java.awt
Class AWTEventMulticaster

java.lang.Object
  java.awt.AWTEventMulticaster

All Implemented Interfaces:

ActionListener, AdjustmentListener, ComponentListener, ContainerListener, FocusListener, HierarchyBoundsListener, HierarchyListener, InputMethodListener, ItemListener, KeyListener, MouseListener, MouseMotionListener, MouseWheelListener, TextListener, WindowFocusListener, WindowListener, WindowStateListener, EventListener

public class AWTEventMulticaster
extends Object
implements ComponentListener, ContainerListener, FocusListener, KeyListener, MouseListener, MouseMotionListener, WindowListener, WindowFocusListener, WindowStateListener, ActionListener, ItemListener, AdjustmentListener, TextListener, InputMethodListener, HierarchyListener, HierarchyBoundsListener, MouseWheelListener

AWTEventMulticaster implements efficient and thread-safe multi-cast event dispatching for the AWT events defined in the java.awt.event package.

The following example illustrates how to use this class:

 public myComponent extends Component {
     ActionListener actionListener = null;

     public synchronized void addActionListener(ActionListener l) {
           actionListener = AWTEventMulticaster.add(actionListener, l);
     }
     public synchronized void removeActionListener(ActionListener l) {
           actionListener = AWTEventMulticaster.remove(actionListener, l);
     }
     public void processEvent(AWTEvent e) {
         // when event occurs which causes "action" semantic
         ActionListener listener = actionListener;
         if (listener != null) {
             listener.actionPerformed(new ActionEvent());
         }
     }
 }
 

AWTEventMulticaster is implemented as a pair of EventListeners that are set at construction time. AWTEventMulticaster is immutable. The add and remove methods do not alter AWTEventMulticaster in anyway. If necessary, a new AWTEventMulticaster is created. In this way it is safe to add and remove listeners during the process of an event dispatching. However, event listeners added during the process of an event dispatch operation are not notified of the event currently being dispatched.

All of the add methods allow null arguments. If the first argument is null, the second argument is returned. If the first argument is not null and the second argument is null, the first argument is returned. If both arguments are non-null, a new AWTEventMulticaster is created using the two arguments and returned.

For the remove methods that take two arguments, the following is returned:

• null, if the first argument is null, or the arguments are equal, by way of ==.
• the first argument, if the first argument is not an instance of AWTEventMulticaster.
• result of invoking remove(EventListener) on the first argument, supplying the second argument to the remove(EventListener) method.

Swing makes use of EventListenerList for similar logic. Refer to it for details.

Since:

1.1

See Also:

EventListenerList

Field Summary
protected  EventListener	a
protected  EventListener	b

 

Constructor Summary
protected	AWTEventMulticaster(EventListener a, EventListener b)           Creates an event multicaster instance which chains listener-a with listener-b.

 

