call must be performed and/or 0 or 1 {@link SynchronousSink#error(Throwable)} or * {@link SynchronousSink#complete()}. * *

Error Mode Support: This operator supports {@link #onErrorContinue(BiConsumer) resuming on errors} (including when * fusion is enabled) when the {@link BiConsumer} throws an exception or if an error is signaled explicitly via * {@link SynchronousSink#error(Throwable)}. * * @param handler the handling {@link BiConsumer} * * @param the transformed type * * @return a transformed {@link Flux} */ public final Flux handle(BiConsumer> handler) { if (this instanceof Fuseable) { return onAssembly(new FluxHandleFuseable<>(this, handler)); } return onAssembly(new FluxHandle<>(this, handler)); } /** * Emit a single boolean true if any of the elements of this {@link Flux} sequence is * equal to the provided value. *

* The implementation uses short-circuit logic and completes with true if * an element matches the value. * *

* * * @param value constant compared to incoming signals * * @return a new {@link Flux} with true if any element is equal to a given value and false * otherwise * */ public final Mono hasElement(T value) { Objects.requireNonNull(value, "value"); return any(t -> Objects.equals(value, t)); } /** * Emit a single boolean true if this {@link Flux} sequence has at least one element. *

* The implementation uses short-circuit logic and completes with true on onNext. * *

* * * @return a new {@link Mono} with true if any value is emitted and false * otherwise */ public final Mono hasElements() { return Mono.onAssembly(new MonoHasElements<>(this)); } /** * Hides the identities of this {@link Flux} instance. *

The main purpose of this operator is to prevent certain identity-based * optimizations from happening, mostly for diagnostic purposes. * * @return a new {@link Flux} preventing {@link Publisher} / {@link Subscription} based Reactor optimizations */ public Flux hide() { return new FluxHide<>(this); } /** * Keep information about the order in which source values were received by * indexing them with a 0-based incrementing long, returning a {@link Flux} * of {@link Tuple2 Tuple2<(index, value)>}. *

* * * @return an indexed {@link Flux} with each source value combined with its 0-based index. */ public final Flux> index() { return index(tuple2Function()); } /** * Keep information about the order in which source values were received by * indexing them internally with a 0-based incrementing long then combining this * information with the source value into a {@code I} using the provided {@link BiFunction}, * returning a {@link Flux Flux<I>}. *

* Typical usage would be to produce a {@link Tuple2} similar to {@link #index()}, but * 1-based instead of 0-based: *

* {@code index((i, v) -> Tuples.of(i+1, v))} *

* * * @param indexMapper the {@link BiFunction} to use to combine elements and their index. * @return an indexed {@link Flux} with each source value combined with its computed index. */ public final Flux index(BiFunction indexMapper) { if (this instanceof Fuseable) { return onAssembly(new FluxIndexFuseable<>(this, indexMapper)); } return onAssembly(new FluxIndex<>(this, indexMapper)); } /** * Ignores onNext signals (dropping them) and only propagate termination events. * *

* *

* *

Discard Support: This operator discards the upstream's elements. * * @return a new empty {@link Mono} representing the completion of this {@link Flux}. */ public final Mono ignoreElements() { return Mono.onAssembly(new MonoIgnoreElements<>(this)); } /** * Combine values from two Publishers in case their windows overlap. Each incoming * value triggers a creation of a new Publisher via the given {@link Function}. If the * Publisher signals its first value or completes, the time windows for the original * element is immediately closed. The emitted elements are obtained by passing the * values from this {@link Flux} and the other {@link Publisher} to a {@link BiFunction}. *

* There are no guarantees in what order the items get combined when multiple items from * one or both source Publishers overlap. * *

* * * * @param other the other {@link Publisher} to correlate items with * @param leftEnd a function that returns a Publisher whose emissions indicate the * time window for the source value to be considered * @param rightEnd a function that returns a Publisher whose emissions indicate the * time window for the {@code right} Publisher value to be considered * @param resultSelector a function that takes an item emitted by each Publisher and returns the * value to be emitted by the resulting {@link Flux} * @param the type of the elements from the right {@link Publisher} * @param the type for this {@link Flux} window signals * @param the type for the right {@link Publisher} window signals * @param the combined result type * * @return a joining {@link Flux} * @see #groupJoin(Publisher, Function, Function, BiFunction) */ public final Flux join( Publisher other, Function> leftEnd, Function> rightEnd, BiFunction resultSelector ) { return onAssembly(new FluxJoin( this, other, leftEnd, rightEnd, resultSelector)); } /** * Emit the last element observed before complete signal as a {@link Mono}, or emit * {@link NoSuchElementException} error if the source was empty. * For a passive version use {@link #takeLast(int)} * *

* * *

Discard Support: This operator discards elements before the last. * * @return a {@link Mono} with the last value in this {@link Flux} */ public final Mono last() { if (this instanceof Callable) { @SuppressWarnings("unchecked") Callable thiz = (Callable) this; Mono callableMono = wrapToMono(thiz); if (callableMono == Mono.empty()) { return Mono.onAssembly(new MonoError<>(new NoSuchElementException("Flux#last() didn't observe any onNext signal from Callable flux"))); } return Mono.onAssembly(callableMono); } return Mono.onAssembly(new MonoTakeLastOne<>(this)); } /** * Emit the last element observed before complete signal as a {@link Mono}, or emit * the {@code defaultValue} if the source was empty. * For a passive version use {@link #takeLast(int)} * *

* * *

Discard Support: This operator discards elements before the last. * * @param defaultValue a single fallback item if this {@link Flux} is empty * * @return a {@link Mono} with the last value in this {@link Flux} */ public final Mono last(T defaultValue) { if (this instanceof Callable) { @SuppressWarnings("unchecked") Callable thiz = (Callable)this; if(thiz instanceof Fuseable.ScalarCallable){ @SuppressWarnings("unchecked") Fuseable.ScalarCallable c = (Fuseable.ScalarCallable)thiz; T v; try { v = c.call(); } catch (Exception e) { return Mono.error(Exceptions.unwrap(e)); } if(v == null){ return Mono.just(defaultValue); } return Mono.just(v); } Mono.onAssembly(new MonoCallable<>(thiz)); } return Mono.onAssembly(new MonoTakeLastOne<>(this, defaultValue)); } /** * Ensure that backpressure signals from downstream subscribers are split into batches * capped at the provided {@code prefetchRate} when propagated upstream, effectively * rate limiting the upstream {@link Publisher}. *

* Note that this is an upper bound, and that this operator uses a prefetch-and-replenish * strategy, requesting a replenishing amount when 75% of the prefetch amount has been * emitted. *

* Typically used for scenarios where consumer(s) request a large amount of data * (eg. {@code Long.MAX_VALUE}) but the data source behaves better or can be optimized * with smaller requests (eg. database paging, etc...). All data is still processed, * unlike with {@link #limitRequest(long)} which will cap the grand total request * amount. *

* Equivalent to {@code flux.publishOn(Schedulers.immediate(), prefetchRate).subscribe() }. * Note that the {@code prefetchRate} is an upper bound, and that this operator uses a * prefetch-and-replenish strategy, requesting a replenishing amount when 75% of the * prefetch amount has been emitted. *

* * * @param prefetchRate the limit to apply to downstream's backpressure * * @return a {@link Flux} limiting downstream's backpressure * @see #publishOn(Scheduler, int) * @see #limitRequest(long) */ public final Flux limitRate(int prefetchRate) { return onAssembly(this.publishOn(Schedulers.immediate(), prefetchRate)); } /** * Ensure that backpressure signals from downstream subscribers are split into batches * capped at the provided {@code highTide} first, then replenishing at the provided * {@code lowTide}, effectively rate limiting the upstream {@link Publisher}. *

* Note that this is an upper bound, and that this operator uses a prefetch-and-replenish * strategy, requesting a replenishing amount when 75% of the prefetch amount has been * emitted. *

* Typically used for scenarios where consumer(s) request a large amount of data * (eg. {@code Long.MAX_VALUE}) but the data source behaves better or can be optimized * with smaller requests (eg. database paging, etc...). All data is still processed, * unlike with {@link #limitRequest(long)} which will cap the grand total request * amount. *

* Similar to {@code flux.publishOn(Schedulers.immediate(), prefetchRate).subscribe() }, * except with a customized "low tide" instead of the default 75%. * Note that the smaller the lowTide is, the higher the potential for concurrency * between request and data production. And thus the more extraneous replenishment * requests this operator could make. For example, for a global downstream * request of 14, with a highTide of 10 and a lowTide of 2, the operator would perform * low tide requests ({@code request(2)}) seven times in a row, whereas with the default * lowTide of 8 it would only perform one low tide request ({@code request(8)}). * Using a {@code lowTide} equal to {@code highTide} reverts to the default 75% strategy, * while using a {@code lowTide} of {@literal 0} disables the lowTide, resulting in * all requests strictly adhering to the highTide. *

* * * @param highTide the initial request amount * @param lowTide the subsequent (or replenishing) request amount, {@literal 0} to * disable early replenishing, {@literal highTide} to revert to a 75% replenish strategy. * * @return a {@link Flux} limiting downstream's backpressure and customizing the * replenishment request amount * @see #publishOn(Scheduler, int) * @see #limitRequest(long) */ public final Flux limitRate(int highTide, int lowTide) { return onAssembly(this.publishOn(Schedulers.immediate(), true, highTide, lowTide)); } /** * Take only the first N values from this {@link Flux}, if available. * Furthermore, ensure that the total amount requested upstream is capped at {@code n}. * If n is zero, the source isn't even subscribed to and the operator completes immediately * upon subscription. *

* *

* Backpressure signals from downstream subscribers are smaller than the cap are * propagated as is, but if they would cause the total requested amount to go over the * cap, they are reduced to the minimum value that doesn't go over. *

* As a result, this operator never let the upstream produce more elements than the * cap. * Typically useful for cases where a race between request and cancellation can lead the upstream to * producing a lot of extraneous data, and such a production is undesirable (e.g. * a source that would send the extraneous data over the network). * * @param n the number of elements to emit from this flux, which is also the backpressure * cap for all of downstream's request * * @return a {@link Flux} of {@code n} elements from the source, that requests AT MOST {@code n} from upstream in total. * @see #take(long) * @see #take(long, boolean) * @deprecated replace with {@link #take(long, boolean) take(n, true)} in 3.4.x, then {@link #take(long)} in 3.5.0. * To be removed in 3.6.0 at the earliest. See https://github.com/reactor/reactor-core/issues/2339 */ @Deprecated public final Flux limitRequest(long n) { return take(n, true); } /** * Observe all Reactive Streams signals and trace them using {@link Logger} support. * Default will use {@link Level#INFO} and {@code java.util.logging}. * If SLF4J is available, it will be used instead. *

* *

* The default log category will be "reactor.Flux.", followed by a suffix generated from * the source operator, e.g. "reactor.Flux.Map". * * @return a new {@link Flux} that logs signals */ public final Flux log() { return log(null, Level.INFO); } /** * Observe all Reactive Streams signals and trace them using {@link Logger} support. * Default will use {@link Level#INFO} and {@code java.util.logging}. * If SLF4J is available, it will be used instead. *

* * * @param category to be mapped into logger configuration (e.g. org.springframework * .reactor). If category ends with "." like "reactor.", a generated operator * suffix will be added, e.g. "reactor.Flux.Map". * * @return a new {@link Flux} that logs signals */ public final Flux log(String category) { return log(category, Level.INFO); } /** * Observe Reactive Streams signals matching the passed filter {@code options} and * trace them using {@link Logger} support. Default will use {@link Level#INFO} and * {@code java.util.logging}. If SLF4J is available, it will be used instead. *

* Options allow fine grained filtering of the traced signal, for instance to only * capture onNext and onError: *

	 *     flux.log("category", Level.INFO, SignalType.ON_NEXT, SignalType.ON_ERROR)
	 * 
*

* * * @param category to be mapped into logger configuration (e.g. org.springframework * .reactor). If category ends with "." like "reactor.", a generated operator * suffix will be added, e.g. "reactor.Flux.Map". * @param level the {@link Level} to enforce for this tracing Flux (only FINEST, FINE, * INFO, WARNING and SEVERE are taken into account) * @param options a vararg {@link SignalType} option to filter log messages * * @return a new {@link Flux} that logs signals */ public final Flux log(@Nullable String category, Level level, SignalType... options) { return log(category, level, false, options); } /** * Observe Reactive Streams signals matching the passed filter {@code options} and * trace them using {@link Logger} support. Default will use {@link Level#INFO} and * {@code java.util.logging}. If SLF4J is available, it will be used instead. *

* Options allow fine grained filtering of the traced signal, for instance to only * capture onNext and onError: *

	 *     flux.log("category", Level.INFO, SignalType.ON_NEXT, SignalType.ON_ERROR)
	 * 
*

* * * @param category to be mapped into logger configuration (e.g. org.springframework * .reactor). If category ends with "." like "reactor.", a generated operator * suffix will be added, e.g. "reactor.Flux.Map". * @param level the {@link Level} to enforce for this tracing Flux (only FINEST, FINE, * INFO, WARNING and SEVERE are taken into account) * @param showOperatorLine capture the current stack to display operator class/line number. * @param options a vararg {@link SignalType} option to filter log messages * * @return a new {@link Flux} that logs signals */ public final Flux log(@Nullable String category, Level level, boolean showOperatorLine, SignalType... options) { SignalLogger log = new SignalLogger<>(this, category, level, showOperatorLine, options); if (this instanceof Fuseable) { return onAssembly(new FluxLogFuseable<>(this, log)); } return onAssembly(new FluxLog<>(this, log)); } /** * Observe Reactive Streams signals matching the passed filter {@code options} and * trace them using a specific user-provided {@link Logger}, at {@link Level#INFO} level. *

* * * @param logger the {@link Logger} to use, instead of resolving one through a category. * * @return a new {@link Flux} that logs signals */ public final Flux log(Logger logger) { return log(logger, Level.INFO, false); } /** * Observe Reactive Streams signals matching the passed filter {@code options} and * trace them using a specific user-provided {@link Logger}, at the given {@link Level}. *

* Options allow fine grained filtering of the traced signal, for instance to only * capture onNext and onError: *

	 *     flux.log(myCustomLogger, Level.INFO, SignalType.ON_NEXT, SignalType.ON_ERROR)
	 * 
*

* * * @param logger the {@link Logger} to use, instead of resolving one through a category. * @param level the {@link Level} to enforce for this tracing Flux (only FINEST, FINE, * INFO, WARNING and SEVERE are taken into account) * @param showOperatorLine capture the current stack to display operator class/line number (default in overload is false). * @param options a vararg {@link SignalType} option to filter log messages * * @return a new {@link Flux} that logs signals */ public final Flux log(Logger logger, Level level, boolean showOperatorLine, SignalType... options) { SignalLogger log = new SignalLogger<>(this, "IGNORED", level, showOperatorLine, s -> logger, options); if (this instanceof Fuseable) { return onAssembly(new FluxLogFuseable<>(this, log)); } return onAssembly(new FluxLog<>(this, log)); } /** * Transform the items emitted by this {@link Flux} by applying a synchronous function * to each item. *

* * *

Error Mode Support: This operator supports {@link #onErrorContinue(BiConsumer) resuming on errors} * (including when fusion is enabled). Exceptions thrown by the mapper then cause the * source value to be dropped and a new element ({@code request(1)}) being requested * from upstream. * * @param mapper the synchronous transforming {@link Function} * * @param the transformed type * * @return a transformed {@link Flux} */ public final Flux map(Function mapper) { if (this instanceof Fuseable) { return onAssembly(new FluxMapFuseable<>(this, mapper)); } return onAssembly(new FluxMap<>(this, mapper)); } /** * Transform the items emitted by this {@link Flux} by applying a synchronous function * to each item, which may produce {@code null} values. In that case, no value is emitted. * This operator effectively behaves like {@link #map(Function)} followed by {@link #filter(Predicate)} * although {@code null} is not a supported value, so it can't be filtered out. * *

* * *

Error Mode Support: This operator supports {@link #onErrorContinue(BiConsumer) resuming on errors} * (including when fusion is enabled). Exceptions thrown by the mapper then cause the * source value to be dropped and a new element ({@code request(1)}) being requested * from upstream. * * @param mapper the synchronous transforming {@link Function} * * @param the transformed type * * @return a transformed {@link Flux} */ public final Flux mapNotNull(Function mapper) { return this.handle((t, sink) -> { V v = mapper.apply(t); if (v != null) { sink.next(v); } }); } /** * Transform incoming onNext, onError and onComplete signals into {@link Signal} instances, * materializing these signals. * Since the error is materialized as a {@code Signal}, the propagation will be stopped and onComplete will be * emitted. Complete signal will first emit a {@code Signal.complete()} and then effectively complete the flux. * All these {@link Signal} have a {@link Context} associated to them. * *

* * * @return a {@link Flux} of materialized {@link Signal} * @see #dematerialize() */ public final Flux> materialize() { return onAssembly(new FluxMaterialize<>(this)); } /** * Merge data from this {@link Flux} and a {@link Publisher} into a reordered merge * sequence, by picking the smallest value from each sequence as defined by a provided * {@link Comparator}. Note that subsequent calls are combined, and their comparators are * in lexicographic order as defined by {@link Comparator#thenComparing(Comparator)}. *

* The combination step is avoided if the two {@link Comparator Comparators} are * {@link Comparator#equals(Object) equal} (which can easily be achieved by using the * same reference, and is also always true of {@link Comparator#naturalOrder()}). *

* Note that merge is tailored to work with asynchronous sources or finite sources. When dealing with * an infinite source that doesn't already publish on a dedicated Scheduler, you must isolate that source * in its own Scheduler, as merge would otherwise attempt to drain it before subscribing to * another source. *

* Note that it is delaying errors until all data is consumed. *

* * * @param other the {@link Publisher} to merge with * @param otherComparator the {@link Comparator} to use for merging * * @return a new {@link Flux} that compares latest values from the given publisher * and this flux, using the smallest value and replenishing the source that produced it * @deprecated Use {@link #mergeComparingWith(Publisher, Comparator)} instead * (with the caveat that it defaults to NOT delaying errors, unlike this operator). * To be removed in 3.6.0 at the earliest. */ @Deprecated public final Flux mergeOrderedWith(Publisher other, Comparator otherComparator) { if (this instanceof FluxMergeComparing) { FluxMergeComparing fluxMerge = (FluxMergeComparing) this; return fluxMerge.mergeAdditionalSource(other, otherComparator); } return mergeOrdered(otherComparator, this, other); } /** * Merge data from this {@link Flux} and a {@link Publisher} into a reordered merge * sequence, by picking the smallest value from each sequence as defined by a provided * {@link Comparator}. Note that subsequent calls are combined, and their comparators are * in lexicographic order as defined by {@link Comparator#thenComparing(Comparator)}. *

* The combination step is avoided if the two {@link Comparator Comparators} are * {@link Comparator#equals(Object) equal} (which can easily be achieved by using the * same reference, and is also always true of {@link Comparator#naturalOrder()}). *

