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:

Field Summary

Modifier and Type Field Description
static final int BACKWARD_TRAVERSAL_KEYS
The identifier for the Backward focus traversal keys.
static final int DOWN_CYCLE_TRAVERSAL_KEYS
The identifier for the Down Cycle focus traversal keys.
static final int FORWARD_TRAVERSAL_KEYS
The identifier for the Forward focus traversal keys.
static final int UP_CYCLE_TRAVERSAL_KEYS
The identifier for the Up Cycle focus traversal keys.

Constructor Summary

Constructor Description
KeyboardFocusManager()
Initializes a KeyboardFocusManager.

Method Summary

Modifier and Type Method Description
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(VetoableChangeListener listener)
Adds a VetoableChangeListener to the listener list.
void addVetoableChangeListener(String propertyName, VetoableChangeListener listener)
Adds a VetoableChangeListener to the listener list for a specific property.
void clearFocusOwner()
Clears the focus owner at both the Java and native levels if the focus owner exists and resides in the same context as the calling thread, otherwise the method returns silently.
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.
final 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.
final 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.
final 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.
final 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(VetoableChangeListener listener)
Removes a VetoableChangeListener from the listener list.
void removeVetoableChangeListener(String propertyName, VetoableChangeListener listener)
Removes a VetoableChangeListener from the listener list for a specific property.
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.
final void upFocusCycle()
Moves the focus up one focus traversal cycle from the current focus owner.
abstract void upFocusCycle(Component aComponent)
Moves the focus up one focus traversal cycle.

Methods declared in class java.lang.Object

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

Field Details

FORWARD_TRAVERSAL_KEYS

public static final int FORWARD_TRAVERSAL_KEYS
The identifier for the Forward focus traversal keys.
See Also:

BACKWARD_TRAVERSAL_KEYS

public static final int BACKWARD_TRAVERSAL_KEYS
The identifier for the Backward focus traversal keys.
See Also:

UP_CYCLE_TRAVERSAL_KEYS

public static final int UP_CYCLE_TRAVERSAL_KEYS
The identifier for the Up Cycle focus traversal keys.
See Also:

DOWN_CYCLE_TRAVERSAL_KEYS

public static final int DOWN_CYCLE_TRAVERSAL_KEYS
The identifier for the Down Cycle focus traversal keys.
See Also:

Constructor Details

KeyboardFocusManager

public KeyboardFocusManager()
Initializes a KeyboardFocusManager.

Method Details

getCurrentKeyboardFocusManager

public static KeyboardFocusManager getCurrentKeyboardFocusManager()
Returns the current KeyboardFocusManager instance for the calling thread's context.
Returns:
this thread's context's KeyboardFocusManager
See Also:

setCurrentKeyboardFocusManager

public static void setCurrentKeyboardFocusManager(KeyboardFocusManager newManager) throws SecurityException
Sets the current KeyboardFocusManager instance for the calling thread's context. If null is specified, then the current KeyboardFocusManager is replaced with a new instance of DefaultKeyboardFocusManager.

If a SecurityManager is installed, the calling thread must be granted the AWTPermission "replaceKeyboardFocusManager" in order to replace the the current KeyboardFocusManager. If this permission is not granted, this method will throw a SecurityException, and the current KeyboardFocusManager will be unchanged.

Parameters:
newManager - the new KeyboardFocusManager for this thread's context
Throws:
SecurityException - if the calling thread does not have permission to replace the current KeyboardFocusManager
See Also:

getFocusOwner

public Component getFocusOwner()
Returns the focus owner, if the focus owner is in the same context as the calling thread. The focus owner is defined as the Component in an application that will typically receive all KeyEvents generated by the user. KeyEvents which map to the focus owner's focus traversal keys will not be delivered if focus traversal keys are enabled for the focus owner. In addition, KeyEventDispatchers may retarget or consume KeyEvents before they reach the focus owner.
Returns:
the focus owner, or null if the focus owner is not a member of the calling thread's context
See Also:

getGlobalFocusOwner

protected Component getGlobalFocusOwner() throws SecurityException
Returns the focus owner, even if the calling thread is in a different context than the focus owner. The focus owner is defined as the Component in an application that will typically receive all KeyEvents generated by the user. KeyEvents which map to the focus owner's focus traversal keys will not be delivered if focus traversal keys are enabled for the focus owner. In addition, KeyEventDispatchers may retarget or consume KeyEvents before they reach the focus owner.

