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 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 * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
34 * @author <a href="http://gleamynode.net/">Trustin Lee</a>
35 *
36 * @version $Rev: 2185 $, $Date: 2010-02-19 14:13:48 +0900 (Fri, 19 Feb 2010) $
37 */
38 public interface ChannelFutureListener extends EventListener {
39
40 /**
41 * A {@link ChannelFutureListener} that closes the {@link Channel} which is
42 * associated with the specified {@link ChannelFuture}.
43 */
44 static ChannelFutureListener CLOSE = new ChannelFutureListener() {
45 public void operationComplete(ChannelFuture future) {
46 future.getChannel().close();
47 }
48 };
49
50 /**
51 * A {@link ChannelFutureListener} that closes the {@link Channel} when the
52 * operation ended up with a failure or cancellation rather than a success.
53 */
54 static ChannelFutureListener CLOSE_ON_FAILURE = new ChannelFutureListener() {
55 public void operationComplete(ChannelFuture future) {
56 if (!future.isSuccess()) {
57 future.getChannel().close();
58 }
59 }
60 };
61
62 /**
63 * Invoked when the I/O operation associated with the {@link ChannelFuture}
64 * has been completed.
65 *
66 * @param future the source {@link ChannelFuture} which called this
67 * callback
68 */
69 void operationComplete(ChannelFuture future) throws Exception;
70 }