java.lang.Object
javafx.collections.WeakMapChangeListener<K,V>
- Type Parameters:
K
- the key element typeV
- the value element type
- All Implemented Interfaces:
WeakListener
,MapChangeListener<K,V>
public final class WeakMapChangeListener<K,V> extends Object implements MapChangeListener<K,V>, WeakListener
A
WeakMapChangeListener
can be used, if an ObservableMap
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.
WeakMapChangeListener
are created by passing in the original
MapChangeListener
. The WeakMapChangeListener
should then be
registered to listen for changes of the observed object.
Note: You have to keep a reference to the MapChangeListener
, 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:
MapChangeListener
,ObservableMap
,WeakListener
-
Nested Class Summary
Nested classes/interfaces inherited from interface javafx.collections.MapChangeListener
MapChangeListener.Change<K,V>
-
Constructor Summary
Constructors Constructor Description WeakMapChangeListener(MapChangeListener<K,V> listener)
The constructor ofWeakMapChangeListener
. -
Method Summary
Modifier and Type Method Description void
onChanged(MapChangeListener.Change<? extends K,? extends V> change)
Called after a change has been made to an ObservableMap.boolean
wasGarbageCollected()
Returnstrue
if the linked listener was garbage-collected.
-
Constructor Details
-
WeakMapChangeListener
The constructor ofWeakMapChangeListener
.- Parameters:
listener
- The original listener that should be notified
-
-
Method Details
-
wasGarbageCollected
public boolean wasGarbageCollected()Returnstrue
if the linked listener was garbage-collected. In this case, the listener can be removed from the observable.- Specified by:
wasGarbageCollected
in interfaceWeakListener
- Returns:
true
if the linked listener was garbage-collected.
-
onChanged
Called after a change has been made to an ObservableMap. This method is called on every elementary change (put/remove) once. This means, complex changes like keySet().removeAll(Collection) or clear() may result in more than one call of onChanged method.- Specified by:
onChanged
in interfaceMapChangeListener<K,V>
- Parameters:
change
- the change that was made
-