This method will throw a SecurityException if this KeyboardFocusManager is not the current KeyboardFocusManager for the calling thread's context.

Returns:
the focus owner
Throws:
SecurityException - if this KeyboardFocusManager is not the current KeyboardFocusManager for the calling thread's context and if the calling thread does not have "replaceKeyboardFocusManager" permission
See Also:

setGlobalFocusOwner

protected void setGlobalFocusOwner(Component focusOwner) throws SecurityException
Sets the focus owner. The operation will be cancelled if the Component is not focusable. The focus owner is defined as the Component in an application that will typically receive all KeyEvents generated by the user. KeyEvents which map to the focus owner's focus traversal keys will not be delivered if focus traversal keys are enabled for the focus owner. In addition, KeyEventDispatchers may retarget or consume KeyEvents before they reach the focus owner.

This method does not actually set the focus to the specified Component. It merely stores the value to be subsequently returned by getFocusOwner(). Use Component.requestFocus() or Component.requestFocusInWindow() to change the focus owner, subject to platform limitations.

Parameters:
focusOwner - the focus owner
Throws:
SecurityException - if this KeyboardFocusManager is not the current KeyboardFocusManager for the calling thread's context and if the calling thread does not have "replaceKeyboardFocusManager" permission
See Also:

clearFocusOwner

public void clearFocusOwner()
Clears the focus owner at both the Java and native levels if the focus owner exists and resides in the same context as the calling thread, otherwise the method returns silently.

The focus owner component will receive a permanent FOCUS_LOST event. After this operation completes, the native windowing system will discard all user-generated KeyEvents until the user selects a new Component to receive focus, or a Component is given focus explicitly via a call to requestFocus(). This operation does not change the focused or active Windows.

Since:
1.8
See Also:

clearGlobalFocusOwner

public void clearGlobalFocusOwner() throws SecurityException
Clears the global focus owner at both the Java and native levels. If there exists a focus owner, that Component will receive a permanent FOCUS_LOST event. After this operation completes, the native windowing system will discard all user-generated KeyEvents until the user selects a new Component to receive focus, or a Component is given focus explicitly via a call to requestFocus(). This operation does not change the focused or active Windows.

If a SecurityManager is installed, the calling thread must be granted the "replaceKeyboardFocusManager" AWTPermission. If this permission is not granted, this method will throw a SecurityException, and the current focus owner will not be cleared.

This method is intended to be used only by KeyboardFocusManager set as current KeyboardFocusManager for the calling thread's context. It is not for general client use.

Throws:
SecurityException - if the calling thread does not have "replaceKeyboardFocusManager" permission
See Also:

getPermanentFocusOwner

public Component getPermanentFocusOwner()
Returns the permanent focus owner, if the permanent focus owner is in the same context as the calling thread. The permanent focus owner is defined as the last Component in an application to receive a permanent FOCUS_GAINED event. The focus owner and permanent focus owner are equivalent unless a temporary focus change is currently in effect. In such a situation, the permanent focus owner will again be the focus owner when the temporary focus change ends.
Returns:
the permanent focus owner, or null if the permanent focus owner is not a member of the calling thread's context
See Also:

getGlobalPermanentFocusOwner

protected Component getGlobalPermanentFocusOwner() throws SecurityException
Returns the permanent focus owner, even if the calling thread is in a different context than the permanent focus owner. The permanent focus owner is defined as the last Component in an application to receive a permanent FOCUS_GAINED event. The focus owner and permanent focus owner are equivalent unless a temporary focus change is currently in effect. In such a situation, the permanent focus owner will again be the focus owner when the temporary focus change ends.
Returns:
the permanent focus owner
Throws:
SecurityException - if this KeyboardFocusManager is not the current KeyboardFocusManager for the calling thread's context and if the calling thread does not have "replaceKeyboardFocusManager" permission
See Also:

setGlobalPermanentFocusOwner

protected void setGlobalPermanentFocusOwner(Component permanentFocusOwner) throws SecurityException
Sets the permanent focus owner. The operation will be cancelled if the Component is not focusable. The permanent focus owner is defined as the last Component in an application to receive a permanent FOCUS_GAINED event. The focus owner and permanent focus owner are equivalent unless a temporary focus change is currently in effect. In such a situation, the permanent focus owner will again be the focus owner when the temporary focus change ends.

This method does not actually set the focus to the specified Component. It merely stores the value to be subsequently returned by getPermanentFocusOwner(). Use Component.requestFocus() or Component.requestFocusInWindow() to change the focus owner, subject to platform limitations.

