- Type Parameters:
T- The type of the observed value
public final class WeakChangeListener<T> extends Object implements ChangeListener<T>, WeakListenerA
WeakChangeListenercan be used if an
ObservableValueshould only maintain a weak reference to the listener. This helps to avoid memory leaks which can occur if observers are not unregistered from observed objects after use.
WeakChangeListenerinstances are created by passing in the original
WeakChangeListenershould then be registered to listen for changes of the observed object.
Note: You have to keep a reference to the
ChangeListenerthat was passed in for as long as it is in use, otherwise it will be garbage collected too soon.
All Methods Instance Methods Concrete Methods Modifier and Type Method Description
changed(ObservableValue<? extends T> observable, T oldValue, T newValue)This method needs to be provided by an implementation of
trueif the linked listener was garbage-collected.
public boolean wasGarbageCollected()Returns
trueif the linked listener was garbage-collected. In this case, the listener can be removed from the observable.
public void changed(ObservableValue<? extends T> observable, T oldValue, T newValue)This method needs to be provided by an implementation of
ChangeListener. It is called if the value of an
In general, it is considered bad practice to modify the observed value in this method.