1 /* 2 * Copyright (c) 1996, 2003, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.util; 27 28 /** 29 * <p> 30 * The root class from which all event state objects shall be derived. 31 * <p> 32 * All Events are constructed with a reference to the object, the "source", 33 * that is logically deemed to be the object upon which the Event in question 34 * initially occurred upon. 35 * 36 * @since JDK1.1 37 */ 38 39 public class EventObject implements java.io.Serializable { 40 41 private static final long serialVersionUID = 5516075349620653480L; 42 43 /** 44 * The object on which the Event initially occurred. 45 */ 46 protected transient Object source; 47 48 /** 49 * Constructs a prototypical Event. 50 * 51 * @param source The object on which the Event initially occurred. 52 * @exception IllegalArgumentException if source is null. 53 */ EventObject(Object source)54 public EventObject(Object source) { 55 if (source == null) 56 throw new IllegalArgumentException("null source"); 57 58 this.source = source; 59 } 60 61 /** 62 * The object on which the Event initially occurred. 63 * 64 * @return The object on which the Event initially occurred. 65 */ getSource()66 public Object getSource() { 67 return source; 68 } 69 70 /** 71 * Returns a String representation of this EventObject. 72 * 73 * @return A a String representation of this EventObject. 74 */ toString()75 public String toString() { 76 return getClass().getName() + "[source=" + source + "]"; 77 } 78 } 79