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rxjava2-extensions developed by David Karnok
/*
* Copyright 2016-2018 David Karnok
*
* 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
*
* http://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 hu.akarnokd.rxjava2.operators;
import java.util.Comparator;
import java.util.concurrent.*;
import org.reactivestreams.Publisher;
import io.reactivex.*;
import io.reactivex.annotations.*;
import io.reactivex.functions.*;
import io.reactivex.internal.functions.*;
import io.reactivex.internal.schedulers.ImmediateThinScheduler;
import io.reactivex.plugins.RxJavaPlugins;
import io.reactivex.schedulers.Schedulers;
/**
* Utility class to create Flowable sources.
*/
public final class Flowables {
/** Utility class. */
private Flowables() {
throw new IllegalStateException("No instances!");
}
/**
* Merges the source Publishers in an ordered fashion picking the smallest of the available value from
* them (determined by their natural order).
* @param the value type of all sources
* @param sources the iterable sequence of sources
* @return the new Flowable instance
*
* @since 0.8.0
*/
@BackpressureSupport(BackpressureKind.FULL)
@SchedulerSupport(SchedulerSupport.NONE)
public static > Flowable orderedMerge(Publisher... sources) {
return orderedMerge(Functions.naturalOrder(), false, Flowable.bufferSize(), sources);
}
/**
* Merges the source Publishers in an ordered fashion picking the smallest of the available value from
* them (determined by their natural order) and allows delaying any error they may signal.
* @param the value type of all sources
* @param sources the iterable sequence of sources
* @param delayErrors if true, source errors are delayed until all sources terminate in some way
* @return the new Flowable instance
*
* @since 0.8.0
*/
@BackpressureSupport(BackpressureKind.FULL)
@SchedulerSupport(SchedulerSupport.NONE)
public static > Flowable orderedMerge(boolean delayErrors, Publisher... sources) {
return orderedMerge(Functions.naturalOrder(), delayErrors, Flowable.bufferSize(), sources);
}
/**
* Merges the source Publishers in an ordered fashion picking the smallest of the available value from
* them (determined by their natural order), allows delaying any error they may signal and sets the prefetch
* amount when requesting from these Publishers.
* @param the value type of all sources
* @param sources the iterable sequence of sources
* @param delayErrors if true, source errors are delayed until all sources terminate in some way
* @param prefetch the number of items to prefetch from the sources
* @return the new Flowable instance
*
* @since 0.8.0
*/
@BackpressureSupport(BackpressureKind.FULL)
@SchedulerSupport(SchedulerSupport.NONE)
public static > Flowable orderedMerge(boolean delayErrors, int prefetch, Publisher... sources) {
return orderedMerge(Functions.naturalOrder(), delayErrors, prefetch, sources);
}
/**
* Merges the source Publishers in an ordered fashion picking the smallest of the available value from
* them (determined by the Comparator).
* @param the value type of all sources
* @param sources the iterable sequence of sources
* @param comparator the comparator to use for comparing items;
* it is called with the last known smallest in its first argument
* @return the new Flowable instance
*
* @since 0.8.0
*/
@BackpressureSupport(BackpressureKind.FULL)
@SchedulerSupport(SchedulerSupport.NONE)
public static Flowable orderedMerge(Comparator comparator, Publisher... sources) {
return orderedMerge(comparator, false, Flowable.bufferSize(), sources);
}
/**
* Merges the source Publishers in an ordered fashion picking the smallest of the available value from
* them (determined by the Comparator) and allows delaying any error they may signal.
* @param the value type of all sources
* @param sources the iterable sequence of sources
* @param comparator the comparator to use for comparing items;
* it is called with the last known smallest in its first argument
* @param delayErrors if true, source errors are delayed until all sources terminate in some way
* @return the new Flowable instance
*
* @since 0.8.0
*/
@BackpressureSupport(BackpressureKind.FULL)
@SchedulerSupport(SchedulerSupport.NONE)
public static Flowable orderedMerge(Comparator comparator, boolean delayErrors, Publisher... sources) {
return orderedMerge(comparator, delayErrors, Flowable.bufferSize(), sources);
}
/**
* Merges the source Publishers in an ordered fashion picking the smallest of the available value from
* them (determined by the Comparator), allows delaying any error they may signal and sets the prefetch
* amount when requesting from these Publishers.
