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;
21
22 import org.apache.mina.core.buffer.IoBuffer;
23 import org.apache.mina.core.session.IoSession;
24
25 /**
26 * A {@link ProtocolDecoder} implementation which decorates an existing decoder
27 * to be thread-safe. Please be careful if you're going to use this decorator
28 * because it can be a root of performance degradation in a multi-thread
29 * environment. Also, by default, appropriate synchronization is done
30 * on a per-session basis by {@link ProtocolCodecFilter}. Please use this
31 * decorator only when you need to synchronize on a per-decoder basis, which
32 * is not common.
33 *
34 * @author The Apache MINA Project (dev@mina.apache.org)
35 * @version $Rev: 671827 $, $Date: 2008-06-26 10:49:48 +0200 (jeu, 26 jun 2008) $
36 */
37 public class SynchronizedProtocolDecoder implements ProtocolDecoder {
38 private final ProtocolDecoder decoder;
39
40 /**
41 * Creates a new instance which decorates the specified <tt>decoder</tt>.
42 */
43 public SynchronizedProtocolDecoder(ProtocolDecoder decoder) {
44 if (decoder == null) {
45 throw new NullPointerException("decoder");
46 }
47 this.decoder = decoder;
48 }
49
50 /**
51 * Returns the decoder this decoder is decorating.
52 */
53 public ProtocolDecoder getDecoder() {
54 return decoder;
55 }
56
57 public void decode(IoSession session, IoBuffer in,
58 ProtocolDecoderOutput out) throws Exception {
59 synchronized (decoder) {
60 decoder.decode(session, in, out);
61 }
62 }
63
64 public void finishDecode(IoSession session, ProtocolDecoderOutput out)
65 throws Exception {
66 synchronized (decoder) {
67 decoder.finishDecode(session, out);
68 }
69 }
70
71 public void dispose(IoSession session) throws Exception {
72 synchronized (decoder) {
73 decoder.dispose(session);
74 }
75 }
76 }