Method Summary
void	actionPerformed(ActionEvent e)           Handles the actionPerformed event by invoking the actionPerformed methods on listener-a and listener-b.
static ActionListener	add(ActionListener a, ActionListener b)           Adds action-listener-a with action-listener-b and returns the resulting multicast listener.
static AdjustmentListener	add(AdjustmentListener a, AdjustmentListener b)           Adds adjustment-listener-a with adjustment-listener-b and returns the resulting multicast listener.
static ComponentListener	add(ComponentListener a, ComponentListener b)           Adds component-listener-a with component-listener-b and returns the resulting multicast listener.
static ContainerListener	add(ContainerListener a, ContainerListener b)           Adds container-listener-a with container-listener-b and returns the resulting multicast listener.
static FocusListener	add(FocusListener a, FocusListener b)           Adds focus-listener-a with focus-listener-b and returns the resulting multicast listener.
static HierarchyBoundsListener	add(HierarchyBoundsListener a, HierarchyBoundsListener b)           Adds hierarchy-bounds-listener-a with hierarchy-bounds-listener-b and returns the resulting multicast listener.
static HierarchyListener	add(HierarchyListener a, HierarchyListener b)           Adds hierarchy-listener-a with hierarchy-listener-b and returns the resulting multicast listener.
static InputMethodListener	add(InputMethodListener a, InputMethodListener b)           Adds input-method-listener-a with input-method-listener-b and returns the resulting multicast listener.
static ItemListener	add(ItemListener a, ItemListener b)           Adds item-listener-a with item-listener-b and returns the resulting multicast listener.
static KeyListener	add(KeyListener a, KeyListener b)           Adds key-listener-a with key-listener-b and returns the resulting multicast listener.
static MouseListener	add(MouseListener a, MouseListener b)           Adds mouse-listener-a with mouse-listener-b and returns the resulting multicast listener.
static MouseMotionListener	add(MouseMotionListener a, MouseMotionListener b)           Adds mouse-motion-listener-a with mouse-motion-listener-b and returns the resulting multicast listener.
static MouseWheelListener	add(MouseWheelListener a, MouseWheelListener b)           Adds mouse-wheel-listener-a with mouse-wheel-listener-b and returns the resulting multicast listener.
static TextListener	add(TextListener a, TextListener b)
static WindowFocusListener	add(WindowFocusListener a, WindowFocusListener b)           Adds window-focus-listener-a with window-focus-listener-b and returns the resulting multicast listener.
static WindowListener	add(WindowListener a, WindowListener b)           Adds window-listener-a with window-listener-b and returns the resulting multicast listener.
static WindowStateListener	add(WindowStateListener a, WindowStateListener b)           Adds window-state-listener-a with window-state-listener-b and returns the resulting multicast listener.
protected static EventListener	addInternal(EventListener a, EventListener b)           Returns the resulting multicast listener from adding listener-a and listener-b together.
void	adjustmentValueChanged(AdjustmentEvent e)           Handles the adjustmentValueChanged event by invoking the adjustmentValueChanged methods on listener-a and listener-b.
void	ancestorMoved(HierarchyEvent e)           Handles the ancestorMoved event by invoking the ancestorMoved methods on listener-a and listener-b.
void	ancestorResized(HierarchyEvent e)           Handles the ancestorResized event by invoking the ancestorResized methods on listener-a and listener-b.
void	caretPositionChanged(InputMethodEvent e)           Handles the caretPositionChanged event by invoking the caretPositionChanged methods on listener-a and listener-b.
void	componentAdded(ContainerEvent e)           Handles the componentAdded container event by invoking the componentAdded methods on listener-a and listener-b.
void	componentHidden(ComponentEvent e)           Handles the componentHidden event by invoking the componentHidden methods on listener-a and listener-b.
void	componentMoved(ComponentEvent e)           Handles the componentMoved event by invoking the componentMoved methods on listener-a and listener-b.
void	componentRemoved(ContainerEvent e)           Handles the componentRemoved container event by invoking the componentRemoved methods on listener-a and listener-b.
void	componentResized(ComponentEvent e)           Handles the componentResized event by invoking the componentResized methods on listener-a and listener-b.
void	componentShown(ComponentEvent e)           Handles the componentShown event by invoking the componentShown methods on listener-a and listener-b.
void	focusGained(FocusEvent e)           Handles the focusGained event by invoking the focusGained methods on listener-a and listener-b.
void	focusLost(FocusEvent e)           Handles the focusLost event by invoking the focusLost methods on listener-a and listener-b.
static <T extends EventListener> T[]	getListeners(EventListener l, Class<T> listenerType)           Returns an array of all the objects chained as FooListeners by the specified java.util.EventListener.
void	hierarchyChanged(HierarchyEvent e)           Handles the hierarchyChanged event by invoking the hierarchyChanged methods on listener-a and listener-b.
void	inputMethodTextChanged(InputMethodEvent e)           Handles the inputMethodTextChanged event by invoking the inputMethodTextChanged methods on listener-a and listener-b.
void	itemStateChanged(ItemEvent e)           Handles the itemStateChanged event by invoking the itemStateChanged methods on listener-a and listener-b.
void	keyPressed(KeyEvent e)           Handles the keyPressed event by invoking the keyPressed methods on listener-a and listener-b.
void	keyReleased(KeyEvent e)           Handles the keyReleased event by invoking the keyReleased methods on listener-a and listener-b.
void	keyTyped(KeyEvent e)           Handles the keyTyped event by invoking the keyTyped methods on listener-a and listener-b.
