01: /*
02: * Copyright 1996-2003 Sun Microsystems, Inc. All Rights Reserved.
03: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
04: *
05: * This code is free software; you can redistribute it and/or modify it
06: * under the terms of the GNU General Public License version 2 only, as
07: * published by the Free Software Foundation. Sun designates this
08: * particular file as subject to the "Classpath" exception as provided
09: * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22: * CA 95054 USA or visit www.sun.com if you need additional information or
23: * have any 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: */
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: */
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: */
75: public String toString() {
76: return getClass().getName() + "[source=" + source + "]";
77: }
78: }
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