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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.apache.commons.net.util;
19  
20  import java.io.Serializable;
21  import java.util.EventListener;
22  import java.util.Iterator;
23  import java.util.concurrent.CopyOnWriteArrayList;
24  
25  /**
26   * @author Daniel F. Savarese
27   */
28  
29  public class ListenerList implements Serializable, Iterable<EventListener>
30  {
31      private final CopyOnWriteArrayList<EventListener> __listeners;
32  
33      public ListenerList()
34      {
35          __listeners = new CopyOnWriteArrayList<EventListener>();
36      }
37  
38      public void addListener(EventListener listener)
39      {
40              __listeners.add(listener);
41      }
42  
43      public  void removeListener(EventListener listener)
44      {
45              __listeners.remove(listener);
46      }
47  
48      public int getListenerCount()
49      {
50          return __listeners.size();
51      }
52      
53      /**
54       * Return an {@link Iterator} for the {@link EventListener} instances
55       * 
56       * @since 2.0
57       * TODO Check that this is a good defensive strategy
58       */
59      public Iterator<EventListener> iterator() {
60              return __listeners.iterator();
61      }
62  
63  }