Package com.luciad.util

Class ALcdWeakSelectionListener<T>

java.lang.Object

com.luciad.util.ALcdWeakSelectionListener<T>

Type Parameters:

T - The type of the short-lived object

All Implemented Interfaces:

ILcdSelectionListener, Serializable, EventListener

public abstract class ALcdWeakSelectionListener<T>
extends Object
implements ILcdSelectionListener

A ILcdSelectionListener implementation which only keeps a WeakReference to the object it wants to update when selection 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 ILcdSelection.
• The listener must be registered using ILcdSelection#addSelectionListener.

Since:

2015.1

See Also:

• Serialized Form

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
final void	selectionChanged(TLcdSelectionChangedEvent aSelectionEvent)	This method will be called by an ILcdSelection when this ILcdSelectionListener has been registered to it, and when the selection state of some Object has changed in the ILcdSelection.
protected abstract void	selectionChangedImpl(T aToModify, TLcdSelectionChangedEvent aSelectionEvent)

Methods inherited from class java.lang.Object

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

Constructor Details

ALcdWeakSelectionListener

protected ALcdWeakSelectionListener(T aObjectToModify)

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

Parameters:

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

Method Details

selectionChanged

public final void selectionChanged(TLcdSelectionChangedEvent aSelectionEvent)

This method will be called by an ILcdSelection when this ILcdSelectionListener has been registered to it, and when the selection state of some Object has changed in the ILcdSelection.

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 selectionChangedImpl(Object, TLcdSelectionChangedEvent) method. If the short-living object is already garbage collected, this method will de-register the listener from the source.

Specified by:

selectionChanged in interface ILcdSelectionListener<T>

Parameters:

aSelectionEvent - a TLcdSelectionChangedEvent detailing the changes in the selection.

See Also:

• selectionChangedImpl(Object, TLcdSelectionChangedEvent)

selectionChangedImpl

protected abstract void selectionChangedImpl(T aToModify,
 TLcdSelectionChangedEvent aSelectionEvent)