/*

  * Copyright (c) 1996, 2010, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.  Oracle designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Oracle in the LICENSE file that accompanied this code.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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  * questions.

  */

 package java.beans;

 /**

  * A "PropertyChange" event gets delivered whenever a bean changes a "bound"

  * or "constrained" property.  A PropertyChangeEvent object is sent as an

  * argument to the PropertyChangeListener and VetoableChangeListener methods.

  * <P>

  * Normally PropertyChangeEvents are accompanied by the name and the old

  * and new value of the changed property.  If the new value is a primitive

  * type (such as int or boolean) it must be wrapped as the

  * corresponding java.lang.* Object type (such as Integer or Boolean).

  * <P>

  * Null values may be provided for the old and the new values if their

  * true values are not known.

  * <P>

  * An event source may send a null object as the name to indicate that an

  * arbitrary set of if its properties have changed.  In this case the

  * old and new values should also be null.

  */

 public class PropertyChangeEvent extends java.util.EventObject {

     private static final long serialVersionUID = 7042693688939648123L;

     /**

      * Constructs a new <code>PropertyChangeEvent</code>.

      *

      * @param source  The bean that fired the event.

      * @param propertyName  The programmatic name of the property

      *          that was changed.

      * @param oldValue  The old value of the property.

      * @param newValue  The new value of the property.

      */

     public PropertyChangeEvent(Object source, String propertyName,

                                      Object oldValue, Object newValue) {

         super(source);

         this.propertyName = propertyName;

         this.newValue = newValue;

         this.oldValue = oldValue;

     }

     /**

      * Gets the programmatic name of the property that was changed.

      *

      * @return  The programmatic name of the property that was changed.

      *          May be null if multiple properties have changed.

      */

     public String getPropertyName() {

         return propertyName;

     }

     /**

      * Gets the new value for the property, expressed as an Object.

      *

      * @return  The new value for the property, expressed as an Object.

      *          May be null if multiple properties have changed.

      */

     public Object getNewValue() {

         return newValue;

     }

     /**

      * Gets the old value for the property, expressed as an Object.

      *

      * @return  The old value for the property, expressed as an Object.

      *          May be null if multiple properties have changed.

      */

     public Object getOldValue() {

         return oldValue;

     }

     /**

      * Sets the propagationId object for the event.

      *

      * @param propagationId  The propagationId object for the event.

      */

     public void setPropagationId(Object propagationId) {

         this.propagationId = propagationId;

     }

     /**

      * The "propagationId" field is reserved for future use.  In Beans 1.0

      * the sole requirement is that if a listener catches a PropertyChangeEvent

      * and then fires a PropertyChangeEvent of its own, then it should

      * make sure that it propagates the propagationId field from its

      * incoming event to its outgoing event.

      *

      * @return the propagationId object associated with a bound/constrained

      *          property update.

      */

     public Object getPropagationId() {

         return propagationId;

     }

     /**

      * name of the property that changed.  May be null, if not known.

      * @serial

      */

     private String propertyName;

     /**

      * New value for property.  May be null if not known.

      * @serial

      */

     private Object newValue;

     /**

      * Previous value for property.  May be null if not known.

      * @serial

      */

     private Object oldValue;

     /**

      * Propagation ID.  May be null.

      * @serial

      * @see #getPropagationId

      */

     private Object propagationId;

     /**

      * Returns a string representation of the object.

      *

      * @return a string representation of the object

      *

      * @since 1.7

      */

     public String toString() {

         StringBuilder sb = new StringBuilder(getClass().getName());

         sb.append("[propertyName=").append(getPropertyName());

         appendTo(sb);

         sb.append("; oldValue=").append(getOldValue());

         sb.append("; newValue=").append(getNewValue());

         sb.append("; propagationId=").append(getPropagationId());

         sb.append("; source=").append(getSource());

         return sb.append("]").toString();

     }

     void appendTo(StringBuilder sb) {

     }

 }