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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.statemachine.context;
21  
22  import org.apache.mina.core.session.IoSession;
23  
24  /**
25   * MINA specific {@link StateContextLookup} which uses an {@link IoSession}
26   * attribute to store the {@link StateContextLookup}.
27   *
28   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
29   */
30  public class IoSessionStateContextLookup extends AbstractStateContextLookup {
31      /**
32       * The default name of the {@link IoSession} attribute used to store the
33       * {@link StateContext} object.
34       */
35      public static final String DEFAULT_SESSION_ATTRIBUTE_NAME = IoSessionStateContextLookup.class.getName()
36              + ".stateContext";
37  
38      private final String sessionAttributeName;
39  
40      /**
41       * Creates a new instance using a {@link DefaultStateContextFactory} to
42       * create {@link StateContext} objects for new {@link IoSession}s.
43       */
44      public IoSessionStateContextLookup() {
45          this(new DefaultStateContextFactory(), DEFAULT_SESSION_ATTRIBUTE_NAME);
46      }
47  
48      /**
49       * Creates a new instance using a {@link DefaultStateContextFactory} to
50       * create {@link StateContext} objects for new {@link IoSession}s.
51       * 
52       * @param sessionAttributeName the name of the {@link IoSession} attribute
53       *        used to store the {@link StateContext} object.
54       */
55      public IoSessionStateContextLookup(String sessionAttributeName) {
56          this(new DefaultStateContextFactory(), sessionAttributeName);
57      }
58  
59      /**
60       * Creates a new instance using the specified {@link StateContextFactory} to
61       * create {@link StateContext} objects for new {@link IoSession}s.
62       * 
63       * @param contextFactory the {@link StateContextFactory}.
64       */
65      public IoSessionStateContextLookup(StateContextFactory contextFactory) {
66          this(contextFactory, DEFAULT_SESSION_ATTRIBUTE_NAME);
67      }
68  
69      /**
70       * Creates a new instance using the specified {@link StateContextFactory} to
71       * create {@link StateContext} objects for new {@link IoSession}s.
72       * 
73       * @param contextFactory the {@link StateContextFactory}.
74       * @param sessionAttributeName the name of the {@link IoSession} attribute
75       *        used to store the {@link StateContext} object.
76       */
77      public IoSessionStateContextLookup(StateContextFactory contextFactory, String sessionAttributeName) {
78          super(contextFactory);
79          this.sessionAttributeName = sessionAttributeName;
80      }
81  
82      protected StateContext lookup(Object eventArg) {
83          IoSession session = (IoSession) eventArg;
84          return (StateContext) session.getAttribute(sessionAttributeName);
85      }
86  
87      protected void store(Object eventArg, StateContext context) {
88          IoSession session = (IoSession) eventArg;
89          session.setAttribute(sessionAttributeName, context);
90      }
91  
92      protected boolean supports(Class<?> c) {
93          return IoSession.class.isAssignableFrom(c);
94      }
95  }