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Java > Open Source Codes > org > apache > mina > filter > codec > SynchronizedProtocolDecoder


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.common.ByteBuffer;
23 import org.apache.mina.common.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 Directory Project (mina-dev@directory.apache.org)
35  * @version $Rev: 555855 $, $Date: 2007-07-13 12:19:00 +0900 (금, 13 7월 2007) $
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 JavaDoc("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, ByteBuffer in,
58             ProtocolDecoderOutput out) throws Exception JavaDoc {
59         synchronized (decoder) {
60             decoder.decode(session, in, out);
61         }
62     }
63
64     public void finishDecode(IoSession session, ProtocolDecoderOutput out)
65             throws Exception JavaDoc {
66         synchronized (decoder) {
67             decoder.finishDecode(session, out);
68         }
69     }
70
71     public void dispose(IoSession session) throws Exception JavaDoc {
72         synchronized (decoder) {
73             decoder.dispose(session);
74         }
75     }
76 }
77
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