001 /* PreferenceChangeEvent - ObjectEvent fired when a Preferences entry changes
002 Copyright (C) 2001, 2006 Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038 package java.util.prefs;
039
040 import java.io.IOException;
041 import java.io.NotSerializableException;
042 import java.io.ObjectInputStream;
043 import java.io.ObjectOutputStream;
044 import java.util.EventObject;
045
046 /**
047 * ObjectEvent fired when a Preferences entry changes.
048 * This event is generated when a entry is added, changed or removed.
049 * When an entry is removed then <code>getNewValue</code> will return null.
050 * <p>
051 * Preference change events are only generated for entries in one particular
052 * preference node. Notification of subnode addition/removal is given by a
053 * <code>NodeChangeEvent</code>.
054 * <p>
055 * Note that although this class is marked as serializable, attempts to
056 * serialize it will fail with NotSerializableException.
057 *
058 * @since 1.4
059 * @author Mark Wielaard (mark@klomp.org)
060 */
061 public class PreferenceChangeEvent extends EventObject {
062
063 // We have this to placate the compiler.
064 private static final long serialVersionUID = 793724513368024975L;
065
066 /**
067 * The key of the changed entry.
068 */
069 private final String key;
070
071 /**
072 * The new value of the changed entry, or null when the entry was removed.
073 */
074 private final String newValue;
075
076 /**
077 * Creates a new PreferenceChangeEvent.
078 *
079 * @param node The source preference node for which an entry was added,
080 * changed or removed
081 * @param key The key of the entry that was added, changed or removed
082 * @param value The new value of the entry that was added or changed, or
083 * null when the entry was removed
084 */
085 public PreferenceChangeEvent(Preferences node, String key, String value) {
086 super(node);
087 this.key = key;
088 this.newValue = value;
089 }
090
091 /**
092 * Returns the source Preference node from which an entry was added,
093 * changed or removed.
094 */
095 public Preferences getNode() {
096 return (Preferences) source;
097 }
098
099 /**
100 * Returns the key of the entry that was added, changed or removed.
101 */
102 public String getKey() {
103 return key;
104 }
105
106 /**
107 * Returns the new value of the entry that was added or changed, or
108 * returns null when the entry was removed.
109 */
110 public String getNewValue() {
111 return newValue;
112 }
113
114 private void readObject(ObjectInputStream ois)
115 throws IOException
116 {
117 throw new NotSerializableException("LineEvent is not serializable");
118 }
119
120 private void writeObject(ObjectOutputStream oos)
121 throws IOException
122 {
123 throw new NotSerializableException("LineEvent is not serializable");
124 }
125 }