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| 1 | +/*************************************************** |
| 2 | + * Licensed under MIT No Attribution (SPDX: MIT-0) * |
| 3 | + ***************************************************/ |
| 4 | +package org.reactivestreams.example.unicast; |
| 5 | + |
| 6 | +import org.reactivestreams.Publisher; |
| 7 | +import org.reactivestreams.Subscriber; |
| 8 | +import org.reactivestreams.Subscription; |
| 9 | +import org.reactivestreams.tck.PublisherVerification; |
| 10 | +import org.reactivestreams.tck.TestEnvironment; |
| 11 | +import org.testng.annotations.AfterClass; |
| 12 | +import org.testng.annotations.BeforeClass; |
| 13 | +import org.testng.annotations.Test; |
| 14 | + |
| 15 | +import java.util.concurrent.BlockingQueue; |
| 16 | +import java.util.concurrent.Executor; |
| 17 | +import java.util.concurrent.ExecutorService; |
| 18 | +import java.util.concurrent.Executors; |
| 19 | +import java.util.concurrent.LinkedBlockingQueue; |
| 20 | + |
| 21 | +@Test // Must be here for TestNG to find and run this, do not remove |
| 22 | +public class AsyncRangePublisherTest extends PublisherVerification<Integer> { |
| 23 | + private static final int TERMINAL_DELAY_MS = 20; |
| 24 | + private static final int DEFAULT_TIMEOUT_MS = 5000; |
| 25 | + private static final int DEFAULT_POLL_INTERVAL_MS = TERMINAL_DELAY_MS / 2; |
| 26 | + private ExecutorService e; |
| 27 | + @BeforeClass |
| 28 | + void before() { e = Executors.newCachedThreadPool(); } |
| 29 | + @AfterClass |
| 30 | + void after() { if (e != null) e.shutdown(); } |
| 31 | + |
| 32 | + public AsyncRangePublisherTest() { |
| 33 | + super(new TestEnvironment(DEFAULT_TIMEOUT_MS, 50, DEFAULT_POLL_INTERVAL_MS)); |
| 34 | + } |
| 35 | + |
| 36 | + @Override |
| 37 | + public Publisher<Integer> createPublisher(long elements) { |
| 38 | + return new AsyncPublisher<Integer>(new RangePublisher(1, (int)elements), e); |
| 39 | + } |
| 40 | + |
| 41 | + @Override |
| 42 | + public Publisher<Integer> createFailedPublisher() { |
| 43 | + return null; |
| 44 | + } |
| 45 | + |
| 46 | + private static final class AsyncPublisher<T> implements Publisher<T> { |
| 47 | + private final Publisher<T> original; |
| 48 | + private final Executor executor; |
| 49 | + |
| 50 | + private AsyncPublisher(Publisher<T> original, Executor executor) { |
| 51 | + this.original = requireNonNull(original); |
| 52 | + this.executor = requireNonNull(executor); |
| 53 | + } |
| 54 | + |
| 55 | + @Override |
| 56 | + public void subscribe(Subscriber<? super T> s) { |
| 57 | + AsyncSubscriber.wrapAndSubscribe(original, requireNonNull(s), executor); |
| 58 | + } |
| 59 | + |
| 60 | + private static final class AsyncSubscriber<T> implements Subscriber<T> { |
| 61 | + private final BlockingQueue<Object> signalQueue = new LinkedBlockingQueue<Object>(); |
| 62 | + |
| 63 | + static <T> void wrapAndSubscribe(final Publisher<T> publisher, |
| 64 | + final Subscriber<? super T> targetSubscriber, final Executor executor) { |
| 65 | + final AsyncSubscriber<T> asyncSubscriber = new AsyncSubscriber<T>(); |
| 66 | + try { |
| 67 | + executor.execute(new Runnable() { |
| 68 | + private Subscription subscription; |
| 69 | + private boolean terminated; |
| 70 | + @Override |
| 71 | + public void run() { |
| 72 | + try { |
| 73 | + for (; ; ) { |
| 74 | + final Object signal = asyncSubscriber.signalQueue.take(); |
| 75 | + if (signal instanceof Cancelled) { |
| 76 | + return; |
| 77 | + } else if (signal instanceof TerminalSignal) { |
| 78 | + // sleep intentional to verify TestEnvironment.expectError behavior. |
| 79 | + Thread.sleep(TERMINAL_DELAY_MS); |
| 80 | + |
| 81 | + TerminalSignal terminalSignal = (TerminalSignal) signal; |
| 82 | + terminated = true; |
| 83 | + if (terminalSignal.cause == null) { |
| 84 | + targetSubscriber.onComplete(); |
| 85 | + } else { |
| 86 | + targetSubscriber.onError(terminalSignal.cause); |
| 87 | + } |
| 88 | + return; |
| 89 | + } else if (signal instanceof OnSubscribeSignal) { |
| 90 | + // We distribute the subscription downstream and may also call cancel on this |
