Package org.eclipse.jface.util

Class PropertyChangeEvent

java.lang.Object

java.util.EventObject

org.eclipse.jface.util.PropertyChangeEvent

All Implemented Interfaces:

Serializable

public class PropertyChangeEvent
extends EventObject

An event object describing a change to a named property.

This concrete class was designed to be instantiated, but may also be subclassed if required.

The JFace frameworks contain classes that report property change events for internal state changes that may be of interest to external parties. A special listener interface (IPropertyChangeListener) is defined for this purpose, and a typical class allow listeners to be registered via an addPropertyChangeListener method.

See Also:

IPropertyChangeListener, Serialized Form

Field Summary

Fields inherited from class java.util.EventObject

source

Constructor Summary

Constructors

Constructor	Description
PropertyChangeEvent(Object source, String property, Object oldValue, Object newValue)	Creates a new property change event.

Method Summary

Modifier and Type	Method	Description
Object	getNewValue()	Returns the new value of the property.
Object	getOldValue()	Returns the old value of the property.
String	getProperty()	Returns the name of the property that changed.

Methods inherited from class java.util.EventObject

getSource, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

PropertyChangeEvent

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

Creates a new property change event.

Parameters:

source - the object whose property has changed

property - the property that has changed (must not be null)

oldValue - the old value of the property, or null if none

newValue - the new value of the property, or null if none

Method Detail

getNewValue

public Object getNewValue()

Returns the new value of the property.

Returns:

the new value, or null if not known or not relevant (for instance if the property was removed).

getOldValue

public Object getOldValue()

Returns the old value of the property.

Returns:

the old value, or null if not known or not relevant (for instance if the property was just added and there was no old value).

getProperty

public String getProperty()

Returns the name of the property that changed.

Warning: there is no guarantee that the property name returned is a constant string. Callers must compare property names using equals, not ==.

Returns:

the name of the property that changed