/*
 * Copyright (c) 2011-2017 Pivotal Software Inc, 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.RejectedExecutionException;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;

import org.reactivestreams.Subscription;
import reactor.core.CoreSubscriber;
import reactor.core.Disposable;
import reactor.core.Scannable;
import reactor.core.scheduler.Scheduler;
import reactor.util.annotation.Nullable;

Schedules the emission of the value or completion of the wrapped Mono via the given Scheduler.
Type parameters:
  • <T> – the value type
/** * Schedules the emission of the value or completion of the wrapped Mono via * the given Scheduler. * * @param <T> the value type */
final class MonoPublishOn<T> extends InternalMonoOperator<T, T> { final Scheduler scheduler; MonoPublishOn(Mono<? extends T> source, Scheduler scheduler) { super(source); this.scheduler = scheduler; } @Override public CoreSubscriber<? super T> subscribeOrReturn(CoreSubscriber<? super T> actual) { return new PublishOnSubscriber<T>(actual, scheduler); } @Override public Object scanUnsafe(Attr key) { if (key == Attr.RUN_ON) return scheduler; if (key == Attr.RUN_STYLE) return Attr.RunStyle.ASYNC; return super.scanUnsafe(key); } static final class PublishOnSubscriber<T> implements InnerOperator<T, T>, Runnable { final CoreSubscriber<? super T> actual; final Scheduler scheduler; Subscription s; volatile Disposable future; @SuppressWarnings("rawtypes") static final AtomicReferenceFieldUpdater<PublishOnSubscriber, Disposable> FUTURE = AtomicReferenceFieldUpdater.newUpdater(PublishOnSubscriber.class, Disposable.class, "future"); volatile T value; @SuppressWarnings("rawtypes") static final AtomicReferenceFieldUpdater<PublishOnSubscriber, Object> VALUE = AtomicReferenceFieldUpdater.newUpdater(PublishOnSubscriber.class, Object.class, "value"); volatile Throwable error; PublishOnSubscriber(CoreSubscriber<? super T> actual, Scheduler scheduler) { this.actual = actual; this.scheduler = scheduler; } @Override @Nullable public Object scanUnsafe(Attr key) { if (key == Attr.CANCELLED) return future == OperatorDisposables.DISPOSED; if (key == Attr.PARENT) return s; if (key == Attr.ERROR) return error; if (key == Attr.RUN_ON) return scheduler; if (key == Attr.RUN_STYLE) return Attr.RunStyle.ASYNC; return InnerOperator.super.scanUnsafe(key); } @Override public CoreSubscriber<? super T> actual() { return actual; } @Override public void onSubscribe(Subscription s) { if (Operators.validate(this.s, s)) { this.s = s; actual.onSubscribe(this); } } @Override public void onNext(T t) { value = t; trySchedule(this, null, t); } @Override public void onError(Throwable t) { error = t; trySchedule(null, t, null); } @Override public void onComplete() { if (value == null) { trySchedule(null, null, null); } } void trySchedule( @Nullable Subscription subscription, @Nullable Throwable suppressed, @Nullable Object dataSignal) { if(future != null){ return; } try { future = this.scheduler.schedule(this); } catch (RejectedExecutionException ree) { actual.onError(Operators.onRejectedExecution(ree, subscription, suppressed, dataSignal, actual.currentContext())); } } @Override public void request(long n) { s.request(n); } @Override public void cancel() { Disposable c = future; if (c != OperatorDisposables.DISPOSED) { c = FUTURE.getAndSet(this, OperatorDisposables.DISPOSED); if (c != null && !OperatorDisposables.isDisposed(c)) { c.dispose(); } value = null; } s.cancel(); } @Override @SuppressWarnings("unchecked") public void run() { if (OperatorDisposables.isDisposed(future)) { return; } T v = (T)VALUE.getAndSet(this, null); if (v != null) { actual.onNext(v); actual.onComplete(); } else { Throwable e = error; if (e != null) { actual.onError(e); } else { actual.onComplete(); } } } } }