View Javadoc

    1   /*
    2    * Copyright 2009 Red Hat, Inc.
    3    *
    4    * Red Hat licenses this file to you under the Apache License, version 2.0
    5    * (the "License"); you may not use this file except in compliance with the
    6    * 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  /**
    19   * A {@link ChannelHandler} that is notified when it is added to or removed
    20   * from a {@link ChannelPipeline}.
    21   *
    22   * <h3>Invalid access to the {@link ChannelHandlerContext}</h3>
    23   *
    24   * Calling {@link ChannelHandlerContext#sendUpstream(ChannelEvent)} or
    25   * {@link ChannelHandlerContext#sendDownstream(ChannelEvent)} in
    26   * {@link #beforeAdd(ChannelHandlerContext)} or {@link #afterRemove(ChannelHandlerContext)}
    27   * might lead to an unexpected behavior.  It is because the context object
    28   * might not have been fully added to the pipeline or the context object is not
    29   * a part of the pipeline anymore respectively.
    30   *
    31   * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
    32   * @author <a href="http://gleamynode.net/">Trustin Lee</a>
    33   * @version $Rev: 2080 $, $Date: 2010-01-26 18:04:19 +0900 (Tue, 26 Jan 2010) $
    34   */
    35  public interface LifeCycleAwareChannelHandler extends ChannelHandler {
    36      void beforeAdd(ChannelHandlerContext ctx) throws Exception;
    37      void afterAdd(ChannelHandlerContext ctx) throws Exception;
    38      void beforeRemove(ChannelHandlerContext ctx) throws Exception;
    39      void afterRemove(ChannelHandlerContext ctx) throws Exception;
    40  }