Parameters:
permanentFocusOwner - the permanent focus owner
Throws:
SecurityException - if this KeyboardFocusManager is not the current KeyboardFocusManager for the calling thread's context and if the calling thread does not have "replaceKeyboardFocusManager" permission
See Also:

getFocusedWindow

public Window getFocusedWindow()
Returns the focused Window, if the focused Window is in the same context as the calling thread. The focused Window is the Window that is or contains the focus owner.
Returns:
the focused Window, or null if the focused Window is not a member of the calling thread's context
See Also:

getGlobalFocusedWindow

protected Window getGlobalFocusedWindow() throws SecurityException
Returns the focused Window, even if the calling thread is in a different context than the focused Window. The focused Window is the Window that is or contains the focus owner.
Returns:
the focused Window
Throws:
SecurityException - if this KeyboardFocusManager is not the current KeyboardFocusManager for the calling thread's context and if the calling thread does not have "replaceKeyboardFocusManager" permission
See Also:

setGlobalFocusedWindow

protected void setGlobalFocusedWindow(Window focusedWindow) throws SecurityException
Sets the focused Window. The focused Window is the Window that is or contains the focus owner. The operation will be cancelled if the specified Window to focus is not a focusable Window.

This method does not actually change the focused Window as far as the native windowing system is concerned. It merely stores the value to be subsequently returned by getFocusedWindow(). Use Component.requestFocus() or Component.requestFocusInWindow() to change the focused Window, subject to platform limitations.

Parameters:
focusedWindow - the focused Window
Throws:
SecurityException - if this KeyboardFocusManager is not the current KeyboardFocusManager for the calling thread's context and if the calling thread does not have "replaceKeyboardFocusManager" permission
See Also:

getActiveWindow

public Window getActiveWindow()
Returns the active Window, if the active Window is in the same context as the calling thread. 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.
Returns:
the active Window, or null if the active Window is not a member of the calling thread's context
See Also:

getGlobalActiveWindow

protected Window getGlobalActiveWindow() throws SecurityException
Returns the active Window, even if the calling thread is in a different context than the active Window. 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.
Returns:
the active Window
Throws:
SecurityException - if this KeyboardFocusManager is not the current KeyboardFocusManager for the calling thread's context and if the calling thread does not have "replaceKeyboardFocusManager" permission
See Also:

setGlobalActiveWindow

protected void setGlobalActiveWindow(Window activeWindow) throws SecurityException
Sets the active Window. 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.

This method does not actually change the active Window as far as the native windowing system is concerned. It merely stores the value to be subsequently returned by getActiveWindow(). Use Component.requestFocus() or Component.requestFocusInWindow() to change the active Window, subject to platform limitations.

Parameters:
activeWindow - the active Window
Throws:
SecurityException - if this KeyboardFocusManager is not the current KeyboardFocusManager for the calling thread's context and if the calling thread does not have "replaceKeyboardFocusManager" permission
See Also:

getDefaultFocusTraversalPolicy

public FocusTraversalPolicy getDefaultFocusTraversalPolicy()
Returns the default FocusTraversalPolicy. Top-level components use this value on their creation to initialize their own focus traversal policy by explicit call to Container.setFocusTraversalPolicy.
Returns:
the default FocusTraversalPolicy. null will never be returned.
See Also:

setDefaultFocusTraversalPolicy

public void setDefaultFocusTraversalPolicy(FocusTraversalPolicy defaultPolicy)
Sets the default FocusTraversalPolicy. Top-level components use this value on their creation to initialize their own focus traversal policy by explicit call to Container.setFocusTraversalPolicy. Note: this call doesn't affect already created components as they have their policy initialized. Only new components will use this policy as their default policy.
Parameters:
defaultPolicy - the new, default FocusTraversalPolicy
Throws:
IllegalArgumentException - if defaultPolicy is null
See Also:

setDefaultFocusTraversalKeys

public void setDefaultFocusTraversalKeys(int id, Set<? extends AWTKeyStroke> keystrokes)
Sets the default focus traversal keys for a given traversal operation. This traversal key Set will be in effect on all Windows that have no such Set of their own explicitly defined. This Set will also be inherited, recursively, by any child Component of those Windows that has no such Set of its own explicitly defined.

The default values for the default focus traversal keys are implementation-dependent. Sun recommends that all implementations for a particular native platform use the same default values. The recommendations for Windows and Unix are listed below. These recommendations are used in the Sun AWT implementations.

