com.luciad.util

LuciadLightspeedClass ALcdWeakPropertyChangeListener<T>

java.lang.Object

com.luciad.util.ALcdWeakPropertyChangeListener<T>

Type Parameters:

T - The type of the short-lived object

All Implemented Interfaces:

PropertyChangeListener, EventListener

public abstract class ALcdWeakPropertyChangeListener<T>
extends Object
implements PropertyChangeListener

A PropertyChangeListener implementation which only keeps a WeakReference to the object it wants to update when property changes are received. This avoids memory leaks, even without removing the listener.

The class javadoc of ALcdWeakModelListener contains an example of a weak listener, and some rules on the usage of weak listeners.

This particular listener has two extra rules compared to the general rules of weak listeners:

• The object to listen to must implement ILcdPropertyChangeSource.
• Do not register the listener for a particular property, so avoid addPropertyChangeListener(String, ...)

Since:

2015.1

See Also:

ILcdPropertyChangeSource

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ALcdWeakPropertyChangeListener(T aObjectToModify) Creates a new ALcdWeakPropertyChangeListener instance which can update aObjectToModify when it receives events.

Method Summary

Modifier and Type	Method and Description
void	propertyChange(PropertyChangeEvent evt)
protected abstract void	propertyChangeImpl(T aToModify, PropertyChangeEvent aPropertyChangeEvent) This method is called each time a PropertyChangeEvent is received by this listener, and the short-living object to modify passed in the constructor of this listener is not yet GC-ed.

Methods inherited from class java.lang.Object

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

Constructor Detail

ALcdWeakPropertyChangeListener

protected ALcdWeakPropertyChangeListener(T aObjectToModify)

Creates a new ALcdWeakPropertyChangeListener instance which can update aObjectToModify when it receives events.

Warning: this listener can only be registered to a ILcdPropertyChangeSource. The listener will throw exceptions when it receives PropertyChangeEvent instances where the source is not an ILcdPropertyChangeSource instance.

Parameters:

aObjectToModify - The object you want to modify when a PropertyChangeEvent is received. This is a short-lived object, while the listener will be attached to a long-living ILcdPropertyChangeSource object.

Method Detail

propertyChange

public final void propertyChange(PropertyChangeEvent evt)

This method will check whether the short-living object is still available. If it is, this method will pass the short-living object and the event to the propertyChangeImpl(Object, java.beans.PropertyChangeEvent) method. If the short-living object is already garbage collected, this method will de-register the listener from the source.

Specified by:

propertyChange in interface PropertyChangeListener

See Also:

propertyChangeImpl(Object, java.beans.PropertyChangeEvent)

propertyChangeImpl

protected abstract void propertyChangeImpl(T aToModify,
                                           PropertyChangeEvent aPropertyChangeEvent)

This method is called each time a PropertyChangeEvent is received by this listener, and the short-living object to modify passed in the constructor of this listener is not yet GC-ed.

Parameters:

aToModify - The object to modify, as passed in the constructor of this class.

aPropertyChangeEvent - The received event