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/* |
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* Written by Doug Lea and Martin Buchholz with assistance from members of |
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* JCP JSR-166 Expert Group and released to the public domain, as explained |
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* at http://creativecommons.org/publicdomain/zero/1.0/ |
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*/ |
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|
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import java.util.concurrent.*; |
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import java.util.concurrent.atomic.*; |
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|
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/** |
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* Tries to demonstrate a leaked interrupt. |
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*/ |
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public class FutureTaskCancelLoops { |
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static final AtomicLong count = new AtomicLong(0); |
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|
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static volatile Future<?> cancelMe = null; |
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|
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static volatile boolean leakedInterrupt = false; |
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|
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static class InterruptMeTask extends FutureTask<Void> { |
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static class InterruptMe implements Runnable { |
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volatile Future<?> myFuture; |
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|
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public void run() { |
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assert myFuture != null; |
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if (cancelMe != null) { |
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// We're likely to get the interrupt meant for previous task. |
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// Clear interrupts first to prove *we* got interrupted. |
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Thread.interrupted(); |
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while (cancelMe != null && !leakedInterrupt) { |
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if (Thread.interrupted()) { |
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leakedInterrupt = true; |
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System.err.println("leaked interrupt!"); |
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} |
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} |
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} else { |
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cancelMe = myFuture; |
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do {} while (! myFuture.isCancelled() && !leakedInterrupt); |
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} |
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count.getAndIncrement(); |
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} |
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} |
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InterruptMeTask() { this(new InterruptMe()); } |
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InterruptMeTask(InterruptMe r) { |
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super(r, null); |
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r.myFuture = this; |
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} |
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} |
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|
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static long millisElapsedSince(long startTimeNanos) { |
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return (System.nanoTime() - startTimeNanos)/(1000L*1000L); |
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} |
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|
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public static void main(String[] args) throws Exception { |
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long startTime = System.nanoTime(); |
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final ThreadPoolExecutor pool = |
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new ThreadPoolExecutor(1, 1, |
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0L, TimeUnit.MILLISECONDS, |
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new LinkedBlockingQueue<Runnable>(10000)); |
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|
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final Thread cancelBot = new Thread(new Runnable() { |
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public void run() { |
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while (!leakedInterrupt) { |
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Future<?> future = cancelMe; |
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if (future != null) { |
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future.cancel(true); |
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cancelMe = null; |
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}}}}); |
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cancelBot.setDaemon(true); |
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cancelBot.start(); |
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|
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while (!leakedInterrupt && millisElapsedSince(startTime) < 1000L) { |
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try { |
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pool.execute(new InterruptMeTask()); |
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} catch (RejectedExecutionException ree) { |
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Thread.sleep(1); |
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} |
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} |
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pool.shutdownNow(); |
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if (leakedInterrupt) { |
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String msg = String.format |
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("%d tasks run, %d millis elapsed, till leaked interrupt%n", |
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count.get(), millisElapsedSince(startTime)); |
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throw new IllegalStateException(msg); |
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} else { |
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System.out.printf |
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("%d tasks run, %d millis elapsed%n", |
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count.get(), millisElapsedSince(startTime)); |
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} |
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} |
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} |
