    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    }