AdjustmentEvent's. However, this
* same approach is useful for all events in the java.awt.event
* package, and more if this class is subclassed.
*
*
* AdjustmentListener al;
* public void addAdjustmentListener(AdjustmentListener listener)
* {
* al = AWTEventMulticaster.add(al, listener);
* }
* public void removeAdjustmentListener(AdjustmentListener listener)
* {
* al = AWTEventMulticaster.remove(al, listener);
* }
*
*
*
When it come time to process an event, simply call al,
* assuming it is not null, and all listeners in the chain will
* be fired.
*
*
The first time add is called it is passed
* null and listener as its arguments. This
* starts building the chain. This class returns listener
* which becomes the new al. The next time, add
* is called with al and listener and the
* new listener is then chained to the old.
*
* @author Bryce McKinlay
* @author Aaron M. Renn (arenn@urbanophile.com)
* @author Eric Blake (ebb9@email.byu.edu)
* @since 1.1
* @status updated to 1.4
*/
public class AWTEventMulticaster
implements ComponentListener, ContainerListener, FocusListener, KeyListener,
MouseListener, MouseMotionListener, WindowListener,
WindowFocusListener, WindowStateListener, ActionListener,
ItemListener, AdjustmentListener, TextListener,
InputMethodListener, HierarchyListener, HierarchyBoundsListener,
MouseWheelListener
{
/**
* A variable in the event chain.
*/
protected final EventListener a;
/**
* A variable in the event chain.
*/
protected final EventListener b;
/**
* Initializes a new instance of AWTEventMulticaster with
* the specified event listener parameters. The parameters should not be
* null, although it is not required to enforce this with a
* NullPointerException.
*
* @param a the "a" listener object
* @param b the "b" listener object
*/
protected AWTEventMulticaster(EventListener a, EventListener b)
{
this.a = a;
this.b = b;
}
/**
* Removes one instance of the specified listener from this multicaster
* chain. This descends recursively if either child is a multicaster, and
* returns a multicaster chain with the old listener removed.
*
* @param oldl the object to remove from this multicaster
* @return the resulting multicaster with the specified listener removed
*/
protected EventListener remove(EventListener oldl)
{
// If oldl is an immediate child, return the other child.
if (a == oldl)
return b;
if (b == oldl)
return a;
// If a and/or b are Multicaster's, search them recursively.
if (a instanceof AWTEventMulticaster)
{
EventListener newa = ((AWTEventMulticaster) a).remove(oldl);
if (newa != a)
return new AWTEventMulticaster(newa, b);
}
if (b instanceof AWTEventMulticaster)
{
EventListener newb = ((AWTEventMulticaster) b).remove(oldl);
if (newb != b)
return new AWTEventMulticaster(a, newb);
}
// oldl was not found.
return this;
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void componentResized(ComponentEvent e)
{
((ComponentListener) a).componentResized(e);
((ComponentListener) b).componentResized(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void componentMoved(ComponentEvent e)
{
((ComponentListener) a).componentMoved(e);
((ComponentListener) b).componentMoved(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void componentShown(ComponentEvent e)
{
((ComponentListener) a).componentShown(e);
((ComponentListener) b).componentShown(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void componentHidden(ComponentEvent e)
{
((ComponentListener) a).componentHidden(e);
((ComponentListener) b).componentHidden(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void componentAdded(ContainerEvent e)
{
((ContainerListener) a).componentAdded(e);
((ContainerListener) b).componentAdded(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void componentRemoved(ContainerEvent e)
{
((ContainerListener) a).componentRemoved(e);
((ContainerListener) b).componentRemoved(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void focusGained(FocusEvent e)
{
((FocusListener) a).focusGained(e);
((FocusListener) b).focusGained(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void focusLost(FocusEvent e)
{
((FocusListener) a).focusLost(e);
((FocusListener) b).focusLost(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void keyTyped(KeyEvent e)
{
((KeyListener) a).keyTyped(e);
((KeyListener) b).keyTyped(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void keyPressed(KeyEvent e)
{
((KeyListener) a).keyPressed(e);
((KeyListener) b).keyPressed(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void keyReleased(KeyEvent e)
{
((KeyListener) a).keyReleased(e);
((KeyListener) b).keyReleased(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void mouseClicked(MouseEvent e)
{
((MouseListener) a).mouseClicked(e);
((MouseListener) b).mouseClicked(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void mousePressed(MouseEvent e)
{
((MouseListener) a).mousePressed(e);
((MouseListener) b).mousePressed(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void mouseReleased(MouseEvent e)
