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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.handler.chain;
21  
22  import org.apache.mina.core.service.IoHandler;
23  import org.apache.mina.core.service.IoHandlerAdapter;
24  import org.apache.mina.core.session.IoSession;
25  
26  /**
27   * An {@link IoHandler} which executes an {@link IoHandlerChain}
28   * on a <tt>messageReceived</tt> event.
29   *
30   * @author The Apache MINA Project (dev@mina.apache.org)
31   * @version $Rev: 671827 $, $Date: 2008-06-26 10:49:48 +0200 (jeu, 26 jun 2008) $
32   */
33  public class ChainedIoHandler extends IoHandlerAdapter {
34      private final IoHandlerChain chain;
35  
36      /**
37       * Creates a new instance which contains an empty {@link IoHandlerChain}.
38       */
39      public ChainedIoHandler() {
40          chain = new IoHandlerChain();
41      }
42  
43      /**
44       * Creates a new instance which executes the specified
45       * {@link IoHandlerChain} on a <tt>messageReceived</tt> event.
46       *
47       * @param chain an {@link IoHandlerChain} to execute
48       */
49      public ChainedIoHandler(IoHandlerChain chain) {
50          if (chain == null) {
51              throw new NullPointerException("chain");
52          }
53          this.chain = chain;
54      }
55  
56      /**
57       * Returns the {@link IoHandlerCommand} this handler will use to
58       * handle <tt>messageReceived</tt> events.
59       */
60      public IoHandlerChain getChain() {
61          return chain;
62      }
63  
64      /**
65       * Handles the specified <tt>messageReceived</tt> event with the
66       * {@link IoHandlerCommand} or {@link IoHandlerChain} you specified
67       * in the constructor.
68       */
69      @Override
70      public void messageReceived(IoSession session, Object message)
71              throws Exception {
72          chain.execute(null, session, message);
73      }
74  }