* @param the value type of all sources
* @param sources the iterable sequence of sources
* @param comparator the comparator to use for comparing items;
* it is called with the last known smallest in its first argument
* @param delayErrors if true, source errors are delayed until all sources terminate in some way
* @param prefetch the number of items to prefetch from the sources
* @return the new Flowable instance
*
* @since 0.8.0
*/
@BackpressureSupport(BackpressureKind.FULL)
@SchedulerSupport(SchedulerSupport.NONE)
public static Flowable orderedMerge(Comparator comparator, boolean delayErrors, int prefetch, Publisher... sources) {
ObjectHelper.requireNonNull(comparator, "comparator is null");
ObjectHelper.requireNonNull(sources, "sources is null");
ObjectHelper.verifyPositive(prefetch, "prefetch");
return RxJavaPlugins.onAssembly(new FlowableOrderedMerge(sources, null, comparator, delayErrors, prefetch));
}
/**
* Merges the source Publishers in an ordered fashion picking the smallest of the available value from
* them (determined by the Comparator).
* @param the value type of all sources
* @param sources the iterable sequence of sources
* @param comparator the comparator to use for comparing items;
* it is called with the last known smallest in its first argument
* @return the new Flowable instance
*
* @since 0.8.0
*/
@BackpressureSupport(BackpressureKind.FULL)
@SchedulerSupport(SchedulerSupport.NONE)
public static Flowable orderedMerge(Iterable> sources, Comparator comparator) {
return orderedMerge(sources, comparator, false, Flowable.bufferSize());
}
/**
* Merges the source Publishers in an ordered fashion picking the smallest of the available value from
* them (determined by the Comparator) and allows delaying any error they may signal.
* @param the value type of all sources
* @param sources the iterable sequence of sources
* @param comparator the comparator to use for comparing items;
* it is called with the last known smallest in its first argument
* @param delayErrors if true, source errors are delayed until all sources terminate in some way
* @return the new Flowable instance
*
* @since 0.8.0
*/
@BackpressureSupport(BackpressureKind.FULL)
@SchedulerSupport(SchedulerSupport.NONE)
public static Flowable orderedMerge(Iterable> sources, Comparator comparator, boolean delayErrors) {
return orderedMerge(sources, comparator, delayErrors, Flowable.bufferSize());
}
/**
* Merges the source Publishers in an ordered fashion picking the smallest of the available value from
* them (determined by the Comparator), allows delaying any error they may signal and sets the prefetch
* amount when requesting from these Publishers.
* @param the value type of all sources
* @param sources the iterable sequence of sources
* @param comparator the comparator to use for comparing items;
* it is called with the last known smallest in its first argument
* @param delayErrors if true, source errors are delayed until all sources terminate in some way
* @param prefetch the number of items to prefetch from the sources
* @return the new Flowable instance
*
* @since 0.8.0
*/
@BackpressureSupport(BackpressureKind.FULL)
@SchedulerSupport(SchedulerSupport.NONE)
public static Flowable orderedMerge(Iterable> sources, Comparator comparator, boolean delayErrors, int prefetch) {
ObjectHelper.requireNonNull(comparator, "comparator is null");
ObjectHelper.requireNonNull(sources, "sources is null");
ObjectHelper.verifyPositive(prefetch, "prefetch");
return RxJavaPlugins.onAssembly(new FlowableOrderedMerge(null, sources, comparator, delayErrors, prefetch));
}
/**
* Merges the source Publishers in an ordered fashion picking the smallest of the available value from
* them (determined by their natural order).
* @param the value type of all sources
* @param sources the iterable sequence of sources
* @return the new Flowable instance
*
* @since 0.8.0
*/
@BackpressureSupport(BackpressureKind.FULL)
@SchedulerSupport(SchedulerSupport.NONE)
public static > Flowable orderedMerge(Iterable> sources) {
return orderedMerge(sources, Functions.naturalOrder(), false, Flowable.bufferSize());
}
/**
* Merges the source Publishers in an ordered fashion picking the smallest of the available value from
* them (determined by their natural order) and allows delaying any error they may signal.
* @param the value type of all sources
* @param sources the iterable sequence of sources
* @param delayErrors if true, source errors are delayed until all sources terminate in some way
* @return the new Flowable instance
*
* @since 0.8.0
*/
@BackpressureSupport(BackpressureKind.FULL)
@SchedulerSupport(SchedulerSupport.NONE)
public static > Flowable orderedMerge(Iterable> sources, boolean delayErrors) {
return orderedMerge(sources, Functions.naturalOrder(), delayErrors, Flowable.bufferSize());
}
/**
* Merges the source Publishers in an ordered fashion picking the smallest of the available value from
* them (determined by their natural order), allows delaying any error they may signal and sets the prefetch
* amount when requesting from these Publishers.