{
((MouseListener) a).mouseReleased(e);
((MouseListener) b).mouseReleased(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void mouseEntered(MouseEvent e)
{
((MouseListener) a).mouseEntered(e);
((MouseListener) b).mouseEntered(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void mouseExited(MouseEvent e)
{
((MouseListener) a).mouseExited(e);
((MouseListener) b).mouseExited(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void mouseDragged(MouseEvent e)
{
((MouseMotionListener) a).mouseDragged(e);
((MouseMotionListener) b).mouseDragged(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void mouseMoved(MouseEvent e)
{
((MouseMotionListener) a).mouseMoved(e);
((MouseMotionListener) b).mouseMoved(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void windowOpened(WindowEvent e)
{
((WindowListener) a).windowOpened(e);
((WindowListener) b).windowOpened(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void windowClosing(WindowEvent e)
{
((WindowListener) a).windowClosing(e);
((WindowListener) b).windowClosing(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void windowClosed(WindowEvent e)
{
((WindowListener) a).windowClosed(e);
((WindowListener) b).windowClosed(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void windowIconified(WindowEvent e)
{
((WindowListener) a).windowIconified(e);
((WindowListener) b).windowIconified(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void windowDeiconified(WindowEvent e)
{
((WindowListener) a).windowDeiconified(e);
((WindowListener) b).windowDeiconified(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void windowActivated(WindowEvent e)
{
((WindowListener) a).windowActivated(e);
((WindowListener) b).windowActivated(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void windowDeactivated(WindowEvent e)
{
((WindowListener) a).windowDeactivated(e);
((WindowListener) b).windowDeactivated(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
* @since 1.4
*/
public void windowStateChanged(WindowEvent e)
{
((WindowStateListener) a).windowStateChanged(e);
((WindowStateListener) b).windowStateChanged(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
* @since 1.4
*/
public void windowGainedFocus(WindowEvent e)
{
((WindowFocusListener) a).windowGainedFocus(e);
((WindowFocusListener) b).windowGainedFocus(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
* @since 1.4
*/
public void windowLostFocus(WindowEvent e)
{
((WindowFocusListener) a).windowLostFocus(e);
((WindowFocusListener) b).windowLostFocus(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void actionPerformed(ActionEvent e)
{
((ActionListener) a).actionPerformed(e);
((ActionListener) b).actionPerformed(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void itemStateChanged(ItemEvent e)
{
((ItemListener) a).itemStateChanged(e);
((ItemListener) b).itemStateChanged(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void adjustmentValueChanged(AdjustmentEvent e)
{
((AdjustmentListener) a).adjustmentValueChanged(e);
((AdjustmentListener) b).adjustmentValueChanged(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
*/
public void textValueChanged(TextEvent e)
{
((TextListener) a).textValueChanged(e);
((TextListener) b).textValueChanged(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
* @since 1.2
*/
public void inputMethodTextChanged(InputMethodEvent e)
{
((InputMethodListener) a).inputMethodTextChanged(e);
((InputMethodListener) b).inputMethodTextChanged(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
* @since 1.2
*/
public void caretPositionChanged(InputMethodEvent e)
{
((InputMethodListener) a).caretPositionChanged(e);
((InputMethodListener) b).caretPositionChanged(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
* @since 1.3
*/
public void hierarchyChanged(HierarchyEvent e)
{
((HierarchyListener) a).hierarchyChanged(e);
((HierarchyListener) b).hierarchyChanged(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
* @since 1.3
*/
public void ancestorMoved(HierarchyEvent e)
{
((HierarchyBoundsListener) a).ancestorMoved(e);
((HierarchyBoundsListener) b).ancestorMoved(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
* @since 1.3
*/
public void ancestorResized(HierarchyEvent e)
{
((HierarchyBoundsListener) a).ancestorResized(e);
((HierarchyBoundsListener) b).ancestorResized(e);
}
/**
* Handles this event by dispatching it to the "a" and "b" listener
* instances.
*
* @param e the event to handle
* @since 1.4
*/
public void mouseWheelMoved(MouseWheelEvent e)
{
((MouseWheelListener) a).mouseWheelMoved(e);
((MouseWheelListener) b).mouseWheelMoved(e);
}
/**
* Chain ComponentListener a and b.
*
* @param a the "a" listener, may be null
* @param b the "b" listener, may be null
* @return latest entry in the chain
*/
public static ComponentListener add(ComponentListener a, ComponentListener b)
{
return (ComponentListener) addInternal(a, b);
}
/**
* Chain ContainerListener a and b.
