/** * Copyright (c) 2016-present, RxJava Contributors. * * 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 com.github.davidmoten.rx2.flowable; import java.util.Arrays; import java.util.List; import java.util.Queue; import java.util.concurrent.ConcurrentLinkedQueue; import java.util.concurrent.atomic.AtomicLong; import org.reactivestreams.Subscriber; import org.reactivestreams.Subscription; import io.reactivex.Flowable; import io.reactivex.internal.subscriptions.SubscriptionHelper; import io.reactivex.internal.util.BackpressureHelper; /** * Creates {@link Flowable} of a number of items followed by either an error or * completion. Cancellation has no effect on preventing emissions until the * currently outstanding requests have been met. The primary purpose for the * existence of this class is testing that an operator that calls `onError` when * processing `onNext` for instance does not emit multiple terminal events. * * @param <T> * the value type */ public final class Burst<T> extends Flowable<T> { private final List<T> items; private final Throwable error; private Burst(Throwable error, List<T> items) { if (items.isEmpty()) { throw new IllegalArgumentException("items cannot be empty"); } for (T item : items) { if (item == null) { throw new IllegalArgumentException("items cannot include null"); } } this.error = error; this.items = items; } @Override protected void subscribeActual(final Subscriber<? super T> subscriber) { subscriber.onSubscribe(new Subscription() { final Queue<T> q = new ConcurrentLinkedQueue<T>(items); final AtomicLong requested = new AtomicLong(); volatile boolean cancelled; @Override public void request(long n) { if (cancelled) { // required by reactive-streams-jvm 3.6 return; } if (SubscriptionHelper.validate(n)) { // just for testing, don't care about perf // so no attempt made to reduce volatile reads if (BackpressureHelper.add(requested, n) == 0) { if (q.isEmpty()) { return; } while (!q.isEmpty() && requested.get() > 0) { T item = q.poll(); requested.decrementAndGet(); subscriber.onNext(item); } if (q.isEmpty()) { if (error != null) { subscriber.onError(error); } else { subscriber.onComplete(); } } } } } @Override public void cancel() { cancelled = true; } }); } @SuppressWarnings("unchecked") public static <T> Builder<T> item(T item) { return items(item); } public static <T> Builder<T> items(T... items) { return new Builder<T>(Arrays.asList(items)); } public static final class Builder<T> { private final List<T> items; private Throwable error; private Builder(List<T> items) { this.items = items; } public Flowable<T> error(Throwable e) { this.error = e; return create(); } public Flowable<T> create() { return new Burst<T>(error, items); } } }