1 /*
2 * Copyright 1996-2006 Sun Microsystems, Inc. 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. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * 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.beans;
27
28 /**
29 * A "PropertyChange" event gets delivered whenever a bean changes a "bound"
30 * or "constrained" property. A PropertyChangeEvent object is sent as an
31 * argument to the PropertyChangeListener and VetoableChangeListener methods.
32 * <P>
33 * Normally PropertyChangeEvents are accompanied by the name and the old
34 * and new value of the changed property. If the new value is a primitive
35 * type (such as int or boolean) it must be wrapped as the
36 * corresponding java.lang.* Object type (such as Integer or Boolean).
37 * <P>
38 * Null values may be provided for the old and the new values if their
39 * true values are not known.
40 * <P>
41 * An event source may send a null object as the name to indicate that an
42 * arbitrary set of if its properties have changed. In this case the
43 * old and new values should also be null.
44 */
45
46 public class PropertyChangeEvent extends java.util.EventObject {
47
48 /**
49 * Constructs a new <code>PropertyChangeEvent</code>.
50 *
51 * @param source The bean that fired the event.
52 * @param propertyName The programmatic name of the property
53 * that was changed.
54 * @param oldValue The old value of the property.
55 * @param newValue The new value of the property.
56 */
57 public PropertyChangeEvent(Object source, String propertyName,
58 Object oldValue, Object newValue) {
59 super(source);
60 this.propertyName = propertyName;
61 this.newValue = newValue;
62 this.oldValue = oldValue;
63 }
64
65 /**
66 * Gets the programmatic name of the property that was changed.
67 *
68 * @return The programmatic name of the property that was changed.
69 * May be null if multiple properties have changed.
70 */
71 public String getPropertyName() {
72 return propertyName;
73 }
74
75 /**
76 * Gets the new value for the property, expressed as an Object.
77 *
78 * @return The new value for the property, expressed as an Object.
79 * May be null if multiple properties have changed.
80 */
81 public Object getNewValue() {
82 return newValue;
83 }
84
85 /**
86 * Gets the old value for the property, expressed as an Object.
87 *
88 * @return The old value for the property, expressed as an Object.
89 * May be null if multiple properties have changed.
90 */
91 public Object getOldValue() {
92 return oldValue;
93 }
94
95 /**
96 * Sets the propagationId object for the event.
97 *
98 * @param propagationId The propagationId object for the event.
99 */
100 public void setPropagationId(Object propagationId) {
101 this.propagationId = propagationId;
102 }
103
104 /**
105 * The "propagationId" field is reserved for future use. In Beans 1.0
106 * the sole requirement is that if a listener catches a PropertyChangeEvent
107 * and then fires a PropertyChangeEvent of its own, then it should
108 * make sure that it propagates the propagationId field from its
109 * incoming event to its outgoing event.
110 *
111 * @return the propagationId object associated with a bound/constrained
112 * property update.
113 */
114 public Object getPropagationId() {
115 return propagationId;
116 }
117
118 /**
119 * name of the property that changed. May be null, if not known.
120 * @serial
121 */
122 private String propertyName;
123
124 /**
125 * New value for property. May be null if not known.
126 * @serial
127 */
128 private Object newValue;
129
130 /**
131 * Previous value for property. May be null if not known.
132 * @serial
133 */
134 private Object oldValue;
135
136 /**
137 * Propagation ID. May be null.
138 * @serial
139 * @see #getPropagationId
140 */
141 private Object propagationId;
142 }
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