* @param the value type of all sources
* @param sources the iterable sequence of sources
* @param delayErrors if true, source errors are delayed until all sources terminate in some way
* @param prefetch the number of items to prefetch from the sources
* @return the new Flowable instance
*
* @since 0.8.0
*/
@BackpressureSupport(BackpressureKind.FULL)
@SchedulerSupport(SchedulerSupport.NONE)
public static > Flowable orderedMerge(Iterable> sources, boolean delayErrors, int prefetch) {
return orderedMerge(sources, Functions.naturalOrder(), delayErrors, prefetch);
}
/**
* Repeats a scalar value indefinitely.
* @param the value type
* @param item the value to repeat
* @return the new Flowable instance
*
* @since 0.14.2
*/
@BackpressureSupport(BackpressureKind.FULL)
@SchedulerSupport(SchedulerSupport.NONE)
public static Flowable repeat(T item) {
ObjectHelper.requireNonNull(item, "item is null");
return RxJavaPlugins.onAssembly(new FlowableRepeatScalar(item));
}
/**
* Repeatedly calls the given Callable to produce items indefinitely.
* @param the value type
* @param callable the Callable to call
* @return the new Flowable instance
*
* @since 0.14.2
*/
@BackpressureSupport(BackpressureKind.FULL)
@SchedulerSupport(SchedulerSupport.NONE)
public static Flowable repeatCallable(Callable callable) {
ObjectHelper.requireNonNull(callable, "callable is null");
return RxJavaPlugins.onAssembly(new FlowableRepeatCallable(callable));
}
/**
* Periodically tries to emit an ever increasing long value or
* buffers (efficiently) such emissions until the downstream requests.
*
* - Backpressure:
* - The operator honors the backpressure of the downstream and
* no emission is lost, however, the timing of the reception of the
* values is now dependent on the downstream backpressure.
* - Scheduler:
* - The operator uses the {@code computation} {@link Scheduler} to time
* the emission and likely deliver the value (unless backpressured).
*
*
* @param period the emission period (including the delay for the first emission)
* @param unit the emission time unit
* @return the new Flowable instance
*
* @since 0.15.0
*/
@BackpressureSupport(BackpressureKind.FULL)
@SchedulerSupport(SchedulerSupport.COMPUTATION)
public static Flowable intervalBackpressure(long period, TimeUnit unit) {
return intervalBackpressure(period, period, unit, Schedulers.computation());
}
/**
* Periodically tries to emit an ever increasing long value or
* buffers (efficiently) such emissions until the downstream requests.
*
* - Backpressure:
* - The operator honors the backpressure of the downstream and
* no emission is lost, however, the timing of the reception of the
* values is now dependent on the downstream backpressure.
* - Scheduler:
* - The operator uses the {@code computation} {@link Scheduler} to time
* the emission and likely deliver the value (unless backpressured).
*
*
* @param period the emission period (including the delay for the first emission)
* @param unit the emission time unit
* @param scheduler the scheduler to use for timing and likely emitting items
* @return the new Flowable instance
*
* @since 0.15.0
*/
@BackpressureSupport(BackpressureKind.FULL)
@SchedulerSupport(SchedulerSupport.CUSTOM)
public static Flowable intervalBackpressure(long period, TimeUnit unit, Scheduler scheduler) {
return intervalBackpressure(period, period, unit, scheduler);
}
/**
* Periodically tries to emit an ever increasing long value or
* buffers (efficiently) such emissions until the downstream requests.
*
* - Backpressure:
* - The operator honors the backpressure of the downstream and
* no emission is lost, however, the timing of the reception of the
* values is now dependent on the downstream backpressure.
* - Scheduler:
* - The operator uses the {@code computation} {@link Scheduler} to time
* the emission and likely deliver the value (unless backpressured).
*
*
* @param initialDelay the initial delay before emitting the first 0L
* @param period the emission period after the first emission
* @param unit the emission time unit
* @return the new Flowable instance
*
* @since 0.15.0
*/
@BackpressureSupport(BackpressureKind.FULL)
@SchedulerSupport(SchedulerSupport.COMPUTATION)
public static Flowable intervalBackpressure(long initialDelay, long period, TimeUnit unit) {
return intervalBackpressure(initialDelay, period, unit, Schedulers.computation());
}
/**
* Periodically tries to emit an ever increasing long value or
* buffers (efficiently) such emissions until the downstream requests.
*
* - Backpressure:
* - The operator honors the backpressure of the downstream and
* no emission is lost, however, the timing of the reception of the
* values is now dependent on the downstream backpressure.
* - Scheduler:
* - The operator uses the {@link Scheduler} provided to time
* the emission and likely deliver the value (unless backpressured).