* Note that merge is tailored to work with asynchronous sources or finite sources. When dealing with * an infinite source that doesn't already publish on a dedicated Scheduler, you must isolate that source * in its own Scheduler, as merge would otherwise attempt to drain it before subscribing to * another source. *

* *

* mergeComparingWith doesn't delay errors by default, but it will inherit the delayError * behavior of a mergeComparingDelayError directly above it. * * @param other the {@link Publisher} to merge with * @param otherComparator the {@link Comparator} to use for merging * * @return a new {@link Flux} that compares latest values from the given publisher * and this flux, using the smallest value and replenishing the source that produced it */ public final Flux mergeComparingWith(Publisher other, Comparator otherComparator) { if (this instanceof FluxMergeComparing) { FluxMergeComparing fluxMerge = (FluxMergeComparing) this; return fluxMerge.mergeAdditionalSource(other, otherComparator); } return mergeComparing(otherComparator, this, other); } /** * Merge data from this {@link Flux} and a {@link Publisher} into an interleaved merged * sequence. Unlike {@link #concatWith(Publisher) concat}, inner sources are subscribed * to eagerly. *

* *

* Note that merge is tailored to work with asynchronous sources or finite sources. When dealing with * an infinite source that doesn't already publish on a dedicated Scheduler, you must isolate that source * in its own Scheduler, as merge would otherwise attempt to drain it before subscribing to * another source. * * @param other the {@link Publisher} to merge with * * @return a new {@link Flux} */ public final Flux mergeWith(Publisher other) { if (this instanceof FluxMerge) { FluxMerge fluxMerge = (FluxMerge) this; return fluxMerge.mergeAdditionalSource(other, Queues::get); } return merge(this, other); } /** * Activate metrics for this sequence, provided there is an instrumentation facade * on the classpath (otherwise this method is a pure no-op). *

* Metrics are gathered on {@link Subscriber} events, and it is recommended to also * {@link #name(String) name} (and optionally {@link #tag(String, String) tag}) the * sequence. *

* The name serves as a prefix in the reported metrics names. In case no name has been provided, the default name "reactor" will be applied. *

* The {@link MeterRegistry} used by reactor can be configured via * {@link reactor.util.Metrics.MicrometerConfiguration#useRegistry(MeterRegistry)} * prior to using this operator, the default being * {@link io.micrometer.core.instrument.Metrics#globalRegistry}. * * @return an instrumented {@link Flux} * * @see #name(String) * @see #tag(String, String) */ public final Flux metrics() { if (!Metrics.isInstrumentationAvailable()) { return this; } if (this instanceof Fuseable) { return onAssembly(new FluxMetricsFuseable<>(this)); } return onAssembly(new FluxMetrics<>(this)); } /** * Give a name to this sequence, which can be retrieved using {@link Scannable#name()} * as long as this is the first reachable {@link Scannable#parents()}. *

* If {@link #metrics()} operator is called later in the chain, this name will be used as a prefix for meters' name. * * @param name a name for the sequence * * @return the same sequence, but bearing a name * *@see #metrics() *@see #tag(String, String) */ public final Flux name(String name) { return FluxName.createOrAppend(this, name); } /** * Emit only the first item emitted by this {@link Flux}, into a new {@link Mono}. * If called on an empty {@link Flux}, emits an empty {@link Mono}. *

* * * @return a new {@link Mono} emitting the first value in this {@link Flux} */ public final Mono next() { if(this instanceof Callable){ @SuppressWarnings("unchecked") Callable m = (Callable)this; return Mono.onAssembly(wrapToMono(m)); } return Mono.onAssembly(new MonoNext<>(this)); } /** * Evaluate each accepted value against the given {@link Class} type. If the * value matches the type, it is passed into the resulting {@link Flux}. Otherwise * the value is ignored and a request of 1 is emitted. * *

* * * @param clazz the {@link Class} type to test values against * * @return a new {@link Flux} filtered on items of the requested type */ public final Flux ofType(final Class clazz) { Objects.requireNonNull(clazz, "clazz"); return filter(o -> clazz.isAssignableFrom(o.getClass())).cast(clazz); } /** * Request an unbounded demand and push to the returned {@link Flux}, or park the * observed elements if not enough demand is requested downstream. Errors will be * delayed until the buffer gets consumed. * *

* * *

Discard Support: This operator discards the buffered overflow elements upon cancellation or error triggered by a data signal. * * @return a backpressured {@link Flux} that buffers with unbounded capacity * */ public final Flux onBackpressureBuffer() { return onAssembly(new FluxOnBackpressureBuffer<>(this, Queues .SMALL_BUFFER_SIZE, true, null)); } /** * Request an unbounded demand and push to the returned {@link Flux}, or park up to * {@code maxSize} elements when not enough demand is requested downstream. * The first element past this buffer to arrive out of sync with the downstream * subscriber's demand (the "overflowing" element) immediately triggers an overflow * error and cancels the source. * The {@link Flux} is going to terminate with an overflow error, but this error is * delayed, which lets the subscriber make more requests for the content of the buffer. *

* * *

Discard Support: This operator discards the buffered overflow elements upon cancellation or error triggered by a data signal, * as well as elements that are rejected by the buffer due to {@code maxSize}. * * @param maxSize maximum number of elements overflowing request before the source is cancelled * * @return a backpressured {@link Flux} that buffers with bounded capacity * */ public final Flux onBackpressureBuffer(int maxSize) { return onAssembly(new FluxOnBackpressureBuffer<>(this, maxSize, false, null)); } /** * Request an unbounded demand and push to the returned {@link Flux}, or park up to * {@code maxSize} elements when not enough demand is requested downstream. * The first element past this buffer to arrive out of sync with the downstream * subscriber's demand (the "overflowing" element) is immediately passed to a * {@link Consumer} and the source is cancelled. * The {@link Flux} is going to terminate with an overflow error, but this error is * delayed, which lets the subscriber make more requests for the content of the buffer. *

* Note that should the cancelled source produce further overflowing elements, these * would be passed to the {@link Hooks#onNextDropped(Consumer) onNextDropped hook}. *

* * *

Discard Support: This operator discards the buffered overflow elements upon cancellation or error triggered by a data signal, * as well as elements that are rejected by the buffer due to {@code maxSize} (even though * they are passed to the {@code onOverflow} {@link Consumer} first). * * @param maxSize maximum number of elements overflowing request before callback is called and source is cancelled * @param onOverflow callback to invoke on overflow * * @return a backpressured {@link Flux} that buffers with a bounded capacity * */ public final Flux onBackpressureBuffer(int maxSize, Consumer onOverflow) { Objects.requireNonNull(onOverflow, "onOverflow"); return onAssembly(new FluxOnBackpressureBuffer<>(this, maxSize, false, onOverflow)); } /** * Request an unbounded demand and push to the returned {@link Flux}, or park the observed * elements if not enough demand is requested downstream, within a {@code maxSize} * limit. Over that limit, the overflow strategy is applied (see {@link BufferOverflowStrategy}). *

* Note that for the {@link BufferOverflowStrategy#ERROR ERROR} strategy, the overflow * error will be delayed after the current backlog is consumed. * *

* * *

Discard Support: This operator discards the buffered overflow elements upon cancellation or error triggered by a data signal, * as well as elements that are rejected by the buffer due to {@code maxSize} (even though * they are passed to the {@code bufferOverflowStrategy} first). * * * @param maxSize maximum buffer backlog size before overflow strategy is applied * @param bufferOverflowStrategy strategy to apply to overflowing elements * * @return a backpressured {@link Flux} that buffers up to a capacity then applies an * overflow strategy */ public final Flux onBackpressureBuffer(int maxSize, BufferOverflowStrategy bufferOverflowStrategy) { Objects.requireNonNull(bufferOverflowStrategy, "bufferOverflowStrategy"); return onAssembly(new FluxOnBackpressureBufferStrategy<>(this, maxSize, null, bufferOverflowStrategy)); } /** * Request an unbounded demand and push to the returned {@link Flux}, or park the observed * elements if not enough demand is requested downstream, within a {@code maxSize} * limit. Over that limit, the overflow strategy is applied (see {@link BufferOverflowStrategy}). *

* A {@link Consumer} is immediately invoked when there is an overflow, receiving the * value that was discarded because of the overflow (which can be different from the * latest element emitted by the source in case of a * {@link BufferOverflowStrategy#DROP_LATEST DROP_LATEST} strategy). * *

* Note that for the {@link BufferOverflowStrategy#ERROR ERROR} strategy, the overflow * error will be delayed after the current backlog is consumed. The consumer is still * invoked immediately. * *

* * *

Discard Support: This operator discards the buffered overflow elements upon cancellation or error triggered by a data signal, * as well as elements that are rejected by the buffer due to {@code maxSize} (even though * they are passed to the {@code onOverflow} {@link Consumer} AND the {@code bufferOverflowStrategy} first). * * @param maxSize maximum buffer backlog size before overflow callback is called * @param onBufferOverflow callback to invoke on overflow * @param bufferOverflowStrategy strategy to apply to overflowing elements * * @return a backpressured {@link Flux} that buffers up to a capacity then applies an * overflow strategy */ public final Flux onBackpressureBuffer(int maxSize, Consumer onBufferOverflow, BufferOverflowStrategy bufferOverflowStrategy) { Objects.requireNonNull(onBufferOverflow, "onBufferOverflow"); Objects.requireNonNull(bufferOverflowStrategy, "bufferOverflowStrategy"); return onAssembly(new FluxOnBackpressureBufferStrategy<>(this, maxSize, onBufferOverflow, bufferOverflowStrategy)); } /** * Request an unbounded demand and push to the returned {@link Flux}, or park the observed * elements if not enough demand is requested downstream, within a {@code maxSize} * limit and for a maximum {@link Duration} of {@code ttl} (as measured on the * {@link Schedulers#parallel() parallel Scheduler}). Over that limit, oldest * elements from the source are dropped. *

* Elements evicted based on the TTL are passed to a cleanup {@link Consumer}, which * is also immediately invoked when there is an overflow. * *

* * *

Discard Support: This operator discards its internal buffer of elements that overflow, * after having applied the {@code onBufferEviction} handler. * * @param ttl maximum {@link Duration} for which an element is kept in the backlog * @param maxSize maximum buffer backlog size before overflow callback is called * @param onBufferEviction callback to invoke once TTL is reached or on overflow * * @return a backpressured {@link Flux} that buffers with a TTL and up to a capacity then applies an * overflow strategy */ public final Flux onBackpressureBuffer(Duration ttl, int maxSize, Consumer onBufferEviction) { return onBackpressureBuffer(ttl, maxSize, onBufferEviction, Schedulers.parallel()); } /** * Request an unbounded demand and push to the returned {@link Flux}, or park the observed * elements if not enough demand is requested downstream, within a {@code maxSize} * limit and for a maximum {@link Duration} of {@code ttl} (as measured on the provided * {@link Scheduler}). Over that limit, oldest elements from the source are dropped. *

* Elements evicted based on the TTL are passed to a cleanup {@link Consumer}, which * is also immediately invoked when there is an overflow. * *

* * *

Discard Support: This operator discards its internal buffer of elements that overflow, * after having applied the {@code onBufferEviction} handler. * * @param ttl maximum {@link Duration} for which an element is kept in the backlog * @param maxSize maximum buffer backlog size before overflow callback is called * @param onBufferEviction callback to invoke once TTL is reached or on overflow * @param scheduler the scheduler on which to run the timeout check * * @return a backpressured {@link Flux} that buffers with a TTL and up to a capacity then applies an * overflow strategy */ public final Flux onBackpressureBuffer(Duration ttl, int maxSize, Consumer onBufferEviction, Scheduler scheduler) { Objects.requireNonNull(ttl, "ttl"); Objects.requireNonNull(onBufferEviction, "onBufferEviction"); return onAssembly(new FluxOnBackpressureBufferTimeout<>(this, ttl, scheduler, maxSize, onBufferEviction)); } /** * Request an unbounded demand and push to the returned {@link Flux}, or drop * the observed elements if not enough demand is requested downstream. * *

* * *

Discard Support: This operator discards elements that it drops. * * @return a backpressured {@link Flux} that drops overflowing elements */ public final Flux onBackpressureDrop() { return onAssembly(new FluxOnBackpressureDrop<>(this)); } /** * Request an unbounded demand and push to the returned {@link Flux}, or drop and * notify dropping {@link Consumer} with the observed elements if not enough demand * is requested downstream. * *

* * *

Discard Support: This operator discards elements that it drops after having passed * them to the provided {@code onDropped} handler. * * @param onDropped the Consumer called when a value gets dropped due to lack of downstream requests * @return a backpressured {@link Flux} that drops overflowing elements */ public final Flux onBackpressureDrop(Consumer onDropped) { return onAssembly(new FluxOnBackpressureDrop<>(this, onDropped)); } /** * Request an unbounded demand and push to the returned {@link Flux}, or emit onError * fom {@link Exceptions#failWithOverflow} if not enough demand is requested * downstream. * *

* * *

Discard Support: This operator discards elements that it drops, after having propagated * the error. * * @return a backpressured {@link Flux} that errors on overflowing elements */ public final Flux onBackpressureError() { return onBackpressureDrop(t -> { throw Exceptions.failWithOverflow();}); } /** * Request an unbounded demand and push to the returned {@link Flux}, or only keep * the most recent observed item if not enough demand is requested downstream. * *

* *

*

Discard Support: Each time a new element comes in (the new "latest"), this operator * discards the previously retained element. * * @return a backpressured {@link Flux} that will only keep a reference to the last observed item */ public final Flux onBackpressureLatest() { return onAssembly(new FluxOnBackpressureLatest<>(this)); } /** * Let compatible operators upstream recover from errors by dropping the * incriminating element from the sequence and continuing with subsequent elements. * The recovered error and associated value are notified via the provided {@link BiConsumer}. * Alternatively, throwing from that biconsumer will propagate the thrown exception downstream * in place of the original error, which is added as a suppressed exception to the new one. *

* *

* Note that onErrorContinue() is a specialist operator that can make the behaviour of your * reactive chain unclear. It operates on upstream, not downstream operators, it requires specific * operator support to work, and the scope can easily propagate upstream into library code * that didn't anticipate it (resulting in unintended behaviour.) *

* In most cases, you should instead handle the error inside the specific function which may cause * it. Specifically, on each inner publisher you can use {@code doOnError} to log the error, and * {@code onErrorResume(e -> Mono.empty())} to drop erroneous elements: *

*

	 * .flatMap(id -> repository.retrieveById(id)
	 *                          .doOnError(System.err::println)
	 *                          .onErrorResume(e -> Mono.empty()))
	 * 
*

* This has the advantage of being much clearer, has no ambiguity with regards to operator support, * and cannot leak upstream. * * @param errorConsumer a {@link BiConsumer} fed with errors matching the predicate and the value * that triggered the error. * @return a {@link Flux} that attempts to continue processing on errors. */ public final Flux onErrorContinue(BiConsumer errorConsumer) { BiConsumer genericConsumer = errorConsumer; return subscriberContext(Context.of( OnNextFailureStrategy.KEY_ON_NEXT_ERROR_STRATEGY, OnNextFailureStrategy.resume(genericConsumer) )); } /** * Let compatible operators upstream recover from errors by dropping the * incriminating element from the sequence and continuing with subsequent elements. * Only errors matching the specified {@code type} are recovered from. * The recovered error and associated value are notified via the provided {@link BiConsumer}. * Alternatively, throwing from that biconsumer will propagate the thrown exception downstream * in place of the original error, which is added as a suppressed exception to the new one. *

* *

* Note that onErrorContinue() is a specialist operator that can make the behaviour of your * reactive chain unclear. It operates on upstream, not downstream operators, it requires specific * operator support to work, and the scope can easily propagate upstream into library code * that didn't anticipate it (resulting in unintended behaviour.) *

* In most cases, you should instead handle the error inside the specific function which may cause * it. Specifically, on each inner publisher you can use {@code doOnError} to log the error, and * {@code onErrorResume(e -> Mono.empty())} to drop erroneous elements: *

*

	 * .flatMap(id -> repository.retrieveById(id)
	 *                          .doOnError(MyException.class, System.err::println)
	 *                          .onErrorResume(MyException.class, e -> Mono.empty()))
	 * 
*

* This has the advantage of being much clearer, has no ambiguity with regards to operator support, * and cannot leak upstream. * * @param type the {@link Class} of {@link Exception} that are resumed from. * @param errorConsumer a {@link BiConsumer} fed with errors matching the {@link Class} * and the value that triggered the error. * @return a {@link Flux} that attempts to continue processing on some errors. */ public final Flux onErrorContinue(Class type, BiConsumer errorConsumer) { return onErrorContinue(type::isInstance, errorConsumer); } /** * Let compatible operators upstream recover from errors by dropping the * incriminating element from the sequence and continuing with subsequent elements. * Only errors matching the {@link Predicate} are recovered from (note that this * predicate can be applied several times and thus must be idempotent). * The recovered error and associated value are notified via the provided {@link BiConsumer}. * Alternatively, throwing from that biconsumer will propagate the thrown exception downstream * in place of the original error, which is added as a suppressed exception to the new one. *

* *

* Note that onErrorContinue() is a specialist operator that can make the behaviour of your * reactive chain unclear. It operates on upstream, not downstream operators, it requires specific * operator support to work, and the scope can easily propagate upstream into library code * that didn't anticipate it (resulting in unintended behaviour.) *

* In most cases, you should instead handle the error inside the specific function which may cause * it. Specifically, on each inner publisher you can use {@code doOnError} to log the error, and * {@code onErrorResume(e -> Mono.empty())} to drop erroneous elements: *

*

	 * .flatMap(id -> repository.retrieveById(id)
	 *                          .doOnError(errorPredicate, System.err::println)
	 *                          .onErrorResume(errorPredicate, e -> Mono.empty()))
	 * 
*

* This has the advantage of being much clearer, has no ambiguity with regards to operator support, * and cannot leak upstream. * * @param errorPredicate a {@link Predicate} used to filter which errors should be resumed from. * This MUST be idempotent, as it can be used several times. * @param errorConsumer a {@link BiConsumer} fed with errors matching the predicate and the value * that triggered the error. * @return a {@link Flux} that attempts to continue processing on some errors. */ public final Flux onErrorContinue(Predicate errorPredicate, BiConsumer errorConsumer) { //this cast is ok as only T values will be propagated in this sequence @SuppressWarnings("unchecked") Predicate genericPredicate = (Predicate) errorPredicate; BiConsumer genericErrorConsumer = errorConsumer; return subscriberContext(Context.of( OnNextFailureStrategy.KEY_ON_NEXT_ERROR_STRATEGY, OnNextFailureStrategy.resumeIf(genericPredicate, genericErrorConsumer) )); } /** * If an {@link #onErrorContinue(BiConsumer)} variant has been used downstream, reverts * to the default 'STOP' mode where errors are terminal events upstream. It can be * used for easier scoping of the on next failure strategy or to override the * inherited strategy in a sub-stream (for example in a flatMap). It has no effect if * {@link #onErrorContinue(BiConsumer)} has not been used downstream. * * @return a {@link Flux} that terminates on errors, even if {@link #onErrorContinue(BiConsumer)} * was used downstream */ public final Flux onErrorStop() { return subscriberContext(Context.of( OnNextFailureStrategy.KEY_ON_NEXT_ERROR_STRATEGY, OnNextFailureStrategy.stop())); } /** * Transform any error emitted by this {@link Flux} by synchronously applying a function to it. *

