Class PropertyChangeEvent

java.lang.Object

java.util.EventObject

java.beans.PropertyChangeEvent

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

IndexedPropertyChangeEvent

public class PropertyChangeEvent
extends EventObject

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.

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).

Null values may be provided for the old and the new values if their true values are not known.

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.

Since:

1.1

See Also:

• Serialized Form

Field Summary

Fields declared in class EventObject

source

Modifier and Type	Field	Description
protected Object	source	The object on which the Event initially occurred.

Constructor Summary

Constructors

Constructor	Description
PropertyChangeEvent(Object source, String propertyName, Object oldValue, Object newValue)	Constructs a new PropertyChangeEvent.

Method Summary

Modifier and Type	Method	Description
Object	getNewValue()	Gets the new value for the property, expressed as an Object.
Object	getOldValue()	Gets the old value for the property, expressed as an Object.
Object	getPropagationId()	The "propagationId" field is reserved for future use.
String	getPropertyName()	Gets the programmatic name of the property that was changed.
void	setPropagationId(Object propagationId)	Sets the propagationId object for the event.
String	toString()	Returns a string representation of the object.

Methods declared in class EventObject

getSource

Modifier and Type	Method	Description
Object	getSource()	The object on which the Event initially occurred.

Methods declared in class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Modifier and Type	Method	Description
protected Object	clone()	Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
boolean	equals(Object o)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. May cause performance issues, deadlocks and hangs.
final Class<? extends Object>	getClass()	Answers the unique instance of java.lang.Class which represents the class of the receiver.
int	hashCode()	Answers an integer hash code for the receiver.
final void	notify()	Causes one thread which is waiting on the receiver to be made ready to run.
final void	notifyAll()	Causes all threads which are waiting on the receiver to be made ready to run.
final void	wait()	Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
final void	wait(long time)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
final void	wait(long time, int frac)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

Constructor Details

PropertyChangeEvent

public PropertyChangeEvent(Object source,
 String propertyName,
 Object oldValue,
 Object newValue)

Constructs a new PropertyChangeEvent.

Parameters:

source - the bean that fired the event

propertyName - the programmatic name of the property that was changed

oldValue - the old value of the property

newValue - the new value of the property

Throws:

IllegalArgumentException - if source is null

Method Details

getPropertyName

public String getPropertyName()

Gets the programmatic name of the property that was changed.

Returns:

The programmatic name of the property that was changed. May be null if multiple properties have changed.

getNewValue

public Object getNewValue()

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

Returns:

The new value for the property, expressed as an Object. May be null if multiple properties have changed.

getOldValue

public Object getOldValue()

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

Returns:

The old value for the property, expressed as an Object. May be null if multiple properties have changed.

setPropagationId

public void setPropagationId(Object propagationId)

Sets the propagationId object for the event.

Parameters:

propagationId - The propagationId object for the event.

getPropagationId

public Object getPropagationId()

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.

Returns:

the propagationId object associated with a bound/constrained property update.

toString

public String toString()

Returns a string representation of the object.

Overrides:

toString in class EventObject

Returns:

a string representation of the object

Since:

1.7