*
*
* @param initialDelay the initial delay before emitting the first 0L
* @param period the emission period (including the delay for the first emission)
* @param unit the emission time unit
* @param scheduler the scheduler to use for timing and likely emitting items
* @return the new Flowable instance
*
* @since 0.15.0
*/
@BackpressureSupport(BackpressureKind.FULL)
@SchedulerSupport(SchedulerSupport.CUSTOM)
public static Flowable intervalBackpressure(long initialDelay, long period, TimeUnit unit, Scheduler scheduler) {
return RxJavaPlugins.onAssembly(new FlowableIntervalBackpressure(initialDelay, period, unit, scheduler));
}
/**
* Zips the latest available values of the source Publishers via a combiner function where the
* emission rate is determined by the slowest Publisher and the downstream consumption rate.
*
* Non-consumed source values are overwritten by newer values. Unlike {@code combineLatest}, source
* values are not reused to form new combinations.
*
* If any of the sources runs out of items, the other sources are cancelled and the sequence completes.
*
* A: ---o-o-o------o-o----o---o-|-------
* B: ---------x-x--x-------x-----x--x---
* ======= zipLatest (o, x -> M) ========
* R: ---------M----M-------M-----M|-----
*
*
* - Backpressure:
* - The operator honors the backpressure of the downstream and consumes
* the source Publishers in an unbounded manner, keeping only their latest values temporarily.
* - Scheduler:
* - The operator doesn't run on any particular {@link Scheduler}
* and the combined item emission happens on the thread that won the internal emission-right race.
*
*
* @param the common source value type
* @param the result type
* @param combiner the function receiving the latest values of the sources and returns a value
* to be emitted to the downstream.
* @param sources the array of source Publishers to zip/combine
* @return the new Flowable instance.
*/
@BackpressureSupport(BackpressureKind.UNBOUNDED_IN)
@SchedulerSupport(SchedulerSupport.NONE)
public static Flowable zipLatest(Function combiner, Publisher... sources) {
return zipLatest(combiner, ImmediateThinScheduler.INSTANCE, sources);
}
/**
* Zips the latest available values of the source Publishers via a combiner function where the
* emission rate is determined by the slowest Publisher and the downstream consumption rate.
*
* Non-consumed source values are overwritten by newer values. Unlike {@code combineLatest}, source
* values are not reused to form new combinations.
*
* If any of the sources runs out of items, the other sources are cancelled and the sequence completes.
*
* A: ---o-o-o------o-o----o---o-|-------
* B: ---------x-x--x-------x-----x--x---
* ======= zipLatest (o, x -> M) ========
* R: ---------M----M-------M-----M|-----
*
*
* - Backpressure:
* - The operator honors the backpressure of the downstream and consumes
* the source Publishers in an unbounded manner, keeping only their latest values temporarily.
* - Scheduler:
* - The operator emits the combined items on the {@link Scheduler} provided.
*
*
* @param the common source value type
* @param the result type
* @param combiner the function receiving the latest values of the sources and returns a value
* to be emitted to the downstream.
* @param sources the array of source Publishers to zip/combine
* @param scheduler the Scheduler to use for emitting items and/or terminal signals
* @return the new Flowable instance.
*/
@BackpressureSupport(BackpressureKind.UNBOUNDED_IN)
@SchedulerSupport(SchedulerSupport.CUSTOM)
public static Flowable zipLatest(Function combiner, Scheduler scheduler, Publisher... sources) {
ObjectHelper.requireNonNull(combiner, "combiner is null");
ObjectHelper.requireNonNull(scheduler, "scheduler is null");
ObjectHelper.requireNonNull(sources, "sources is null");
return RxJavaPlugins.onAssembly(new FlowableZipLatest(sources, null, combiner, scheduler));
}
/**
* Zips the latest available values of the source Publishers via a combiner function where the
* emission rate is determined by the slowest Publisher and the downstream consumption rate.
*
* Non-consumed source values are overwritten by newer values. Unlike {@code combineLatest}, source
* values are not reused to form new combinations.
*
* If any of the sources runs out of items, the other sources are cancelled and the sequence completes.
*
* A: ---o-o-o------o-o----o---o-|-------
* B: ---------x-x--x-------x-----x--x---
* ======= zipLatest (o, x -> M) ========
* R: ---------M----M-------M-----M|-----
*
*
* - Backpressure:
* - The operator honors the backpressure of the downstream and consumes
* the source Publishers in an unbounded manner, keeping only their latest values temporarily.
* - Scheduler:
* - The operator doesn't run on any particular {@link Scheduler} scheduler
* and the combined item emission happens on the thread that won the internal emission-right race.
*
*
* @param the common source value type
* @param the result type
* @param combiner the function receiving the latest values of the sources and returns a value
* to be emitted to the downstream.
* @param sources the array of source Publishers to zip/combine
* @return the new Flowable instance.
