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/*
* Copyright (c) 2016-2021 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.concurrent.atomic.AtomicReferenceFieldUpdater;
import java.util.function.Consumer;
import org.reactivestreams.Subscriber;
import org.reactivestreams.Subscription;
import reactor.core.Disposable;
import reactor.core.Exceptions;
import reactor.util.annotation.Nullable;
import reactor.util.context.Context;
import static reactor.core.Scannable.Attr.RUN_STYLE;
import static reactor.core.Scannable.Attr.RunStyle.SYNC;
/**
* An unbounded Java Lambda adapter to {@link Subscriber}, targeted at {@link Mono}.
*
* @param the value type
*/
final class LambdaMonoSubscriber implements InnerConsumer, Disposable {
final Consumer consumer;
final Consumer errorConsumer;
final Runnable completeConsumer;
final Consumer subscriptionConsumer;
final Context initialContext;
volatile Subscription subscription;
static final AtomicReferenceFieldUpdater S =
AtomicReferenceFieldUpdater.newUpdater(LambdaMonoSubscriber.class,
Subscription.class,
"subscription");
/**
* Create a {@link Subscriber} reacting onNext, onError and onComplete. The subscriber
* will automatically request Long.MAX_VALUE onSubscribe.
*
* The argument {@code subscriptionHandler} is executed once by new subscriber to
* generate a context shared by every request calls.
*
* @param consumer A {@link Consumer} with argument onNext data
* @param errorConsumer A {@link Consumer} called onError
* @param completeConsumer A {@link Runnable} called onComplete with the actual
* context if any
* @param subscriptionConsumer A {@link Consumer} called with the {@link Subscription}
* to perform initial request, or null to request max
* @param initialContext A {@link Context} for this subscriber, or null to use the default
* of an {@link Context#empty() empty Context}.
*/
LambdaMonoSubscriber(@Nullable Consumer consumer,
@Nullable Consumer errorConsumer,
@Nullable Runnable completeConsumer,
@Nullable Consumer subscriptionConsumer,
@Nullable Context initialContext) {
this.consumer = consumer;
this.errorConsumer = errorConsumer;
this.completeConsumer = completeConsumer;
this.subscriptionConsumer = subscriptionConsumer;
this.initialContext = initialContext == null ? Context.empty() : initialContext;
}
/**
* Create a {@link Subscriber} reacting onNext, onError and onComplete. The subscriber
* will automatically request Long.MAX_VALUE onSubscribe.
*
* The argument {@code subscriptionHandler} is executed once by new subscriber to
* generate a context shared by every request calls.
*
* @param consumer A {@link Consumer} with argument onNext data
* @param errorConsumer A {@link Consumer} called onError
* @param completeConsumer A {@link Runnable} called onComplete with the actual
* context if any
* @param subscriptionConsumer A {@link Consumer} called with the {@link Subscription}
* to perform initial request, or null to request max
*/ //left mainly for the benefit of tests
LambdaMonoSubscriber(@Nullable Consumer consumer,
@Nullable Consumer errorConsumer,
@Nullable Runnable completeConsumer,
@Nullable Consumer subscriptionConsumer) {
this(consumer, errorConsumer, completeConsumer, subscriptionConsumer, null);
}
@Override
public Context currentContext() {
return this.initialContext;
}
@Override
public final void onSubscribe(Subscription s) {
if (Operators.validate(subscription, s)) {
this.subscription = s;
if (subscriptionConsumer != null) {
try {
subscriptionConsumer.accept(s);
}
catch (Throwable t) {
Exceptions.throwIfFatal(t);
s.cancel();
onError(t);
}
}
else {
s.request(Long.MAX_VALUE);
}
}
}
@Override
public final void onComplete() {
Subscription s = S.getAndSet(this, Operators.cancelledSubscription());
if (s == Operators.cancelledSubscription()) {
return;
}
if (completeConsumer != null) {
try {
completeConsumer.run();
}
catch (Throwable t) {
Operators.onErrorDropped(t, this.initialContext);
}
}
}
@Override
public final void onError(Throwable t) {
Subscription s = S.getAndSet(this, Operators.cancelledSubscription());
if (s == Operators.cancelledSubscription()) {
Operators.onErrorDropped(t, this.initialContext);
return;
}
doError(t);
}
void doError(Throwable t) {
if (errorConsumer != null) {
errorConsumer.accept(t);
}
else {
Operators.onErrorDropped(Exceptions.errorCallbackNotImplemented(t), this.initialContext);
}
}
@Override
public final void onNext(T x) {
Subscription s = S.getAndSet(this, Operators.cancelledSubscription());
if (s == Operators.cancelledSubscription()) {
Operators.onNextDropped(x, this.initialContext);
return;
}
if (consumer != null) {
try {
consumer.accept(x);
}
catch (Throwable t) {
Exceptions.throwIfFatal(t);
s.cancel();
doError(t);
}
}
if (completeConsumer != null) {
try {
completeConsumer.run();
}
catch (Throwable t) {
Operators.onErrorDropped(t, this.initialContext);
}
}
}
@Override
@Nullable
public Object scanUnsafe(Attr key) {
if (key == Attr.PARENT) {
return subscription;
}
if (key == Attr.PREFETCH) {
return Integer.MAX_VALUE;
}
if (key == Attr.TERMINATED || key == Attr.CANCELLED) {
return isDisposed();
}
if (key == RUN_STYLE) {
return SYNC;
}
return null;
}
@Override
public boolean isDisposed() {
return subscription == Operators.cancelledSubscription();
}
@Override
public void dispose() {
Subscription s = S.getAndSet(this, Operators.cancelledSubscription());
if (s != null && s != Operators.cancelledSubscription()) {
s.cancel();
}
}
}