void	mouseClicked(MouseEvent e)           Handles the mouseClicked event by invoking the mouseClicked methods on listener-a and listener-b.
void	mouseDragged(MouseEvent e)           Handles the mouseDragged event by invoking the mouseDragged methods on listener-a and listener-b.
void	mouseEntered(MouseEvent e)           Handles the mouseEntered event by invoking the mouseEntered methods on listener-a and listener-b.
void	mouseExited(MouseEvent e)           Handles the mouseExited event by invoking the mouseExited methods on listener-a and listener-b.
void	mouseMoved(MouseEvent e)           Handles the mouseMoved event by invoking the mouseMoved methods on listener-a and listener-b.
void	mousePressed(MouseEvent e)           Handles the mousePressed event by invoking the mousePressed methods on listener-a and listener-b.
void	mouseReleased(MouseEvent e)           Handles the mouseReleased event by invoking the mouseReleased methods on listener-a and listener-b.
void	mouseWheelMoved(MouseWheelEvent e)           Handles the mouseWheelMoved event by invoking the mouseWheelMoved methods on listener-a and listener-b.
static ActionListener	remove(ActionListener l, ActionListener oldl)           Removes the old action-listener from action-listener-l and returns the resulting multicast listener.
static AdjustmentListener	remove(AdjustmentListener l, AdjustmentListener oldl)           Removes the old adjustment-listener from adjustment-listener-l and returns the resulting multicast listener.
static ComponentListener	remove(ComponentListener l, ComponentListener oldl)           Removes the old component-listener from component-listener-l and returns the resulting multicast listener.
static ContainerListener	remove(ContainerListener l, ContainerListener oldl)           Removes the old container-listener from container-listener-l and returns the resulting multicast listener.
protected  EventListener	remove(EventListener oldl)           Removes a listener from this multicaster.
static FocusListener	remove(FocusListener l, FocusListener oldl)           Removes the old focus-listener from focus-listener-l and returns the resulting multicast listener.
static HierarchyBoundsListener	remove(HierarchyBoundsListener l, HierarchyBoundsListener oldl)           Removes the old hierarchy-bounds-listener from hierarchy-bounds-listener-l and returns the resulting multicast listener.
static HierarchyListener	remove(HierarchyListener l, HierarchyListener oldl)           Removes the old hierarchy-listener from hierarchy-listener-l and returns the resulting multicast listener.
static InputMethodListener	remove(InputMethodListener l, InputMethodListener oldl)           Removes the old input-method-listener from input-method-listener-l and returns the resulting multicast listener.
static ItemListener	remove(ItemListener l, ItemListener oldl)           Removes the old item-listener from item-listener-l and returns the resulting multicast listener.
static KeyListener	remove(KeyListener l, KeyListener oldl)           Removes the old key-listener from key-listener-l and returns the resulting multicast listener.
static MouseListener	remove(MouseListener l, MouseListener oldl)           Removes the old mouse-listener from mouse-listener-l and returns the resulting multicast listener.
static MouseMotionListener	remove(MouseMotionListener l, MouseMotionListener oldl)           Removes the old mouse-motion-listener from mouse-motion-listener-l and returns the resulting multicast listener.
static MouseWheelListener	remove(MouseWheelListener l, MouseWheelListener oldl)           Removes the old mouse-wheel-listener from mouse-wheel-listener-l and returns the resulting multicast listener.
static TextListener	remove(TextListener l, TextListener oldl)
static WindowFocusListener	remove(WindowFocusListener l, WindowFocusListener oldl)           Removes the old window-focus-listener from window-focus-listener-l and returns the resulting multicast listener.
static WindowListener	remove(WindowListener l, WindowListener oldl)           Removes the old window-listener from window-listener-l and returns the resulting multicast listener.
static WindowStateListener	remove(WindowStateListener l, WindowStateListener oldl)           Removes the old window-state-listener from window-state-listener-l and returns the resulting multicast listener.
protected static EventListener	removeInternal(EventListener l, EventListener oldl)           Returns the resulting multicast listener after removing the old listener from listener-l.
protected static void	save(ObjectOutputStream s, String k, EventListener l)
protected  void	saveInternal(ObjectOutputStream s, String k)
void	textValueChanged(TextEvent e)           Invoked when the value of the text has changed.
void	windowActivated(WindowEvent e)           Handles the windowActivated event by invoking the windowActivated methods on listener-a and listener-b.
void	windowClosed(WindowEvent e)           Handles the windowClosed event by invoking the windowClosed methods on listener-a and listener-b.
void	windowClosing(WindowEvent e)           Handles the windowClosing event by invoking the windowClosing methods on listener-a and listener-b.
void	windowDeactivated(WindowEvent e)           Handles the windowDeactivated event by invoking the windowDeactivated methods on listener-a and listener-b.
void	windowDeiconified(WindowEvent e)           Handles the windowDeiconfied event by invoking the windowDeiconified methods on listener-a and listener-b.
void	windowGainedFocus(WindowEvent e)           Handles the windowGainedFocus event by invoking the windowGainedFocus methods on listener-a and listener-b.
void	windowIconified(WindowEvent e)           Handles the windowIconified event by invoking the windowIconified methods on listener-a and listener-b.
void	windowLostFocus(WindowEvent e)           Handles the windowLostFocus event by invoking the windowLostFocus methods on listener-a and listener-b.
void	windowOpened(WindowEvent e)           Handles the windowOpened event by invoking the windowOpened methods on listener-a and listener-b.
void	windowStateChanged(WindowEvent e)           Handles the windowStateChanged event by invoking the windowStateChanged methods on listener-a and listener-b.

