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PropertyChangeEvent.java
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1998-09-22
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/*
* @(#)PropertyChangeEvent.java 1.22 98/07/01
*
* Copyright 1996-1998 by Sun Microsystems, Inc.,
* 901 San Antonio Road, Palo Alto, California, 94303, U.S.A.
* All rights reserved.
*
* This software is the confidential and proprietary information
* of Sun Microsystems, Inc. ("Confidential Information"). You
* shall not disclose such Confidential Information and shall use
* it only in accordance with the terms of the license agreement
* you entered into with Sun.
*/
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 builtin
* 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 {
/**
* @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;
}
/**
* @return The programmatic name of the property that was changed.
* May be null if multiple properties have changed.
*/
public String getPropertyName() {
return propertyName;
}
/**
* @return The new value for the property, expressed as an Object.
* May be null if multiple properties have changed.
*/
public Object getNewValue() {
return newValue;
}
/**
* @return The old value for the property, expressed as an Object.
* May be null if multiple properties have changed.
*/
public Object getOldValue() {
return oldValue;
}
/**
* @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;
}
private String propertyName;
private Object newValue;
private Object oldValue;
private Object propagationId;
}