javafx.event

Class WeakEventHandler<T extends Event>

java.lang.Object

javafx.event.WeakEventHandler<T>

Type Parameters:

T - the event class this handler can handle

All Implemented Interfaces:

java.util.EventListener, EventHandler<T>

public final class WeakEventHandler<T extends Event>
extends java.lang.Object
implements EventHandler<T>

Used in event handler registration in place of its associated event handler. Its sole purpose is to break the otherwise strong reference between an event handler container and its associated event handler. While the container still holds strong reference to the registered WeakEventHandler proxy, the proxy itself references the original handler only weakly and so doesn't prevent it from being garbage collected. Until this weak reference is broken, any event notification received by the proxy is forwarded to the original handler.

Since:

JavaFX 8.0

Field Summary

Fields

Modifier and Type	Field and Description
private java.lang.ref.WeakReference<EventHandler<T>>	weakRef

Constructor Summary

Constructors

Constructor and Description
WeakEventHandler(EventHandler<T> eventHandler) Creates a new instance of WeakEventHandler.

Method Summary

Modifier and Type	Method and Description
(package private) void	clear()
void	handle(T event) Forwards event notification to the associated event handler.
boolean	wasGarbageCollected() Indicates whether the associated event handler has been garbage collected.

Methods inherited from class java.lang.Object

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

Field Detail

weakRef

private final java.lang.ref.WeakReference<EventHandler<T extends Event>> weakRef

Constructor Detail

WeakEventHandler

public WeakEventHandler(EventHandler<T> eventHandler)

Creates a new instance of WeakEventHandler.

Parameters:

eventHandler - the original event handler to which to forward event notifications

Method Detail

wasGarbageCollected

public boolean wasGarbageCollected()

Indicates whether the associated event handler has been garbage collected. Used by containers to detect when the storage of corresponding references to this WeakEventHandler is no longer necessary.

Returns:

true if the associated handler has been garbage collected, false otherwise

handle

public void handle(T event)

Forwards event notification to the associated event handler.

Specified by:

handle in interface EventHandler<T extends Event>

Parameters:

event - the event which occurred

clear

void clear()