java.awt
Class KeyboardFocusManager

java.lang.Object   
  java.awt.KeyboardFocusManager

All Implemented Interfaces:

KeyEventDispatcher , KeyEventPostProcessor

Direct Known Subclasses:

DefaultKeyboardFocusManager

public abstract class KeyboardFocusManager
extends Object   
implements KeyEventDispatcher   , KeyEventPostProcessor   

The KeyboardFocusManager is responsible for managing the active and focused Windows, and the current focus owner. The focus owner is defined as the Component in an application that will typically receive all KeyEvents generated by the user. The focused Window is the Window that is, or contains, the focus owner. Only a Frame or a Dialog can be the active Window. The native windowing system may denote the active Window or its children with special decorations, such as a highlighted title bar. The active Window is always either the focused Window, or the first Frame or Dialog that is an owner of the focused Window.

The KeyboardFocusManager is both a centralized location for client code to query for the focus owner and initiate focus changes, and an event dispatcher for all FocusEvents, WindowEvents related to focus, and KeyEvents.

Some browsers partition applets in different code bases into separate contexts, and establish walls between these contexts. In such a scenario, there will be one KeyboardFocusManager per context. Other browsers place all applets into the same context, implying that there will be only a single, global KeyboardFocusManager for all applets. This behavior is implementation-dependent. Consult your browser's documentation for more information. No matter how many contexts there may be, however, there can never be more than one focus owner, focused Window, or active Window, per ClassLoader.

Please see How to Use the Focus Subsystem, a section in The Java Tutorial, and the Focus Specification for more information.

Since:

1.4

See Also:

Window , Frame , Dialog , FocusEvent , WindowEvent , KeyEvent

Field Summary

static int	BACKWARD_TRAVERSAL_KEYS The identifier for the Backward focus traversal keys.
static int	DOWN_CYCLE_TRAVERSAL_KEYS The identifier for the Down Cycle focus traversal keys.
static int	FORWARD_TRAVERSAL_KEYS The identifier for the Forward focus traversal keys.
static int	UP_CYCLE_TRAVERSAL_KEYS The identifier for the Up Cycle focus traversal keys.

Constructor Summary

KeyboardFocusManager ()
Initializes a KeyboardFocusManager.

