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package java.util.concurrent; |
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/** |
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* A cancellable asynchronous computation. |
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* |
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* <p><tt>FutureTask</tt> provides methods to start and cancel the |
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* computation, query to see if the computation is complete, and |
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* A cancellable asynchronous computation. This class provides a base |
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* implementation of {@link Future}, with methods to start and cancel |
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* a computation, query to see if the computation is complete, and |
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* retrieve the result of the computation. The result can only be |
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* retrieved when the computation has completed; the <tt>get</tt> |
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* method will block if the computation has not yet completed. Once |
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* the computation is completed, the result cannot be changed, nor can |
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* the computation be restarted or cancelled. |
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* |
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* <p>Because <tt>FutureTask</tt> implements <tt>Runnable</tt>, a |
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* <tt>FutureTask</tt> can be submitted to an {@link Executor} for |
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* current or deferred execution. |
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* |
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* <p>A <tt>FutureTask</tt> can be used to wrap a <tt>Callable</tt> or |
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* <tt>Runnable</tt> object so that it can be scheduled for execution in a |
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* thread or an <tt>Executor</tt>, cancel |
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* computation before the computation completes, and wait for or |
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* retrieve the results. If the computation threw an exception, the |
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* exception is propagated to any thread that attempts to retrieve the |
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* result. |
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* the computation has completed, the computation cannot be restarted |
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* or cancelled. |
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* |
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* @see Executor |
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* <p>A <tt>FutureTask</tt> can be used to wrap a {@link Callable} or |
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* {@link java.lang.Runnable} object. Because <tt>FutureTask</tt> |
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* implements <tt>Runnable</tt>, a <tt>FutureTask</tt> can be |
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* submitted to an {@link Executor} for execution. |
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* |
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* @since 1.5 |
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* @spec JSR-166 |
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* @revised $Date$ |
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* @editor $Author$ |
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* @author Doug Lea |
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*/ |
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public class FutureTask<V> extends CancellableTask implements Future<V> { |