* * * @param mapper the error transforming {@link Function} * * @return a {@link Flux} that transforms source errors to other errors */ public final Flux onErrorMap(Function mapper) { return onErrorResume(e -> Mono.error(mapper.apply(e))); } /** * Transform an error emitted by this {@link Flux} by synchronously applying a function * to it if the error matches the given type. Otherwise let the error pass through. *

* * * @param type the class of the exception type to react to * @param mapper the error transforming {@link Function} * @param the error type * * @return a {@link Flux} that transforms some source errors to other errors */ public final Flux onErrorMap(Class type, Function mapper) { @SuppressWarnings("unchecked") Function handler = (Function)mapper; return onErrorMap(type::isInstance, handler); } /** * Transform an error emitted by this {@link Flux} by synchronously applying a function * to it if the error matches the given predicate. Otherwise let the error pass through. *

* * * @param predicate the error predicate * @param mapper the error transforming {@link Function} * * @return a {@link Flux} that transforms some source errors to other errors */ public final Flux onErrorMap(Predicate predicate, Function mapper) { return onErrorResume(predicate, e -> Mono.error(mapper.apply(e))); } /** * Subscribe to a returned fallback publisher when any error occurs, using a function to * choose the fallback depending on the error. * *

* * * @param fallback the function to choose the fallback to an alternative {@link Publisher} * * @return a {@link Flux} falling back upon source onError */ public final Flux onErrorResume(Function> fallback) { return onAssembly(new FluxOnErrorResume<>(this, fallback)); } /** * Subscribe to a fallback publisher when an error matching the given type * occurs, using a function to choose the fallback depending on the error. *

* * * @param type the error type to match * @param fallback the function to choose the fallback to an alternative {@link Publisher} * @param the error type * * @return a {@link Flux} falling back upon source onError */ public final Flux onErrorResume(Class type, Function> fallback) { Objects.requireNonNull(type, "type"); @SuppressWarnings("unchecked") Function> handler = (Function>)fallback; return onErrorResume(type::isInstance, handler); } /** * Subscribe to a fallback publisher when an error matching a given predicate * occurs. *

* * * @param predicate the error predicate to match * @param fallback the function to choose the fallback to an alternative {@link Publisher} * * @return a {@link Flux} falling back upon source onError */ public final Flux onErrorResume(Predicate predicate, Function> fallback) { Objects.requireNonNull(predicate, "predicate"); return onErrorResume(e -> predicate.test(e) ? fallback.apply(e) : error(e)); } /** * Simply emit a captured fallback value when any error is observed on this {@link Flux}. *

* * * @param fallbackValue the value to emit if an error occurs * * @return a new falling back {@link Flux} */ public final Flux onErrorReturn(T fallbackValue) { return onErrorResume(t -> just(fallbackValue)); } /** * Simply emit a captured fallback value when an error of the specified type is * observed on this {@link Flux}. *

* * * @param type the error type to match * @param fallbackValue the value to emit if an error occurs that matches the type * @param the error type * * @return a new falling back {@link Flux} */ public final Flux onErrorReturn(Class type, T fallbackValue) { return onErrorResume(type, t -> just(fallbackValue)); } /** * Simply emit a captured fallback value when an error matching the given predicate is * observed on this {@link Flux}. *

* * * @param predicate the error predicate to match * @param fallbackValue the value to emit if an error occurs that matches the predicate * * @return a new falling back {@link Flux} */ public final Flux onErrorReturn(Predicate predicate, T fallbackValue) { return onErrorResume(predicate, t -> just(fallbackValue)); } /** * Detaches both the child {@link Subscriber} and the {@link Subscription} on * termination or cancellation. *

This is an advanced interoperability operator that should help with odd * retention scenarios when running with non-reactor {@link Subscriber}. * * @return a detachable {@link Flux} */ public final Flux onTerminateDetach() { return new FluxDetach<>(this); } /** * Pick the first {@link Publisher} between this {@link Flux} and another publisher * to emit any signal (onNext/onError/onComplete) and replay all signals from that * {@link Publisher}, effectively behaving like the fastest of these competing sources. * *

* * * @param other the {@link Publisher} to race with * * @return the fastest sequence * @see #firstWithSignal */ public final Flux or(Publisher other) { if (this instanceof FluxFirstWithSignal) { FluxFirstWithSignal orPublisher = (FluxFirstWithSignal) this; FluxFirstWithSignal result = orPublisher.orAdditionalSource(other); if (result != null) { return result; } } return firstWithSignal(this, other); } /** * Prepare this {@link Flux} by dividing data on a number of 'rails' matching the * number of CPU cores, in a round-robin fashion. Note that to actually perform the * work in parallel, you should call {@link ParallelFlux#runOn(Scheduler)} afterward. * *

* * * @return a new {@link ParallelFlux} instance */ public final ParallelFlux parallel() { return parallel(Schedulers.DEFAULT_POOL_SIZE); } /** * Prepare this {@link Flux} by dividing data on a number of 'rails' matching the * provided {@code parallelism} parameter, in a round-robin fashion. Note that to * actually perform the work in parallel, you should call {@link ParallelFlux#runOn(Scheduler)} * afterward. * *

* * * @param parallelism the number of parallel rails * * @return a new {@link ParallelFlux} instance */ public final ParallelFlux parallel(int parallelism) { return parallel(parallelism, Queues.SMALL_BUFFER_SIZE); } /** * Prepare this {@link Flux} by dividing data on a number of 'rails' matching the * provided {@code parallelism} parameter, in a round-robin fashion and using a * custom prefetch amount and queue for dealing with the source {@link Flux}'s values. * Note that to actually perform the work in parallel, you should call * {@link ParallelFlux#runOn(Scheduler)} afterward. * *

* * * @param parallelism the number of parallel rails * @param prefetch the number of values to prefetch from the source * * @return a new {@link ParallelFlux} instance */ public final ParallelFlux parallel(int parallelism, int prefetch) { return ParallelFlux.from(this, parallelism, prefetch, Queues.get(prefetch)); } /** * Prepare a {@link ConnectableFlux} which shares this {@link Flux} sequence and * dispatches values to subscribers in a backpressure-aware manner. Prefetch will * default to {@link Queues#SMALL_BUFFER_SIZE}. This will effectively turn * any type of sequence into a hot sequence. *

* Backpressure will be coordinated on {@link Subscription#request} and if any * {@link Subscriber} is missing demand (requested = 0), multicast will pause * pushing/pulling. *

* * * @return a new {@link ConnectableFlux} */ public final ConnectableFlux publish() { return publish(Queues.SMALL_BUFFER_SIZE); } /** * Prepare a {@link ConnectableFlux} which shares this {@link Flux} sequence and * dispatches values to subscribers in a backpressure-aware manner. This will * effectively turn any type of sequence into a hot sequence. *

* Backpressure will be coordinated on {@link Subscription#request} and if any * {@link Subscriber} is missing demand (requested = 0), multicast will pause * pushing/pulling. *

* * * @param prefetch bounded requested demand * * @return a new {@link ConnectableFlux} */ public final ConnectableFlux publish(int prefetch) { return onAssembly(new FluxPublish<>(this, prefetch, Queues .get(prefetch))); } /** * Shares a sequence for the duration of a function that may transform it and * consume it as many times as necessary without causing multiple subscriptions * to the upstream. * * @param transform the transformation function * @param the output value type * * @return a new {@link Flux} */ public final Flux publish(Function, ? extends Publisher> transform) { return publish(transform, Queues.SMALL_BUFFER_SIZE); } /** * Shares a sequence for the duration of a function that may transform it and * consume it as many times as necessary without causing multiple subscriptions * to the upstream. * * @param transform the transformation function * @param prefetch the request size * @param the output value type * * @return a new {@link Flux} */ public final Flux publish(Function, ? extends Publisher> transform, int prefetch) { return onAssembly(new FluxPublishMulticast<>(this, transform, prefetch, Queues .get(prefetch))); } /** * Prepare a {@link Mono} which shares this {@link Flux} sequence and dispatches the * first observed item to subscribers in a backpressure-aware manner. * This will effectively turn any type of sequence into a hot sequence when the first * {@link Subscriber} subscribes. *

* * * @return a new {@link Mono} * @deprecated use {@link #shareNext()} instead, or use `publish().next()` if you need * to `{@link ConnectableFlux#connect() connect()}. To be removed in 3.5.0 */ @Deprecated public final Mono publishNext() { //Should add a ConnectableMono to align with #publish() return shareNext(); } /** * Run onNext, onComplete and onError on a supplied {@link Scheduler} * {@link Worker Worker}. *

* This operator influences the threading context where the rest of the operators in * the chain below it will execute, up to a new occurrence of {@code publishOn}. *

* *

* Typically used for fast publisher, slow consumer(s) scenarios. *

	 * {@code flux.publishOn(Schedulers.single()).subscribe() }
	 * 
* *

Discard Support: This operator discards elements it internally queued for backpressure upon cancellation or error triggered by a data signal. * * @param scheduler a {@link Scheduler} providing the {@link Worker} where to publish * * @return a {@link Flux} producing asynchronously on a given {@link Scheduler} */ public final Flux publishOn(Scheduler scheduler) { return publishOn(scheduler, Queues.SMALL_BUFFER_SIZE); } /** * Run onNext, onComplete and onError on a supplied {@link Scheduler} * {@link Worker}. *

* This operator influences the threading context where the rest of the operators in * the chain below it will execute, up to a new occurrence of {@code publishOn}. *

* *

* Typically used for fast publisher, slow consumer(s) scenarios. *

	 * {@code flux.publishOn(Schedulers.single()).subscribe() }
	 * 
* *

Discard Support: This operator discards elements it internally queued for backpressure upon cancellation or error triggered by a data signal. * * @param scheduler a {@link Scheduler} providing the {@link Worker} where to publish * @param prefetch the asynchronous boundary capacity * * @return a {@link Flux} producing asynchronously */ public final Flux publishOn(Scheduler scheduler, int prefetch) { return publishOn(scheduler, true, prefetch); } /** * Run onNext, onComplete and onError on a supplied {@link Scheduler} * {@link Worker}. *

* This operator influences the threading context where the rest of the operators in * the chain below it will execute, up to a new occurrence of {@code publishOn}. *

* *

* Typically used for fast publisher, slow consumer(s) scenarios. *

	 * {@code flux.publishOn(Schedulers.single()).subscribe() }
	 * 
* *

Discard Support: This operator discards elements it internally queued for backpressure upon cancellation or error triggered by a data signal. * * @param scheduler a {@link Scheduler} providing the {@link Worker} where to publish * @param delayError should the buffer be consumed before forwarding any error * @param prefetch the asynchronous boundary capacity * * @return a {@link Flux} producing asynchronously */ public final Flux publishOn(Scheduler scheduler, boolean delayError, int prefetch) { return publishOn(scheduler, delayError, prefetch, prefetch); } final Flux publishOn(Scheduler scheduler, boolean delayError, int prefetch, int lowTide) { if (this instanceof Callable) { if (this instanceof Fuseable.ScalarCallable) { @SuppressWarnings("unchecked") Fuseable.ScalarCallable s = (Fuseable.ScalarCallable) this; try { return onAssembly(new FluxSubscribeOnValue<>(s.call(), scheduler)); } catch (Exception e) { //leave FluxSubscribeOnCallable defer exception call } } @SuppressWarnings("unchecked") Callable c = (Callable)this; return onAssembly(new FluxSubscribeOnCallable<>(c, scheduler)); } return onAssembly(new FluxPublishOn<>(this, scheduler, delayError, prefetch, lowTide, Queues.get(prefetch))); } /** * Reduce the values from this {@link Flux} sequence into a single object of the same * type than the emitted items. Reduction is performed using a {@link BiFunction} that * takes the intermediate result of the reduction and the current value and returns * the next intermediate value of the reduction. Note, {@link BiFunction} will not * be invoked for a sequence with 0 or 1 elements. In case of one element's * sequence, the result will be directly sent to the subscriber. * *

* * *

Discard Support: This operator discards the internally accumulated value upon cancellation or error. * * @param aggregator the reducing {@link BiFunction} * * @return a reduced {@link Flux} */ public final Mono reduce(BiFunction aggregator) { if (this instanceof Callable){ @SuppressWarnings("unchecked") Callable thiz = (Callable)this; return Mono.onAssembly(wrapToMono(thiz)); } return Mono.onAssembly(new MonoReduce<>(this, aggregator)); } /** * Reduce the values from this {@link Flux} sequence into a single object matching the * type of a seed value. Reduction is performed using a {@link BiFunction} that * takes the intermediate result of the reduction and the current value and returns * the next intermediate value of the reduction. First element is paired with the seed * value, {@literal initial}. * *

* * *

Discard Support: This operator discards the internally accumulated value upon cancellation or error. * * @param accumulator the reducing {@link BiFunction} * @param initial the seed, the initial leftmost argument to pass to the reducing {@link BiFunction} * @param the type of the seed and the reduced object * * @return a reduced {@link Flux} * */ public final Mono reduce(A initial, BiFunction accumulator) { return reduceWith(() -> initial, accumulator); } /** * Reduce the values from this {@link Flux} sequence into a single object matching the * type of a lazily supplied seed value. Reduction is performed using a * {@link BiFunction} that takes the intermediate result of the reduction and the * current value and returns the next intermediate value of the reduction. First * element is paired with the seed value, supplied via {@literal initial}. * *

* * *

Discard Support: This operator discards the internally accumulated value upon cancellation or error. * * @param accumulator the reducing {@link BiFunction} * @param initial a {@link Supplier} of the seed, called on subscription and passed to the the reducing {@link BiFunction} * @param the type of the seed and the reduced object * * @return a reduced {@link Flux} * */ public final Mono reduceWith(Supplier initial, BiFunction accumulator) { return Mono.onAssembly(new MonoReduceSeed<>(this, initial, accumulator)); } /** * Repeatedly and indefinitely subscribe to the source upon completion of the * previous subscription. * *

* * * @return an indefinitely repeated {@link Flux} on onComplete */ public final Flux repeat() { return repeat(ALWAYS_BOOLEAN_SUPPLIER); } /** * Repeatedly subscribe to the source if the predicate returns true after completion of the previous subscription. * *

* * * @param predicate the boolean to evaluate on onComplete. * * @return a {@link Flux} that repeats on onComplete while the predicate matches */ public final Flux repeat(BooleanSupplier predicate) { return onAssembly(new FluxRepeatPredicate<>(this, predicate)); } /** * Repeatedly subscribe to the source {@code numRepeat} times. This results in * {@code numRepeat + 1} total subscriptions to the original source. As a consequence, * using 0 plays the original sequence once. * *

* * * @param numRepeat the number of times to re-subscribe on onComplete (positive, or 0 for original sequence only) * * @return a {@link Flux} that repeats on onComplete, up to the specified number of repetitions */ public final Flux repeat(long numRepeat) { if(numRepeat == 0L){ return this; } return onAssembly(new FluxRepeat<>(this, numRepeat)); } /** * Repeatedly subscribe to the source if the predicate returns true after completion of the previous * subscription. A specified maximum of repeat will limit the number of re-subscribe. * *

* * * @param numRepeat the number of times to re-subscribe on complete (positive, or 0 for original sequence only) * @param predicate the boolean to evaluate on onComplete * * @return a {@link Flux} that repeats on onComplete while the predicate matches, * up to the specified number of repetitions */ public final Flux repeat(long numRepeat, BooleanSupplier predicate) { if (numRepeat < 0L) { throw new IllegalArgumentException("numRepeat >= 0 required"); } if (numRepeat == 0) { return this; } return defer( () -> repeat(countingBooleanSupplier(predicate, numRepeat))); } /** * Repeatedly subscribe to this {@link Flux} when a companion sequence emits elements in * response to the flux completion signal. Any terminal signal from the companion * sequence will terminate the resulting {@link Flux} with the same signal immediately. *

If the companion sequence signals when this {@link Flux} is active, the repeat * attempt is suppressed. *

* *

* Note that if the companion {@link Publisher} created by the {@code repeatFactory} * emits {@link Context} as trigger objects, these {@link Context} will be merged with * the previous Context: *


	 * .repeatWhen(emittedEachAttempt -> emittedEachAttempt.handle((lastEmitted, sink) -> {
	 * 	    Context ctx = sink.currentContext();
	 * 	    int rl = ctx.getOrDefault("repeatsLeft", 0);
	 * 	    if (rl > 0) {
	 *		    sink.next(Context.of(
	 *		        "repeatsLeft", rl - 1,
	 *		        "emitted", lastEmitted
	 *		    ));
	 * 	    } else {
	 * 	        sink.error(new IllegalStateException("repeats exhausted"));
	 * 	    }
	 * }))
	 * 
* * @param repeatFactory the {@link Function} that returns the associated {@link Publisher} * companion, given a {@link Flux} that signals each onComplete as a {@link Long} * representing the number of source elements emitted in the latest attempt. * * @return a {@link Flux} that repeats on onComplete when the companion {@link Publisher} produces an * onNext signal */ public final Flux repeatWhen(Function, ? extends Publisher> repeatFactory) { return onAssembly(new FluxRepeatWhen<>(this, repeatFactory)); } /** * Turn this {@link Flux} into a hot source and cache last emitted signals for further {@link Subscriber}. Will * retain an unbounded amount of onNext signals. Completion and Error will also be * replayed. *

* * * @return a replaying {@link ConnectableFlux} */ public final ConnectableFlux replay() { return replay(Integer.MAX_VALUE); } /** * Turn this {@link Flux} into a connectable hot source and cache last emitted * signals for further {@link Subscriber}. * Will retain up to the given history size onNext signals. Completion and Error will also be * replayed. *

* Note that {@code cache(0)} will only cache the terminal signal without * expiration. * *

* * * @param history number of events retained in history excluding complete and * error * * @return a replaying {@link ConnectableFlux} * */ public final ConnectableFlux replay(int history) { if (history == 0) { //TODO Flux.replay with history == 0 doesn't make much sense. This was replaced by Flux.publish, but such calls will be rejected in a future version return onAssembly(new FluxPublish<>(this, Queues.SMALL_BUFFER_SIZE, Queues.get(Queues.SMALL_BUFFER_SIZE))); } return onAssembly(new FluxReplay<>(this, history, 0L, null)); } /** * Turn this {@link Flux} into a connectable hot source and cache last emitted signals * for further {@link Subscriber}. Will retain each onNext up to the given per-item * expiry timeout. *