Recommended default values for focus traversal keys
Identifier Meaning Default
KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS Normal forward keyboard traversal TAB on KEY_PRESSED, CTRL-TAB on KEY_PRESSED
KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS Normal reverse keyboard traversal SHIFT-TAB on KEY_PRESSED, CTRL-SHIFT-TAB on KEY_PRESSED
KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS Go up one focus traversal cycle none
KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS Go down one focus traversal cycle none
To disable a traversal key, use an empty Set; Collections.EMPTY_SET is recommended.

Using the AWTKeyStroke API, client code can specify on which of two specific KeyEvents, KEY_PRESSED or KEY_RELEASED, the focus traversal operation will occur. Regardless of which KeyEvent is specified, however, all KeyEvents related to the focus traversal key, including the associated KEY_TYPED event, will be consumed, and will not be dispatched to any Component. It is a runtime error to specify a KEY_TYPED event as mapping to a focus traversal operation, or to map the same event to multiple default focus traversal operations.

This method may throw a ClassCastException if any Object in keystrokes is not an AWTKeyStroke.

Parameters:
id - one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS
keystrokes - the Set of AWTKeyStrokes for the specified operation
Throws:
IllegalArgumentException - if id is not one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS, or if keystrokes is null, or if keystrokes contains null, or if any keystroke represents a KEY_TYPED event, or if any keystroke already maps to another default focus traversal operation
See Also:

getDefaultFocusTraversalKeys

public Set<AWTKeyStroke> getDefaultFocusTraversalKeys(int id)
Returns a Set of default focus traversal keys for a given traversal operation. This traversal key Set will be in effect on all Windows that have no such Set of their own explicitly defined. This Set will also be inherited, recursively, by any child Component of those Windows that has no such Set of its own explicitly defined. (See setDefaultFocusTraversalKeys for a full description of each operation.)
Parameters:
id - one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS
Returns:
the Set of AWTKeyStrokes for the specified operation; the Set will be unmodifiable, and may be empty; null will never be returned
Throws:
IllegalArgumentException - if id is not one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS
See Also:

getCurrentFocusCycleRoot

public Container getCurrentFocusCycleRoot()
Returns the current focus cycle root, if the current focus cycle root is in the same context as the calling thread. If the focus owner is itself a focus cycle root, then it may be ambiguous as to which Components represent the next and previous Components to focus during normal focus traversal. In that case, the current focus cycle root is used to differentiate among the possibilities.

This method is intended to be used only by KeyboardFocusManagers and focus implementations. It is not for general client use.

Returns:
the current focus cycle root, or null if the current focus cycle root is not a member of the calling thread's context
See Also:

getGlobalCurrentFocusCycleRoot

protected Container getGlobalCurrentFocusCycleRoot() throws SecurityException
Returns the current focus cycle root, even if the calling thread is in a different context than the current focus cycle root. If the focus owner is itself a focus cycle root, then it may be ambiguous as to which Components represent the next and previous Components to focus during normal focus traversal. In that case, the current focus cycle root is used to differentiate among the possibilities.
Returns:
the current focus cycle root, or null if the current focus cycle root is not a member of the calling thread's context
Throws:
SecurityException - if this KeyboardFocusManager is not the current KeyboardFocusManager for the calling thread's context and if the calling thread does not have "replaceKeyboardFocusManager" permission
See Also:

setGlobalCurrentFocusCycleRoot

public void setGlobalCurrentFocusCycleRoot(Container newFocusCycleRoot) throws SecurityException
Sets the current focus cycle root. If the focus owner is itself a focus cycle root, then it may be ambiguous as to which Components represent the next and previous Components to focus during normal focus traversal. In that case, the current focus cycle root is used to differentiate among the possibilities.

If a SecurityManager is installed, the calling thread must be granted the "replaceKeyboardFocusManager" AWTPermission. If this permission is not granted, this method will throw a SecurityException, and the current focus cycle root will not be changed.

This method is intended to be used only by KeyboardFocusManagers and focus implementations. It is not for general client use.