Method Summary

void	addKeyEventDispatcher (KeyEventDispatcher dispatcher) Adds a KeyEventDispatcher to this KeyboardFocusManager's dispatcher chain.
void	addKeyEventPostProcessor (KeyEventPostProcessor processor) Adds a KeyEventPostProcessor to this KeyboardFocusManager's post- processor chain.
void	addPropertyChangeListener (PropertyChangeListener listener) Adds a PropertyChangeListener to the listener list.
void	addPropertyChangeListener (String propertyName, PropertyChangeListener listener) Adds a PropertyChangeListener to the listener list for a specific property.
void	addVetoableChangeListener (String propertyName, VetoableChangeListener listener) Adds a VetoableChangeListener to the listener list for a specific property.
void	addVetoableChangeListener (VetoableChangeListener listener) Adds a VetoableChangeListener to the listener list.
void	clearGlobalFocusOwner () Clears the global focus owner at both the Java and native levels.
protected abstract void	dequeueKeyEvents (long after, Component untilFocused) Called by the AWT to notify the KeyboardFocusManager that it should cancel delayed dispatching of KeyEvents.
protected abstract void	discardKeyEvents (Component comp) Called by the AWT to notify the KeyboardFocusManager that it should cancel delayed dispatching of KeyEvents.
abstract boolean	dispatchEvent (AWTEvent e) This method is called by the AWT event dispatcher requesting that the current KeyboardFocusManager dispatch the specified event on its behalf.
abstract boolean	dispatchKeyEvent (KeyEvent e) Typically this method will be called by dispatchEvent if no other KeyEventDispatcher in the dispatcher chain dispatched the KeyEvent, or if no other KeyEventDispatchers are registered.
void	downFocusCycle () Moves the focus down one focus traversal cycle from the current focus owner, if and only if the current focus owner is a Container that is a focus cycle root.
abstract void	downFocusCycle (Container aContainer) Moves the focus down one focus traversal cycle.
protected abstract void	enqueueKeyEvents (long after, Component untilFocused) Called by the AWT to notify the KeyboardFocusManager that it should delay dispatching of KeyEvents until the specified Component becomes the focus owner.
protected void	firePropertyChange (String propertyName, Object oldValue, Object newValue) Fires a PropertyChangeEvent in response to a change in a bound property.
protected void	fireVetoableChange (String propertyName, Object oldValue, Object newValue) Fires a PropertyChangeEvent in response to a change in a vetoable property.
void	focusNextComponent () Focuses the Component after the current focus owner.
abstract void	focusNextComponent (Component aComponent) Focuses the Component after aComponent, typically based on a FocusTraversalPolicy.
void	focusPreviousComponent () Focuses the Component before the current focus owner.
abstract void	focusPreviousComponent (Component aComponent) Focuses the Component before aComponent, typically based on a FocusTraversalPolicy.
Window	getActiveWindow () Returns the active Window, if the active Window is in the same context as the calling thread.
Container	getCurrentFocusCycleRoot () Returns the current focus cycle root, if the current focus cycle root is in the same context as the calling thread.
static KeyboardFocusManager	getCurrentKeyboardFocusManager () Returns the current KeyboardFocusManager instance for the calling thread's context.
Set <AWTKeyStroke >	getDefaultFocusTraversalKeys (int id) Returns a Set of default focus traversal keys for a given traversal operation.
FocusTraversalPolicy	getDefaultFocusTraversalPolicy () Returns the default FocusTraversalPolicy.
Window	getFocusedWindow () Returns the focused Window, if the focused Window is in the same context as the calling thread.
Component	getFocusOwner () Returns the focus owner, if the focus owner is in the same context as the calling thread.
protected Window	getGlobalActiveWindow () Returns the active Window, even if the calling thread is in a different context than the active Window.
protected Container	getGlobalCurrentFocusCycleRoot () Returns the current focus cycle root, even if the calling thread is in a different context than the current focus cycle root.
protected Window	getGlobalFocusedWindow () Returns the focused Window, even if the calling thread is in a different context than the focused Window.
protected Component	getGlobalFocusOwner () Returns the focus owner, even if the calling thread is in a different context than the focus owner.
protected Component	getGlobalPermanentFocusOwner () Returns the permanent focus owner, even if the calling thread is in a different context than the permanent focus owner.
protected List <KeyEventDispatcher >	getKeyEventDispatchers () Returns this KeyboardFocusManager's KeyEventDispatcher chain as a List.
protected List <KeyEventPostProcessor >	getKeyEventPostProcessors () Returns this KeyboardFocusManager's KeyEventPostProcessor chain as a List.
Component	getPermanentFocusOwner () Returns the permanent focus owner, if the permanent focus owner is in the same context as the calling thread.
PropertyChangeListener []	getPropertyChangeListeners () Returns an array of all the property change listeners registered on this keyboard focus manager.
PropertyChangeListener []	getPropertyChangeListeners (String propertyName) Returns an array of all the PropertyChangeListeners associated with the named property.
VetoableChangeListener []	getVetoableChangeListeners () Returns an array of all the vetoable change listeners registered on this keyboard focus manager.
VetoableChangeListener []	getVetoableChangeListeners (String propertyName) Returns an array of all the VetoableChangeListeners associated with the named property.
abstract boolean	postProcessKeyEvent (KeyEvent e) This method will be called by dispatchKeyEvent.
abstract void	processKeyEvent (Component focusedComponent, KeyEvent e) This method initiates a focus traversal operation if and only if the KeyEvent represents a focus traversal key for the specified focusedComponent.
void	redispatchEvent (Component target, AWTEvent e) Redispatches an AWTEvent in such a way that the AWT event dispatcher will not recursively request that the KeyboardFocusManager, or any installed KeyEventDispatchers, dispatch the event again.
void	removeKeyEventDispatcher (KeyEventDispatcher dispatcher) Removes a KeyEventDispatcher which was previously added to this KeyboardFocusManager's dispatcher chain.
void	removeKeyEventPostProcessor (KeyEventPostProcessor processor) Removes a previously added KeyEventPostProcessor from this KeyboardFocusManager's post-processor chain.
void	removePropertyChangeListener (PropertyChangeListener listener) Removes a PropertyChangeListener from the listener list.
void	removePropertyChangeListener (String propertyName, PropertyChangeListener listener) Removes a PropertyChangeListener from the listener list for a specific property.
void	removeVetoableChangeListener (String propertyName, VetoableChangeListener listener) Removes a VetoableChangeListener from the listener list for a specific property.
void	removeVetoableChangeListener (VetoableChangeListener listener) Removes a VetoableChangeListener from the listener list.
static void	setCurrentKeyboardFocusManager (KeyboardFocusManager newManager) Sets the current KeyboardFocusManager instance for the calling thread's context.
void	setDefaultFocusTraversalKeys (int id, Set <? extends AWTKeyStroke > keystrokes) Sets the default focus traversal keys for a given traversal operation.
void	setDefaultFocusTraversalPolicy (FocusTraversalPolicy defaultPolicy) Sets the default FocusTraversalPolicy.
protected void	setGlobalActiveWindow (Window activeWindow) Sets the active Window.
void	setGlobalCurrentFocusCycleRoot (Container newFocusCycleRoot) Sets the current focus cycle root.
protected void	setGlobalFocusedWindow (Window focusedWindow) Sets the focused Window.
protected void	setGlobalFocusOwner (Component focusOwner) Sets the focus owner.
protected void	setGlobalPermanentFocusOwner (Component permanentFocusOwner) Sets the permanent focus owner.
void	upFocusCycle