*/
@BackpressureSupport(BackpressureKind.UNBOUNDED_IN)
@SchedulerSupport(SchedulerSupport.NONE)
public static Flowable zipLatest(Iterable> sources, Function combiner) {
return zipLatest(sources, combiner, ImmediateThinScheduler.INSTANCE);
}
/**
* Zips the latest available values of the source Publishers via a combiner function where the
* emission rate is determined by the slowest Publisher and the downstream consumption rate.
*
* Non-consumed source values are overwritten by newer values. Unlike {@code combineLatest}, source
* values are not reused to form new combinations.
*
* If any of the sources runs out of items, the other sources are cancelled and the sequence completes.
*
* A: ---o-o-o------o-o----o---o-|-------
* B: ---------x-x--x-------x-----x--x---
* ======= zipLatest (o, x -> M) ========
* R: ---------M----M-------M-----M|-----
*
*
* - Backpressure:
* - The operator honors the backpressure of the downstream and consumes
* the source Publishers in an unbounded manner, keeping only their latest values temporarily.
* - Scheduler:
* - The operator emits the combined items on the {@link Scheduler} provided.
*
*
* @param the common source value type
* @param the result type
* @param combiner the function receiving the latest values of the sources and returns a value
* to be emitted to the downstream.
* @param sources the array of source Publishers to zip/combine
* @param scheduler the Scheduler to use for emitting items and/or terminal signals
* @return the new Flowable instance.
*/
@BackpressureSupport(BackpressureKind.UNBOUNDED_IN)
@SchedulerSupport(SchedulerSupport.CUSTOM)
public static Flowable zipLatest(Iterable> sources, Function combiner, Scheduler scheduler) {
ObjectHelper.requireNonNull(sources, "sources is null");
ObjectHelper.requireNonNull(combiner, "combiner is null");
ObjectHelper.requireNonNull(scheduler, "scheduler is null");
return RxJavaPlugins.onAssembly(new FlowableZipLatest(null, sources, combiner, scheduler));
}
/**
* Zips the latest available values of the source Publishers via a combiner function where the
* emission rate is determined by the slowest Publisher and the downstream consumption rate.
*
* Non-consumed source values are overwritten by newer values. Unlike {@code combineLatest}, source
* values are not reused to form new combinations.
*
* If any of the sources runs out of items, the other sources are cancelled and the sequence completes.
*
* A: ---o-o-o------o-o----o---o-|-------
* B: ---------x-x--x-------x-----x--x---
* ======= zipLatest (o, x -> M) ========
* R: ---------M----M-------M-----M|-----
*
*
* - Backpressure:
* - The operator honors the backpressure of the downstream and consumes
* the source Publishers in an unbounded manner, keeping only their latest values temporarily.
* - Scheduler:
* - The operator doesn't run on any particular {@link Scheduler} scheduler
* and the combined item emission happens on the thread that won the internal emission-right race.
*
*
* @param the value type of the first source Publisher
* @param the value type of the second source Publisher
* @param the result type
* @param combiner the function receiving the latest values of the sources and returns a value
* to be emitted to the downstream.
* @param source1 the first source Publisher instance
* @param source2 the second source Publisher instance
* @return the new Flowable instance.
*/
@BackpressureSupport(BackpressureKind.UNBOUNDED_IN)
@SchedulerSupport(SchedulerSupport.NONE)
public static Flowable zipLatest(Publisher source1, Publisher source2, BiFunction combiner) {
return zipLatest(source1, source2, combiner, ImmediateThinScheduler.INSTANCE);
}
/**
* Zips the latest available values of the source Publishers via a combiner function where the
* emission rate is determined by the slowest Publisher and the downstream consumption rate.
*
* Non-consumed source values are overwritten by newer values. Unlike {@code combineLatest}, source
* values are not reused to form new combinations.
*
* If any of the sources runs out of items, the other sources are cancelled and the sequence completes.
*
* A: ---o-o-o------o-o----o---o-|-------
* B: ---------x-x--x-------x-----x--x---
* ======= zipLatest (o, x -> M) ========
* R: ---------M----M-------M-----M|-----
*
*
* - Backpressure:
* - The operator honors the backpressure of the downstream and consumes
* the source Publishers in an unbounded manner, keeping only their latest values temporarily.
* - Scheduler:
* - The operator emits the combined items on the {@link Scheduler} provided.
*
*
* @param the value type of the first source Publisher
* @param the value type of the second source Publisher
* @param the result type
* @param combiner the function receiving the latest values of the sources and returns a value
* to be emitted to the downstream.
* @param source1 the first source Publisher instance
* @param source2 the second source Publisher instance
* @param scheduler the Scheduler to use for emitting items and/or terminal signals
* @return the new Flowable instance.
