001    /* NodeChangeEvent - ObjectEvent fired when a Preference node is added/removed
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 Preference node is added/removed.
048     * This event is only generated when a new subnode is added or a subnode is
049     * removed from a preference node. Changes in the entries of a preference node
050     * are indicated with a <code>PreferenceChangeEvent</code>.
051     * <p>
052     * Note that although this class is marked as serializable, attempts to
053     * serialize it will fail with NotSerializableException.
054     *
055     * @since 1.4
056     * @author Mark Wielaard (mark@klomp.org)
057     */
058    public class NodeChangeEvent extends EventObject {
059    
060      // We have this to placate the compiler.
061      private static final long serialVersionUID =8068949086596572957L; 
062      
063        /**
064         * The sub node that was added or removed.
065         * Defined transient just like <code>EventObject.source</code> since
066         * this object should be serializable, but Preferences is in general not
067         * serializable.
068         */
069        private final transient Preferences child;
070    
071        /**
072         * Creates a new NodeChangeEvent.
073         *
074         * @param parentNode The source preference node from which a subnode was
075         * added or removed
076         * @param childNode The preference node that was added or removed
077         */
078        public NodeChangeEvent(Preferences parentNode, Preferences childNode) {
079            super(parentNode);
080            child = childNode;
081        }
082    
083        /**
084         * Returns the source parent preference node from which a subnode was
085         * added or removed.
086         */
087        public Preferences getParent() {
088            return (Preferences) source;
089        }
090    
091        /**
092         * Returns the child preference subnode that was added or removed.
093         * To see wether it is still a valid preference node one has to call
094         * <code>event.getChild().nodeExists("")</code>.
095         */
096        public Preferences getChild() {
097            return child;
098        }
099    
100        private void readObject(ObjectInputStream ois)
101          throws IOException
102        {
103          throw new NotSerializableException("LineEvent is not serializable");
104        }
105      
106        private void writeObject(ObjectOutputStream oos)
107          throws IOException
108        {
109          throw new NotSerializableException("LineEvent is not serializable");
110        }
111    }