*
* @param a the "a" listener, may be null
* @param b the "b" listener, may be null
* @return latest entry in the chain
*/
public static ContainerListener add(ContainerListener a, ContainerListener b)
{
return (ContainerListener) addInternal(a, b);
}
/**
* Chain FocusListener a and b.
*
* @param a the "a" listener, may be null
* @param b the "b" listener, may be null
* @return latest entry in the chain
*/
public static FocusListener add(FocusListener a, FocusListener b)
{
return (FocusListener) addInternal(a, b);
}
/**
* Chain KeyListener a and b.
*
* @param a the "a" listener, may be null
* @param b the "b" listener, may be null
* @return latest entry in the chain
*/
public static KeyListener add(KeyListener a, KeyListener b)
{
return (KeyListener) addInternal(a, b);
}
/**
* Chain MouseListener a and b.
*
* @param a the "a" listener, may be null
* @param b the "b" listener, may be null
* @return latest entry in the chain
*/
public static MouseListener add(MouseListener a, MouseListener b)
{
return (MouseListener) addInternal(a, b);
}
/**
* Chain MouseMotionListener a and b.
*
* @param a the "a" listener, may be null
* @param b the "b" listener, may be null
* @return latest entry in the chain
*/
public static MouseMotionListener add(MouseMotionListener a,
MouseMotionListener b)
{
return (MouseMotionListener) addInternal(a, b);
}
/**
* Chain WindowListener a and b.
*
* @param a the "a" listener, may be null
* @param b the "b" listener, may be null
* @return latest entry in the chain
*/
public static WindowListener add(WindowListener a, WindowListener b)
{
return (WindowListener) addInternal(a, b);
}
/**
* Chain WindowStateListener a and b.
*
* @param a the "a" listener, may be null
* @param b the "b" listener, may be null
* @return latest entry in the chain
* @since 1.4
*/
public static WindowStateListener add(WindowStateListener a,
WindowStateListener b)
{
return (WindowStateListener) addInternal(a, b);
}
/**
* Chain WindowFocusListener a and b.
*
* @param a the "a" listener, may be null
* @param b the "b" listener, may be null
* @return latest entry in the chain
* @since 1.4
*/
public static WindowFocusListener add(WindowFocusListener a,
WindowFocusListener b)
{
return (WindowFocusListener) addInternal(a, b);
}
/**
* Chain ActionListener a and b.
*
* @param a the "a" listener, may be null
* @param b the "b" listener, may be null
* @return latest entry in the chain
*/
public static ActionListener add(ActionListener a, ActionListener b)
{
return (ActionListener) addInternal(a, b);
}
/**
* Chain ItemListener a and b.
*
* @param a the "a" listener, may be null
* @param b the "b" listener, may be null
* @return latest entry in the chain
*/
public static ItemListener add(ItemListener a, ItemListener b)
{
return (ItemListener) addInternal(a, b);
}
/**
* Chain AdjustmentListener a and b.
*
* @param a the "a" listener, may be null
* @param b the "b" listener, may be null
* @return latest entry in the chain
*/
public static AdjustmentListener add(AdjustmentListener a,
AdjustmentListener b)
{
return (AdjustmentListener) addInternal(a, b);
}
/**
* Chain AdjustmentListener a and b.
*
* @param a the "a" listener, may be null
* @param b the "b" listener, may be null
* @return latest entry in the chain
*/
public static TextListener add(TextListener a, TextListener b)
{
return (TextListener) addInternal(a, b);
}
/**
* Chain InputMethodListener a and b.
*
* @param a the "a" listener, may be null
* @param b the "b" listener, may be null
* @return latest entry in the chain
* @since 1.2
*/
public static InputMethodListener add(InputMethodListener a,
InputMethodListener b)
{
return (InputMethodListener) addInternal(a, b);
}
/**
* Chain HierarchyListener a and b.
*
* @param a the "a" listener, may be null
* @param b the "b" listener, may be null
* @return latest entry in the chain
* @since 1.3
*/
public static HierarchyListener add(HierarchyListener a, HierarchyListener b)
{
return (HierarchyListener) addInternal(a, b);
}
/**
* Chain HierarchyBoundsListener a and b.
*
* @param a the "a" listener, may be null
* @param b the "b" listener, may be null
* @return latest entry in the chain
* @since 1.3
*/
public static HierarchyBoundsListener add(HierarchyBoundsListener a,
HierarchyBoundsListener b)
{
return (HierarchyBoundsListener) addInternal(a, b);
}
/**
* Chain MouseWheelListener a and b.
