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Easy Redis Java client and Real-Time Data Platform. Valkey compatible. Sync/Async/RxJava3/Reactive API. Client side caching. Over 50 Redis based Java objects and services: JCache API, Apache Tomcat, Hibernate, Spring, Set, Multimap, SortedSet, Map, List, Queue, Deque, Semaphore, Lock, AtomicLong, Map Reduce, Bloom filter, Scheduler, RPC
/*
* Copyright (c) 2018-2023 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.util.Objects;
import java.util.concurrent.Callable;
import java.util.function.BiFunction;
import java.util.function.Function;
import org.reactivestreams.Publisher;
import org.reactivestreams.Subscriber;
import org.reactivestreams.Subscription;
import reactor.core.CoreSubscriber;
import reactor.core.Exceptions;
import reactor.core.publisher.FluxUsingWhen.UsingWhenSubscriber;
import reactor.core.publisher.Operators.DeferredSubscription;
import reactor.util.annotation.Nullable;
import reactor.util.context.Context;
/**
* 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, 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).
*
* @param the value type streamed
* @param the resource type
*/
final class MonoUsingWhen extends Mono implements SourceProducer {
final Publisher resourceSupplier;
final Function> resourceClosure;
final Function> asyncComplete;
final BiFunction> asyncError;
@Nullable
final Function> asyncCancel;
MonoUsingWhen(Publisher resourceSupplier,
Function> resourceClosure,
Function> asyncComplete,
BiFunction> asyncError,
@Nullable Function> asyncCancel) {
this.resourceSupplier = Objects.requireNonNull(resourceSupplier, "resourceSupplier");
this.resourceClosure = Objects.requireNonNull(resourceClosure, "resourceClosure");
this.asyncComplete = Objects.requireNonNull(asyncComplete, "asyncComplete");
this.asyncError = Objects.requireNonNull(asyncError, "asyncError");
this.asyncCancel = asyncCancel;
}
@Override
@SuppressWarnings("unchecked")
public void subscribe(CoreSubscriber actual) {
if (resourceSupplier instanceof Callable) {
try {
Callable resourceCallable = (Callable) resourceSupplier;
S resource = resourceCallable.call();
if (resource == null) {
Operators.complete(actual);
}
else {
final Mono p = deriveMonoFromResource(resource, resourceClosure);
final UsingWhenSubscriber subscriber = prepareSubscriberForResource(resource,
actual,
asyncComplete,
asyncError,
asyncCancel,
null);
fromDirect(p).subscribe(subscriber);
}
}
catch (Throwable e) {
Operators.error(actual, e);
}
return;
}
// Ensure onLastOperatorHook is called by invoking Publisher::subscribe(Subscriber)
((Publisher) Operators.toFluxOrMono(resourceSupplier)).subscribe(
new ResourceSubscriber(actual, resourceClosure, asyncComplete, asyncError, asyncCancel, resourceSupplier instanceof Mono));
}
@Override
public Object scanUnsafe(Attr key) {
if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC;
return SourceProducer.super.scanUnsafe(key);
}
private static Mono deriveMonoFromResource(
RESOURCE resource,
Function> resourceClosure) {
Mono p;
try {
p = Objects.requireNonNull(resourceClosure.apply(resource),
"The resourceClosure function returned a null value");
}
catch (Throwable e) {
p = Mono.error(e);
}
return p;
}
private static MonoUsingWhenSubscriber prepareSubscriberForResource(
RESOURCE resource,
CoreSubscriber actual,
Function> asyncComplete,
BiFunction> asyncError,
@Nullable Function> asyncCancel,
@Nullable DeferredSubscription arbiter) {
//MonoUsingWhen cannot support ConditionalSubscriber as there's no way to defer tryOnNext
return new MonoUsingWhenSubscriber<>(actual,
resource,
asyncComplete,
asyncError,
asyncCancel,
arbiter);
}
//needed to correctly call prepareSubscriberForResource with Mono.from conversions
static class ResourceSubscriber extends DeferredSubscription implements InnerConsumer {
final CoreSubscriber actual;
final Function> resourceClosure;
final Function> asyncComplete;
final BiFunction> asyncError;
@Nullable
final Function> asyncCancel;
final boolean isMonoSource;
Subscription resourceSubscription;
boolean resourceProvided;
ResourceSubscriber(CoreSubscriber actual,
Function> resourceClosure,
Function> asyncComplete,
BiFunction> asyncError,
@Nullable Function> asyncCancel,
boolean isMonoSource) {
this.actual = Objects.requireNonNull(actual, "actual");
this.resourceClosure = Objects.requireNonNull(resourceClosure, "resourceClosure");
this.asyncComplete = Objects.requireNonNull(asyncComplete, "asyncComplete");
this.asyncError = Objects.requireNonNull(asyncError, "asyncError");
this.asyncCancel = asyncCancel;
this.isMonoSource = isMonoSource;
}
@Override
public Context currentContext() {
return actual.currentContext();
}
@Override
public void onNext(S resource) {
if (resourceProvided) {
Operators.onNextDropped(resource, actual.currentContext());
return;
}
resourceProvided = true;
final Mono p = deriveMonoFromResource(resource, resourceClosure);
fromDirect(p).subscribe(MonoUsingWhen.prepareSubscriberForResource(resource,
this.actual,
this.asyncComplete,
this.asyncError,
this.asyncCancel,
this));
if (!isMonoSource) {
resourceSubscription.cancel();
}
}
@Override
public void onError(Throwable throwable) {
if (resourceProvided) {
Operators.onErrorDropped(throwable, actual.currentContext());
return;
}
//even if no resource provided, actual.onSubscribe has been called
//let's immediately fail actual
actual.onError(throwable);
}
@Override
public void onComplete() {
if (resourceProvided) {
return;
}
//even if no resource provided, actual.onSubscribe has been called
//let's immediately complete actual
actual.onComplete();
}
@Override
public void onSubscribe(Subscription s) {
if (Operators.validate(this.resourceSubscription, s)) {
this.resourceSubscription = s;
actual.onSubscribe(this);
s.request(Long.MAX_VALUE);
}
}
@Override
public void cancel() {
if (!resourceProvided) {
resourceSubscription.cancel();
}
super.cancel();
}
@Override
public Object scanUnsafe(Attr key) {
if (key == Attr.PARENT) return resourceSubscription;
if (key == Attr.ACTUAL) return actual;
if (key == Attr.PREFETCH) return Integer.MAX_VALUE;
if (key == Attr.TERMINATED) return resourceProvided;
if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC;
return null;
}
}
static class MonoUsingWhenSubscriber extends FluxUsingWhen.UsingWhenSubscriber {
MonoUsingWhenSubscriber(CoreSubscriber actual,
S resource,
Function> asyncComplete,
BiFunction> asyncError,
@Nullable Function> asyncCancel,
@Nullable DeferredSubscription arbiter) {
super(actual, resource, asyncComplete, asyncError, asyncCancel, arbiter);
}
T value;
@Override
public void onNext(T value) {
this.value = value;
}
@Override
public void deferredComplete() {
this.error = Exceptions.TERMINATED;
if (this.value != null) {
actual.onNext(value);
}
this.actual.onComplete();
}
@Override
public void deferredError(Throwable error) {
Operators.onDiscard(this.value, actual.currentContext());
this.error = error;
this.actual.onError(error);
}
}
}
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