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src/java.desktop/share/classes/javax/swing/event/EventListenerList.java

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   1 /*
   2  * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any


  85  * notification method in the FooListener interface.
  86  * <p>
  87  * <strong>Warning:</strong>
  88  * Serialized objects of this class will not be compatible with
  89  * future Swing releases. The current serialization support is
  90  * appropriate for short term storage or RMI between applications running
  91  * the same version of Swing.  As of 1.4, support for long term storage
  92  * of all JavaBeans&trade;
  93  * has been added to the <code>java.beans</code> package.
  94  * Please see {@link java.beans.XMLEncoder}.
  95  *
  96  * @author Georges Saab
  97  * @author Hans Muller
  98  * @author James Gosling
  99  */
 100 @SuppressWarnings("serial")
 101 public class EventListenerList implements Serializable {
 102     /* A null array to be shared by all empty listener lists*/
 103     private static final Object[] NULL_ARRAY = new Object[0];
 104     /** The list of ListenerType - Listener pairs */
 105     protected transient Object[] listenerList = NULL_ARRAY;
 106 
 107     /**
 108      * Passes back the event listener list as an array
 109      * of ListenerType-listener pairs.  Note that for
 110      * performance reasons, this implementation passes back
 111      * the actual data structure in which the listener data
 112      * is stored internally!
 113      * This method is guaranteed to pass back a non-null
 114      * array, so that no null-checking is required in
 115      * fire methods.  A zero-length array of Object should
 116      * be returned if there are currently no listeners.
 117      *
 118      * WARNING!!! Absolutely NO modification of
 119      * the data contained in this array should be made -- if
 120      * any such manipulation is necessary, it should be done
 121      * on a copy of the array returned rather than the array
 122      * itself.
 123      *
 124      * @return array of ListenerType-listener pairs
 125      */


   1 /*
   2  * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any


  85  * notification method in the FooListener interface.
  86  * <p>
  87  * <strong>Warning:</strong>
  88  * Serialized objects of this class will not be compatible with
  89  * future Swing releases. The current serialization support is
  90  * appropriate for short term storage or RMI between applications running
  91  * the same version of Swing.  As of 1.4, support for long term storage
  92  * of all JavaBeans&trade;
  93  * has been added to the <code>java.beans</code> package.
  94  * Please see {@link java.beans.XMLEncoder}.
  95  *
  96  * @author Georges Saab
  97  * @author Hans Muller
  98  * @author James Gosling
  99  */
 100 @SuppressWarnings("serial")
 101 public class EventListenerList implements Serializable {
 102     /* A null array to be shared by all empty listener lists*/
 103     private static final Object[] NULL_ARRAY = new Object[0];
 104     /** The list of ListenerType - Listener pairs */
 105     protected volatile transient Object[] listenerList = NULL_ARRAY;
 106 
 107     /**
 108      * Passes back the event listener list as an array
 109      * of ListenerType-listener pairs.  Note that for
 110      * performance reasons, this implementation passes back
 111      * the actual data structure in which the listener data
 112      * is stored internally!
 113      * This method is guaranteed to pass back a non-null
 114      * array, so that no null-checking is required in
 115      * fire methods.  A zero-length array of Object should
 116      * be returned if there are currently no listeners.
 117      *
 118      * WARNING!!! Absolutely NO modification of
 119      * the data contained in this array should be made -- if
 120      * any such manipulation is necessary, it should be done
 121      * on a copy of the array returned rather than the array
 122      * itself.
 123      *
 124      * @return array of ListenerType-listener pairs
 125      */


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