* Completion and Error will also be replayed until {@code ttl} triggers in which case * the next {@link Subscriber} will start over a new subscription * *

* * * @param ttl Per-item and post termination timeout duration * * @return a replaying {@link ConnectableFlux} */ public final ConnectableFlux replay(Duration ttl) { return replay(Integer.MAX_VALUE, ttl); } /** * Turn this {@link Flux} into a connectable hot source and cache last emitted signals * for further {@link Subscriber}. Will retain up to the given history size onNext * signals with a per-item ttl. *

* Completion and Error will also be replayed until {@code ttl} triggers in which case * the next {@link Subscriber} will start over a new subscription * *

* * * @param history number of events retained in history excluding complete and error * @param ttl Per-item and post termination timeout duration * * @return a replaying {@link ConnectableFlux} */ public final ConnectableFlux replay(int history, Duration ttl) { return replay(history, ttl, Schedulers.parallel()); } /** * Turn this {@link Flux} into a connectable hot source and cache last emitted signals * for further {@link Subscriber}. Will retain onNext signal for up to the given * {@link Duration} with a per-item ttl. *

* Completion and Error will also be replayed until {@code ttl} triggers in which case * the next {@link Subscriber} will start over a new subscription *

* * * @param ttl Per-item and post termination timeout duration * @param timer a time-capable {@link Scheduler} instance to read current time from * * @return a replaying {@link ConnectableFlux} */ public final ConnectableFlux replay(Duration ttl, Scheduler timer) { return replay(Integer.MAX_VALUE, ttl, timer); } /** * Turn this {@link Flux} into a connectable hot source and cache last emitted signals * for further {@link Subscriber}. Will retain up to the given history size onNext * signals with a per-item ttl. *

* Completion and Error will also be replayed until {@code ttl} triggers in which case * the next {@link Subscriber} will start over a new subscription *

* * * @param history number of events retained in history excluding complete and error * @param ttl Per-item and post termination timeout duration * @param timer a {@link Scheduler} instance to read current time from * * @return a replaying {@link ConnectableFlux} */ public final ConnectableFlux replay(int history, Duration ttl, Scheduler timer) { Objects.requireNonNull(timer, "timer"); if (history == 0) { //TODO Flux.replay with history == 0 doesn't make much sense. This was replaced by Flux.publish, but such calls will be rejected in a future version return onAssembly(new FluxPublish<>(this, Queues.SMALL_BUFFER_SIZE, Queues.get(Queues.SMALL_BUFFER_SIZE))); } return onAssembly(new FluxReplay<>(this, history, ttl.toNanos(), timer)); } /** * Re-subscribes to this {@link Flux} sequence if it signals any error, indefinitely. *

* * * @return a {@link Flux} that retries on onError */ public final Flux retry() { return retry(Long.MAX_VALUE); } /** * Re-subscribes to this {@link Flux} sequence if it signals any error, for a fixed * number of times. *

* Note that passing {@literal Long.MAX_VALUE} is treated as infinite retry. *

* * * @param numRetries the number of times to tolerate an error * * @return a {@link Flux} that retries on onError up to the specified number of retry attempts. * */ public final Flux retry(long numRetries) { return onAssembly(new FluxRetry<>(this, numRetries)); } /** * Retries this {@link Flux} in response to signals emitted by a companion {@link Publisher}. * The companion is generated by the provided {@link Retry} instance, see {@link Retry#max(long)}, {@link Retry#maxInARow(long)} * and {@link Retry#backoff(long, Duration)} for readily available strategy builders. *

* The operator generates a base for the companion, a {@link Flux} of {@link reactor.util.retry.Retry.RetrySignal} * which each give metadata about each retryable failure whenever this {@link Flux} signals an error. The final companion * should be derived from that base companion and emit data in response to incoming onNext (although it can emit less * elements, or delay the emissions). *

* Terminal signals in the companion terminate the sequence with the same signal, so emitting an {@link Subscriber#onError(Throwable)} * will fail the resulting {@link Flux} with that same error. *

* *

* Note that the {@link reactor.util.retry.Retry.RetrySignal} state can be * transient and change between each source * {@link org.reactivestreams.Subscriber#onError(Throwable) onError} or * {@link org.reactivestreams.Subscriber#onNext(Object) onNext}. If processed with a delay, * this could lead to the represented state being out of sync with the state at which the retry * was evaluated. Map it to {@link reactor.util.retry.Retry.RetrySignal#copy()} * right away to mediate this. *

* Note that if the companion {@link Publisher} created by the {@code whenFactory} * emits {@link Context} as trigger objects, these {@link Context} will be merged with * the previous Context: *

	 * {@code
	 * Retry customStrategy = Retry.from(companion -> companion.handle((retrySignal, sink) -> {
	 * 	    Context ctx = sink.currentContext();
	 * 	    int rl = ctx.getOrDefault("retriesLeft", 0);
	 * 	    if (rl > 0) {
	 *		    sink.next(Context.of(
	 *		        "retriesLeft", rl - 1,
	 *		        "lastError", retrySignal.failure()
	 *		    ));
	 * 	    } else {
	 * 	        sink.error(Exceptions.retryExhausted("retries exhausted", retrySignal.failure()));
	 * 	    }
	 * }));
	 * Flux retried = originalFlux.retryWhen(customStrategy);
	 * }
*
* * @param retrySpec the {@link Retry} strategy that will generate the companion {@link Publisher}, * given a {@link Flux} that signals each onError as a {@link reactor.util.retry.Retry.RetrySignal}. * * @return a {@link Flux} that retries on onError when a companion {@link Publisher} produces an onNext signal * @see reactor.util.retry.Retry#max(long) * @see reactor.util.retry.Retry#maxInARow(long) * @see reactor.util.retry.Retry#backoff(long, Duration) */ public final Flux retryWhen(Retry retrySpec) { return onAssembly(new FluxRetryWhen<>(this, retrySpec)); } /** * Sample this {@link Flux} by periodically emitting an item corresponding to that * {@link Flux} latest emitted value within the periodical time window. * Note that if some elements are emitted quicker than the timespan just before source * completion, the last of these elements will be emitted along with the onComplete * signal. * *

* * *

Discard Support: This operator discards elements that are not part of the sampling. * * @param timespan the duration of the window after which to emit the latest observed item * * @return a {@link Flux} sampled to the last item seen over each periodic window */ public final Flux sample(Duration timespan) { return sample(interval(timespan)); } /** * Sample this {@link Flux} by emitting an item corresponding to that {@link Flux} * latest emitted value whenever a companion sampler {@link Publisher} signals a value. *

* Termination of either {@link Publisher} will result in termination for the {@link Subscriber} * as well. * Note that if some elements are emitted just before source completion and before a * last sampler can trigger, the last of these elements will be emitted along with the * onComplete signal. *

* Both {@link Publisher} will run in unbounded mode because the backpressure * would interfere with the sampling precision. * *

* * *

Discard Support: This operator discards elements that are not part of the sampling. * * @param sampler the sampler companion {@link Publisher} * * @param the type of the sampler sequence * * @return a {@link Flux} sampled to the last item observed each time the sampler {@link Publisher} signals */ public final Flux sample(Publisher sampler) { return onAssembly(new FluxSample<>(this, sampler)); } /** * Repeatedly take a value from this {@link Flux} then skip the values that follow * within a given duration. * *

* * *

Discard Support: This operator discards elements that are not part of the sampling. * * @param timespan the duration during which to skip values after each sample * * @return a {@link Flux} sampled to the first item of each duration-based window */ public final Flux sampleFirst(Duration timespan) { return sampleFirst(t -> Mono.delay(timespan)); } /** * Repeatedly take a value from this {@link Flux} then skip the values that follow * before the next signal from a companion sampler {@link Publisher}. * *

* * *

Discard Support: This operator discards elements that are not part of the sampling. * * @param samplerFactory supply a companion sampler {@link Publisher} which signals the end of the skip window * @param the companion reified type * * @return a {@link Flux} sampled to the first item observed in each window closed by the sampler signals */ public final Flux sampleFirst(Function> samplerFactory) { return onAssembly(new FluxSampleFirst<>(this, samplerFactory)); } /** * Emit the latest value from this {@link Flux} only if there were no new values emitted * during the window defined by a companion {@link Publisher} derived from that particular * value. *

* Note that this means that the last value in the sequence is always emitted. * *

* * *

Discard Support: This operator discards elements that are not part of the sampling. * * @param throttlerFactory supply a companion sampler {@link Publisher} which signals * the end of the window during which no new emission should occur. If it is the case, * the original value triggering the window is emitted. * @param the companion reified type * * @return a {@link Flux} sampled to items not followed by any other item within a window * defined by a companion {@link Publisher} */ public final Flux sampleTimeout(Function> throttlerFactory) { return sampleTimeout(throttlerFactory, Queues.XS_BUFFER_SIZE); } /** * Emit the latest value from this {@link Flux} only if there were no new values emitted * during the window defined by a companion {@link Publisher} derived from that particular * value. *

The provided {@literal maxConcurrency} will keep a bounded maximum of concurrent timeouts and drop any new * items until at least one timeout terminates. *

* Note that this means that the last value in the sequence is always emitted. * *

* * *

Discard Support: This operator discards elements that are not part of the sampling. * * @param throttlerFactory supply a companion sampler {@link Publisher} which signals * the end of the window during which no new emission should occur. If it is the case, * the original value triggering the window is emitted. * @param maxConcurrency the maximum number of concurrent timeouts * @param the throttling type * * @return a {@link Flux} sampled to items not followed by any other item within a window * defined by a companion {@link Publisher} */ //FIXME re-evaluate the wording on maxConcurrency, seems more related to request/buffering. If so redo the marble public final Flux sampleTimeout(Function> throttlerFactory, int maxConcurrency) { return onAssembly(new FluxSampleTimeout<>(this, throttlerFactory, Queues.get(maxConcurrency))); } /** * Reduce this {@link Flux} values with an accumulator {@link BiFunction} and * also emit the intermediate results of this function. *

* Unlike {@link #scan(Object, BiFunction)}, this operator doesn't take an initial value * but treats the first {@link Flux} value as initial value. *
* The accumulation works as follows: *


	 * result[0] = source[0]
	 * result[1] = accumulator(result[0], source[1])
	 * result[2] = accumulator(result[1], source[2])
	 * result[3] = accumulator(result[2], source[3])
	 * ...
	 * 
* *

* * * @param accumulator the accumulating {@link BiFunction} * * @return an accumulating {@link Flux} */ public final Flux scan(BiFunction accumulator) { return onAssembly(new FluxScan<>(this, accumulator)); } /** * Reduce this {@link Flux} values with an accumulator {@link BiFunction} and * also emit the intermediate results of this function. *

* The accumulation works as follows: *


	 * result[0] = initialValue;
	 * result[1] = accumulator(result[0], source[0])
	 * result[2] = accumulator(result[1], source[1])
	 * result[3] = accumulator(result[2], source[2])
	 * ...
	 * 
* *

* * * @param initial the initial leftmost argument to pass to the reduce function * @param accumulator the accumulating {@link BiFunction} * @param the accumulated type * * @return an accumulating {@link Flux} starting with initial state * */ public final Flux scan(A initial, BiFunction accumulator) { Objects.requireNonNull(initial, "seed"); return scanWith(() -> initial, accumulator); } /** * Reduce this {@link Flux} values with the help of an accumulator {@link BiFunction} * and also emits the intermediate results. A seed value is lazily provided by a * {@link Supplier} invoked for each {@link Subscriber}. *

* The accumulation works as follows: *


	 * result[0] = initialValue;
	 * result[1] = accumulator(result[0], source[0])
	 * result[2] = accumulator(result[1], source[1])
	 * result[3] = accumulator(result[2], source[2])
	 * ...
	 * 
* *

* * * @param initial the supplier providing the seed, the leftmost parameter initially * passed to the reduce function * @param accumulator the accumulating {@link BiFunction} * @param the accumulated type * * @return an accumulating {@link Flux} starting with initial state * */ public final Flux scanWith(Supplier initial, BiFunction accumulator) { return onAssembly(new FluxScanSeed<>(this, initial, accumulator)); } /** * Returns a new {@link Flux} that multicasts (shares) the original {@link Flux}. * As long as there is at least one {@link Subscriber} this {@link Flux} will be subscribed and * emitting data. * When all subscribers have cancelled it will cancel the source * {@link Flux}. *

This is an alias for {@link #publish()}.{@link ConnectableFlux#refCount()}. * * @return a {@link Flux} that upon first subscribe causes the source {@link Flux} * to subscribe once, late subscribers might therefore miss items. */ public final Flux share() { return onAssembly(new FluxRefCount<>( new FluxPublish<>(this, Queues.SMALL_BUFFER_SIZE, Queues.small()), 1) ); } /** * Prepare a {@link Mono} which shares this {@link Flux} sequence and dispatches the * first observed item to subscribers. * This will effectively turn any type of sequence into a hot sequence when the first * {@link Subscriber} subscribes. *

* * * @return a new {@link Mono} */ public final Mono shareNext() { final NextProcessor nextProcessor = new NextProcessor<>(this); return Mono.onAssembly(nextProcessor); } /** * Expect and emit a single item from this {@link Flux} source or signal * {@link java.util.NoSuchElementException} for an empty source, or * {@link IndexOutOfBoundsException} for a source with more than one element. * *

* * * @return a {@link Mono} with the single item or an error signal */ public final Mono single() { if (this instanceof Callable) { if (this instanceof Fuseable.ScalarCallable) { @SuppressWarnings("unchecked") Fuseable.ScalarCallable scalarCallable = (Fuseable.ScalarCallable) this; T v; try { v = scalarCallable.call(); } catch (Exception e) { return Mono.error(Exceptions.unwrap(e)); } if (v == null) { return Mono.error(new NoSuchElementException("Source was a (constant) empty")); } return Mono.just(v); } @SuppressWarnings("unchecked") Callable thiz = (Callable)this; return Mono.onAssembly(new MonoSingleCallable<>(thiz)); } return Mono.onAssembly(new MonoSingle<>(this)); } /** * Expect and emit a single item from this {@link Flux} source and emit a default * value for an empty source, but signal an {@link IndexOutOfBoundsException} for a * source with more than one element. * *

* * * @param defaultValue a single fallback item if this {@link Flux} is empty * * @return a {@link Mono} with the expected single item, the supplied default value or * an error signal */ public final Mono single(T defaultValue) { if (this instanceof Callable) { if (this instanceof Fuseable.ScalarCallable) { @SuppressWarnings("unchecked") Fuseable.ScalarCallable scalarCallable = (Fuseable.ScalarCallable) this; T v; try { v = scalarCallable.call(); } catch (Exception e) { return Mono.error(Exceptions.unwrap(e)); } if (v == null) { return Mono.just(defaultValue); } return Mono.just(v); } @SuppressWarnings("unchecked") Callable thiz = (Callable)this; return Mono.onAssembly(new MonoSingleCallable<>(thiz, defaultValue)); } return Mono.onAssembly(new MonoSingle<>(this, defaultValue, false)); } /** * Expect and emit a single item from this {@link Flux} source, and accept an empty * source but signal an {@link IndexOutOfBoundsException} for a source with more than * one element. *

* * * @return a {@link Mono} with the expected single item, no item or an error */ public final Mono singleOrEmpty() { if (this instanceof Callable) { @SuppressWarnings("unchecked") Callable thiz = (Callable)this; return Mono.onAssembly(wrapToMono(thiz)); } return Mono.onAssembly(new MonoSingle<>(this, null, true)); } /** * Skip the specified number of elements from the beginning of this {@link Flux} then * emit the remaining elements. * *

* * *

Discard Support: This operator discards elements that are skipped. * * @param skipped the number of elements to drop * * @return a dropping {@link Flux} with the specified number of elements skipped at * the beginning */ public final Flux skip(long skipped) { if (skipped == 0L) { return this; } else { return onAssembly(new FluxSkip<>(this, skipped)); } } /** * Skip elements from this {@link Flux} emitted within the specified initial duration. * *

* * *

Discard Support: This operator discards elements that are skipped. * * @param timespan the initial time window during which to drop elements * * @return a {@link Flux} dropping at the beginning until the end of the given duration */ public final Flux skip(Duration timespan) { return skip(timespan, Schedulers.parallel()); } /** * Skip elements from this {@link Flux} emitted within the specified initial duration, * as measured on the provided {@link Scheduler}. * *

* * *

Discard Support: This operator discards elements that are skipped. * * @param timespan the initial time window during which to drop elements * @param timer a time-capable {@link Scheduler} instance to measure the time window on * * @return a {@link Flux} dropping at the beginning for the given duration */ public final Flux skip(Duration timespan, Scheduler timer) { if(!timespan.isZero()) { return skipUntilOther(Mono.delay(timespan, timer)); } else{ return this; } } /** * Skip a specified number of elements at the end of this {@link Flux} sequence. * *

* * *

Discard Support: This operator discards elements that are skipped. * * @param n the number of elements to drop before completion * * @return a {@link Flux} dropping the specified number of elements at the end of the * sequence * */ public final Flux skipLast(int n) { if (n == 0) { return this; } return onAssembly(new FluxSkipLast<>(this, n)); } /** * Skips values from this {@link Flux} until a {@link Predicate} returns true for the * value. The resulting {@link Flux} will include and emit the matching value. * *

* * *

Discard Support: This operator discards elements that are skipped. * * @param untilPredicate the {@link Predicate} evaluated to stop skipping. * * @return a {@link Flux} dropping until the {@link Predicate} matches */ public final Flux skipUntil(Predicate untilPredicate) { return onAssembly(new FluxSkipUntil<>(this, untilPredicate)); } /** * Skip values from this {@link Flux} until a specified {@link Publisher} signals * an onNext or onComplete. * *

* * *

Discard Support: This operator discards elements that are skipped. * * @param other the companion {@link Publisher} to coordinate with to stop skipping * * @return a {@link Flux} dropping until the other {@link Publisher} emits * */ public final Flux skipUntilOther(Publisher other) { return onAssembly(new FluxSkipUntilOther<>(this, other)); } /** * Skips values from this {@link Flux} while a {@link Predicate} returns true for the value. * *

* * *

Discard Support: This operator discards elements that are skipped. * * @param skipPredicate the {@link Predicate} that causes skipping while evaluating to true. * * @return a {@link Flux} dropping while the {@link Predicate} matches */ public final Flux skipWhile(Predicate skipPredicate) { return onAssembly(new FluxSkipWhile<>(this, skipPredicate)); } /** * Sort elements from this {@link Flux} by collecting and sorting them in the background * then emitting the sorted sequence once this sequence completes. * Each item emitted by the {@link Flux} must implement {@link Comparable} with * respect to all other items in the sequence. * *

Note that calling {@code sort} with long, non-terminating or infinite sources * might cause {@link OutOfMemoryError}. Use sequence splitting like {@link #window} to sort batches in that case. *

