001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one
003 *  or more contributor license agreements.  See the NOTICE file
004 *  distributed with this work for additional information
005 *  regarding copyright ownership.  The ASF licenses this file
006 *  to you under the Apache License, Version 2.0 (the
007 *  "License"); you may not use this file except in compliance
008 *  with the License.  You may obtain a copy of the License at
009 *
010 *    http://www.apache.org/licenses/LICENSE-2.0
011 *
012 *  Unless required by applicable law or agreed to in writing,
013 *  software distributed under the License is distributed on an
014 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 *  KIND, either express or implied.  See the License for the
016 *  specific language governing permissions and limitations
017 *  under the License.
018 *
019 */
020package org.apache.mina.handler.chain;
021
022import org.apache.mina.core.service.IoHandler;
023import org.apache.mina.core.service.IoHandlerAdapter;
024import org.apache.mina.core.session.IoSession;
025
026/**
027 * An {@link IoHandler} which executes an {@link IoHandlerChain}
028 * on a <tt>messageReceived</tt> event.
029 *
030 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
031 */
032public class ChainedIoHandler extends IoHandlerAdapter {
033    private final IoHandlerChain chain;
034
035    /**
036     * Creates a new instance which contains an empty {@link IoHandlerChain}.
037     */
038    public ChainedIoHandler() {
039        chain = new IoHandlerChain();
040    }
041
042    /**
043     * Creates a new instance which executes the specified
044     * {@link IoHandlerChain} on a <tt>messageReceived</tt> event.
045     *
046     * @param chain an {@link IoHandlerChain} to execute
047     */
048    public ChainedIoHandler(IoHandlerChain chain) {
049        if (chain == null) {
050            throw new IllegalArgumentException("chain");
051        }
052        this.chain = chain;
053    }
054
055    /**
056     * @return the {@link IoHandlerCommand} this handler will use to
057     * handle <tt>messageReceived</tt> events.
058     */
059    public IoHandlerChain getChain() {
060        return chain;
061    }
062
063    /**
064     * Handles the specified <tt>messageReceived</tt> event with the
065     * {@link IoHandlerCommand} or {@link IoHandlerChain} you specified
066     * in the constructor.
067     */
068    @Override
069    public void messageReceived(IoSession session, Object message) throws Exception {
070        chain.execute(null, session, message);
071    }
072}