*/
@BackpressureSupport(BackpressureKind.UNBOUNDED_IN)
@SchedulerSupport(SchedulerSupport.CUSTOM)
@SuppressWarnings("unchecked")
public static Flowable zipLatest(Publisher source1, Publisher source2, BiFunction combiner, Scheduler scheduler) {
ObjectHelper.requireNonNull(source1, "source1 is null");
ObjectHelper.requireNonNull(source2, "source2 is null");
ObjectHelper.requireNonNull(combiner, "combiner is null");
ObjectHelper.requireNonNull(scheduler, "scheduler is null");
return RxJavaPlugins.onAssembly(new FlowableZipLatest(
new Publisher[] { source1, source2 }, null,
Functions.toFunction(combiner), scheduler));
}
/**
* Zips the latest available values of the source Publishers via a combiner function where the
* emission rate is determined by the slowest Publisher and the downstream consumption rate.
*
* Non-consumed source values are overwritten by newer values. Unlike {@code combineLatest}, source
* values are not reused to form new combinations.
*
* If any of the sources runs out of items, the other sources are cancelled and the sequence completes.
*
* A: ---o-o-o------o-o----o---o-|-------
* B: ---------x-x--x-------x-----x--x---
* ======= zipLatest (o, x -> M) ========
* R: ---------M----M-------M-----M|-----
*
*
* - Backpressure:
* - The operator honors the backpressure of the downstream and consumes
* the source Publishers in an unbounded manner, keeping only their latest values temporarily.
* - Scheduler:
* - The operator doesn't run on any particular {@link Scheduler} scheduler
* and the combined item emission happens on the thread that won the internal emission-right race.
*
*
* @param the value type of the first source Publisher
* @param the value type of the second source Publisher
* @param the value type of the third source Publisher
* @param the result type
* @param combiner the function receiving the latest values of the sources and returns a value
* to be emitted to the downstream.
* @param source1 the first source Publisher instance
* @param source2 the second source Publisher instance
* @param source3 the third source Publisher instance
* @return the new Flowable instance.
*/
@BackpressureSupport(BackpressureKind.UNBOUNDED_IN)
@SchedulerSupport(SchedulerSupport.NONE)
public static Flowable zipLatest(Publisher source1, Publisher source2,
Publisher source3, Function3 combiner) {
return zipLatest(source1, source2, source3, combiner, ImmediateThinScheduler.INSTANCE);
}
/**
* Zips the latest available values of the source Publishers via a combiner function where the
* emission rate is determined by the slowest Publisher and the downstream consumption rate.
*
* Non-consumed source values are overwritten by newer values. Unlike {@code combineLatest}, source
* values are not reused to form new combinations.
*
* If any of the sources runs out of items, the other sources are cancelled and the sequence completes.
*
* A: ---o-o-o------o-o----o---o-|-------
* B: ---------x-x--x-------x-----x--x---
* ======= zipLatest (o, x -> M) ========
* R: ---------M----M-------M-----M|-----
*
*
* - Backpressure:
* - The operator honors the backpressure of the downstream and consumes
* the source Publishers in an unbounded manner, keeping only their latest values temporarily.
* - Scheduler:
* - The operator emits the combined items on the {@link Scheduler} provided.
*
*
* @param the value type of the first source Publisher
* @param the value type of the second source Publisher
* @param the value type of the third source Publisher
* @param the result type
* @param combiner the function receiving the latest values of the sources and returns a value
* to be emitted to the downstream.
* @param source1 the first source Publisher instance
* @param source2 the second source Publisher instance
* @param source3 the third source Publisher instance
* @param scheduler the Scheduler to use for emitting items and/or terminal signals
* @return the new Flowable instance.
*/
@BackpressureSupport(BackpressureKind.UNBOUNDED_IN)
@SchedulerSupport(SchedulerSupport.CUSTOM)
@SuppressWarnings("unchecked")
public static Flowable zipLatest(Publisher source1, Publisher source2,
Publisher source3, Function3 combiner,
Scheduler scheduler) {
ObjectHelper.requireNonNull(source1, "source1 is null");
ObjectHelper.requireNonNull(source2, "source2 is null");
ObjectHelper.requireNonNull(source3, "source3 is null");
ObjectHelper.requireNonNull(combiner, "combiner is null");
ObjectHelper.requireNonNull(scheduler, "scheduler is null");
return RxJavaPlugins.onAssembly(new FlowableZipLatest(
new Publisher[] { source1, source2, source3 }, null,
Functions.toFunction(combiner), scheduler));
}
/**
* Zips the latest available values of the source Publishers via a combiner function where the
* emission rate is determined by the slowest Publisher and the downstream consumption rate.
*
* Non-consumed source values are overwritten by newer values. Unlike {@code combineLatest}, source
* values are not reused to form new combinations.
