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.net.SocketAddress;
19
20
21 /**
22 * A {@link ChannelDownstreamHandler} which provides an individual handler
23 * method for each event type. This handler down-casts the received downstream
24 * event into more meaningful sub-type event and calls an appropriate handler
25 * method with the down-cast event. The names of the methods starts with the
26 * name of the operation and ends with {@code "Requested"}
27 * (e.g. {@link #writeRequested(ChannelHandlerContext, MessageEvent) writeRequested}.)
28 * <p>
29 * Please use {@link SimpleChannelHandler} if you need to implement both
30 * {@link ChannelUpstreamHandler} and {@link ChannelDownstreamHandler}.
31 *
32 * <h3>Overriding the {@link #handleDownstream(ChannelHandlerContext, ChannelEvent) handleDownstream} method</h3>
33 * <p>
34 * You can override the {@link #handleDownstream(ChannelHandlerContext, ChannelEvent) handleDownstream}
35 * method just like overriding an ordinary Java method. Please make sure to
36 * call {@code super.handleDownstream()} so that other handler methods are
37 * invoked properly:
38 * </p>
39 * <pre>public class MyChannelHandler extends {@link SimpleChannelDownstreamHandler} {
40 *
41 * {@code @Override}
42 * public void handleDownstream({@link ChannelHandlerContext} ctx, {@link ChannelEvent} e) throws Exception {
43 *
44 * // Log all channel state changes.
45 * if (e instanceof {@link MessageEvent}) {
46 * logger.info("Writing:: " + e);
47 * }
48 *
49 * <strong>super.handleDownstream(ctx, e);</strong>
50 * }
51 * }</pre>
52 * <p>
53 * <strong>Caution:</strong>
54 * <p>
55 * Use the *Later(..) methods of the {@link Channels} class if you want to send an upstream event
56 * from a {@link ChannelDownstreamHandler} otherwise you may run into threading issues.
57 *
58 */
59 public class SimpleChannelDownstreamHandler implements ChannelDownstreamHandler {
60
61 /**
62 * {@inheritDoc} Down-casts the received downstream event into more
63 * meaningful sub-type event and calls an appropriate handler method with
64 * the down-casted event.
65 */
66 public void handleDownstream(ChannelHandlerContext ctx, ChannelEvent e)
67 throws Exception {
68
69 if (e instanceof MessageEvent) {
70 writeRequested(ctx, (MessageEvent) e);
71 } else if (e instanceof ChannelStateEvent) {
72 ChannelStateEvent evt = (ChannelStateEvent) e;
73 switch (evt.getState()) {
74 case OPEN:
75 if (!Boolean.TRUE.equals(evt.getValue())) {
76 closeRequested(ctx, evt);
77 }
78 break;
79 case BOUND:
80 if (evt.getValue() != null) {
81 bindRequested(ctx, evt);
82 } else {
83 unbindRequested(ctx, evt);
84 }
85 break;
86 case CONNECTED:
87 if (evt.getValue() != null) {
88 connectRequested(ctx, evt);
89 } else {
90 disconnectRequested(ctx, evt);
91 }
92 break;
93 case INTEREST_OPS:
94 setInterestOpsRequested(ctx, evt);
95 break;
96 default:
97 ctx.sendDownstream(e);
98 }
99 } else {
100 ctx.sendDownstream(e);
101 }
102 }
103
104 /**
105 * Invoked when {@link Channel#write(Object)} is called.
106 */
107 public void writeRequested(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
108 ctx.sendDownstream(e);
109 }
110
111 /**
112 * Invoked when {@link Channel#bind(SocketAddress)} was called.
113 */
114 public void bindRequested(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
115 ctx.sendDownstream(e);
116
117 }
118
119 /**
120 * Invoked when {@link Channel#connect(SocketAddress)} was called.
121 */
122 public void connectRequested(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
123 ctx.sendDownstream(e);
124
125 }
126
127 /**
128 * Invoked when {@link Channel#setInterestOps(int)} was called.
129 */
130 public void setInterestOpsRequested(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
131 ctx.sendDownstream(e);
132 }
133
134 /**
135 * Invoked when {@link Channel#disconnect()} was called.
136 */
137 public void disconnectRequested(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
138 ctx.sendDownstream(e);
139
140 }
141
142 /**
143 * Invoked when {@link Channel#unbind()} was called.
144 */
145 public void unbindRequested(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
146 ctx.sendDownstream(e);
147
148 }
149
150 /**
151 * Invoked when {@link Channel#close()} was called.
152 */
153 public void closeRequested(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
154 ctx.sendDownstream(e);
155 }
156 }