Parameters:
newFocusCycleRoot - the new focus cycle root
Throws:
SecurityException - if the calling thread does not have "replaceKeyboardFocusManager" permission
See Also:

addPropertyChangeListener

public void addPropertyChangeListener(PropertyChangeListener listener)
Adds a PropertyChangeListener to the listener list. The listener is registered for all bound properties of this class, including the following:
  • whether the KeyboardFocusManager is currently managing focus for this application or applet's browser context ("managingFocus")
  • the focus owner ("focusOwner")
  • the permanent focus owner ("permanentFocusOwner")
  • the focused Window ("focusedWindow")
  • the active Window ("activeWindow")
  • the default focus traversal policy ("defaultFocusTraversalPolicy")
  • the Set of default FORWARD_TRAVERSAL_KEYS ("forwardDefaultFocusTraversalKeys")
  • the Set of default BACKWARD_TRAVERSAL_KEYS ("backwardDefaultFocusTraversalKeys")
  • the Set of default UP_CYCLE_TRAVERSAL_KEYS ("upCycleDefaultFocusTraversalKeys")
  • the Set of default DOWN_CYCLE_TRAVERSAL_KEYS ("downCycleDefaultFocusTraversalKeys")
  • the current focus cycle root ("currentFocusCycleRoot")
If listener is null, no exception is thrown and no action is performed.
Parameters:
listener - the PropertyChangeListener to be added
See Also:

removePropertyChangeListener

public void removePropertyChangeListener(PropertyChangeListener listener)
Removes a PropertyChangeListener from the listener list. This method should be used to remove the PropertyChangeListeners that were registered for all bound properties of this class.

If listener is null, no exception is thrown and no action is performed.

Parameters:
listener - the PropertyChangeListener to be removed
See Also:

getPropertyChangeListeners

public PropertyChangeListener[] getPropertyChangeListeners()
Returns an array of all the property change listeners registered on this keyboard focus manager.
Returns:
all of this keyboard focus manager's PropertyChangeListeners or an empty array if no property change listeners are currently registered
Since:
1.4
See Also:

addPropertyChangeListener

public void addPropertyChangeListener(String propertyName, PropertyChangeListener listener)
Adds a PropertyChangeListener to the listener list for a specific property. The specified property may be user-defined, or one of the following:
  • whether the KeyboardFocusManager is currently managing focus for this application or applet's browser context ("managingFocus")
  • the focus owner ("focusOwner")
  • the permanent focus owner ("permanentFocusOwner")
  • the focused Window ("focusedWindow")
  • the active Window ("activeWindow")
  • the default focus traversal policy ("defaultFocusTraversalPolicy")
  • the Set of default FORWARD_TRAVERSAL_KEYS ("forwardDefaultFocusTraversalKeys")
  • the Set of default BACKWARD_TRAVERSAL_KEYS ("backwardDefaultFocusTraversalKeys")
  • the Set of default UP_CYCLE_TRAVERSAL_KEYS ("upCycleDefaultFocusTraversalKeys")
  • the Set of default DOWN_CYCLE_TRAVERSAL_KEYS ("downCycleDefaultFocusTraversalKeys")
  • the current focus cycle root ("currentFocusCycleRoot")
If listener is null, no exception is thrown and no action is performed.
Parameters:
propertyName - one of the property names listed above
listener - the PropertyChangeListener to be added
See Also:

removePropertyChangeListener

public void removePropertyChangeListener(String propertyName, PropertyChangeListener listener)
Removes a PropertyChangeListener from the listener list for a specific property. This method should be used to remove PropertyChangeListeners that were registered for a specific bound property.

If listener is null, no exception is thrown and no action is performed.

Parameters:
propertyName - a valid property name
listener - the PropertyChangeListener to be removed
See Also:

getPropertyChangeListeners

public PropertyChangeListener[] getPropertyChangeListeners(String propertyName)
Returns an array of all the PropertyChangeListeners associated with the named property.
Parameters:
propertyName - the property name
Returns:
all of the PropertyChangeListeners associated with the named property or an empty array if no such listeners have been added.
Since:
1.4
See Also:

firePropertyChange

protected void firePropertyChange(String propertyName, Object oldValue, Object newValue)
Fires a PropertyChangeEvent in response to a change in a bound property. The event will be delivered to all registered PropertyChangeListeners. No event will be delivered if oldValue and newValue are the same.
Parameters:
propertyName - the name of the property that has changed
oldValue - the property's previous value
newValue - the property's new value

addVetoableChangeListener

public void addVetoableChangeListener(VetoableChangeListener listener)
Adds a VetoableChangeListener to the listener list. The listener is registered for all vetoable properties of this class, including the following:
  • the focus owner ("focusOwner")
  • the permanent focus owner ("permanentFocusOwner")
  • the focused Window ("focusedWindow")
  • the active Window ("activeWindow")
If listener is null, no exception is thrown and no action is performed.
Parameters:
listener - the VetoableChangeListener to be added
See Also:

removeVetoableChangeListener

public void removeVetoableChangeListener(VetoableChangeListener listener)
Removes a VetoableChangeListener from the listener list. This method should be used to remove the VetoableChangeListeners that were registered for all vetoable properties of this class.