* * * @throws ClassCastException if any item emitted by the {@link Flux} does not implement * {@link Comparable} with respect to all other items emitted by the {@link Flux} * @return a sorted {@link Flux} */ public final Flux sort(){ return collectSortedList().flatMapIterable(identityFunction()); } /** * Sort elements from this {@link Flux} using a {@link Comparator} function, by * collecting and sorting elements in the background then emitting the sorted sequence * once this sequence completes. * *

Note that calling {@code sort} with long, non-terminating or infinite sources * might cause {@link OutOfMemoryError} *

* * * @param sortFunction a function that compares two items emitted by this {@link Flux} * to indicate their sort order * @return a sorted {@link Flux} */ public final Flux sort(Comparator sortFunction) { return collectSortedList(sortFunction).flatMapIterable(identityFunction()); } /** * Prepend the given {@link Iterable} before this {@link Flux} sequence. * *

* * * @param iterable the sequence of values to start the resulting {@link Flux} with * * @return a new {@link Flux} prefixed with elements from an {@link Iterable} */ public final Flux startWith(Iterable iterable) { return startWith(fromIterable(iterable)); } /** * Prepend the given values before this {@link Flux} sequence. * *

* * * @param values the array of values to start the resulting {@link Flux} with * * @return a new {@link Flux} prefixed with the given elements */ @SafeVarargs public final Flux startWith(T... values) { return startWith(just(values)); } /** * Prepend the given {@link Publisher} sequence to this {@link Flux} sequence. * *

* * * @param publisher the Publisher whose values to prepend * * @return a new {@link Flux} prefixed with the given {@link Publisher} sequence */ public final Flux startWith(Publisher publisher) { if (this instanceof FluxConcatArray) { FluxConcatArray fluxConcatArray = (FluxConcatArray) this; return fluxConcatArray.concatAdditionalSourceFirst(publisher); } return concat(publisher, this); } /** * Subscribe to this {@link Flux} and request unbounded demand. *

* This version doesn't specify any consumption behavior for the events from the * chain, especially no error handling, so other variants should usually be preferred. * *

* * * @return a new {@link Disposable} that can be used to cancel the underlying {@link Subscription} */ public final Disposable subscribe() { return subscribe(null, null, null); } /** * Subscribe a {@link Consumer} to this {@link Flux} that will consume all the * elements in the sequence. It will request an unbounded demand ({@code Long.MAX_VALUE}). *

* For a passive version that observe and forward incoming data see {@link #doOnNext(java.util.function.Consumer)}. *

* For a version that gives you more control over backpressure and the request, see * {@link #subscribe(Subscriber)} with a {@link BaseSubscriber}. *

* Keep in mind that since the sequence can be asynchronous, this will immediately * return control to the calling thread. This can give the impression the consumer is * not invoked when executing in a main thread or a unit test for instance. * *

* * * @param consumer the consumer to invoke on each value (onNext signal) * * @return a new {@link Disposable} that can be used to cancel the underlying {@link Subscription} */ public final Disposable subscribe(Consumer consumer) { Objects.requireNonNull(consumer, "consumer"); return subscribe(consumer, null, null); } /** * Subscribe to this {@link Flux} with a {@link Consumer} that will consume all the * elements in the sequence, as well as a {@link Consumer} that will handle errors. * The subscription will request an unbounded demand ({@code Long.MAX_VALUE}). *

* For a passive version that observe and forward incoming data see * {@link #doOnNext(java.util.function.Consumer)} and {@link #doOnError(java.util.function.Consumer)}. *

For a version that gives you more control over backpressure and the request, see * {@link #subscribe(Subscriber)} with a {@link BaseSubscriber}. *

* Keep in mind that since the sequence can be asynchronous, this will immediately * return control to the calling thread. This can give the impression the consumers are * not invoked when executing in a main thread or a unit test for instance. * *

* * * @param consumer the consumer to invoke on each next signal * @param errorConsumer the consumer to invoke on error signal * * @return a new {@link Disposable} that can be used to cancel the underlying {@link Subscription} */ public final Disposable subscribe(@Nullable Consumer consumer, Consumer errorConsumer) { Objects.requireNonNull(errorConsumer, "errorConsumer"); return subscribe(consumer, errorConsumer, null); } /** * Subscribe {@link Consumer} to this {@link Flux} that will respectively consume all the * elements in the sequence, handle errors and react to completion. The subscription * will request unbounded demand ({@code Long.MAX_VALUE}). *

* For a passive version that observe and forward incoming data see {@link #doOnNext(java.util.function.Consumer)}, * {@link #doOnError(java.util.function.Consumer)} and {@link #doOnComplete(Runnable)}. *

For a version that gives you more control over backpressure and the request, see * {@link #subscribe(Subscriber)} with a {@link BaseSubscriber}. *

* Keep in mind that since the sequence can be asynchronous, this will immediately * return control to the calling thread. This can give the impression the consumer is * not invoked when executing in a main thread or a unit test for instance. * *

* * * @param consumer the consumer to invoke on each value * @param errorConsumer the consumer to invoke on error signal * @param completeConsumer the consumer to invoke on complete signal * * @return a new {@link Disposable} that can be used to cancel the underlying {@link Subscription} */ public final Disposable subscribe( @Nullable Consumer consumer, @Nullable Consumer errorConsumer, @Nullable Runnable completeConsumer) { return subscribe(consumer, errorConsumer, completeConsumer, (Context) null); } /** * Subscribe {@link Consumer} to this {@link Flux} that will respectively consume all the * elements in the sequence, handle errors, react to completion, and request upon subscription. * It will let the provided {@link Subscription subscriptionConsumer} * request the adequate amount of data, or request unbounded demand * {@code Long.MAX_VALUE} if no such consumer is provided. *

* For a passive version that observe and forward incoming data see {@link #doOnNext(java.util.function.Consumer)}, * {@link #doOnError(java.util.function.Consumer)}, {@link #doOnComplete(Runnable)} * and {@link #doOnSubscribe(Consumer)}. *

For a version that gives you more control over backpressure and the request, see * {@link #subscribe(Subscriber)} with a {@link BaseSubscriber}. *

* Keep in mind that since the sequence can be asynchronous, this will immediately * return control to the calling thread. This can give the impression the consumer is * not invoked when executing in a main thread or a unit test for instance. * *

* * * @param consumer the consumer to invoke on each value * @param errorConsumer the consumer to invoke on error signal * @param completeConsumer the consumer to invoke on complete signal * @param subscriptionConsumer the consumer to invoke on subscribe signal, to be used * for the initial {@link Subscription#request(long) request}, or null for max request * * @return a new {@link Disposable} that can be used to cancel the underlying {@link Subscription} * @deprecated Because users tend to forget to {@link Subscription#request(long) request} the subsciption. If * the behavior is really needed, consider using {@link #subscribeWith(Subscriber)}. To be removed in 3.5. */ @Deprecated public final Disposable subscribe( @Nullable Consumer consumer, @Nullable Consumer errorConsumer, @Nullable Runnable completeConsumer, @Nullable Consumer subscriptionConsumer) { return subscribeWith(new LambdaSubscriber<>(consumer, errorConsumer, completeConsumer, subscriptionConsumer, null)); } /** * Subscribe {@link Consumer} to this {@link Flux} that will respectively consume all the * elements in the sequence, handle errors and react to completion. Additionally, a {@link Context} * is tied to the subscription. At subscription, an unbounded request is implicitly made. *

* For a passive version that observe and forward incoming data see {@link #doOnNext(java.util.function.Consumer)}, * {@link #doOnError(java.util.function.Consumer)}, {@link #doOnComplete(Runnable)} * and {@link #doOnSubscribe(Consumer)}. *

For a version that gives you more control over backpressure and the request, see * {@link #subscribe(Subscriber)} with a {@link BaseSubscriber}. *

* Keep in mind that since the sequence can be asynchronous, this will immediately * return control to the calling thread. This can give the impression the consumer is * not invoked when executing in a main thread or a unit test for instance. * *

* * * @param consumer the consumer to invoke on each value * @param errorConsumer the consumer to invoke on error signal * @param completeConsumer the consumer to invoke on complete signal * @param initialContext the base {@link Context} tied to the subscription that will * be visible to operators upstream * * @return a new {@link Disposable} that can be used to cancel the underlying {@link Subscription} */ public final Disposable subscribe( @Nullable Consumer consumer, @Nullable Consumer errorConsumer, @Nullable Runnable completeConsumer, @Nullable Context initialContext) { return subscribeWith(new LambdaSubscriber<>(consumer, errorConsumer, completeConsumer, null, initialContext)); } @Override @SuppressWarnings("unchecked") public final void subscribe(Subscriber actual) { CorePublisher publisher = Operators.onLastAssembly(this); CoreSubscriber subscriber = Operators.toCoreSubscriber(actual); try { if (publisher instanceof OptimizableOperator) { OptimizableOperator operator = (OptimizableOperator) publisher; while (true) { subscriber = operator.subscribeOrReturn(subscriber); if (subscriber == null) { // null means "I will subscribe myself", returning... return; } OptimizableOperator newSource = operator.nextOptimizableSource(); if (newSource == null) { publisher = operator.source(); break; } operator = newSource; } } publisher.subscribe(subscriber); } catch (Throwable e) { Operators.reportThrowInSubscribe(subscriber, e); return; } } /** * An internal {@link Publisher#subscribe(Subscriber)} that will bypass * {@link Hooks#onLastOperator(Function)} pointcut. *

* In addition to behave as expected by {@link Publisher#subscribe(Subscriber)} * in a controlled manner, it supports direct subscribe-time {@link Context} passing. * * @param actual the {@link Subscriber} interested into the published sequence * @see Flux#subscribe(Subscriber) */ public abstract void subscribe(CoreSubscriber actual); /** * Enrich a potentially empty downstream {@link Context} by adding all values * from the given {@link Context}, producing a new {@link Context} that is propagated * upstream. *

* The {@link Context} propagation happens once per subscription (not on each onNext): * it is done during the {@code subscribe(Subscriber)} phase, which runs from * the last operator of a chain towards the first. *

* So this operator enriches a {@link Context} coming from under it in the chain * (downstream, by default an empty one) and makes the new enriched {@link Context} * visible to operators above it in the chain. * * @param mergeContext the {@link Context} to merge with a previous {@link Context} * state, returning a new one. * * @return a contextualized {@link Flux} * @see Context * @deprecated Use {@link #contextWrite(ContextView)} instead. To be removed in 3.5.0. */ @Deprecated public final Flux subscriberContext(Context mergeContext) { return subscriberContext(c -> c.putAll(mergeContext.readOnly())); } /** * Enrich a potentially empty downstream {@link Context} by applying a {@link Function} * to it, producing a new {@link Context} that is propagated upstream. *

* The {@link Context} propagation happens once per subscription (not on each onNext): * it is done during the {@code subscribe(Subscriber)} phase, which runs from * the last operator of a chain towards the first. *

* So this operator enriches a {@link Context} coming from under it in the chain * (downstream, by default an empty one) and makes the new enriched {@link Context} * visible to operators above it in the chain. * * @param doOnContext the function taking a previous {@link Context} state * and returning a new one. * * @return a contextualized {@link Flux} * @see Context * @deprecated Use {@link #contextWrite(Function)} instead. To be removed in 3.5.0. */ @Deprecated public final Flux subscriberContext(Function doOnContext) { return contextWrite(doOnContext); } /** * Run subscribe, onSubscribe and request on a specified {@link Scheduler}'s {@link Worker}. * As such, placing this operator anywhere in the chain will also impact the execution * context of onNext/onError/onComplete signals from the beginning of the chain up to * the next occurrence of a {@link #publishOn(Scheduler) publishOn}. *

* Note that if you are using an eager or blocking * {@link #create(Consumer, FluxSink.OverflowStrategy)} * as the source, it can lead to deadlocks due to requests piling up behind the emitter. * In such case, you should call {@link #subscribeOn(Scheduler, boolean) subscribeOn(scheduler, false)} * instead. *

* *

* Typically used for slow publisher e.g., blocking IO, fast consumer(s) scenarios. * *

	 * {@code flux.subscribeOn(Schedulers.single()).subscribe() }
	 * 
* *

* Note that {@link Worker#schedule(Runnable)} raising * {@link java.util.concurrent.RejectedExecutionException} on late * {@link Subscription#request(long)} will be propagated to the request caller. * * @param scheduler a {@link Scheduler} providing the {@link Worker} where to subscribe * * @return a {@link Flux} requesting asynchronously * @see #publishOn(Scheduler) * @see #subscribeOn(Scheduler, boolean) */ public final Flux subscribeOn(Scheduler scheduler) { return subscribeOn(scheduler, true); } /** * Run subscribe and onSubscribe on a specified {@link Scheduler}'s {@link Worker}. * Request will be run on that worker too depending on the {@code requestOnSeparateThread} * parameter (which defaults to true in the {@link #subscribeOn(Scheduler)} version). * As such, placing this operator anywhere in the chain will also impact the execution * context of onNext/onError/onComplete signals from the beginning of the chain up to * the next occurrence of a {@link #publishOn(Scheduler) publishOn}. *

* Note that if you are using an eager or blocking * {@link Flux#create(Consumer, FluxSink.OverflowStrategy)} * as the source, it can lead to deadlocks due to requests piling up behind the emitter. * Thus this operator has a {@code requestOnSeparateThread} parameter, which should be * set to {@code false} in this case. *

* *

* Typically used for slow publisher e.g., blocking IO, fast consumer(s) scenarios. * *

	 * {@code flux.subscribeOn(Schedulers.single()).subscribe() }
	 * 
* *

* Note that {@link Worker#schedule(Runnable)} raising * {@link java.util.concurrent.RejectedExecutionException} on late * {@link Subscription#request(long)} will be propagated to the request caller. * * @param scheduler a {@link Scheduler} providing the {@link Worker} where to subscribe * @param requestOnSeparateThread whether or not to also perform requests on the worker. * {@code true} to behave like {@link #subscribeOn(Scheduler)} * * @return a {@link Flux} requesting asynchronously * @see #publishOn(Scheduler) * @see #subscribeOn(Scheduler) */ public final Flux subscribeOn(Scheduler scheduler, boolean requestOnSeparateThread) { if (this instanceof Callable) { if (this instanceof Fuseable.ScalarCallable) { try { @SuppressWarnings("unchecked") T value = ((Fuseable.ScalarCallable) this).call(); return onAssembly(new FluxSubscribeOnValue<>(value, scheduler)); } catch (Exception e) { //leave FluxSubscribeOnCallable defer error } } @SuppressWarnings("unchecked") Callable c = (Callable)this; return onAssembly(new FluxSubscribeOnCallable<>(c, scheduler)); } return onAssembly(new FluxSubscribeOn<>(this, scheduler, requestOnSeparateThread)); } /** * Subscribe the given {@link Subscriber} to this {@link Flux} and return said * {@link Subscriber} (eg. a {@link FluxProcessor}). * *

	 * {@code flux.subscribeWith(EmitterProcessor.create()).subscribe() }
	 * 
* * If you need more control over backpressure and the request, use a {@link BaseSubscriber}. * * @param subscriber the {@link Subscriber} to subscribe with and return * @param the reified type from the input/output subscriber * * @return the passed {@link Subscriber} */ public final > E subscribeWith(E subscriber) { subscribe(subscriber); return subscriber; } /** * Transform the current {@link Flux} once it emits its first element, making a * conditional transformation possible. This operator first requests one element * from the source then applies a transformation derived from the first {@link Signal} * and the source. The whole source (including the first signal) is passed as second * argument to the {@link BiFunction} and it is very strongly advised to always build * upon with operators (see below). *

* Note that the source might complete or error immediately instead of emitting, * in which case the {@link Signal} would be onComplete or onError. It is NOT * necessarily an onNext Signal, and must be checked accordingly. *

* For example, this operator could be used to define a dynamic transformation that depends * on the first element (which could contain routing metadata for instance): * *

	 * {@code
	 *  fluxOfIntegers.switchOnFirst((signal, flux) -> {
	 *      if (signal.hasValue()) {
	 *          ColoredShape firstColor = signal.get();
	 *          return flux.filter(v -> !v.hasSameColorAs(firstColor))
	 *      }
	 *      return flux; //either early complete or error, this forwards the termination in any case
	 *      //`return flux.onErrorResume(t -> Mono.empty());` instead would suppress an early error
	 *      //`return Flux.just(1,2,3);` instead would suppress an early error and return 1, 2, 3.
	 *      //It would also only cancel the original `flux` at the completion of `just`.
	 *  })
	 * }
	 * 
*

* *

* It is advised to return a {@link Publisher} derived from the original {@link Flux} * in all cases, as not doing so would keep the original {@link Publisher} open and * hanging with a single request until the inner {@link Publisher} terminates or * the whole {@link Flux} is cancelled. * * @param transformer A {@link BiFunction} executed once the first signal is * available and used to transform the source conditionally. The whole source (including * first signal) is passed as second argument to the BiFunction. * @param the item type in the returned {@link Flux} * * @return a new {@link Flux} that transform the upstream once a signal is available */ public final Flux switchOnFirst(BiFunction, Flux, Publisher> transformer) { return switchOnFirst(transformer, true); } /** * Transform the current {@link Flux} once it emits its first element, making a * conditional transformation possible. This operator first requests one element * from the source then applies a transformation derived from the first {@link Signal} * and the source. The whole source (including the first signal) is passed as second * argument to the {@link BiFunction} and it is very strongly advised to always build * upon with operators (see below). *

* Note that the source might complete or error immediately instead of emitting, * in which case the {@link Signal} would be onComplete or onError. It is NOT * necessarily an onNext Signal, and must be checked accordingly. *

* For example, this operator could be used to define a dynamic transformation that depends * on the first element (which could contain routing metadata for instance): * *

	 * {@code
	 *  fluxOfIntegers.switchOnFirst((signal, flux) -> {
	 *      if (signal.hasValue()) {
	 *          ColoredShape firstColor = signal.get();
	 *          return flux.filter(v -> !v.hasSameColorAs(firstColor))
	 *      }
	 *      return flux; //either early complete or error, this forwards the termination in any case
	 *      //`return flux.onErrorResume(t -> Mono.empty());` instead would suppress an early error
	 *      //`return Flux.just(1,2,3);` instead would suppress an early error and return 1, 2, 3.
	 *      //It would also only cancel the original `flux` at the completion of `just`.
	 *  })
	 * }
	 * 
*