*
* If any of the sources runs out of items, the other sources are cancelled and the sequence completes.
*
* A: ---o-o-o------o-o----o---o-|-------
* B: ---------x-x--x-------x-----x--x---
* ======= zipLatest (o, x -> M) ========
* R: ---------M----M-------M-----M|-----
*
*
* - Backpressure:
* - The operator honors the backpressure of the downstream and consumes
* the source Publishers in an unbounded manner, keeping only their latest values temporarily.
* - Scheduler:
* - The operator doesn't run on any particular {@link Scheduler} scheduler
* and the combined item emission happens on the thread that won the internal emission-right race.
*
*
* @param the value type of the first source Publisher
* @param the value type of the second source Publisher
* @param the value type of the third source Publisher
* @param the value type of the fourth source Publisher
* @param the result type
* @param combiner the function receiving the latest values of the sources and returns a value
* to be emitted to the downstream.
* @param source1 the first source Publisher instance
* @param source2 the second source Publisher instance
* @param source3 the third source Publisher instance
* @param source4 the fourth source Publisher instance
* @return the new Flowable instance.
*/
@BackpressureSupport(BackpressureKind.UNBOUNDED_IN)
@SchedulerSupport(SchedulerSupport.NONE)
public static Flowable zipLatest(Publisher source1, Publisher source2,
Publisher source3, Publisher source4,
Function4 combiner) {
return zipLatest(source1, source2, source3, source4, combiner, ImmediateThinScheduler.INSTANCE);
}
/**
* Zips the latest available values of the source Publishers via a combiner function where the
* emission rate is determined by the slowest Publisher and the downstream consumption rate.
*
* Non-consumed source values are overwritten by newer values. Unlike {@code combineLatest}, source
* values are not reused to form new combinations.
*
* If any of the sources runs out of items, the other sources are cancelled and the sequence completes.
*
* A: ---o-o-o------o-o----o---o-|-------
* B: ---------x-x--x-------x-----x--x---
* ======= zipLatest (o, x -> M) ========
* R: ---------M----M-------M-----M|-----
*
*
* - Backpressure:
* - The operator honors the backpressure of the downstream and consumes
* the source Publishers in an unbounded manner, keeping only their latest values temporarily.
* - Scheduler:
* - The operator emits the combined items on the {@link Scheduler} provided.
*
*
* @param the value type of the first source Publisher
* @param the value type of the second source Publisher
* @param the value type of the third source Publisher
* @param the value type of the fourth source Publisher
* @param the result type
* @param combiner the function receiving the latest values of the sources and returns a value
* to be emitted to the downstream.
* @param source1 the first source Publisher instance
* @param source2 the second source Publisher instance
* @param source3 the third source Publisher instance
* @param source4 the fourth source Publisher instance
* @param scheduler the Scheduler to use for emitting items and/or terminal signals
* @return the new Flowable instance.
*/
@BackpressureSupport(BackpressureKind.UNBOUNDED_IN)
@SchedulerSupport(SchedulerSupport.CUSTOM)
@SuppressWarnings("unchecked")
public static Flowable zipLatest(Publisher source1, Publisher source2,
Publisher source3, Publisher source4,
Function4 combiner,
Scheduler scheduler) {
ObjectHelper.requireNonNull(source1, "source1 is null");
ObjectHelper.requireNonNull(source2, "source2 is null");
ObjectHelper.requireNonNull(source3, "source3 is null");
ObjectHelper.requireNonNull(source4, "source4 is null");
ObjectHelper.requireNonNull(combiner, "combiner is null");
ObjectHelper.requireNonNull(scheduler, "scheduler is null");
return RxJavaPlugins.onAssembly(new FlowableZipLatest(
new Publisher[] { source1, source2, source3, source4 }, null,
Functions.toFunction(combiner), scheduler));
}
/**
* Generates items by invoking a callback, for each downstream request one by one, that sets up an
* asynchronous call to some API that eventually responds with an item, an error or termination, while
* making sure there is only one such outstanding API call in progress and honoring the
* backpressure of the downstream.
*
* This operator allows the bridging of the asynchronous and backpressurable world with the reactive world,
* where backpressure is the emergent effect of making sure there is only one outstanding API call
* at a time which responds with at most one item per invocation.
*
* Note that the implementation may have one outstanding API call even if the downstream hasn't requested more
* and as such, the resulting item may get cached until the downstream requests for more.
*
* During the async response, the invocation protocol of the {@link FlowableAsyncEmitter} should be as follows:
*
* (onNext | onNothing)? (onError | onComplete)?
*
* In words, an {@code onNext} or {@code onNothing} (which indicates this particular API call resulted in no
* items and the next API call can proceed) may be followed by a terminal event.
