1/*
2 *  Licensed to the Apache Software Foundation (ASF) under one or more
3 *  contributor license agreements.  See the NOTICE file distributed with
4 *  this work for additional information regarding copyright ownership.
5 *  The ASF licenses this file to You under the Apache License, Version 2.0
6 *  (the "License"); you may not use this file except in compliance with
7 *  the License.  You may obtain a copy of the License at
8 *
9 *     http://www.apache.org/licenses/LICENSE-2.0
10 *
11 *  Unless required by applicable law or agreed to in writing, software
12 *  distributed under the License is distributed on an "AS IS" BASIS,
13 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 *  See the License for the specific language governing permissions and
15 *  limitations under the License.
16 */
17
18package java.beans;
19
20import java.util.EventObject;
21
22/**
23 * An event that indicates that a constraint or a boundary of a property has
24 * changed.
25 *
26 * @since Android 1.0
27 */
28public class PropertyChangeEvent extends EventObject {
29
30    private static final long serialVersionUID = 7042693688939648123L;
31
32    String propertyName;
33
34    Object oldValue;
35
36    Object newValue;
37
38    Object propagationId;
39
40    /**
41     * The constructor used to create a new {@code PropertyChangeEvent}.
42     *
43     * @param source
44     *            the changed bean.
45     * @param propertyName
46     *            the changed property, or <code>null</code> to indicate an
47     *            unspecified set of the properties has changed.
48     * @param oldValue
49     *            the previous value of the property, or <code>null</code> if
50     *            the <code>propertyName</code> is <code>null</code> or the
51     *            previous value is unknown.
52     * @param newValue
53     *            the new value of the property, or <code>null</code> if the
54     *            <code>propertyName</code> is <code>null</code> or the new
55     *            value is unknown.
56     */
57    public PropertyChangeEvent(Object source, String propertyName,
58            Object oldValue, Object newValue) {
59        super(source);
60
61        this.propertyName = propertyName;
62        this.oldValue = oldValue;
63        this.newValue = newValue;
64    }
65
66    /**
67     * Returns the name of the property that has changed. If an unspecified set
68     * of properties has changed it returns null.
69     *
70     * @return the name of the property that has changed, or null.
71     */
72    public String getPropertyName() {
73        return propertyName;
74    }
75
76    /**
77     * Sets the propagationId object.
78     *
79     * @see #getPropagationId()
80     */
81    public void setPropagationId(Object propagationId) {
82        this.propagationId = propagationId;
83    }
84
85    /**
86     * Returns the propagationId object. This is reserved for future use. Beans
87     * 1.0 demands that a listener receiving this property and then sending its
88     * own PropertyChangeEvent sets the received propagationId on the new
89     * PropertyChangeEvent's propagationId field.
90     *
91     * @return the propagationId object.
92     */
93    public Object getPropagationId() {
94        return propagationId;
95    }
96
97    /**
98     * Returns the old value that the property had. If the old value is unknown
99     * this method returns null.
100     *
101     * @return the old property value or null.
102     */
103    public Object getOldValue() {
104        return oldValue;
105    }
106
107    /**
108     * Returns the new value that the property now has. If the new value is
109     * unknown this method returns null.
110     *
111     * @return the old property value or null.
112     */
113    public Object getNewValue() {
114        return newValue;
115    }
116}
117