org.openide.util
Class WeakListener

java.lang.Object
  |
  +--org.openide.util.WeakListener

All Implemented Interfaces:

EventListener

Direct Known Subclasses:

WeakListener.Change, WeakListener.Document, WeakListener.FileChange, WeakListener.FileStatus, WeakListener.Focus, WeakListener.PropertyChange, WeakListener.Repository, WeakListener.VetoableChange

public abstract class WeakListener

extends Object

implements EventListener

Property change listener that delegates to another one change listener but hold only weak reference to that listener, so it does not prevent it to be finalized.

Inner Class Summary

static class	WeakListener.Change Deprecated. use appropriate method instead
static class	WeakListener.Document Deprecated. use appropriate method instead
static class	WeakListener.FileChange Deprecated. use appropriate method instead
static class	WeakListener.FileStatus Deprecated. use appropriate method instead
static class	WeakListener.Focus Deprecated. use appropriate method instead
static class	WeakListener.Node Deprecated. use appropriate method instead
static class	WeakListener.PropertyChange Deprecated. use appropriate method instead
static class	WeakListener.Repository Deprecated. use appropriate method instead
static class	WeakListener.VetoableChange Deprecated. use appropriate method instead

Constructor Summary

protected

WeakListener(Class listenerClass, EventListener l)

Method Summary

static ChangeListener	change(ChangeListener l, Object source)
static EventListener	create(Class lType, EventListener l, Object source)
static DocumentListener	document(DocumentListener l, Object source)
static FileChangeListener	fileChange(FileChangeListener l, Object source)
static FileStatusListener	fileStatus(FileStatusListener l, Object source)
static FocusListener	focus(FocusListener l, Object source)
protected EventListener	get(EventObject ev) Getter for the target listener.
static NodeListener	node(NodeListener l, Object source) Creates a weak listener.
static OperationListener	operation(OperationListener l, Object source)
static PropertyChangeListener	propertyChange(PropertyChangeListener l, Object source)
protected abstract String	removeMethodName() Method name to use for removing the listener.
static RepositoryListener	repository(RepositoryListener l, Object source)
protected void	setSource(Object source) Setter for the source field.
String	toString() To string.
static VetoableChangeListener	vetoableChange(VetoableChangeListener l, Object source)

Methods inherited from class java.lang.Object

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

Constructor Detail

WeakListener

protected WeakListener(Class listenerClass,
                       EventListener l)

Parameters:

listenerClass - class of the listener

l - listener to delegate to

Method Detail

setSource

protected final void setSource(Object source)

Setter for the source field. If a WeakReference to an underlying listener is cleared and enqueued, that is, the original listener is garbage collected, then the source field is used for deregistration of this WeakListener, thus making it eligible for garbage collection if no more references exist. This method is particularly useful in cases where the underlying listener was garbage collected and the event source, on which this listener is listening on, is quiet, i.e. does not fire any events for long periods. In this case, this listener is not removed from the event source until an event is fired. If the source field is set however, WeakListeners that lost their underlying listeners are removed on a regular basis, which is currently 25s (see CLEANER_TIME constant).

Parameters:

source - is any Object or null, though only setting an object that has an appropriate remove*listenerClass*Listener method and on which this listener is listening on, is useful.

removeMethodName

protected abstract String removeMethodName()

Method name to use for removing the listener.

Returns:

name of method of the source object that should be used to remove the listener from listening on source of events

get

protected final EventListener get(EventObject ev)

Getter for the target listener.

Parameters:

event - the event the we want to distribute

Returns:

null if there is no listener because it has been finalized

toString

public String toString()

To string.

Overrides:

toString in class Object

node

public static NodeListener node(NodeListener l,
                                Object source)

Creates a weak listener. The sample usage code is

   AnySource source;
   AnyListener listener;
   
   AnyListener weak = WeakListener.any (listener, source);
   source.addAnyListener (weak);
 

Parameters:

l - the listener to delegate to

source - the source that the listener should detach from when listener l is no longer used, can be null

propertyChange

public static PropertyChangeListener propertyChange(PropertyChangeListener l,
                                                    Object source)

vetoableChange

public static VetoableChangeListener vetoableChange(VetoableChangeListener l,
                                                    Object source)

fileChange

public static FileChangeListener fileChange(FileChangeListener l,
                                            Object source)

fileStatus

public static FileStatusListener fileStatus(FileStatusListener l,
                                            Object source)

repository

public static RepositoryListener repository(RepositoryListener l,
                                            Object source)

document

public static DocumentListener document(DocumentListener l,
                                        Object source)

change

public static ChangeListener change(ChangeListener l,
                                    Object source)

focus

public static FocusListener focus(FocusListener l,
                                  Object source)

operation

public static OperationListener operation(OperationListener l,
                                          Object source)

create

public static EventListener create(Class lType,
                                   EventListener l,
                                   Object source)