ProtocolCommandSupport.java

/*
 * Copyright 2010 netling project <http://netling.org>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * This file may incorporate work covered by the following copyright and
 * permission notice:
 *
 *     Licensed to the Apache Software Foundation (ASF) under one
 *     or more contributor license agreements.  See the NOTICE file
 *     distributed with this work for additional information
 *     regarding copyright ownership.  The ASF licenses this file
 *     to you under the Apache License, Version 2.0 (the
 *     "License"); you may not use this file except in compliance
 *     with the License.  You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 *      Unless required by applicable law or agreed to in writing,
 *      software distributed under the License is distributed on an
 *      "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 *      KIND, either express or implied.  See the License for the
 *      specific language governing permissions and limitations
 *      under the License.
 */
package org.netling;

import java.io.Serializable;
import java.util.concurrent.CopyOnWriteArrayList;

/***
 * ProtocolCommandSupport is a convenience class for managing a list of
 * ProtocolCommandListeners and firing ProtocolCommandEvents.  You can
 * simply delegate ProtocolCommandEvent firing and listener
 * registering/unregistering tasks to this class.
 * <p>
 * <p>
 * @see ProtocolCommandEvent
 * @see ProtocolCommandListener
 ***/
public class ProtocolCommandSupport implements Serializable
{
	private final CopyOnWriteArrayList<ProtocolCommandListener> listeners = new CopyOnWriteArrayList<ProtocolCommandListener>();
    private final Object source;

    /***
     * Creates a ProtocolCommandSupport instant using the indicated source
     * as the source of fired ProtocolCommandEvents.
     * <p>
     * @param source  The source to use for all generated ProtocolCommandEvents.
     ***/
    public ProtocolCommandSupport(Object source)
    {
        this.source = source;
    }

    /***
     * Fires a ProtocolCommandEvent signalling the sending of a command to all
     * registered listeners, invoking their
     * {@link org.netling.ProtocolCommandListener#protocolCommandSent protocolCommandSent() }
     *  methods.
     * <p>
     * @param command The string representation of the command type sent, not
     *      including the arguments (e.g., "STAT" or "GET").
     * @param message The entire command string verbatim as sent to the server,
     *        including all arguments.
     ***/
    public void fireCommandSent(String command, String message)
    {
        final ProtocolCommandEvent event = new ProtocolCommandEvent(source, command, message);
        for (ProtocolCommandListener listener : listeners)
           listener.protocolCommandSent(event);
    }

    /***
     * Fires a ProtocolCommandEvent signalling the reception of a command reply
     * to all registered listeners, invoking their
     * {@link org.netling.ProtocolCommandListener#protocolReplyReceived protocolReplyReceived() }
     *  methods.
     * <p>
     * @param replyCode The integer code indicating the natureof the reply.
     *   This will be the protocol integer value for protocols
     *   that use integer reply codes, or the reply class constant
     *   corresponding to the reply for protocols like POP3 that use
     *   strings like OK rather than integer codes (i.e., POP3Repy.OK).
     * @param message The entire reply as received from the server.
     ***/
    public void fireReplyReceived(int replyCode, String message)
    {
        final ProtocolCommandEvent event = new ProtocolCommandEvent(source, replyCode, message);
        for (ProtocolCommandListener listener : listeners)
            listener.protocolReplyReceived(event);
    }

    /***
     * Adds a ProtocolCommandListener.
     * <p>
     * @param listener  The ProtocolCommandListener to add.
     ***/
    public void addProtocolCommandListener(ProtocolCommandListener listener)
    {
        listeners.add(listener);
    }

    /***
     * Removes a ProtocolCommandListener.
     * <p>
     * @param listener  The ProtocolCommandListener to remove.
     ***/
    public void removeProtocolCommandListener(ProtocolCommandListener listener)
    {
        listeners.remove(listener);
    }

    /***
     * Returns the number of ProtocolCommandListeners currently registered.
     * <p>
     * @return The number of ProtocolCommandListeners currently registered.
     ***/
    public int getListenerCount()
    {
        return listeners.size();
    }

}