 

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

 

Field Detail

a

protected final EventListener a

b

protected final EventListener b

AWTEventMulticaster

protected AWTEventMulticaster(EventListener a,
                              EventListener b)

Creates an event multicaster instance which chains listener-a with listener-b. Input parameters a and b should not be null, though implementations may vary in choosing whether or not to throw NullPointerException in that case.

Parameters:

a - listener-a

b - listener-b

remove

protected EventListener remove(EventListener oldl)

Removes a listener from this multicaster.

The returned multicaster contains all the listeners in this multicaster with the exception of all occurrences of oldl. If the resulting multicaster contains only one regular listener the regular listener may be returned. If the resulting multicaster is empty, then null may be returned instead.

No exception is thrown if oldl is null.

Parameters:

oldl - the listener to be removed

Returns:

resulting listener

componentResized

public void componentResized(ComponentEvent e)

Handles the componentResized event by invoking the componentResized methods on listener-a and listener-b.

Specified by:

componentResized in interface ComponentListener

Parameters:

e - the component event

componentMoved

public void componentMoved(ComponentEvent e)

Handles the componentMoved event by invoking the componentMoved methods on listener-a and listener-b.

Specified by:

componentMoved in interface ComponentListener

Parameters:

e - the component event

componentShown

public void componentShown(ComponentEvent e)

Handles the componentShown event by invoking the componentShown methods on listener-a and listener-b.

Specified by:

componentShown in interface ComponentListener

Parameters:

e - the component event

componentHidden

public void componentHidden(ComponentEvent e)

Handles the componentHidden event by invoking the componentHidden methods on listener-a and listener-b.

Specified by:

componentHidden in interface ComponentListener

Parameters:

e - the component event

componentAdded

public void componentAdded(ContainerEvent e)

Handles the componentAdded container event by invoking the componentAdded methods on listener-a and listener-b.

Specified by:

componentAdded in interface ContainerListener

Parameters:

e - the component event

componentRemoved

public void componentRemoved(ContainerEvent e)

Handles the componentRemoved container event by invoking the componentRemoved methods on listener-a and listener-b.

Specified by:

componentRemoved in interface ContainerListener

Parameters:

e - the component event

focusGained

public void focusGained(FocusEvent e)

Handles the focusGained event by invoking the focusGained methods on listener-a and listener-b.