* *

* It is advised to return a {@link Publisher} derived from the original {@link Flux} * in all cases, as not doing so would keep the original {@link Publisher} open and * hanging with a single request. In case the value of the {@code cancelSourceOnComplete} parameter is {@code true} the original publisher until the inner {@link Publisher} terminates or * the whole {@link Flux} is cancelled. Otherwise the original publisher will hang forever. * * @param transformer A {@link BiFunction} executed once the first signal is * available and used to transform the source conditionally. The whole source (including * first signal) is passed as second argument to the BiFunction. * @param the item type in the returned {@link Flux} * @param cancelSourceOnComplete specify whether original publisher should be cancelled on {@code onComplete} from the derived one * * @return a new {@link Flux} that transform the upstream once a signal is available */ public final Flux switchOnFirst(BiFunction, Flux, Publisher> transformer, boolean cancelSourceOnComplete) { return onAssembly(new FluxSwitchOnFirst<>(this, transformer, cancelSourceOnComplete)); } /** * Switch to an alternative {@link Publisher} if this sequence is completed without any data. *

* * * @param alternate the alternative {@link Publisher} if this sequence is empty * * @return a new {@link Flux} that falls back on a {@link Publisher} if source is empty */ public final Flux switchIfEmpty(Publisher alternate) { return onAssembly(new FluxSwitchIfEmpty<>(this, alternate)); } /** * Switch to a new {@link Publisher} generated via a {@link Function} whenever * this {@link Flux} produces an item. As such, the elements from each generated * Publisher are emitted in the resulting {@link Flux}. * *

* * * @param fn the {@link Function} to generate a {@link Publisher} for each source value * @param the type of the return value of the transformation function * * @return a new {@link Flux} that emits values from an alternative {@link Publisher} * for each source onNext * */ public final Flux switchMap(Function> fn) { return switchMap(fn, Queues.XS_BUFFER_SIZE); } /** * Switch to a new {@link Publisher} generated via a {@link Function} whenever * this {@link Flux} produces an item. As such, the elements from each generated * Publisher are emitted in the resulting {@link Flux}. * *

* * * @param fn the {@link Function} to generate a {@link Publisher} for each source value * @param prefetch the produced demand for inner sources * * @param the type of the return value of the transformation function * * @return a new {@link Flux} that emits values from an alternative {@link Publisher} * for each source onNext * * @deprecated to be removed in 3.6.0 at the earliest. In 3.5.0, you should replace * calls with prefetch=0 with calls to switchMap(fn), as the default behavior of the * single-parameter variant will then change to prefetch=0. */ @Deprecated public final Flux switchMap(Function> fn, int prefetch) { if (prefetch == 0) { return onAssembly(new FluxSwitchMapNoPrefetch<>(this, fn)); } return onAssembly(new FluxSwitchMap<>(this, fn, Queues.unbounded(prefetch), prefetch)); } /** * Tag this flux with a key/value pair. These can be retrieved as a {@link Set} of * all tags throughout the publisher chain by using {@link Scannable#tags()} (as * traversed * by {@link Scannable#parents()}). *

* Note that some monitoring systems like Prometheus require to have the exact same set of * tags for each meter bearing the same name. * * @param key a tag key * @param value a tag value * * @return the same sequence, but bearing tags * *@see #name(String) *@see #metrics() */ public final Flux tag(String key, String value) { return FluxName.createOrAppend(this, key, value); } /** * Take only the first N values from this {@link Flux}, if available. * If n is zero, the source is subscribed to but immediately cancelled, then the operator completes. *

* *

* Warning: The below behavior will change in 3.5.0 from that of * {@link #take(long, boolean) take(n, false)} to that of {@link #take(long, boolean) take(n, true)}. * See https://github.com/reactor/reactor-core/issues/2339 *

* Note that this operator doesn't propagate the backpressure requested amount. * Rather, it makes an unbounded request and cancels once N elements have been emitted. * As a result, the source could produce a lot of extraneous elements in the meantime. * If that behavior is undesirable and you do not own the request from downstream * (e.g. prefetching operators), consider using {@link #limitRequest(long)} instead. * * @param n the number of items to emit from this {@link Flux} * * @return a {@link Flux} limited to size N * @see #take(long, boolean) */ public final Flux take(long n) { return take(n, false); } /** * Take only the first N values from this {@link Flux}, if available. *

* *

* If {@code limitRequest == true}, ensure that the total amount requested upstream is capped * at {@code n}. In that configuration, this operator never let the upstream produce more elements * than the cap, and it can be used to more strictly adhere to backpressure. * If n is zero, the source isn't even subscribed to and the operator completes immediately * upon subscription. *

* This mode is typically useful for cases where a race between request and cancellation can lead * the upstream to producing a lot of extraneous data, and such a production is undesirable (e.g. * a source that would send the extraneous data over the network). *

* takeLimitRequestFalse *

* If {@code limitRequest == false} this operator doesn't propagate the backpressure requested amount. * Rather, it makes an unbounded request and cancels once N elements have been emitted. * If n is zero, the source is subscribed to but immediately cancelled, then the operator completes * (the behavior inherited from {@link #take(long)}). *

* In this mode, the source could produce a lot of extraneous elements despite cancellation. * If that behavior is undesirable and you do not own the request from downstream * (e.g. prefetching operators), consider using {@code limitRequest = true} instead. * * @param n the number of items to emit from this {@link Flux} * @param limitRequest {@code true} to follow the downstream request more closely and limit the upstream request * to {@code n}. {@code false} to request an unbounded amount from upstream. * * @return a {@link Flux} limited to size N */ public final Flux take(long n, boolean limitRequest) { if (limitRequest) { return onAssembly(new FluxLimitRequest<>(this, n)); } if (this instanceof Fuseable) { return onAssembly(new FluxTakeFuseable<>(this, n)); } return onAssembly(new FluxTake<>(this, n)); } /** * Relay values from this {@link Flux} until the specified {@link Duration} elapses. *

* If the duration is zero, the resulting {@link Flux} completes as soon as this {@link Flux} * signals its first value (which is not relayed, though). * *

* * * @param timespan the {@link Duration} of the time window during which to emit elements * from this {@link Flux} * * @return a {@link Flux} limited to elements emitted within a specific duration */ public final Flux take(Duration timespan) { return take(timespan, Schedulers.parallel()); } /** * Relay values from this {@link Flux} until the specified {@link Duration} elapses, * as measured on the specified {@link Scheduler}. *

* If the duration is zero, the resulting {@link Flux} completes as soon as this {@link Flux} * signals its first value (which is not relayed, though). * *

* * * @param timespan the {@link Duration} of the time window during which to emit elements * from this {@link Flux} * @param timer a time-capable {@link Scheduler} instance to run on * * @return a {@link Flux} limited to elements emitted within a specific duration */ public final Flux take(Duration timespan, Scheduler timer) { if (!timespan.isZero()) { return takeUntilOther(Mono.delay(timespan, timer)); } else { return take(0); } } /** * Emit the last N values this {@link Flux} emitted before its completion. * *

* * * @param n the number of items from this {@link Flux} to retain and emit on onComplete * * @return a terminating {@link Flux} sub-sequence * */ public final Flux takeLast(int n) { if(n == 1){ return onAssembly(new FluxTakeLastOne<>(this)); } return onAssembly(new FluxTakeLast<>(this, n)); } /** * Relay values from this {@link Flux} until the given {@link Predicate} matches. * This includes the matching data (unlike {@link #takeWhile}). * *

* * * @param predicate the {@link Predicate} that stops the taking of values from this {@link Flux} * when returning {@literal true}. * * @return a new {@link Flux} limited by the predicate * */ public final Flux takeUntil(Predicate predicate) { return onAssembly(new FluxTakeUntil<>(this, predicate)); } /** * Relay values from this {@link Flux} until the given {@link Publisher} emits. * *

* * * @param other the companion {@link Publisher} that signals when to stop taking values from this {@link Flux} * * @return a new {@link Flux} limited by a companion {@link Publisher} * */ public final Flux takeUntilOther(Publisher other) { return onAssembly(new FluxTakeUntilOther<>(this, other)); } /** * Relay values from this {@link Flux} while a predicate returns {@literal TRUE} * for the values (checked before each value is delivered). * This only includes the matching data (unlike {@link #takeUntil}). * *

* * * @param continuePredicate the {@link Predicate} invoked each onNext returning {@literal TRUE} * to relay a value or {@literal FALSE} to terminate * * @return a new {@link Flux} taking values from the source while the predicate matches */ public final Flux takeWhile(Predicate continuePredicate) { return onAssembly(new FluxTakeWhile<>(this, continuePredicate)); } /** * Return a {@code Mono} that completes when this {@link Flux} completes. * This will actively ignore the sequence and only replay completion or error signals. *

* *

* *

Discard Support: This operator discards elements from the source. * * @return a new {@link Mono} representing the termination of this {@link Flux} */ public final Mono then() { @SuppressWarnings("unchecked") Mono then = (Mono) new MonoIgnoreElements<>(this); return Mono.onAssembly(then); } /** * Let this {@link Flux} complete then play signals from a provided {@link Mono}. *

* In other words ignore element from this {@link Flux} and transform its completion signal into the * emission and completion signal of a provided {@code Mono}. Error signal is * replayed in the resulting {@code Mono}. * *

* * *

Discard Support: This operator discards elements from the source. * * @param other a {@link Mono} to emit from after termination * @param the element type of the supplied Mono * * @return a new {@link Flux} that wait for source completion then emits from the supplied {@link Mono} */ public final Mono then(Mono other) { return Mono.onAssembly(new MonoIgnoreThen<>(new Publisher[] { this }, other)); } /** * Return a {@code Mono} that waits for this {@link Flux} to complete then * for a supplied {@link Publisher Publisher<Void>} to also complete. The * second completion signal is replayed, or any error signal that occurs instead. *

* * *

Discard Support: This operator discards elements from the source. * * @param other a {@link Publisher} to wait for after this Flux's termination * @return a new {@link Mono} completing when both publishers have completed in * sequence */ public final Mono thenEmpty(Publisher other) { return then(Mono.fromDirect(other)); } /** * Let this {@link Flux} complete then play another {@link Publisher}. *

* In other words ignore element from this flux and transform the completion signal into a * {@code Publisher} that will emit elements from the provided {@link Publisher}. *

* * *

Discard Support: This operator discards elements from the source. * * @param other a {@link Publisher} to emit from after termination * @param the element type of the supplied Publisher * * @return a new {@link Flux} that emits from the supplied {@link Publisher} after * this Flux completes. */ public final Flux thenMany(Publisher other) { if (this instanceof FluxConcatArray) { @SuppressWarnings({ "unchecked" }) FluxConcatArray fluxConcatArray = (FluxConcatArray) this; return fluxConcatArray.concatAdditionalIgnoredLast(other); } @SuppressWarnings("unchecked") Flux concat = (Flux)concat(ignoreElements(), other); return concat; } /** * Times {@link Subscriber#onNext(Object)} events, encapsulated into a {@link Timed} object * that lets downstream consumer look at various time information gathered with nanosecond * resolution using the default clock ({@link Schedulers#parallel()}): *

    *
  • {@link Timed#elapsed()}: the time in nanoseconds since last event, as a {@link Duration}. * For the first onNext, "last event" is the subscription. Otherwise it is the previous onNext. * This is functionally equivalent to {@link #elapsed()}, with a more expressive and precise * representation than a {@link Tuple2} with a long.
  • *
  • {@link Timed#timestamp()}: the timestamp of this onNext, as an {@link java.time.Instant} * (with nanoseconds part). This is functionally equivalent to {@link #timestamp()}, with a more * expressive and precise representation than a {@link Tuple2} with a long.
  • *
  • {@link Timed#elapsedSinceSubscription()}: the time in nanoseconds since subscription, * as a {@link Duration}.
  • *
*

* The {@link Timed} object instances are safe to store and use later, as they are created as an * immutable wrapper around the {@code } value and immediately passed downstream. *

* * * @return a timed {@link Flux} * @see #elapsed() * @see #timestamp() */ public final Flux> timed() { return this.timed(Schedulers.parallel()); } /** * Times {@link Subscriber#onNext(Object)} events, encapsulated into a {@link Timed} object * that lets downstream consumer look at various time information gathered with nanosecond * resolution using the provided {@link Scheduler} as a clock: *

    *
  • {@link Timed#elapsed()}: the time in nanoseconds since last event, as a {@link Duration}. * For the first onNext, "last event" is the subscription. Otherwise it is the previous onNext. * This is functionally equivalent to {@link #elapsed()}, with a more expressive and precise * representation than a {@link Tuple2} with a long.
  • *
  • {@link Timed#timestamp()}: the timestamp of this onNext, as an {@link java.time.Instant} * (with nanoseconds part). This is functionally equivalent to {@link #timestamp()}, with a more * expressive and precise representation than a {@link Tuple2} with a long.
  • *
  • {@link Timed#elapsedSinceSubscription()}: the time in nanoseconds since subscription, * as a {@link Duration}.
  • *
*

* The {@link Timed} object instances are safe to store and use later, as they are created as an * immutable wrapper around the {@code } value and immediately passed downstream. *

* * * @return a timed {@link Flux} * @see #elapsed(Scheduler) * @see #timestamp(Scheduler) */ public final Flux> timed(Scheduler clock) { return onAssembly(new FluxTimed<>(this, clock)); } /** * Propagate a {@link TimeoutException} as soon as no item is emitted within the * given {@link Duration} from the previous emission (or the subscription for the first item). * *

* * * @param timeout the timeout between two signals from this {@link Flux} * * @return a {@link Flux} that can time out on a per-item basis */ public final Flux timeout(Duration timeout) { return timeout(timeout, null, Schedulers.parallel()); } /** * Switch to a fallback {@link Flux} as soon as no item is emitted within the * given {@link Duration} from the previous emission (or the subscription for the first item). *

* If the given {@link Publisher} is null, signal a {@link TimeoutException} instead. * *

* * * @param timeout the timeout between two signals from this {@link Flux} * @param fallback the fallback {@link Publisher} to subscribe when a timeout occurs * * @return a {@link Flux} that will fallback to a different {@link Publisher} in case of a per-item timeout */ public final Flux timeout(Duration timeout, @Nullable Publisher fallback) { return timeout(timeout, fallback, Schedulers.parallel()); } /** * Propagate a {@link TimeoutException} as soon as no item is emitted within the * given {@link Duration} from the previous emission (or the subscription for the first * item), as measured by the specified {@link Scheduler}. * *

* * * @param timeout the timeout {@link Duration} between two signals from this {@link Flux} * @param timer a time-capable {@link Scheduler} instance to run on * * @return a {@link Flux} that can time out on a per-item basis */ public final Flux timeout(Duration timeout, Scheduler timer) { return timeout(timeout, null, timer); } /** * Switch to a fallback {@link Flux} as soon as no item is emitted within the * given {@link Duration} from the previous emission (or the subscription for the * first item), as measured on the specified {@link Scheduler}. *

* If the given {@link Publisher} is null, signal a {@link TimeoutException} instead. * *

* * * @param timeout the timeout {@link Duration} between two signals from this {@link Flux} * @param fallback the fallback {@link Publisher} to subscribe when a timeout occurs * @param timer a time-capable {@link Scheduler} instance to run on * * @return a {@link Flux} that will fallback to a different {@link Publisher} in case of a per-item timeout */ public final Flux timeout(Duration timeout, @Nullable Publisher fallback, Scheduler timer) { final Mono _timer = Mono.delay(timeout, timer).onErrorReturn(0L); final Function> rest = o -> _timer; if(fallback == null) { return timeout(_timer, rest, timeout.toMillis() + "ms"); } return timeout(_timer, rest, fallback); } /** * Signal a {@link TimeoutException} in case the first item from this {@link Flux} has * not been emitted before the given {@link Publisher} emits. * *

* * * @param firstTimeout the companion {@link Publisher} that will trigger a timeout if * emitting before the first signal from this {@link Flux} * * @param the type of the timeout Publisher * * @return a {@link Flux} that can time out if the first item does not come before * a signal from a companion {@link Publisher} * */ public final Flux timeout(Publisher firstTimeout) { return timeout(firstTimeout, t -> never()); } /** * Signal a {@link TimeoutException} in case the first item from this {@link Flux} has * not been emitted before the {@code firstTimeout} {@link Publisher} emits, and whenever * each subsequent elements is not emitted before a {@link Publisher} generated from * the latest element signals. * *

* * *

Discard Support: This operator discards an element if it comes right after the timeout. * * @param firstTimeout the timeout {@link Publisher} that must not emit before the first signal from this {@link Flux} * @param nextTimeoutFactory the timeout {@link Publisher} factory for each next item * @param the type of the elements of the first timeout Publisher * @param the type of the elements of the subsequent timeout Publishers * * @return a {@link Flux} that can time out if each element does not come before * a signal from a per-item companion {@link Publisher} */ public final Flux timeout(Publisher firstTimeout, Function> nextTimeoutFactory) { return timeout(firstTimeout, nextTimeoutFactory, "first signal from a Publisher"); } private final Flux timeout(Publisher firstTimeout, Function> nextTimeoutFactory, String timeoutDescription) { return onAssembly(new FluxTimeout<>(this, firstTimeout, nextTimeoutFactory, timeoutDescription)); } /** * Switch to a fallback {@link Publisher} in case the first item from this {@link Flux} has * not been emitted before the {@code firstTimeout} {@link Publisher} emits, and whenever * each subsequent elements is not emitted before a {@link Publisher} generated from * the latest element signals. * *

* * * @param firstTimeout the timeout {@link Publisher} that must not emit before the first signal from this {@link Flux} * @param nextTimeoutFactory the timeout {@link Publisher} factory for each next item * @param fallback the fallback {@link Publisher} to subscribe when a timeout occurs * * @param the type of the elements of the first timeout Publisher * @param the type of the elements of the subsequent timeout Publishers * * @return a {@link Flux} that can time out if each element does not come before * a signal from a per-item companion {@link Publisher} */ public final Flux timeout(Publisher firstTimeout, Function> nextTimeoutFactory, Publisher fallback) { return onAssembly(new FluxTimeout<>(this, firstTimeout, nextTimeoutFactory, fallback)); } /** * Emit a {@link reactor.util.function.Tuple2} pair of T1 the current clock time in * millis (as a {@link Long} measured by the {@link Schedulers#parallel() parallel} * Scheduler) and T2 the emitted data (as a {@code T}), for each item from this {@link Flux}. * *

* * * @return a timestamped {@link Flux} * @see #timed() * @see Timed#timestamp() */ public final Flux> timestamp() { return timestamp(Schedulers.parallel()); } /** * Emit a {@link reactor.util.function.Tuple2} pair of T1 the current clock time in * millis (as a {@link Long} measured by the provided {@link Scheduler}) and T2 * the emitted data (as a {@code T}), for each item from this {@link Flux}. * *

The provider {@link Scheduler} will be asked to {@link Scheduler#now(TimeUnit) provide time} * with a granularity of {@link TimeUnit#MILLISECONDS}. In order for this operator to work as advertised, the * provided Scheduler should thus return results that can be interpreted as unix timestamps.