*
* @param a the "a" listener, may be null
* @param b the "b" listener, may be null
* @return latest entry in the chain
* @since 1.4
*/
public static MouseWheelListener add(MouseWheelListener a,
MouseWheelListener b)
{
return (MouseWheelListener) addInternal(a, b);
}
/**
* Removes the listener oldl from the listener l.
*
* @param l the listener chain to reduce
* @param oldl the listener to remove
* @return the resulting listener chain
*/
public static ComponentListener remove(ComponentListener l,
ComponentListener oldl)
{
return (ComponentListener) removeInternal(l, oldl);
}
/**
* Removes the listener oldl from the listener l.
*
* @param l the listener chain to reduce
* @param oldl the listener to remove
* @return the resulting listener chain
*/
public static ContainerListener remove(ContainerListener l,
ContainerListener oldl)
{
return (ContainerListener) removeInternal(l, oldl);
}
/**
* Removes the listener oldl from the listener l.
*
* @param l the listener chain to reduce
* @param oldl the listener to remove
* @return the resulting listener chain
*/
public static FocusListener remove(FocusListener l, FocusListener oldl)
{
return (FocusListener) removeInternal(l, oldl);
}
/**
* Removes the listener oldl from the listener l.
*
* @param l the listener chain to reduce
* @param oldl the listener to remove
* @return the resulting listener chain
*/
public static KeyListener remove(KeyListener l, KeyListener oldl)
{
return (KeyListener) removeInternal(l, oldl);
}
/**
* Removes the listener oldl from the listener l.
*
* @param l the listener chain to reduce
* @param oldl the listener to remove
* @return the resulting listener chain
*/
public static MouseListener remove(MouseListener l, MouseListener oldl)
{
return (MouseListener) removeInternal(l, oldl);
}
/**
* Removes the listener oldl from the listener l.
*
* @param l the listener chain to reduce
* @param oldl the listener to remove
* @return the resulting listener chain
*/
public static MouseMotionListener remove(MouseMotionListener l,
MouseMotionListener oldl)
{
return (MouseMotionListener) removeInternal(l, oldl);
}
/**
* Removes the listener oldl from the listener l.
*
* @param l the listener chain to reduce
* @param oldl the listener to remove
* @return the resulting listener chain
*/
public static WindowListener remove(WindowListener l, WindowListener oldl)
{
return (WindowListener) removeInternal(l, oldl);
}
/**
* Removes the listener oldl from the listener l.
*
* @param l the listener chain to reduce
* @param oldl the listener to remove
* @return the resulting listener chain
* @since 1.4
*/
public static WindowStateListener remove(WindowStateListener l,
WindowStateListener oldl)
{
return (WindowStateListener) removeInternal(l, oldl);
}
/**
* Removes the listener oldl from the listener l.
*
* @param l the listener chain to reduce
* @param oldl the listener to remove
* @return the resulting listener chain
* @since 1.4
*/
public static WindowFocusListener remove(WindowFocusListener l,
WindowFocusListener oldl)
{
return (WindowFocusListener) removeInternal(l, oldl);
}
/**
* Removes the listener oldl from the listener l.
*
* @param l the listener chain to reduce
* @param oldl the listener to remove
* @return the resulting listener chain
*/
public static ActionListener remove(ActionListener l, ActionListener oldl)
{
return (ActionListener) removeInternal(l, oldl);
}
/**
* Removes the listener oldl from the listener l.
*
* @param l the listener chain to reduce
* @param oldl the listener to remove
* @return the resulting listener chain
*/
public static ItemListener remove(ItemListener l, ItemListener oldl)
{
return (ItemListener) removeInternal(l, oldl);
}
/**
* Removes the listener oldl from the listener l.
*
* @param l the listener chain to reduce
* @param oldl the listener to remove
* @return the resulting listener chain
*/
public static AdjustmentListener remove(AdjustmentListener l,
AdjustmentListener oldl)
{
return (AdjustmentListener) removeInternal(l, oldl);
}
/**
* Removes the listener oldl from the listener l.
*
* @param l the listener chain to reduce
* @param oldl the listener to remove
* @return the resulting listener chain
*/
public static TextListener remove(TextListener l, TextListener oldl)
{
return (TextListener) removeInternal(l, oldl);
}
/**
* Removes the listener oldl from the listener l.
*
* @param l the listener chain to reduce
* @param oldl the listener to remove
* @return the resulting listener chain
* @since 1.2
*/
public static InputMethodListener remove(InputMethodListener l,
InputMethodListener oldl)
{
return (InputMethodListener) removeInternal(l, oldl);
}
/**
* Removes the listener oldl from the listener l.
