Module javafx.base

Package javafx.collections

Class WeakListChangeListener<E>

java.lang.Object

javafx.collections.WeakListChangeListener<E>

Type Parameters:

E - The type of the observed value

All Implemented Interfaces:

WeakListener, ListChangeListener<E>

public final class WeakListChangeListener<E>
extends Object
implements ListChangeListener<E>, WeakListener

A WeakListChangeListener can be used, if an ObservableList should only maintain a weak reference to the listener. This helps to avoid memory leaks, that can occur if observers are not unregistered from observed objects after use.

WeakListChangeListener are created by passing in the original ListChangeListener. The WeakListChangeListener should then be registered to listen for changes of the observed object.

Note: You have to keep a reference to the ListChangeListener, that was passed in as long as it is in use, otherwise it will be garbage collected to soon.

Since:

JavaFX 2.1

See Also:

• ListChangeListener
• ObservableList
• WeakListener

Nested Class Summary

Nested classes/interfaces declared in interface javafx.collections.ListChangeListener

ListChangeListener.Change<E>

Constructor Summary

Constructors

Constructor	Description
WeakListChangeListener(ListChangeListener<E> listener)	The constructor of WeakListChangeListener.

Method Summary

Modifier and Type	Method	Description
void	onChanged(ListChangeListener.Change<? extends E> change)	Called after a change has been made to an ObservableList.
boolean	wasGarbageCollected()	Returns true if the linked listener was garbage-collected.

Methods declared in class java.lang.Object

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

Constructor Details

WeakListChangeListener

public WeakListChangeListener(ListChangeListener<E> listener)

The constructor of WeakListChangeListener.

Parameters:

listener - The original listener that should be notified

Method Details

wasGarbageCollected

public boolean wasGarbageCollected()

Returns true if the linked listener was garbage-collected. In this case, the listener can be removed from the observable.

Specified by:

wasGarbageCollected in interface WeakListener

Returns:

true if the linked listener was garbage-collected.

onChanged

public void onChanged(ListChangeListener.Change<? extends E> change)

Called after a change has been made to an ObservableList.

Specified by:

onChanged in interface ListChangeListener<E>

Parameters:

change - an object representing the change that was done

See Also:

• ListChangeListener.Change