1 /*

     2  * Copyright 2000-2003 Sun Microsystems, Inc.  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.  Sun designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    22  * CA 95054 USA or visit www.sun.com if you need additional information or

    23  * have any questions.

    24  */

    25 

    26 package java.util.prefs;

    27 

    28 import java.io.NotSerializableException;

    29 

    30 /**

    31  * An event emitted by a <tt>Preferences</tt> node to indicate that

    32  * a preference has been added, removed or has had its value changed.<p>

    33  *

    34  * Note, that although PreferenceChangeEvent inherits Serializable interface

    35  * from EventObject, it is not intended to be Serializable. Appropriate

    36  * serialization methods are implemented to throw NotSerializableException.

    37  *

    38  * @author  Josh Bloch

    39  * @see Preferences

    40  * @see PreferenceChangeListener

    41  * @see NodeChangeEvent

    42  * @since   1.4

    43  * @serial exclude

    44  */

    45 public class PreferenceChangeEvent extends java.util.EventObject {

    46 

    47     /**

    48      * Key of the preference that changed.

    49      *

    50      * @serial

    51      */

    52     private String key;

    53 

    54     /**

    55      * New value for preference, or <tt>null</tt> if it was removed.

    56      *

    57      * @serial

    58      */

    59     private String newValue;

    60 

    61     /**

    62      * Constructs a new <code>PreferenceChangeEvent</code> instance.

    63      *

    64      * @param node  The Preferences node that emitted the event.

    65      * @param key  The key of the preference that was changed.

    66      * @param newValue  The new value of the preference, or <tt>null</tt>

    67      *                  if the preference is being removed.

    68      */

    69     public PreferenceChangeEvent(Preferences node, String key,

    70                                  String newValue) {

    71         super(node);

    72         this.key = key;

    73         this.newValue = newValue;

    74     }

    75 

    76     /**

    77      * Returns the preference node that emitted the event.

    78      *

    79      * @return  The preference node that emitted the event.

    80      */

    81     public Preferences getNode() {

    82         return (Preferences) getSource();

    83     }

    84 

    85     /**

    86      * Returns the key of the preference that was changed.

    87      *

    88      * @return  The key of the preference that was changed.

    89      */

    90     public String getKey() {

    91         return key;

    92     }

    93 

    94     /**

    95      * Returns the new value for the preference.

    96      *

    97      * @return  The new value for the preference, or <tt>null</tt> if the

    98      *          preference was removed.

    99      */

   100     public String getNewValue() {

   101         return newValue;

   102     }

   103 

   104     /**

   105      * Throws NotSerializableException, since NodeChangeEvent objects

   106      * are not intended to be serializable.

   107      */

   108      private void writeObject(java.io.ObjectOutputStream out)

   109                                                throws NotSerializableException {

   110          throw new NotSerializableException("Not serializable.");

   111      }

   112 

   113     /**

   114      * Throws NotSerializableException, since PreferenceChangeEvent objects

   115      * are not intended to be serializable.

   116      */

   117      private void readObject(java.io.ObjectInputStream in)

   118                                                throws NotSerializableException {

   119          throw new NotSerializableException("Not serializable.");

   120      }

   121 

   122     // Defined so that this class isn't flagged as a potential problem when

   123     // searches for missing serialVersionUID fields are done.

   124     private static final long serialVersionUID = 793724513368024975L;

   125 }