Specified by:

focusGained in interface FocusListener

Parameters:

e - the focus event

focusLost

public void focusLost(FocusEvent e)

Handles the focusLost event by invoking the focusLost methods on listener-a and listener-b.

Specified by:

focusLost in interface FocusListener

Parameters:

e - the focus event

keyTyped

public void keyTyped(KeyEvent e)

Handles the keyTyped event by invoking the keyTyped methods on listener-a and listener-b.

Specified by:

keyTyped in interface KeyListener

Parameters:

e - the key event

keyPressed

public void keyPressed(KeyEvent e)

Handles the keyPressed event by invoking the keyPressed methods on listener-a and listener-b.

Specified by:

keyPressed in interface KeyListener

Parameters:

e - the key event

keyReleased

public void keyReleased(KeyEvent e)

Handles the keyReleased event by invoking the keyReleased methods on listener-a and listener-b.

Specified by:

keyReleased in interface KeyListener

Parameters:

e - the key event

mouseClicked

public void mouseClicked(MouseEvent e)

Handles the mouseClicked event by invoking the mouseClicked methods on listener-a and listener-b.

Specified by:

mouseClicked in interface MouseListener

Parameters:

e - the mouse event

mousePressed

public void mousePressed(MouseEvent e)

Handles the mousePressed event by invoking the mousePressed methods on listener-a and listener-b.

Specified by:

mousePressed in interface MouseListener

Parameters:

e - the mouse event

mouseReleased

public void mouseReleased(MouseEvent e)

Handles the mouseReleased event by invoking the mouseReleased methods on listener-a and listener-b.

Specified by:

mouseReleased in interface MouseListener

Parameters:

e - the mouse event

mouseEntered

public void mouseEntered(MouseEvent e)

Handles the mouseEntered event by invoking the mouseEntered methods on listener-a and listener-b.

Specified by:

mouseEntered in interface MouseListener

Parameters:

e - the mouse event

mouseExited

public void mouseExited(MouseEvent e)

Handles the mouseExited event by invoking the mouseExited methods on listener-a and listener-b.

Specified by:

mouseExited in interface MouseListener

Parameters:

e - the mouse event

mouseDragged

public void mouseDragged(MouseEvent e)

Handles the mouseDragged event by invoking the mouseDragged methods on listener-a and listener-b.

Specified by:

mouseDragged in interface MouseMotionListener

Parameters:

e - the mouse event

mouseMoved

public void mouseMoved(MouseEvent e)

Handles the mouseMoved event by invoking the mouseMoved methods on listener-a and listener-b.

Specified by:

mouseMoved in interface MouseMotionListener

Parameters:

e - the mouse event

windowOpened

public void windowOpened(WindowEvent e)

Handles the windowOpened event by invoking the windowOpened methods on listener-a and listener-b.

Specified by:

windowOpened in interface WindowListener

Parameters:

e - the window event

windowClosing

public void windowClosing(WindowEvent e)

Handles the windowClosing event by invoking the windowClosing methods on listener-a and listener-b.

Specified by:

windowClosing in interface WindowListener

Parameters:

e - the window event

windowClosed

public void windowClosed(WindowEvent e)

Handles the windowClosed event by invoking the windowClosed methods on listener-a and listener-b.

Specified by:

windowClosed in interface WindowListener

Parameters:

e - the window event

windowIconified

public void windowIconified(WindowEvent e)

Handles the windowIconified event by invoking the windowIconified methods on listener-a and listener-b.

Specified by:

windowIconified in interface WindowListener

Parameters:

e - the window event

See Also:

Frame.setIconImage(java.awt.Image)

windowDeiconified

public void windowDeiconified(WindowEvent e)

Handles the windowDeiconfied event by invoking the windowDeiconified methods on listener-a and listener-b.

Specified by:

windowDeiconified in interface WindowListener

Parameters:

e - the window event

windowActivated

public void windowActivated(WindowEvent e)

Handles the windowActivated event by invoking the windowActivated methods on listener-a and listener-b.

