001/* PreferenceChangeEvent - ObjectEvent fired when a Preferences entry changes 002 Copyright (C) 2001, 2006 Free Software Foundation, Inc. 003 004This file is part of GNU Classpath. 005 006GNU Classpath is free software; you can redistribute it and/or modify 007it under the terms of the GNU General Public License as published by 008the Free Software Foundation; either version 2, or (at your option) 009any later version. 010 011GNU Classpath is distributed in the hope that it will be useful, but 012WITHOUT ANY WARRANTY; without even the implied warranty of 013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014General Public License for more details. 015 016You should have received a copy of the GNU General Public License 017along with GNU Classpath; see the file COPYING. If not, write to the 018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 01902110-1301 USA. 020 021Linking this library statically or dynamically with other modules is 022making a combined work based on this library. Thus, the terms and 023conditions of the GNU General Public License cover the whole 024combination. 025 026As a special exception, the copyright holders of this library give you 027permission to link this library with independent modules to produce an 028executable, regardless of the license terms of these independent 029modules, and to copy and distribute the resulting executable under 030terms of your choice, provided that you also meet, for each linked 031independent module, the terms and conditions of the license of that 032module. An independent module is a module which is not derived from 033or based on this library. If you modify this library, you may extend 034this exception to your version of the library, but you are not 035obligated to do so. If you do not wish to do so, delete this 036exception statement from your version. */ 037 038package java.util.prefs; 039 040import java.io.IOException; 041import java.io.NotSerializableException; 042import java.io.ObjectInputStream; 043import java.io.ObjectOutputStream; 044import 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 */ 061public 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}