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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 <a href="http://mina.apache.org">Apache MINA Project</a>
    31   */
    32  public class ChainedIoHandler extends IoHandlerAdapter {
    33      private final IoHandlerChain chain;
    34
    35      /**
    36       * Creates a new instance which contains an empty {@link IoHandlerChain}.
    37       */
    38      public ChainedIoHandler() {
    39          chain = new IoHandlerChain();
    40      }
    41
    42      /**
    43       * Creates a new instance which executes the specified
    44       * {@link IoHandlerChain} on a <tt>messageReceived</tt> event.
    45       *
    46       * @param chain an {@link IoHandlerChain} to execute
    47       */
    48      public ChainedIoHandler(IoHandlerChain chain) {
    49          if (chain == null) {
    50              throw new IllegalArgumentException("chain");
    51          }
    52          this.chain = chain;
    53      }
    54
    55      /**
    56       * Returns the {@link IoHandlerCommand} this handler will use to
    57       * handle <tt>messageReceived</tt> events.
    58       */
    59      public IoHandlerChain getChain() {
    60          return chain;
    61      }
    62
    63      /**
    64       * Handles the specified <tt>messageReceived</tt> event with the
    65       * {@link IoHandlerCommand} or {@link IoHandlerChain} you specified
    66       * in the constructor.
    67       */
    68      @Override
    69      public void messageReceived(IoSession session, Object message) throws Exception {
    70          chain.execute(null, session, message);
    71      }
    72  }