1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 *
19 */
20 package org.apache.mina.filter.codec.netty;
21
22 import java.nio.ByteBuffer;
23
24 import net.gleamynode.netty2.Message;
25 import net.gleamynode.netty2.MessageParseException;
26 import net.gleamynode.netty2.MessageRecognizer;
27
28 import org.apache.mina.core.buffer.IoBuffer;
29 import org.apache.mina.core.session.IoSession;
30 import org.apache.mina.filter.codec.ProtocolDecoder;
31 import org.apache.mina.filter.codec.ProtocolDecoderAdapter;
32 import org.apache.mina.filter.codec.ProtocolDecoderException;
33 import org.apache.mina.filter.codec.ProtocolDecoderOutput;
34
35 /**
36 * A MINA {@link ProtocolDecoder} that decodes buffers into
37 * Netty2 {@link Message}s using specified {@link MessageRecognizer}s.
38 *
39 * @author The Apache MINA Project (dev@mina.apache.org)
40 * @version $Rev: 671827 $, $Date: 2008-06-26 10:49:48 +0200 (jeu, 26 jun 2008) $,
41 */
42 public class NettyDecoder extends ProtocolDecoderAdapter {
43 private final MessageRecognizer recognizer;
44
45 private ByteBuffer readBuf = ByteBuffer.allocate(1024);
46
47 private Message readingMessage;
48
49 /**
50 * Creates a new instance with the specified {@link MessageRecognizer}.
51 */
52 public NettyDecoder(MessageRecognizer recognizer) {
53 if (recognizer == null) {
54 throw new NullPointerException();
55 }
56
57 this.recognizer = recognizer;
58 }
59
60 private void put(IoBuffer in) {
61 // copy to read buffer
62 if (in.remaining() > readBuf.remaining()) {
63 expand((readBuf.position() + in.remaining()) * 3 / 2);
64 }
65 readBuf.put(in.buf());
66 }
67
68 private void expand(int newCapacity) {
69 ByteBuffer newBuf = ByteBuffer.allocate(newCapacity);
70 readBuf.flip();
71 newBuf.put(readBuf);
72 readBuf = newBuf;
73 }
74
75 public void decode(IoSession session, IoBuffer in,
76 ProtocolDecoderOutput out) throws Exception {
77 put(in);
78
79 Message m = readingMessage;
80 try {
81 for (;;) {
82 readBuf.flip();
83 if (m == null) {
84 int limit = readBuf.limit();
85 boolean failed = true;
86 try {
87 m = recognizer.recognize(readBuf);
88 failed = false;
89 } finally {
90 if (failed) {
91 // clear the read buffer if failed to recognize
92 readBuf.clear();
93 break;
94 } else {
95 if (m == null) {
96 readBuf.limit(readBuf.capacity());
97 readBuf.position(limit);
98 break; // finish decoding
99 } else {
100 // reset buffer for read
101 readBuf.limit(limit);
102 readBuf.position(0);
103 }
104 }
105 }
106 }
107
108 if (m != null) {
109 try {
110 if (m.read(readBuf)) {
111 out.write(m);
112 m = null;
113 } else {
114 break;
115 }
116 } finally {
117 if (readBuf.hasRemaining()) {
118 readBuf.compact();
119 } else {
120 readBuf.clear();
121 break;
122 }
123 }
124 }
125 }
126 } catch (MessageParseException e) {
127 m = null; // discard reading message
128 throw new ProtocolDecoderException("Failed to decode.", e);
129 } finally {
130 readingMessage = m;
131 }
132 }
133 }