FutureListener.java

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package com.sun.jersey.api.client.async;

import java.util.concurrent.CancellationException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;

/**
 * A future listener to receive an event when a Future has reached the
 * completed termination state of normal termination, an exception
 * or cancellation.
 * 
 * @param <T> the type held by the future.
 * @author Paul.Sandoz@Sun.Com
 */
public interface FutureListener<T> {

    /**
     * Invoked when a Future has reached the completed termination state.
     * <p>
     * The catching of a {@link ExecutionException} when
     * <code>Future.get</code> is invoked may be utilized to determine if the
     * future terminated with an exception. The exception can be obtained
     * by invoking {@link ExecutionException#getCause() }.
     * <p>
     * The catching of a {@link CancellationException} when 
     * <code>Future.get</code> is invoked may be utilized to determine if the
     * future terminated with a cancellation.
     *
     * @param f the completed Future. Invocation of {@link Future#isDone() }
     *        will return true. Since the future is complete invocation of
     *        {@link Future#get() } and {@link Future#get(long, java.util.concurrent.TimeUnit) }
     *        will not result in the throwing of an {@link InterruptedException}.
     * @throws InterruptedException this exception is declared so that the
     *         developer does not need to catch it when invoking
     *         <code>Future.get</code>.
     */
    void onComplete(Future<T> f) throws InterruptedException;
}