If listener is null, no exception is thrown and no action is performed.

Parameters:
listener - the VetoableChangeListener to be removed
See Also:

getVetoableChangeListeners

public VetoableChangeListener[] getVetoableChangeListeners()
Returns an array of all the vetoable change listeners registered on this keyboard focus manager.
Returns:
all of this keyboard focus manager's VetoableChangeListeners or an empty array if no vetoable change listeners are currently registered
Since:
1.4
See Also:

addVetoableChangeListener

public void addVetoableChangeListener(String propertyName, VetoableChangeListener listener)
Adds a VetoableChangeListener to the listener list for a specific property. The specified property may be user-defined, or one of the following:
  • the focus owner ("focusOwner")
  • the permanent focus owner ("permanentFocusOwner")
  • the focused Window ("focusedWindow")
  • the active Window ("activeWindow")
If listener is null, no exception is thrown and no action is performed.
Parameters:
propertyName - one of the property names listed above
listener - the VetoableChangeListener to be added
See Also:

removeVetoableChangeListener

public void removeVetoableChangeListener(String propertyName, VetoableChangeListener listener)
Removes a VetoableChangeListener from the listener list for a specific property. This method should be used to remove VetoableChangeListeners that were registered for a specific bound property.

If listener is null, no exception is thrown and no action is performed.

Parameters:
propertyName - a valid property name
listener - the VetoableChangeListener to be removed
See Also:

getVetoableChangeListeners

public VetoableChangeListener[] getVetoableChangeListeners(String propertyName)
Returns an array of all the VetoableChangeListeners associated with the named property.
Parameters:
propertyName - the property name
Returns:
all of the VetoableChangeListeners associated with the named property or an empty array if no such listeners have been added.
Since:
1.4
See Also:

fireVetoableChange

protected void fireVetoableChange(String propertyName, Object oldValue, Object newValue) throws PropertyVetoException
Fires a PropertyChangeEvent in response to a change in a vetoable property. The event will be delivered to all registered VetoableChangeListeners. If a VetoableChangeListener throws a PropertyVetoException, a new event is fired reverting all VetoableChangeListeners to the old value and the exception is then rethrown. No event will be delivered if oldValue and newValue are the same.
Parameters:
propertyName - the name of the property that has changed
oldValue - the property's previous value
newValue - the property's new value
Throws:
PropertyVetoException - if a VetoableChangeListener threw PropertyVetoException

addKeyEventDispatcher

public void addKeyEventDispatcher(KeyEventDispatcher dispatcher)
Adds a KeyEventDispatcher to this KeyboardFocusManager's dispatcher chain. This KeyboardFocusManager will request that each KeyEventDispatcher dispatch KeyEvents generated by the user before finally dispatching the KeyEvent itself. KeyEventDispatchers will be notified in the order in which they were added. Notifications will halt as soon as one KeyEventDispatcher returns true from its dispatchKeyEvent method. There is no limit to the total number of KeyEventDispatchers which can be added, nor to the number of times which a particular KeyEventDispatcher instance can be added.

If a null dispatcher is specified, no action is taken and no exception is thrown.

In a multithreaded application, KeyEventDispatcher behaves the same as other AWT listeners. See AWT Threading Issues for more details.

Parameters:
dispatcher - the KeyEventDispatcher to add to the dispatcher chain
See Also:

removeKeyEventDispatcher

public void removeKeyEventDispatcher(KeyEventDispatcher dispatcher)
Removes a KeyEventDispatcher which was previously added to this KeyboardFocusManager's dispatcher chain. This KeyboardFocusManager cannot itself be removed, unless it was explicitly re-registered via a call to addKeyEventDispatcher.

If a null dispatcher is specified, if the specified dispatcher is not in the dispatcher chain, or if this KeyboardFocusManager is specified without having been explicitly re-registered, no action is taken and no exception is thrown.

In a multithreaded application, KeyEventDispatcher behaves the same as other AWT listeners. See AWT Threading Issues for more details.

