View Javadoc

    1   /*
    2    * Copyright 2012 The Netty Project
    3    *
    4    * The Netty Project licenses this file to you under the Apache License,
    5    * version 2.0 (the "License"); you may not use this file except in compliance
    6    * with the License. You may obtain a copy of the License at:
    7    *
    8    *   http://www.apache.org/licenses/LICENSE-2.0
    9    *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
    12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
    13   * License for the specific language governing permissions and limitations
    14   * under the License.
    15   */
    16  package org.jboss.netty.channel;
    17
    18  import java.util.EventListener;
    19
    20  /**
    21   * Listens to the result of a {@link ChannelFuture}.  The result of the
    22   * asynchronous {@link Channel} I/O operation is notified once this listener
    23   * is added by calling {@link ChannelFuture#addListener(ChannelFutureListener)}.
    24   *
    25   * <h3>Return the control to the caller quickly</h3>
    26   *
    27   * {@link #operationComplete(ChannelFuture)} is directly called by an I/O
    28   * thread.  Therefore, performing a time consuming task or a blocking operation
    29   * in the handler method can cause an unexpected pause during I/O.  If you need
    30   * to perform a blocking operation on I/O completion, try to execute the
    31   * operation in a different thread using a thread pool.
    32   */
    33  public interface ChannelFutureListener extends EventListener {
    34
    35      /**
    36       * A {@link ChannelFutureListener} that closes the {@link Channel} which is
    37       * associated with the specified {@link ChannelFuture}.
    38       */
    39      ChannelFutureListener CLOSE = new ChannelFutureListener() {
    40          public void operationComplete(ChannelFuture future) {
    41              future.getChannel().close();
    42          }
    43      };
    44
    45      /**
    46       * A {@link ChannelFutureListener} that closes the {@link Channel} when the
    47       * operation ended up with a failure or cancellation rather than a success.
    48       */
    49      ChannelFutureListener CLOSE_ON_FAILURE = new ChannelFutureListener() {
    50          public void operationComplete(ChannelFuture future) {
    51              if (!future.isSuccess()) {
    52                  future.getChannel().close();
    53              }
    54          }
    55      };
    56
    57      /**
    58       * Invoked when the I/O operation associated with the {@link ChannelFuture}
    59       * has been completed.
    60       *
    61       * @param future  the source {@link ChannelFuture} which called this
    62       *                callback
    63       */
    64      void operationComplete(ChannelFuture future) throws Exception;
    65  }