*
* @param l the listener chain to reduce
* @param oldl the listener to remove
* @return the resulting listener chain
* @since 1.3
*/
public static HierarchyListener remove(HierarchyListener l,
HierarchyListener oldl)
{
return (HierarchyListener) removeInternal(l, oldl);
}
/**
* Removes the listener oldl from the listener l.
*
* @param l the listener chain to reduce
* @param oldl the listener to remove
* @return the resulting listener chain
* @since 1.3
*/
public static HierarchyBoundsListener remove(HierarchyBoundsListener l,
HierarchyBoundsListener oldl)
{
return (HierarchyBoundsListener) removeInternal(l, oldl);
}
/**
* Removes the listener oldl from the listener l.
*
* @param l the listener chain to reduce
* @param oldl the listener to remove
* @return the resulting listener chain
* @since 1.4
*/
public static MouseWheelListener remove(MouseWheelListener l,
MouseWheelListener oldl)
{
return (MouseWheelListener) removeInternal(l, oldl);
}
/**
* Chain EventListener a and b.
*
* @param a the "a" listener, may be null
* @param b the "b" listener, may be null
* @return latest entry in the chain
*/
protected static EventListener addInternal(EventListener a, EventListener b)
{
if (a == null)
return b;
if (b == null)
return a;
return new AWTEventMulticaster(a, b);
}
/**
* Removes the listener oldl from the listener l.
*
* @param l the listener chain to reduce
* @param oldl the listener to remove
* @return the resulting listener chain
*/
protected static EventListener removeInternal(EventListener l,
EventListener oldl)
{
if (l == oldl)
return null;
if (l instanceof AWTEventMulticaster)
return ((AWTEventMulticaster) l).remove(oldl);
return l;
}
/**
* Saves all Serializable listeners to a serialization stream.
*
* @param s the stream to save to
* @param k a prefix stream put before each serializable listener
* @throws IOException if serialization fails
*/
protected void saveInternal(ObjectOutputStream s, String k)
throws IOException
{
// This is not documented by Sun, but I think it is correct.
if (a instanceof AWTEventMulticaster)
((AWTEventMulticaster) a).saveInternal(s, k);
else if (a instanceof Serializable)
{
s.writeObject(k);
s.writeObject(a);
}
if (b instanceof AWTEventMulticaster)
((AWTEventMulticaster) b).saveInternal(s, k);
else if (b instanceof Serializable)
{
s.writeObject(k);
s.writeObject(b);
}
}
/**
* Saves a Serializable listener chain to a serialization stream.
*
* @param s the stream to save to
* @param k a prefix stream put before each serializable listener
* @param l the listener chain to save
* @throws IOException if serialization fails
*/
protected static void save(ObjectOutputStream s, String k, EventListener l)
throws IOException
{
// This is not documented by Sun, but I think it is correct.
if (l instanceof AWTEventMulticaster)
((AWTEventMulticaster) l).saveInternal(s, k);
else if (l instanceof Serializable)
{
s.writeObject(k);
s.writeObject(l);
}
}
/**
* Returns an array of all chained listeners of the specified type in the
* given chain. A null listener returns an empty array, and a listener
* which is not an AWTEventMulticaster returns an array of one element. If
* no listeners in the chain are of the specified type, an empty array is
* returned.
*
* @param l the listener chain to convert to an array
* @param type the type of listeners to collect
* @return an array of the listeners of that type in the chain
* @throws ClassCastException if type is not assignable from EventListener
* @throws NullPointerException if type is null
* @throws IllegalArgumentException if type is Void.TYPE
* @since 1.4
*/
public static EventListener[] getListeners(EventListener l, Class type)
{
ArrayList list = new ArrayList();
if (l instanceof AWTEventMulticaster)
((AWTEventMulticaster) l).getListeners(list, type);
else if (type.isInstance(l))
list.add(l);
EventListener[] r = (EventListener[]) Array.newInstance(type, list.size());
list.toArray(r);
return r;
}
/**
* Collects all instances of the given type in the chain into the list.
*
* @param l the list to collect into
* @param type the type of listeners to collect
* @throws NullPointerException if type is null
* @see #getListeners(EventListener, Class)
*/
private void getListeners(ArrayList l, Class type)
{
if (a instanceof AWTEventMulticaster)
((AWTEventMulticaster) a).getListeners(l, type);
else if (type.isInstance(a))
l.add(a);
if (b instanceof AWTEventMulticaster)
((AWTEventMulticaster) b).getListeners(l, type);
else if (type.isInstance(b))
l.add(b);
}
} // class AWTEventMulticaster