Parameters:
dispatcher - the KeyEventDispatcher to remove from the dispatcher chain
See Also:

getKeyEventDispatchers

protected List<KeyEventDispatcher> getKeyEventDispatchers()
Returns this KeyboardFocusManager's KeyEventDispatcher chain as a List. The List will not include this KeyboardFocusManager unless it was explicitly re-registered via a call to addKeyEventDispatcher. If no other KeyEventDispatchers are registered, implementations are free to return null or a List of length 0. Client code should not assume one behavior over another, nor should it assume that the behavior, once established, will not change.
Returns:
a possibly null or empty List of KeyEventDispatchers
See Also:

addKeyEventPostProcessor

public void addKeyEventPostProcessor(KeyEventPostProcessor processor)
Adds a KeyEventPostProcessor to this KeyboardFocusManager's post- processor chain. After a KeyEvent has been dispatched to and handled by its target, KeyboardFocusManager will request that each KeyEventPostProcessor perform any necessary post-processing as part of the KeyEvent's final resolution. KeyEventPostProcessors will be notified in the order in which they were added; the current KeyboardFocusManager will be notified last. Notifications will halt as soon as one KeyEventPostProcessor returns true from its postProcessKeyEvent method. There is no limit to the total number of KeyEventPostProcessors that can be added, nor to the number of times that a particular KeyEventPostProcessor instance can be added.

If a null post-processor is specified, no action is taken and no exception is thrown.

In a multithreaded application, KeyEventPostProcessor behaves the same as other AWT listeners. See AWT Threading Issues for more details.

Parameters:
processor - the KeyEventPostProcessor to add to the post-processor chain
See Also:

removeKeyEventPostProcessor

public void removeKeyEventPostProcessor(KeyEventPostProcessor processor)
Removes a previously added KeyEventPostProcessor from this KeyboardFocusManager's post-processor chain. This KeyboardFocusManager cannot itself be entirely removed from the chain. Only additional references added via addKeyEventPostProcessor can be removed.

If a null post-processor is specified, if the specified post-processor is not in the post-processor chain, or if this KeyboardFocusManager is specified without having been explicitly added, no action is taken and no exception is thrown.

In a multithreaded application, KeyEventPostProcessor behaves the same as other AWT listeners. See AWT Threading Issues for more details.

Parameters:
processor - the KeyEventPostProcessor to remove from the post- processor chain
See Also:

getKeyEventPostProcessors

protected List<KeyEventPostProcessor> getKeyEventPostProcessors()
Returns this KeyboardFocusManager's KeyEventPostProcessor chain as a List. The List will not include this KeyboardFocusManager unless it was explicitly added via a call to addKeyEventPostProcessor. If no KeyEventPostProcessors are registered, implementations are free to return null or a List of length 0. Client code should not assume one behavior over another, nor should it assume that the behavior, once established, will not change.
Returns:
a possibly null or empty List of KeyEventPostProcessors
See Also:

dispatchEvent

public 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. It is expected that all KeyboardFocusManagers will dispatch all FocusEvents, all WindowEvents related to focus, and all KeyEvents. These events should be dispatched based on the KeyboardFocusManager's notion of the focus owner and the focused and active Windows, sometimes overriding the source of the specified AWTEvent. Dispatching must be done using redispatchEvent to prevent the AWT event dispatcher from recursively requesting that the KeyboardFocusManager dispatch the event again. If this method returns false, then the AWT event dispatcher will attempt to dispatch the event itself.
Parameters:
e - the AWTEvent to be dispatched
Returns:
true if this method dispatched the event; false otherwise
See Also:

redispatchEvent

public final 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. Client implementations of dispatchEvent and client-defined KeyEventDispatchers must call redispatchEvent(target, e) instead of target.dispatchEvent(e) to dispatch an event.

This method is intended to be used only by KeyboardFocusManagers and KeyEventDispatchers. It is not for general client use.

Parameters:
target - the Component to which the event should be dispatched
e - the event to dispatch
See Also:

dispatchKeyEvent

public 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. If an implementation of this method returns false, dispatchEvent may try to dispatch the KeyEvent itself, or may simply return false. If true is returned, dispatchEvent should return true as well.
Specified by:
dispatchKeyEvent in interface KeyEventDispatcher
Parameters:
e - the KeyEvent which the current KeyboardFocusManager has requested that this KeyEventDispatcher dispatch
Returns:
true if the KeyEvent was dispatched; false otherwise
See Also:

postProcessKeyEvent

public abstract boolean postProcessKeyEvent(KeyEvent e)
This method will be called by dispatchKeyEvent. By default, this method will handle any unconsumed KeyEvents that map to an AWT MenuShortcut by consuming the event and activating the shortcut.
Specified by:
postProcessKeyEvent in interface KeyEventPostProcessor
Parameters:
e - the KeyEvent to post-process
Returns:
true to indicate that no other KeyEventPostProcessor will be notified of the KeyEvent.
See Also:

