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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.common.IoHandler;
    23  import org.apache.mina.common.IoHandlerAdapter;
    24  import org.apache.mina.common.IoSession;
    25
    26  /**
    27   * An {@link IoHandler} which executes an {@link IoHandlerChain}
    28   * on a <tt>messageReceived</tt> event.
    29   *
    30   * @author The Apache Directory Project (mina-dev@directory.apache.org)
    31   * @version $Rev: 555855 $, $Date: 2007-07-13 05:19:00 +0200 (Fri, 13 Jul 2007) $
    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      public void messageReceived(IoSession session, Object message)
    70              throws Exception {
    71          chain.execute(null, session, message);
    72      }
    73  }