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.session.IoSession;
23
24 /**
25 * A {@link ProtocolEncoder} implementation which decorates an existing encoder
26 * to be thread-safe. Please be careful if you're going to use this decorator
27 * because it can be a root of performance degradation in a multi-thread
28 * environment. Please use this decorator only when you need to synchronize
29 * on a per-encoder basis instead of on a per-session basis, which is not
30 * common.
31 *
32 * @author The Apache MINA Project (dev@mina.apache.org)
33 */
34 public class SynchronizedProtocolEncoder implements ProtocolEncoder {
35 private final ProtocolEncoder encoder;
36
37 /**
38 * Creates a new instance which decorates the specified <tt>encoder</tt>.
39 */
40 public SynchronizedProtocolEncoder(ProtocolEncoder encoder) {
41 if (encoder == null) {
42 throw new NullPointerException("encoder");
43 }
44 this.encoder = encoder;
45 }
46
47 /**
48 * Returns the encoder this encoder is decorating.
49 */
50 public ProtocolEncoder getEncoder() {
51 return encoder;
52 }
53
54 public void encode(IoSession session, Object message,
55 ProtocolEncoderOutput out) throws Exception {
56 synchronized (encoder) {
57 encoder.encode(session, message, out);
58 }
59 }
60
61 public void dispose(IoSession session) throws Exception {
62 synchronized (encoder) {
63 encoder.dispose(session);
64 }
65 }
66 }