| 91 | + // thread if an exception is thrown. Since there is no concurrency allowed, make |
| 92 | + // the subscription safe for concurrency. |
| 93 | + subscription = concurrentSafe(((OnSubscribeSignal) signal).subscription); |
| 94 | + targetSubscriber.onSubscribe(subscription); |
| 95 | + } else { |
| 96 | + @SuppressWarnings("unchecked") final T onNextSignal = ((OnNextSignal<T>) signal).onNext; |
| 97 | + targetSubscriber.onNext(onNextSignal); |
| 98 | + } |
| 99 | + } |
| 100 | + } catch (Throwable cause) { |
| 101 | + if (!terminated) { |
| 102 | + try { |
| 103 | + if (subscription == null) { |
| 104 | + targetSubscriber.onSubscribe(noopSubscription()); |
| 105 | + } else { |
| 106 | + subscription.cancel(); |
| 107 | + } |
| 108 | + } finally { |
| 109 | + terminated = true; |
| 110 | + targetSubscriber.onError(new IllegalStateException("run loop interrupted", cause)); |
| 111 | + } |
| 112 | + } |
| 113 | + } |
| 114 | + } |
| 115 | + }); |
| 116 | + } catch (Throwable cause) { |
| 117 | + try { |
| 118 | + targetSubscriber.onSubscribe(noopSubscription()); |
| 119 | + } finally { |
| 120 | + targetSubscriber.onError(new IllegalStateException("Executor rejected", cause)); |
| 121 | + } |
| 122 | + // Publisher rejected the target subscriber and terminated it, don't continue to subscribe to avoid |
| 123 | + // duplicate termination. |
| 124 | + return; |
| 125 | + } |
| 126 | + publisher.subscribe(asyncSubscriber); |
| 127 | + } |
| 128 | + |
| 129 | + @Override |
| 130 | + public void onSubscribe(final Subscription s) { |
| 131 | + signalQueue.add(new OnSubscribeSignal(new Subscription() { |
| 132 | + @Override |
| 133 | + public void request(long n) { |
| 134 | + s.request(n); |
| 135 | + } |
| 136 | + |
| 137 | + @Override |
| 138 | + public void cancel() { |
| 139 | + try { |
| 140 | + s.cancel(); |
| 141 | + } finally { |
| 142 | + signalQueue.add(new Cancelled()); |
| 143 | + } |
| 144 | + } |
| 145 | + })); |
| 146 | + } |
| 147 | + |
| 148 | + @Override |
| 149 | + public void onNext(T t) { |
| 150 | + signalQueue.add(new OnNextSignal<T>(t)); |
| 151 | + } |
| 152 | + |
| 153 | + @Override |
| 154 | + public void onError(Throwable t) { |
| 155 | + signalQueue.add(new TerminalSignal(requireNonNull(t))); |
| 156 | + } |
| 157 | + |
| 158 | + @Override |
| 159 | + public void onComplete() { |
| 160 | + signalQueue.add(new TerminalSignal(null)); |
| 161 | + } |
| 162 | + } |
| 163 | + |
| 164 | + private static Subscription concurrentSafe(final Subscription subscription) { |
| 165 | + // TODO: make concurrent safe. TCK interacts from the subscription concurrently so lock isn't sufficient. |
| 166 | + return subscription; |
| 167 | + } |
| 168 | + |
| 169 | + private static Subscription noopSubscription() { |
| 170 | + return new Subscription() { |
| 171 | + @Override |
| 172 | + public void request(long n) { |
| 173 | + } |
| 174 | + |
| 175 | + @Override |
| 176 | + public void cancel() { |
| 177 | + } |
| 178 | + }; |
| 179 | + } |
| 180 | + |
| 181 | + private static final class TerminalSignal { |
| 182 | + private final Throwable cause; |
| 183 | + |
| 184 | + private TerminalSignal(Throwable cause) { |
| 185 | + this.cause = cause; |
| 186 | + } |
| 187 | + } |
| 188 | + |
| 189 | + private static final class OnSubscribeSignal { |
| 190 | + private final Subscription subscription; |
| 191 | + |
| 192 | + private OnSubscribeSignal(Subscription subscription) { |
| 193 | + this.subscription = subscription; |
| 194 | + } |
| 195 | + } |
| 196 | + |
| 197 | + private static final class OnNextSignal<T> { |
| 198 | + private final T onNext; |
| 199 | + |
| 200 | + private OnNextSignal(T onNext) { |
| 201 | + this.onNext = onNext; |
| 202 | + } |
| 203 | + } |
| 204 | + |
| 205 | + private static final class Cancelled { |
| 206 | + } |
| 207 | + |
| 208 | + private static <T> T requireNonNull(T o) { |
| 209 | + if (o == null) { |
| 210 | + throw new NullPointerException(); |
| 211 | + } |
| 212 | + return o; |
| 213 | + } |
| 214 | + } |
| 215 | +} |
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