1 /* 2 * Copyright (c) 1996, 2011, 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.beans; 27 28 import java.util.EventObject; 29 30 /** 31 * A "PropertyChange" event gets delivered whenever a bean changes a "bound" 32 * or "constrained" property. A PropertyChangeEvent object is sent as an 33 * argument to the PropertyChangeListener and VetoableChangeListener methods. 34 * <P> 35 * Normally PropertyChangeEvents are accompanied by the name and the old 36 * and new value of the changed property. If the new value is a primitive 37 * type (such as int or boolean) it must be wrapped as the 38 * corresponding java.lang.* Object type (such as Integer or Boolean). 39 * <P> 40 * Null values may be provided for the old and the new values if their 41 * true values are not known. 42 * <P> 43 * An event source may send a null object as the name to indicate that an 44 * arbitrary set of if its properties have changed. In this case the 45 * old and new values should also be null. 46 */ 47 public class PropertyChangeEvent extends EventObject { 48 private static final long serialVersionUID = 7042693688939648123L; 49 50 /** 51 * Constructs a new {@code PropertyChangeEvent}. 52 * 53 * @param source the bean that fired the event 54 * @param propertyName the programmatic name of the property that was changed 55 * @param oldValue the old value of the property 56 * @param newValue the new value of the property 57 * 58 * @throws IllegalArgumentException if {@code source} is {@code null} 59 */ 60 public PropertyChangeEvent(Object source, String propertyName, 61 Object oldValue, Object newValue) { 62 super(source); 63 this.propertyName = propertyName; 64 this.newValue = newValue; 65 this.oldValue = oldValue; 66 } 67 68 /** 69 * Gets the programmatic name of the property that was changed. 70 * 71 * @return The programmatic name of the property that was changed. 72 * May be null if multiple properties have changed. 73 */ 74 public String getPropertyName() { 75 return propertyName; 76 } 77 78 /** 79 * Gets the new value for the property, expressed as an Object. 80 * 81 * @return The new value for the property, expressed as an Object. 82 * May be null if multiple properties have changed. 83 */ 84 public Object getNewValue() { 85 return newValue; 86 } 87 88 /** 89 * Gets the old value for the property, expressed as an Object. 90 * 91 * @return The old value for the property, expressed as an Object. 92 * May be null if multiple properties have changed. 93 */ 94 public Object getOldValue() { 95 return oldValue; 96 } 97 98 /** 99 * Sets the propagationId object for the event. 100 * 101 * @param propagationId The propagationId object for the event. 102 */ 103 public void setPropagationId(Object propagationId) { 104 this.propagationId = propagationId; 105 } 106 107 /** 108 * The "propagationId" field is reserved for future use. In Beans 1.0 109 * the sole requirement is that if a listener catches a PropertyChangeEvent 110 * and then fires a PropertyChangeEvent of its own, then it should 111 * make sure that it propagates the propagationId field from its 112 * incoming event to its outgoing event. 113 * 114 * @return the propagationId object associated with a bound/constrained 115 * property update. 116 */ 117 public Object getPropagationId() { 118 return propagationId; 119 } 120 121 /** 122 * name of the property that changed. May be null, if not known. 123 * @serial 124 */ 125 private String propertyName; 126 127 /** 128 * New value for property. May be null if not known. 129 * @serial 130 */ 131 private Object newValue; 132 133 /** 134 * Previous value for property. May be null if not known. 135 * @serial 136 */ 137 private Object oldValue; 138 139 /** 140 * Propagation ID. May be null. 141 * @serial 142 * @see #getPropagationId 143 */ 144 private Object propagationId; 145 146 /** 147 * Returns a string representation of the object. 148 * 149 * @return a string representation of the object 150 * 151 * @since 1.7 152 */ 153 public String toString() { 154 StringBuilder sb = new StringBuilder(getClass().getName()); 155 sb.append("[propertyName=").append(getPropertyName()); 156 appendTo(sb); 157 sb.append("; oldValue=").append(getOldValue()); 158 sb.append("; newValue=").append(getNewValue()); 159 sb.append("; propagationId=").append(getPropagationId()); 160 sb.append("; source=").append(getSource()); 161 return sb.append("]").toString(); 162 } 163 164 void appendTo(StringBuilder sb) { 165 } 166 } 167