*

* * * * @param scheduler the {@link Scheduler} to read time from * @return a timestamped {@link Flux} * @see Scheduler#now(TimeUnit) * @see #timed(Scheduler) * @see Timed#timestamp() */ public final Flux> timestamp(Scheduler scheduler) { Objects.requireNonNull(scheduler, "scheduler"); return map(d -> Tuples.of(scheduler.now(TimeUnit.MILLISECONDS), d)); } /** * Transform this {@link Flux} into a lazy {@link Iterable} blocking on * {@link Iterator#next()} calls. * *

* *

* Note that iterating from within threads marked as "non-blocking only" is illegal and will * cause an {@link IllegalStateException} to be thrown, but obtaining the {@link Iterable} * itself within these threads is ok. * * @return a blocking {@link Iterable} */ public final Iterable toIterable() { return toIterable(Queues.SMALL_BUFFER_SIZE); } /** * Transform this {@link Flux} into a lazy {@link Iterable} blocking on * {@link Iterator#next()} calls. *

* *

* Note that iterating from within threads marked as "non-blocking only" is illegal and will * cause an {@link IllegalStateException} to be thrown, but obtaining the {@link Iterable} * itself within these threads is ok. * * @param batchSize the bounded capacity to prefetch from this {@link Flux} or * {@code Integer.MAX_VALUE} for unbounded demand * @return a blocking {@link Iterable} */ public final Iterable toIterable(int batchSize) { return toIterable(batchSize, null); } /** * Transform this {@link Flux} into a lazy {@link Iterable} blocking on * {@link Iterator#next()} calls. * *

* *

* Note that iterating from within threads marked as "non-blocking only" is illegal and will * cause an {@link IllegalStateException} to be thrown, but obtaining the {@link Iterable} * itself within these threads is ok. * * @param batchSize the bounded capacity to prefetch from this {@link Flux} or * {@code Integer.MAX_VALUE} for unbounded demand * @param queueProvider the supplier of the queue implementation to be used for storing * elements emitted faster than the iteration * * @return a blocking {@link Iterable} */ public final Iterable toIterable(int batchSize, @Nullable Supplier> queueProvider) { final Supplier> provider; if(queueProvider == null){ provider = Queues.get(batchSize); } else{ provider = () -> Hooks.wrapQueue(queueProvider.get()); } return new BlockingIterable<>(this, batchSize, provider); } /** * Transform this {@link Flux} into a lazy {@link Stream} blocking for each source * {@link Subscriber#onNext(Object) onNext} call. * *

* *

* Note that iterating from within threads marked as "non-blocking only" is illegal and will * cause an {@link IllegalStateException} to be thrown, but obtaining the {@link Stream} * itself or applying lazy intermediate operation on the stream within these threads is ok. * * @return a {@link Stream} of unknown size with onClose attached to {@link Subscription#cancel()} */ public final Stream toStream() { return toStream(Queues.SMALL_BUFFER_SIZE); } /** * Transform this {@link Flux} into a lazy {@link Stream} blocking for each source * {@link Subscriber#onNext(Object) onNext} call. *

* *

* Note that iterating from within threads marked as "non-blocking only" is illegal and will * cause an {@link IllegalStateException} to be thrown, but obtaining the {@link Stream} * itself or applying lazy intermediate operation on the stream within these threads is ok. * * * @param batchSize the bounded capacity to prefetch from this {@link Flux} or * {@code Integer.MAX_VALUE} for unbounded demand * @return a {@link Stream} of unknown size with onClose attached to {@link Subscription#cancel()} */ public final Stream toStream(int batchSize) { final Supplier> provider; provider = Queues.get(batchSize); return new BlockingIterable<>(this, batchSize, provider).stream(); } /** * Transform this {@link Flux} in order to generate a target {@link Flux}. Unlike {@link #transformDeferred(Function)}, the * provided function is executed as part of assembly. *

	 * Function applySchedulers = flux -> flux.subscribeOn(Schedulers.boundedElastic())
	 *                                                    .publishOn(Schedulers.parallel());
	 * flux.transform(applySchedulers).map(v -> v * v).subscribe();
	 * 
*

* * * @param transformer the {@link Function} to immediately map this {@link Flux} into a target {@link Flux} * instance. * @param the item type in the returned {@link Flux} * * @return a new {@link Flux} * @see #transformDeferred(Function) transformDeferred(Function) for deferred composition of Flux for each @link Subscriber * @see #as(Function) as(Function) for a loose conversion to an arbitrary type */ @SuppressWarnings({"unchecked", "rawtypes"}) public final Flux transform(Function, ? extends Publisher> transformer) { if (Hooks.DETECT_CONTEXT_LOSS) { transformer = new ContextTrackingFunctionWrapper(transformer); } return onAssembly(from(transformer.apply(this))); } /** * Defer the transformation of this {@link Flux} in order to generate a target {@link Flux} type. * A transformation will occur for each {@link Subscriber}. For instance: *

	 * flux.transformDeferred(original -> original.log());
	 * 
*

* * * @param transformer the {@link Function} to lazily map this {@link Flux} into a target {@link Publisher} * instance for each new subscriber * @param the item type in the returned {@link Publisher} * * @return a new {@link Flux} * @see #transform(Function) transform(Function) for immmediate transformation of Flux * @see #transformDeferredContextual(BiFunction) transformDeferredContextual(BiFunction) for a similarly deferred transformation of Flux reading the ContextView * @see #as(Function) as(Function) for a loose conversion to an arbitrary type */ public final Flux transformDeferred(Function, ? extends Publisher> transformer) { return defer(() -> { if (Hooks.DETECT_CONTEXT_LOSS) { @SuppressWarnings({"rawtypes", "unchecked"}) ContextTrackingFunctionWrapper wrapper = new ContextTrackingFunctionWrapper((Function) transformer); return wrapper.apply(this); } return transformer.apply(this); }); } /** * Defer the given transformation to this {@link Flux} in order to generate a * target {@link Flux} type. A transformation will occur for each * {@link Subscriber}. In addition, the transforming {@link BiFunction} exposes * the {@link ContextView} of each {@link Subscriber}. For instance: * *

	 * Flux<T> fluxLogged = flux.transformDeferredContextual((original, ctx) -> original.log("for RequestID" + ctx.get("RequestID"))
	 * //...later subscribe. Each subscriber has its Context with a RequestID entry
	 * fluxLogged.contextWrite(Context.of("RequestID", "requestA").subscribe();
	 * fluxLogged.contextWrite(Context.of("RequestID", "requestB").subscribe();
	 * 
*

* * * @param transformer the {@link BiFunction} to lazily map this {@link Flux} into a target {@link Flux} * instance upon subscription, with access to {@link ContextView} * @param the item type in the returned {@link Publisher} * @return a new {@link Flux} * @see #transform(Function) transform(Function) for immmediate transformation of Flux * @see #transformDeferred(Function) transformDeferred(Function) for a similarly deferred transformation of Flux without the ContextView * @see #as(Function) as(Function) for a loose conversion to an arbitrary type */ public final Flux transformDeferredContextual(BiFunction, ? super ContextView, ? extends Publisher> transformer) { return deferContextual(ctxView -> { if (Hooks.DETECT_CONTEXT_LOSS) { ContextTrackingFunctionWrapper wrapper = new ContextTrackingFunctionWrapper<>( publisher -> transformer.apply(wrap(publisher), ctxView), transformer.toString() ); return wrapper.apply(this); } return transformer.apply(this, ctxView); }); } /** * Split this {@link Flux} sequence into multiple {@link Flux} windows containing * {@code maxSize} elements (or less for the final window) and starting from the first item. * Each {@link Flux} window will onComplete after {@code maxSize} items have been routed. * *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: This operator discards elements it internally queued for backpressure * upon cancellation or error triggered by a data signal. * * @param maxSize the maximum number of items to emit in the window before closing it * * @return a {@link Flux} of {@link Flux} windows based on element count */ public final Flux> window(int maxSize) { return onAssembly(new FluxWindow<>(this, maxSize, Queues.get(maxSize))); } /** * Split this {@link Flux} sequence into multiple {@link Flux} windows of size * {@code maxSize}, that each open every {@code skip} elements in the source. * *

* When maxSize < skip : dropping windows *

* *

* When maxSize > skip : overlapping windows *

* *

* When maxSize == skip : exact windows *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: The overlapping variant DOES NOT discard elements, as they might be part of another still valid window. * The exact window and dropping window variants bot discard elements they internally queued for backpressure * upon cancellation or error triggered by a data signal. The dropping window variant also discards elements in between windows. * * @param maxSize the maximum number of items to emit in the window before closing it * @param skip the number of items to count before opening and emitting a new window * * @return a {@link Flux} of {@link Flux} windows based on element count and opened every skipCount */ public final Flux> window(int maxSize, int skip) { return onAssembly(new FluxWindow<>(this, maxSize, skip, Queues.unbounded(Queues.XS_BUFFER_SIZE), Queues.unbounded(Queues.XS_BUFFER_SIZE))); } /** * Split this {@link Flux} sequence into continuous, non-overlapping windows * where the window boundary is signalled by another {@link Publisher} * *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: This operator discards elements it internally queued for backpressure * upon cancellation or error triggered by a data signal. * * @param boundary a {@link Publisher} to emit any item for a split signal and complete to terminate * * @return a {@link Flux} of {@link Flux} windows delimited by a given {@link Publisher} */ public final Flux> window(Publisher boundary) { return onAssembly(new FluxWindowBoundary<>(this, boundary, Queues.unbounded(Queues.XS_BUFFER_SIZE))); } /** * Split this {@link Flux} sequence into continuous, non-overlapping windows that open * for a {@code windowingTimespan} {@link Duration} (as measured on the {@link Schedulers#parallel() parallel} * Scheduler). * *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: This operator discards elements it internally queued for backpressure * upon cancellation or error triggered by a data signal. * * @param windowingTimespan the {@link Duration} to delimit {@link Flux} windows * * @return a {@link Flux} of {@link Flux} windows continuously opened for a given {@link Duration} */ public final Flux> window(Duration windowingTimespan) { return window(windowingTimespan, Schedulers.parallel()); } /** * Split this {@link Flux} sequence into multiple {@link Flux} windows that open * for a given {@code windowingTimespan} {@link Duration}, after which it closes with onComplete. * Each window is opened at a regular {@code timeShift} interval, starting from the * first item. * Both durations are measured on the {@link Schedulers#parallel() parallel} Scheduler. * *

* When windowingTimespan < openWindowEvery : dropping windows *

* *

* When windowingTimespan > openWindowEvery : overlapping windows *

* *

* When windowingTimespan == openWindowEvery : exact windows *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: The overlapping variant DOES NOT discard elements, as they might be part of another still valid window. * The exact window and dropping window variants bot discard elements they internally queued for backpressure * upon cancellation or error triggered by a data signal. The dropping window variant also discards elements in between windows. * * @param windowingTimespan the maximum {@link Flux} window {@link Duration} * @param openWindowEvery the period of time at which to create new {@link Flux} windows * * @return a {@link Flux} of {@link Flux} windows opened at regular intervals and * closed after a {@link Duration} * */ public final Flux> window(Duration windowingTimespan, Duration openWindowEvery) { return window(windowingTimespan, openWindowEvery, Schedulers.parallel()); } /** * Split this {@link Flux} sequence into continuous, non-overlapping windows that open * for a {@code windowingTimespan} {@link Duration} (as measured on the provided {@link Scheduler}). * *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: This operator discards elements it internally queued for backpressure * upon cancellation or error triggered by a data signal. * * @param windowingTimespan the {@link Duration} to delimit {@link Flux} windows * @param timer a time-capable {@link Scheduler} instance to run on * * @return a {@link Flux} of {@link Flux} windows continuously opened for a given {@link Duration} */ public final Flux> window(Duration windowingTimespan, Scheduler timer) { return window(interval(windowingTimespan, timer)); } /** * Split this {@link Flux} sequence into multiple {@link Flux} windows that open * for a given {@code windowingTimespan} {@link Duration}, after which it closes with onComplete. * Each window is opened at a regular {@code timeShift} interval, starting from the * first item. * Both durations are measured on the provided {@link Scheduler}. * *

* When windowingTimespan < openWindowEvery : dropping windows *

* *

* When windowingTimespan > openWindowEvery : overlapping windows *

* *

* When openWindowEvery == openWindowEvery : exact windows *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: The overlapping variant DOES NOT discard elements, as they might be part of another still valid window. * The exact window and dropping window variants bot discard elements they internally queued for backpressure * upon cancellation or error triggered by a data signal. The dropping window variant also discards elements in between windows. * * @param windowingTimespan the maximum {@link Flux} window {@link Duration} * @param openWindowEvery the period of time at which to create new {@link Flux} windows * @param timer a time-capable {@link Scheduler} instance to run on * * @return a {@link Flux} of {@link Flux} windows opened at regular intervals and * closed after a {@link Duration} */ public final Flux> window(Duration windowingTimespan, Duration openWindowEvery, Scheduler timer) { if (openWindowEvery.equals(windowingTimespan)) { return window(windowingTimespan); } return windowWhen(interval(Duration.ZERO, openWindowEvery, timer), aLong -> Mono.delay(windowingTimespan, timer)); } /** * Split this {@link Flux} sequence into multiple {@link Flux} windows containing * {@code maxSize} elements (or less for the final window) and starting from the first item. * Each {@link Flux} window will onComplete once it contains {@code maxSize} elements * OR it has been open for the given {@link Duration} (as measured on the {@link Schedulers#parallel() parallel} * Scheduler). * *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: This operator discards elements it internally queued for backpressure * upon cancellation or error triggered by a data signal. * * @param maxSize the maximum number of items to emit in the window before closing it * @param maxTime the maximum {@link Duration} since the window was opened before closing it * * @return a {@link Flux} of {@link Flux} windows based on element count and duration */ public final Flux> windowTimeout(int maxSize, Duration maxTime) { return windowTimeout(maxSize, maxTime , Schedulers.parallel()); } /** * Split this {@link Flux} sequence into multiple {@link Flux} windows containing * {@code maxSize} elements (or less for the final window) and starting from the first item. * Each {@link Flux} window will onComplete once it contains {@code maxSize} elements * OR it has been open for the given {@link Duration} (as measured on the {@link Schedulers#parallel() parallel} * Scheduler). * *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: This operator discards elements it internally queued for backpressure * upon cancellation or error triggered by a data signal. * * @param maxSize the maximum number of items to emit in the window before closing it * @param maxTime the maximum {@link Duration} since the window was opened before closing it * @param fairBackpressure define whether operator request unbounded demand or * prefetch by maxSize * * @return a {@link Flux} of {@link Flux} windows based on element count and duration */ public final Flux> windowTimeout(int maxSize, Duration maxTime, boolean fairBackpressure) { return windowTimeout(maxSize, maxTime , Schedulers.parallel(), fairBackpressure); } /** * Split this {@link Flux} sequence into multiple {@link Flux} windows containing * {@code maxSize} elements (or less for the final window) and starting from the first item. * Each {@link Flux} window will onComplete once it contains {@code maxSize} elements * OR it has been open for the given {@link Duration} (as measured on the provided * {@link Scheduler}). * *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: This operator discards elements it internally queued for backpressure * upon cancellation or error triggered by a data signal. * * @param maxSize the maximum number of items to emit in the window before closing it * @param maxTime the maximum {@link Duration} since the window was opened before closing it * @param timer a time-capable {@link Scheduler} instance to run on * * @return a {@link Flux} of {@link Flux} windows based on element count and duration */ public final Flux> windowTimeout(int maxSize, Duration maxTime, Scheduler timer) { return windowTimeout(maxSize, maxTime, timer, false); } /** * Split this {@link Flux} sequence into multiple {@link Flux} windows containing * {@code maxSize} elements (or less for the final window) and starting from the first item. * Each {@link Flux} window will onComplete once it contains {@code maxSize} elements * OR it has been open for the given {@link Duration} (as measured on the provided * {@link Scheduler}). * *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: This operator discards elements it internally queued for backpressure * upon cancellation or error triggered by a data signal. * * @param maxSize the maximum number of items to emit in the window before closing it * @param maxTime the maximum {@link Duration} since the window was opened before closing it * @param timer a time-capable {@link Scheduler} instance to run on * @param fairBackpressure define whether operator request unbounded demand or * prefetch by maxSize * * @return a {@link Flux} of {@link Flux} windows based on element count and duration */ public final Flux> windowTimeout(int maxSize, Duration maxTime, Scheduler timer, boolean fairBackpressure) { return onAssembly(new FluxWindowTimeout<>(this, maxSize, maxTime.toNanos(), TimeUnit.NANOSECONDS, timer, fairBackpressure)); } /** * Split this {@link Flux} sequence into multiple {@link Flux} windows delimited by the * given predicate. A new window is opened each time the predicate returns true, at which * point the previous window will receive the triggering element then onComplete. *

* Windows are lazily made available downstream at the point where they receive their * first event (an element is pushed, the window errors). This variant shouldn't * expose empty windows, as the separators are emitted into * the windows they close. * *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: This operator discards elements it internally queued for backpressure * upon cancellation or error triggered by a data signal. Upon cancellation of the current window, * it also discards the remaining elements that were bound for it until the main sequence completes * or creation of a new window is triggered. * * @param boundaryTrigger a predicate that triggers the next window when it becomes true. * @return a {@link Flux} of {@link Flux} windows, bounded depending * on the predicate. */ public final Flux> windowUntil(Predicate boundaryTrigger) { return windowUntil(boundaryTrigger, false); } /** * Split this {@link Flux} sequence into multiple {@link Flux} windows delimited by the * given predicate. A new window is opened each time the predicate returns true. *

* Windows are lazily made available downstream at the point where they receive their * first event (an element is pushed, the window completes or errors). *

* If {@code cutBefore} is true, the old window will onComplete and the triggering * element will be emitted in the new window, which becomes immediately available. * This variant can emit an empty window if the sequence starts with a separator. *

* Otherwise, the triggering element will be emitted in the old window before it does * onComplete, similar to {@link #windowUntil(Predicate)}. This variant shouldn't * expose empty windows, as the separators are emitted into the windows they close. *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: This operator discards elements it internally queued for backpressure * upon cancellation or error triggered by a data signal. Upon cancellation of the current window, * it also discards the remaining elements that were bound for it until the main sequence completes * or creation of a new window is triggered. * * @param boundaryTrigger a predicate that triggers the next window when it becomes true. * @param cutBefore set to true to include the triggering element in the new window rather than the old. * @return a {@link Flux} of {@link Flux} windows, bounded depending * on the predicate. */ public final Flux> windowUntil(Predicate boundaryTrigger, boolean cutBefore) { return windowUntil(boundaryTrigger, cutBefore, Queues.SMALL_BUFFER_SIZE); } /** * Split this {@link Flux} sequence into multiple {@link Flux} windows delimited by the given * predicate and using a prefetch. A new window is opened each time the predicate * returns true. *

* Windows are lazily made available downstream at the point where they receive their * first event (an element is pushed, the window completes or errors). *

* If {@code cutBefore} is true, the old window will onComplete and the triggering * element will be emitted in the new window. This variant can emit an empty window * if the sequence starts with a separator. *