*
* The methods {@link FlowableAsyncEmitter#onNext(Object)}, {@link FlowableAsyncEmitter#onError(Throwable)},
* {@link FlowableAsyncEmitter#onComplete()} and {@link FlowableAsyncEmitter#onNothing()} should not be called
* concurrently with each other or outside the context of the generator. The rest of the
* {@link FlowableAsyncEmitter} methods are thread-safe.
*
* Example:
* Let's assume there is an async API with the following interface definition:
*
* interface AsyncAPI<T> extends AutoCloseable {
*
* CompletableFuture<Void> nextValue(Consumer<? super T> onValue);
*
* }
*
* When the call succeeds, the {@code onValue} is invoked with it. If there are no more items, the
* {@code CompletableFuture} returned by the last {@code nextValue} is completed (with null).
* If there is an error, the same {@code CompletableFuture} is completed exceptionally. Each
* {@code nextValue} invocation creates a fresh {@code CompletableFuture} which can be cancelled
* if necesary. {@code nextValue} should not be invoked again until the {@code onValue} callback
* has been notified.
* An instance of this API can be obtained on demand, thus the state of this operator consists of the
* {@code AsyncAPI} instance supplied for each individual {@code Subscriber}. The API can be transformed into
* a {@code Flowable} as follows:
*
* Flowable<Integer> source = Flowable.<Integer, AsyncAPI<Integer>>generateAsync(
*
* // create a fresh API instance for each individual Subscriber
* () -> new AsyncAPIImpl<Integer>(),
*
* // this BiFunction will be called once the operator is ready to receive the next item
* // and will invoke it again only when that item is delivered via emitter.onNext()
* (state, emitter) -> {
*
* // issue the async API call
* CompletableFuture<Void> f = state.nextValue(
*
* // handle the value received
* value -> {
*
* // we have the option to signal that item
* if (value % 2 == 0) {
* emitter.onNext(value);
* } else if (value == 101) {
* // or stop altogether, which will also trigger a cleanup
* emitter.onComplete();
* } else {
* // or drop it and have the operator start a new call
* emitter.onNothing();
* }
* }
* );
*
* // This API call may not produce further items or fail
* f.whenComplete((done, error) -> {
* // As per the CompletableFuture API, error != null is the error outcome,
* // done is always null due to the Void type
* if (error != null) {
* emitter.onError(error);
* } else {
* emitter.onComplete();
* }
* });
*
* // In case the downstream cancels, the current API call
* // should be cancelled as well
* emitter.replaceCancellable(() -> f.cancel(true));
*
* // some sources may want to create a fresh state object
* // after each invocation of this generator
* return state;
* },
*
* // cleanup the state object
* state -> { state.close(); }
* )
*
*
* - Backpressure:
* - The operator honors downstream backpressure.
* - Scheduler:
* - {@code generateAsync} does not operate by default on a particular {@link Scheduler}, however,
* the signals emitted through the {@link FlowableAsyncEmitter} may happen on any thread,
* depending on the asynchronous API.
*
* @param the generated item type
* @param the state associated with an individual subscription.
* @param initialState the {@link Callable} that returns a state object for each individual
* {@link org.reactivestreams.Subscriber Subscriber} to the returned {@code Flowable}.
* @param asyncGenerator the {@link BiFunction} called with the current state value and the
* {@link FlowableAsyncEmitter} object and should return a new state value
* as well as prepare and issue the async API call in a way that
* the call's outcome is (eventually) converted into {@code onNext}, {@code onError} or
* {@code onComplete} calls. The operator ensures the {@code BiFunction} is
* only invoked when the previous async call produced {@code onNext} item and
* this item has been delivered to the downstream.
* @param stateCleanup called at most once with the current state object to allow cleaning it up after
* the flow is cancelled or terminates via {@link FlowableAsyncEmitter#onError(Throwable)}
* or {@link FlowableAsyncEmitter#onComplete()}.
* @return the new Flowable instance
* @see Flowable#generate(Callable, BiFunction, Consumer)
* @see FlowableAsyncEmitter
* @since 0.18.9
*/
@CheckReturnValue
@BackpressureSupport(BackpressureKind.FULL)
@SchedulerSupport(SchedulerSupport.NONE)
public static Flowable generateAsync(Callable initialState, BiFunction, S> asyncGenerator, Consumer stateCleanup) {
ObjectHelper.requireNonNull(initialState, "initialState is null");
ObjectHelper.requireNonNull(asyncGenerator, "asyncGenerator is null");
ObjectHelper.requireNonNull(stateCleanup, "stateCleanup is null");
return RxJavaPlugins.onAssembly(new FlowableGenerateAsync(initialState, asyncGenerator, stateCleanup));
}
}