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 /**
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 public interface LifeCycleAwareChannelHandler extends ChannelHandler {
32 void beforeAdd(ChannelHandlerContext ctx) throws Exception;
33 void afterAdd(ChannelHandlerContext ctx) throws Exception;
34 void beforeRemove(ChannelHandlerContext ctx) throws Exception;
35 void afterRemove(ChannelHandlerContext ctx) throws Exception;
36 }