* Otherwise, the triggering element will be emitted in the old window before it does * onComplete, similar to {@link #windowUntil(Predicate)}. This variant shouldn't * expose empty windows, as the separators are emitted into the windows they close. *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: This operator discards elements it internally queued for backpressure * upon cancellation or error triggered by a data signal. Upon cancellation of the current window, * it also discards the remaining elements that were bound for it until the main sequence completes * or creation of a new window is triggered. * * @param boundaryTrigger a predicate that triggers the next window when it becomes true. * @param cutBefore set to true to include the triggering element in the new window rather than the old. * @param prefetch the request size to use for this {@link Flux}. * @return a {@link Flux} of {@link Flux} windows, bounded depending * on the predicate. */ public final Flux> windowUntil(Predicate boundaryTrigger, boolean cutBefore, int prefetch) { return onAssembly(new FluxWindowPredicate<>(this, Queues.unbounded(prefetch), Queues.unbounded(prefetch), prefetch, boundaryTrigger, cutBefore ? FluxBufferPredicate.Mode.UNTIL_CUT_BEFORE : FluxBufferPredicate.Mode.UNTIL)); } /** * Collect subsequent repetitions of an element (that is, if they arrive right after * one another) into multiple {@link Flux} windows. * *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: This operator discards elements it internally queued for backpressure * upon cancellation or error triggered by a data signal. Upon cancellation of the current window, * it also discards the remaining elements that were bound for it until the main sequence completes * or creation of a new window is triggered. * * @return a microbatched {@link Flux} of {@link Flux} windows. */ public final Flux> windowUntilChanged() { return windowUntilChanged(identityFunction()); } /** * Collect subsequent repetitions of an element (that is, if they arrive right after * one another), as compared by a key extracted through the user provided {@link * Function}, into multiple {@link Flux} windows. * *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: This operator discards elements it internally queued for backpressure * upon cancellation or error triggered by a data signal. Upon cancellation of the current window, * it also discards the remaining elements that were bound for it until the main sequence completes * or creation of a new window is triggered. * * @param keySelector function to compute comparison key for each element * @return a microbatched {@link Flux} of {@link Flux} windows. */ public final Flux> windowUntilChanged(Function keySelector) { return windowUntilChanged(keySelector, equalPredicate()); } /** * Collect subsequent repetitions of an element (that is, if they arrive right after * one another), as compared by a key extracted through the user provided {@link * Function} and compared using a supplied {@link BiPredicate}, into multiple * {@link Flux} windows. * *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: This operator discards elements it internally queued for backpressure * upon cancellation or error triggered by a data signal. Upon cancellation of the current window, * it also discards the remaining elements that were bound for it until the main sequence completes * or creation of a new window is triggered. * * @param keySelector function to compute comparison key for each element * @param keyComparator predicate used to compare keys * @return a microbatched {@link Flux} of {@link Flux} windows. */ public final Flux> windowUntilChanged(Function keySelector, BiPredicate keyComparator) { return Flux.defer(() -> windowUntil(new FluxBufferPredicate.ChangedPredicate (keySelector, keyComparator), true)); } /** * Split this {@link Flux} sequence into multiple {@link Flux} windows that stay open * while a given predicate matches the source elements. Once the predicate returns * false, the window closes with an onComplete and the triggering element is discarded. *

* Windows are lazily made available downstream at the point where they receive their * first event (an element is pushed, the window completes or errors). Empty windows * can happen when a sequence starts with a separator or contains multiple separators, * but a sequence that finishes with a separator won't cause a remainder empty window * to be emitted. *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: This operator discards elements it internally queued for backpressure * upon cancellation or error triggered by a data signal, as well as the triggering element(s) (that doesn't match * the predicate). Upon cancellation of the current window, it also discards the remaining elements * that were bound for it until the main sequence completes or creation of a new window is triggered. * * @param inclusionPredicate a predicate that triggers the next window when it becomes false. * @return a {@link Flux} of {@link Flux} windows, each containing * subsequent elements that all passed a predicate. */ public final Flux> windowWhile(Predicate inclusionPredicate) { return windowWhile(inclusionPredicate, Queues.SMALL_BUFFER_SIZE); } /** * Split this {@link Flux} sequence into multiple {@link Flux} windows that stay open * while a given predicate matches the source elements. Once the predicate returns * false, the window closes with an onComplete and the triggering element is discarded. *

* Windows are lazily made available downstream at the point where they receive their * first event (an element is pushed, the window completes or errors). Empty windows * can happen when a sequence starts with a separator or contains multiple separators, * but a sequence that finishes with a separator won't cause a remainder empty window * to be emitted. *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: This operator discards elements it internally queued for backpressure * upon cancellation or error triggered by a data signal, as well as the triggering element(s) (that doesn't match * the predicate). Upon cancellation of the current window, it also discards the remaining elements * that were bound for it until the main sequence completes or creation of a new window is triggered. * * @param inclusionPredicate a predicate that triggers the next window when it becomes false. * @param prefetch the request size to use for this {@link Flux}. * @return a {@link Flux} of {@link Flux} windows, each containing * subsequent elements that all passed a predicate. */ public final Flux> windowWhile(Predicate inclusionPredicate, int prefetch) { return onAssembly(new FluxWindowPredicate<>(this, Queues.unbounded(prefetch), Queues.unbounded(prefetch), prefetch, inclusionPredicate, FluxBufferPredicate.Mode.WHILE)); } /** * Split this {@link Flux} sequence into potentially overlapping windows controlled by items of a * start {@link Publisher} and end {@link Publisher} derived from the start values. * *

* When Open signal is strictly not overlapping Close signal : dropping windows *

* When Open signal is strictly more frequent than Close signal : overlapping windows *

* When Open signal is exactly coordinated with Close signal : exact windows *

* * *

* Note that windows are a live view of part of the underlying source publisher, * and as such their lifecycle is tied to that source. As a result, it is not possible * to subscribe to a window more than once: they are unicast. * This is most noticeable when trying to {@link #retry()} or {@link #repeat()} a window, * as these operators are based on re-subscription. * *

Discard Support: This operator DOES NOT discard elements. * * @param bucketOpening a {@link Publisher} that opens a new window when it emits any item * @param closeSelector a {@link Function} given an opening signal and returning a {@link Publisher} that * will close the window when emitting * * @param the type of the sequence opening windows * @param the type of the sequence closing windows opened by the bucketOpening Publisher's elements * * @return a {@link Flux} of {@link Flux} windows opened by signals from a first * {@link Publisher} and lasting until a selected second {@link Publisher} emits */ public final Flux> windowWhen(Publisher bucketOpening, final Function> closeSelector) { return onAssembly(new FluxWindowWhen<>(this, bucketOpening, closeSelector, Queues.unbounded(Queues.XS_BUFFER_SIZE))); } /** * Combine the most recently emitted values from both this {@link Flux} and another * {@link Publisher} through a {@link BiFunction} and emits the result. *

* The operator will drop values from this {@link Flux} until the other * {@link Publisher} produces any value. *

* If the other {@link Publisher} completes without any value, the sequence is completed. * *

* * * @param other the {@link Publisher} to combine with * @param resultSelector the bi-function called with each pair of source and other * elements that should return a single value to be emitted * * @param the other {@link Publisher} sequence type * @param the result type * * @return a combined {@link Flux} gated by another {@link Publisher} */ public final Flux withLatestFrom(Publisher other, BiFunction resultSelector){ return onAssembly(new FluxWithLatestFrom<>(this, other, resultSelector)); } /** * Zip this {@link Flux} with another {@link Publisher} source, that is to say wait * for both to emit one element and combine these elements once into a {@link Tuple2}. * The operator will continue doing so until any of the sources completes. * Errors will immediately be forwarded. * This "Step-Merge" processing is especially useful in Scatter-Gather scenarios. *

* * * @param source2 The second source {@link Publisher} to zip with this {@link Flux}. * @param type of the value from source2 * * @return a zipped {@link Flux} * */ public final Flux> zipWith(Publisher source2) { return zipWith(source2, tuple2Function()); } /** * Zip this {@link Flux} with another {@link Publisher} source, that is to say wait * for both to emit one element and combine these elements using a {@code combinator} * {@link BiFunction} * The operator will continue doing so until any of the sources completes. * Errors will immediately be forwarded. * This "Step-Merge" processing is especially useful in Scatter-Gather scenarios. *

* * * @param source2 The second source {@link Publisher} to zip with this {@link Flux}. * @param combinator The aggregate function that will receive a unique value from each * source and return the value to signal downstream * @param type of the value from source2 * @param The produced output after transformation by the combinator * * @return a zipped {@link Flux} */ public final Flux zipWith(Publisher source2, final BiFunction combinator) { if (this instanceof FluxZip) { @SuppressWarnings("unchecked") FluxZip o = (FluxZip) this; Flux result = o.zipAdditionalSource(source2, combinator); if (result != null) { return result; } } return zip(this, source2, combinator); } /** * Zip this {@link Flux} with another {@link Publisher} source, that is to say wait * for both to emit one element and combine these elements using a {@code combinator} * {@link BiFunction} * The operator will continue doing so until any of the sources completes. * Errors will immediately be forwarded. * This "Step-Merge" processing is especially useful in Scatter-Gather scenarios. *

* * * @param source2 The second source {@link Publisher} to zip with this {@link Flux}. * @param prefetch the request size to use for this {@link Flux} and the other {@link Publisher} * @param combinator The aggregate function that will receive a unique value from each * source and return the value to signal downstream * @param type of the value from source2 * @param The produced output after transformation by the combinator * * @return a zipped {@link Flux} */ @SuppressWarnings("unchecked") public final Flux zipWith(Publisher source2, int prefetch, BiFunction combinator) { return zip(objects -> combinator.apply((T) objects[0], (T2) objects[1]), prefetch, this, source2); } /** * Zip this {@link Flux} with another {@link Publisher} source, that is to say wait * for both to emit one element and combine these elements once into a {@link Tuple2}. * The operator will continue doing so until any of the sources completes. * Errors will immediately be forwarded. * This "Step-Merge" processing is especially useful in Scatter-Gather scenarios. * *

* * * @param source2 The second source {@link Publisher} to zip with this {@link Flux}. * @param prefetch the request size to use for this {@link Flux} and the other {@link Publisher} * @param type of the value from source2 * * @return a zipped {@link Flux} */ public final Flux> zipWith(Publisher source2, int prefetch) { return zipWith(source2, prefetch, tuple2Function()); } /** * Zip elements from this {@link Flux} with the content of an {@link Iterable}, that is * to say combine one element from each, pairwise, into a {@link Tuple2}. * *

* * * @param iterable the {@link Iterable} to zip with * @param the value type of the other iterable sequence * * @return a zipped {@link Flux} * */ @SuppressWarnings("unchecked") public final Flux> zipWithIterable(Iterable iterable) { return zipWithIterable(iterable, tuple2Function()); } /** * Zip elements from this {@link Flux} with the content of an {@link Iterable}, that is * to say combine one element from each, pairwise, using the given zipper {@link BiFunction}. * * *

* * * @param iterable the {@link Iterable} to zip with * @param zipper the {@link BiFunction} pair combinator * * @param the value type of the other iterable sequence * @param the result type * * @return a zipped {@link Flux} * */ public final Flux zipWithIterable(Iterable iterable, BiFunction zipper) { return onAssembly(new FluxZipIterable<>(this, iterable, zipper)); } /** * To be used by custom operators: invokes assembly {@link Hooks} pointcut given a * {@link Flux}, potentially returning a new {@link Flux}. This is for example useful * to activate cross-cutting concerns at assembly time, eg. a generalized * {@link #checkpoint()}. * * @param the value type * @param source the source to apply assembly hooks onto * * @return the source, potentially wrapped with assembly time cross-cutting behavior */ @SuppressWarnings("unchecked") protected static Flux onAssembly(Flux source) { Function hook = Hooks.onEachOperatorHook; if(hook != null) { source = (Flux) hook.apply(source); } if (Hooks.GLOBAL_TRACE) { AssemblySnapshot stacktrace = new AssemblySnapshot(null, Traces.callSiteSupplierFactory.get()); source = (Flux) Hooks.addAssemblyInfo(source, stacktrace); } return source; } /** * To be used by custom operators: invokes assembly {@link Hooks} pointcut given a * {@link ConnectableFlux}, potentially returning a new {@link ConnectableFlux}. This * is for example useful to activate cross-cutting concerns at assembly time, eg. a * generalized {@link #checkpoint()}. * * @param the value type * @param source the source to apply assembly hooks onto * * @return the source, potentially wrapped with assembly time cross-cutting behavior */ @SuppressWarnings("unchecked") protected static ConnectableFlux onAssembly(ConnectableFlux source) { Function hook = Hooks.onEachOperatorHook; if(hook != null) { source = (ConnectableFlux) hook.apply(source); } if (Hooks.GLOBAL_TRACE) { AssemblySnapshot stacktrace = new AssemblySnapshot(null, Traces.callSiteSupplierFactory.get()); source = (ConnectableFlux) Hooks.addAssemblyInfo(source, stacktrace); } return source; } @Override public String toString() { return getClass().getSimpleName(); } final Flux flatMap(Function> mapper, boolean delayError, int concurrency, int prefetch) { return onAssembly(new FluxFlatMap<>( this, mapper, delayError, concurrency, Queues.get(concurrency), prefetch, Queues.get(prefetch) )); } final Flux flatMapSequential(Function> mapper, boolean delayError, int maxConcurrency, int prefetch) { return onAssembly(new FluxMergeSequential<>(this, mapper, maxConcurrency, prefetch, delayError ? FluxConcatMap.ErrorMode.END : FluxConcatMap.ErrorMode.IMMEDIATE)); } @SuppressWarnings("unchecked") static Flux doOnSignal(Flux source, @Nullable Consumer onSubscribe, @Nullable Consumer onNext, @Nullable Consumer onError, @Nullable Runnable onComplete, @Nullable Runnable onAfterTerminate, @Nullable LongConsumer onRequest, @Nullable Runnable onCancel) { if (source instanceof Fuseable) { return onAssembly(new FluxPeekFuseable<>(source, onSubscribe, onNext, onError, onComplete, onAfterTerminate, onRequest, onCancel)); } return onAssembly(new FluxPeek<>(source, onSubscribe, onNext, onError, onComplete, onAfterTerminate, onRequest, onCancel)); } /** * Returns the appropriate Mono instance for a known Supplier Flux, WITHOUT applying hooks * (see {@link #wrap(Publisher)}). * * @param supplier the supplier Flux * * @return the mono representing that Flux */ static Mono wrapToMono(Callable supplier) { if (supplier instanceof Fuseable.ScalarCallable) { Fuseable.ScalarCallable scalarCallable = (Fuseable.ScalarCallable) supplier; T v; try { v = scalarCallable.call(); } catch (Exception e) { return new MonoError<>(Exceptions.unwrap(e)); } if (v == null) { return MonoEmpty.instance(); } return new MonoJust<>(v); } return new MonoCallable<>(supplier); } @SafeVarargs static Flux merge(int prefetch, boolean delayError, Publisher... sources) { if (sources.length == 0) { return empty(); } if (sources.length == 1) { return from(sources[0]); } return onAssembly(new FluxMerge<>(sources, delayError, sources.length, Queues.get(sources.length), prefetch, Queues.get(prefetch))); } @SafeVarargs static Flux mergeSequential(int prefetch, boolean delayError, Publisher... sources) { if (sources.length == 0) { return empty(); } if (sources.length == 1) { return from(sources[0]); } return onAssembly(new FluxMergeSequential<>(new FluxArray<>(sources), identityFunction(), sources.length, prefetch, delayError ? FluxConcatMap.ErrorMode.END : FluxConcatMap.ErrorMode.IMMEDIATE)); } static Flux mergeSequential(Publisher> sources, boolean delayError, int maxConcurrency, int prefetch) { return onAssembly(new FluxMergeSequential<>(from(sources), identityFunction(), maxConcurrency, prefetch, delayError ? FluxConcatMap.ErrorMode.END : FluxConcatMap.ErrorMode.IMMEDIATE)); } static Flux mergeSequential(Iterable> sources, boolean delayError, int maxConcurrency, int prefetch) { return onAssembly(new FluxMergeSequential<>(new FluxIterable<>(sources), identityFunction(), maxConcurrency, prefetch, delayError ? FluxConcatMap.ErrorMode.END : FluxConcatMap.ErrorMode.IMMEDIATE)); } static BooleanSupplier countingBooleanSupplier(BooleanSupplier predicate, long max) { if (max <= 0) { return predicate; } return new BooleanSupplier() { long n; @Override public boolean getAsBoolean() { return n++ < max && predicate.getAsBoolean(); } }; } static Predicate countingPredicate(Predicate predicate, long max) { if (max == 0) { return predicate; } return new Predicate() { long n; @Override public boolean test(O o) { return n++ < max && predicate.test(o); } }; } @SuppressWarnings("unchecked") static Supplier> hashSetSupplier() { return SET_SUPPLIER; } @SuppressWarnings("unchecked") static Supplier> listSupplier() { return LIST_SUPPLIER; } @SuppressWarnings("unchecked") static BiPredicate equalPredicate() { return OBJECT_EQUAL; } @SuppressWarnings("unchecked") static Function identityFunction(){ return IDENTITY_FUNCTION; } @SuppressWarnings("unchecked") static BiFunction> tuple2Function() { return TUPLE2_BIFUNCTION; } /** * Unchecked wrap of {@link Publisher} as {@link Flux}, supporting {@link Fuseable} sources. * Note that this bypasses {@link Hooks#onEachOperator(String, Function) assembly hooks}. * * @param source the {@link Publisher} to wrap * @param input upstream type * @return a wrapped {@link Flux} */ @SuppressWarnings("unchecked") static Flux wrap(Publisher source) { if (source instanceof Flux) { return (Flux) source; } //for scalars we'll instantiate the operators directly to avoid onAssembly if (source instanceof Fuseable.ScalarCallable) { try { @SuppressWarnings("unchecked") I t = ((Fuseable.ScalarCallable) source).call(); if (t != null) { return new FluxJust<>(t); } return FluxEmpty.instance(); } catch (Exception e) { return new FluxError<>(Exceptions.unwrap(e)); } } if(source instanceof Mono){ if(source instanceof Fuseable){ return new FluxSourceMonoFuseable<>((Mono)source); } return new FluxSourceMono<>((Mono)source); } if(source instanceof Fuseable){ return new FluxSourceFuseable<>(source); } return new FluxSource<>(source); } @SuppressWarnings("rawtypes") static final BiFunction TUPLE2_BIFUNCTION = Tuples::of; @SuppressWarnings("rawtypes") static final Supplier LIST_SUPPLIER = ArrayList::new; @SuppressWarnings("rawtypes") static final Supplier SET_SUPPLIER = HashSet::new; static final BooleanSupplier ALWAYS_BOOLEAN_SUPPLIER = () -> true; static final BiPredicate OBJECT_EQUAL = Object::equals; @SuppressWarnings("rawtypes") static final Function IDENTITY_FUNCTION = Function.identity(); }