001 /* EventObject.java -- represents an event on an object
002 Copyright (C) 1999, 2000, 2002, 2005 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
039 package java.util;
040
041 import java.io.Serializable;
042
043 /**
044 * Represents Events fired by Objects.
045 *
046 * @author Eric Blake (ebb9@email.byu.edu)
047 * @see EventListener
048 * @since 1.1
049 * @status updated to 1.4
050 */
051 public class EventObject implements Serializable
052 {
053 /**
054 * Compatible with JDK 1.1+.
055 */
056 private static final long serialVersionUID = 5516075349620653480L;
057
058 /**
059 * The source object; in other words, the object which this event takes
060 * place on.
061 */
062 protected transient Object source;
063
064 /**
065 * Constructs an EventObject with the specified source.
066 *
067 * @param source the source of the event
068 * @throws IllegalArgumentException if source is null (This is not
069 * specified, but matches the behavior of the JDK)
070 */
071 public EventObject(Object source)
072 {
073 // This check for null is stupid, if you ask me, since source is
074 // protected and non-final, so a subclass can set it to null later on.
075 if (source == null)
076 throw new IllegalArgumentException();
077 this.source = source;
078 }
079
080 /**
081 * Returns the source of the event.
082 *
083 * @return the event source
084 */
085 public Object getSource()
086 {
087 return source;
088 }
089
090 /**
091 * Converts the event to a String. The format is not specified, but by
092 * observation, the JDK uses:
093 * <code>getClass().getName() + "[source=" + source + "]";</code>.
094 *
095 * @return String representation of the Event
096 */
097 public String toString()
098 {
099 return getClass().getName() + "[source=" + source + "]";
100 }
101 } // class EventObject