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/* |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
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* Expert Group and released to the public domain. Use, modify, and |
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* redistribute this code in any way without acknowledgement. |
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*/ |
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package java.util.concurrent; |
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|
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/** |
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* A {@link CompletionService} that uses a supplied {@link Executor} |
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* to execute tasks. |
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*/ |
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public class ExecutorCompletionService<V> implements CompletionService<V> { |
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private final Executor executor; |
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private final BlockingQueue<Future<V>> completionQueue; |
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|
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/** |
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* FutureTask extension to enqueue upon completion |
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*/ |
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private class QueueingFuture<T> extends FutureTask<T> { |
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QueueingFuture(Callable<T> c) { super(c); } |
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QueueingFuture(Runnable t, T r) { super(t, r); } |
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protected void done() { completionQueue.add((Future<V>)this); } |
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} |
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|
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/** |
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* Creates an ExecutorCompletionService using the supplied |
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* executor for base task execution and a |
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* {@link LinkedBlockingQueue} as a completion queue. |
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* @param executor the executor to use; normally |
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* one dedicated for use by this service |
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8 @throws NullPointerException if executor is <tt>null</tt> |
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*/ |
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public ExecutorCompletionService(Executor executor) { |
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if (executor == null) |
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throw new NullPointerException(); |
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this.executor = executor; |
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this.completionQueue = new LinkedBlockingQueue<Future<V>>(); |
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} |
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|
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/** |
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* Creates an ExecutorCompletionService using the supplied |
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* executor for base task execution and the supplied queue as its |
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* completion queue. |
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* @param executor the executor to use; normally |
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* one dedicated for use by this service |
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* @param completionQueue the queue to use as the completion queue; |
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* normally one dedicated for use by this service |
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8 @throws NullPointerException if executor or completionQueue are <tt>null</tt> |
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*/ |
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public ExecutorCompletionService(Executor executor, |
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BlockingQueue<Future<V>> completionQueue) { |
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if (executor == null || completionQueue == null) |
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throw new NullPointerException(); |
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this.executor = executor; |
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this.completionQueue = completionQueue; |
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} |
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public Future<V> submit(Callable<V> task) { |
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QueueingFuture<V> f = new QueueingFuture<V>(task); |
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executor.execute(f); |
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return f; |
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} |
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public Future<V> submit(Runnable task, V result) { |
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QueueingFuture<V> f = new QueueingFuture<V>(task, result); |
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executor.execute(f); |
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return f; |
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} |
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public Future<V> take() throws InterruptedException { |
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return completionQueue.take(); |
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} |
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public Future<V> poll() { |
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return completionQueue.poll(); |
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} |
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public Future<V> poll(long timeout, TimeUnit unit) throws InterruptedException { |
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return completionQueue.poll(timeout, unit); |
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} |
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} |
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