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 }