001 /*
002 * Copyright 1996-2006 Sun Microsystems, Inc. All Rights Reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation. Sun designates this
008 * particular file as subject to the "Classpath" exception as provided
009 * by Sun in the LICENSE file that accompanied this code.
010 *
011 * This code is distributed in the hope that it will be useful, but WITHOUT
012 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
014 * version 2 for more details (a copy is included in the LICENSE file that
015 * accompanied this code).
016 *
017 * You should have received a copy of the GNU General Public License version
018 * 2 along with this work; if not, write to the Free Software Foundation,
019 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020 *
021 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022 * CA 95054 USA or visit www.sun.com if you need additional information or
023 * have any questions.
024 */
025
026 package java.beans;
027
028 /**
029 * A "PropertyChange" event gets delivered whenever a bean changes a "bound"
030 * or "constrained" property. A PropertyChangeEvent object is sent as an
031 * argument to the PropertyChangeListener and VetoableChangeListener methods.
032 * <P>
033 * Normally PropertyChangeEvents are accompanied by the name and the old
034 * and new value of the changed property. If the new value is a primitive
035 * type (such as int or boolean) it must be wrapped as the
036 * corresponding java.lang.* Object type (such as Integer or Boolean).
037 * <P>
038 * Null values may be provided for the old and the new values if their
039 * true values are not known.
040 * <P>
041 * An event source may send a null object as the name to indicate that an
042 * arbitrary set of if its properties have changed. In this case the
043 * old and new values should also be null.
044 */
045
046 public class PropertyChangeEvent extends java.util.EventObject {
047
048 /**
049 * Constructs a new <code>PropertyChangeEvent</code>.
050 *
051 * @param source The bean that fired the event.
052 * @param propertyName The programmatic name of the property
053 * that was changed.
054 * @param oldValue The old value of the property.
055 * @param newValue The new value of the property.
056 */
057 public PropertyChangeEvent(Object source, String propertyName,
058 Object oldValue, Object newValue) {
059 super (source);
060 this .propertyName = propertyName;
061 this .newValue = newValue;
062 this .oldValue = oldValue;
063 }
064
065 /**
066 * Gets the programmatic name of the property that was changed.
067 *
068 * @return The programmatic name of the property that was changed.
069 * May be null if multiple properties have changed.
070 */
071 public String getPropertyName() {
072 return propertyName;
073 }
074
075 /**
076 * Gets the new value for the property, expressed as an Object.
077 *
078 * @return The new value for the property, expressed as an Object.
079 * May be null if multiple properties have changed.
080 */
081 public Object getNewValue() {
082 return newValue;
083 }
084
085 /**
086 * Gets the old value for the property, expressed as an Object.
087 *
088 * @return The old value for the property, expressed as an Object.
089 * May be null if multiple properties have changed.
090 */
091 public Object getOldValue() {
092 return oldValue;
093 }
094
095 /**
096 * Sets the propagationId object for the event.
097 *
098 * @param propagationId The propagationId object for the event.
099 */
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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