Specified by:

windowActivated in interface WindowListener

Parameters:

e - the window event

windowDeactivated

public void windowDeactivated(WindowEvent e)

Handles the windowDeactivated event by invoking the windowDeactivated methods on listener-a and listener-b.

Specified by:

windowDeactivated in interface WindowListener

Parameters:

e - the window event

windowStateChanged

public void windowStateChanged(WindowEvent e)

Handles the windowStateChanged event by invoking the windowStateChanged methods on listener-a and listener-b.

Specified by:

windowStateChanged in interface WindowStateListener

Parameters:

e - the window event

Since:

1.4

windowGainedFocus

public void windowGainedFocus(WindowEvent e)

Handles the windowGainedFocus event by invoking the windowGainedFocus methods on listener-a and listener-b.

Specified by:

windowGainedFocus in interface WindowFocusListener

Parameters:

e - the window event

Since:

1.4

windowLostFocus

public void windowLostFocus(WindowEvent e)

Handles the windowLostFocus event by invoking the windowLostFocus methods on listener-a and listener-b.

Specified by:

windowLostFocus in interface WindowFocusListener

Parameters:

e - the window event

Since:

1.4

actionPerformed

public void actionPerformed(ActionEvent e)

Handles the actionPerformed event by invoking the actionPerformed methods on listener-a and listener-b.

Specified by:

actionPerformed in interface ActionListener

Parameters:

e - the action event

itemStateChanged

public void itemStateChanged(ItemEvent e)

Handles the itemStateChanged event by invoking the itemStateChanged methods on listener-a and listener-b.

Specified by:

itemStateChanged in interface ItemListener

Parameters:

e - the item event

adjustmentValueChanged

public void adjustmentValueChanged(AdjustmentEvent e)

Handles the adjustmentValueChanged event by invoking the adjustmentValueChanged methods on listener-a and listener-b.

Specified by:

adjustmentValueChanged in interface AdjustmentListener

Parameters:

e - the adjustment event

textValueChanged

public void textValueChanged(TextEvent e)

Description copied from interface: TextListener

Invoked when the value of the text has changed. The code written for this method performs the operations that need to occur when text changes.

Specified by:

textValueChanged in interface TextListener

inputMethodTextChanged

public void inputMethodTextChanged(InputMethodEvent e)

Handles the inputMethodTextChanged event by invoking the inputMethodTextChanged methods on listener-a and listener-b.

Specified by:

inputMethodTextChanged in interface InputMethodListener

Parameters:

e - the item event

caretPositionChanged

public void caretPositionChanged(InputMethodEvent e)

Handles the caretPositionChanged event by invoking the caretPositionChanged methods on listener-a and listener-b.

Specified by:

caretPositionChanged in interface InputMethodListener

Parameters:

e - the item event

hierarchyChanged

public void hierarchyChanged(HierarchyEvent e)

Handles the hierarchyChanged event by invoking the hierarchyChanged methods on listener-a and listener-b.

Specified by:

hierarchyChanged in interface HierarchyListener

Parameters:

e - the item event

Since:

1.3

See Also:

HierarchyEvent.getChangeFlags()

ancestorMoved

public void ancestorMoved(HierarchyEvent e)

Handles the ancestorMoved event by invoking the ancestorMoved methods on listener-a and listener-b.

Specified by:

ancestorMoved in interface HierarchyBoundsListener

Parameters:

e - the item event

Since:

1.3

ancestorResized

public void ancestorResized(HierarchyEvent e)

Handles the ancestorResized event by invoking the ancestorResized methods on listener-a and listener-b.

Specified by:

ancestorResized in interface HierarchyBoundsListener

Parameters:

e - the item event

Since:

1.3

mouseWheelMoved

public void mouseWheelMoved(MouseWheelEvent e)

Handles the mouseWheelMoved event by invoking the mouseWheelMoved methods on listener-a and listener-b.

Specified by:

mouseWheelMoved in interface MouseWheelListener

Parameters:

e - the mouse event

Since:

1.4

See Also:

MouseWheelEvent

add

public static ComponentListener add(ComponentListener a,
                                    ComponentListener b)

Adds component-listener-a with component-listener-b and re