ChannelFutureListener.java

package org.jboss.netty.channel;

import java.util.EventListener;

/**
 * Listens to the result of a {@link ChannelFuture}.  The result of the
 * asynchronous {@link Channel} I/O operation is notified once this listener
 * is added by calling {@link ChannelFuture#addListener(ChannelFutureListener)}.
 *
 * <h3>Return the control to the caller quickly</h3>
 *
 * {@link #operationComplete(ChannelFuture)} is directly called by an I/O
 * thread.  Therefore, performing a time consuming task or a blocking operation
 * in the handler method can cause an unexpected pause during I/O.  If you need
 * to perform a blocking operation on I/O completion, try to execute the
 * operation in a different thread using a thread pool.
 */
public interface ChannelFutureListener extends EventListener {

    /**
     * A {@link ChannelFutureListener} that closes the {@link Channel} which is
     * associated with the specified {@link ChannelFuture}.
     */
    ChannelFutureListener CLOSE = new ChannelFutureListener() {
        public void operationComplete(ChannelFuture future) {
            future.getChannel().close();
        }
    };

    /**
     * A {@link ChannelFutureListener} that closes the {@link Channel} when the
     * operation ended up with a failure or cancellation rather than a success.
     */
    ChannelFutureListener CLOSE_ON_FAILURE = new ChannelFutureListener() {
        public void operationComplete(ChannelFuture future) {
            if (!future.isSuccess()) {
                future.getChannel().close();
            }
        }
    };

    /**
     * Invoked when the I/O operation associated with the {@link ChannelFuture}
     * has been completed.
     *
     * @param future  the source {@link ChannelFuture} which called this
     *                callback
     */
    void operationComplete(ChannelFuture future) throws Exception;
}