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 */
41 public class NettyDecoder extends ProtocolDecoderAdapter {
42 private final MessageRecognizer recognizer;
43
44 private ByteBuffer readBuf = ByteBuffer.allocate(1024);
45
46 private Message readingMessage;
47
48 /**
49 * Creates a new instance with the specified {@link MessageRecognizer}.
50 */
51 public NettyDecoder(MessageRecognizer recognizer) {
52 if (recognizer == null) {
53 throw new NullPointerException();
54 }
55
56 this.recognizer = recognizer;
57 }
58
59 private void put(IoBuffer in) {
60 // copy to read buffer
61 if (in.remaining() > readBuf.remaining()) {
62 expand((readBuf.position() + in.remaining()) * 3 / 2);
63 }
64 readBuf.put(in.buf());
65 }
66
67 private void expand(int newCapacity) {
68 ByteBuffer newBuf = ByteBuffer.allocate(newCapacity);
69 readBuf.flip();
70 newBuf.put(readBuf);
71 readBuf = newBuf;
72 }
73
74 public void decode(IoSession session, IoBuffer in,
75 ProtocolDecoderOutput out) throws Exception {
76 put(in);
77
78 Message m = readingMessage;
79 try {
80 for (;;) {
81 readBuf.flip();
82 if (m == null) {
83 int limit = readBuf.limit();
84 boolean failed = true;
85 try {
86 m = recognizer.recognize(readBuf);
87 failed = false;
88 } finally {
89 if (failed) {
90 // clear the read buffer if failed to recognize
91 readBuf.clear();
92 break;
93 } else {
94 if (m == null) {
95 readBuf.limit(readBuf.capacity());
96 readBuf.position(limit);
97 break; // finish decoding
98 } else {
99 // reset buffer for read
100 readBuf.limit(limit);
101 readBuf.position(0);
102 }
103 }
104 }
105 }
106
107 if (m != null) {
108 try {
109 if (m.read(readBuf)) {
110 out.write(m);
111 m = null;
112 } else {
113 break;
114 }
115 } finally {
116 if (readBuf.hasRemaining()) {
117 readBuf.compact();
118 } else {
119 readBuf.clear();
120 break;
121 }
122 }
123 }
124 }
125 } catch (MessageParseException e) {
126 m = null; // discard reading message
127 throw new ProtocolDecoderException("Failed to decode.", e);
128 } finally {
129 readingMessage = m;
130 }
131 }
132 }