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