001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    
018    package org.apache.commons.net.util;
019    
020    import java.io.Serializable;
021    import java.util.EventListener;
022    import java.util.Iterator;
023    import java.util.concurrent.CopyOnWriteArrayList;
024    
025    /**
026     * @author Daniel F. Savarese
027     */
028    
029    public class ListenerList implements Serializable, Iterable<EventListener>
030    {
031        private final CopyOnWriteArrayList<EventListener> __listeners;
032    
033        public ListenerList()
034        {
035            __listeners = new CopyOnWriteArrayList<EventListener>();
036        }
037    
038        public void addListener(EventListener listener)
039        {
040                __listeners.add(listener);
041        }
042    
043        public  void removeListener(EventListener listener)
044        {
045                __listeners.remove(listener);
046        }
047    
048        public int getListenerCount()
049        {
050            return __listeners.size();
051        }
052        
053        /**
054         * Return an {@link Iterator} for the {@link EventListener} instances
055         * 
056         * @since 2.0
057         * TODO Check that this is a good defensive strategy
058         */
059        public Iterator<EventListener> iterator() {
060                return __listeners.iterator();
061        }
062    
063    }