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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  }