processKeyEvent

public 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. It is expected that focusedComponent is the current focus owner, although this need not be the case. If it is not, focus traversal will nevertheless proceed as if focusedComponent were the current focus owner.
Parameters:
focusedComponent - the Component that will be the basis for a focus traversal operation if the specified event represents a focus traversal key for the Component
e - the event that may represent a focus traversal key

enqueueKeyEvents

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. If client code requests a focus change, and the AWT determines that this request might be granted by the native windowing system, then the AWT will call this method. It is the responsibility of the KeyboardFocusManager to delay dispatching of KeyEvents with timestamps later than the specified time stamp until the specified Component receives a FOCUS_GAINED event, or the AWT cancels the delay request by invoking dequeueKeyEvents or discardKeyEvents.
Parameters:
after - timestamp of current event, or the current, system time if the current event has no timestamp, or the AWT cannot determine which event is currently being handled
untilFocused - Component which should receive a FOCUS_GAINED event before any pending KeyEvents
See Also:

dequeueKeyEvents

protected abstract void dequeueKeyEvents(long after, Component untilFocused)
Called by the AWT to notify the KeyboardFocusManager that it should cancel delayed dispatching of KeyEvents. All KeyEvents which were enqueued because of a call to enqueueKeyEvents with the same timestamp and Component should be released for normal dispatching to the current focus owner. If the given timestamp is less than zero, the outstanding enqueue request for the given Component with the oldest timestamp (if any) should be cancelled.
Parameters:
after - the timestamp specified in the call to enqueueKeyEvents, or any value < 0
untilFocused - the Component specified in the call to enqueueKeyEvents
See Also:

discardKeyEvents

protected abstract void discardKeyEvents(Component comp)
Called by the AWT to notify the KeyboardFocusManager that it should cancel delayed dispatching of KeyEvents. All KeyEvents which were enqueued because of one or more calls to enqueueKeyEvents with the same Component should be discarded.
Parameters:
comp - the Component specified in one or more calls to enqueueKeyEvents
See Also:

focusNextComponent

public abstract void focusNextComponent(Component aComponent)
Focuses the Component after aComponent, typically based on a FocusTraversalPolicy.
Parameters:
aComponent - the Component that is the basis for the focus traversal operation
See Also:

focusPreviousComponent

public abstract void focusPreviousComponent(Component aComponent)
Focuses the Component before aComponent, typically based on a FocusTraversalPolicy.
Parameters:
aComponent - the Component that is the basis for the focus traversal operation
See Also:

upFocusCycle

public abstract void upFocusCycle(Component aComponent)
Moves the focus up one focus traversal cycle. Typically, the focus owner is set to aComponent's focus cycle root, and the current focus cycle root is set to the new focus owner's focus cycle root. If, however, aComponent's focus cycle root is a Window, then typically the focus owner is set to the Window's default Component to focus, and the current focus cycle root is unchanged.
Parameters:
aComponent - the Component that is the basis for the focus traversal operation

downFocusCycle

public abstract void downFocusCycle(Container aContainer)
Moves the focus down one focus traversal cycle. Typically, if aContainer is a focus cycle root, then the focus owner is set to aContainer's default Component to focus, and the current focus cycle root is set to aContainer. If aContainer is not a focus cycle root, then no focus traversal operation occurs.
Parameters:
aContainer - the Container that is the basis for the focus traversal operation

focusNextComponent

public final void focusNextComponent()
Focuses the Component after the current focus owner.

focusPreviousComponent

public final void focusPreviousComponent()
Focuses the Component before the current focus owner.

upFocusCycle

public final void upFocusCycle()
Moves the focus up one focus traversal cycle from the current focus owner. Typically, the new focus owner is set to the current focus owner's focus cycle root, and the current focus cycle root is set to the new focus owner's focus cycle root. If, however, the current focus owner's focus cycle root is a Window, then typically the focus owner is set to the focus cycle root's default Component to focus, and the current focus cycle root is unchanged.

downFocusCycle

public final 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. Typically, the focus owner is set to the current focus owner's default Component to focus, and the current focus cycle root is set to the current focus owner. If the current focus owner is not a Container that is a focus cycle root, then no focus traversal operation occurs.

© 1993, 2021, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
https://docs.oracle.com/en/java/javase/17/docs/api/java.desktop/java/awt/KeyboardFocusManager.html