Module java.desktop
Package java.awt

Class DefaultKeyboardFocusManager

java.lang.Object
java.awt.KeyboardFocusManager
java.awt.DefaultKeyboardFocusManager
All Implemented Interfaces:
KeyEventDispatcher, KeyEventPostProcessor
Direct Known Subclasses:
FocusManager
public class DefaultKeyboardFocusManager
extends KeyboardFocusManager
The default KeyboardFocusManager for AWT applications. Focus traversal is done in response to a Component's focus traversal keys, and using a Container's FocusTraversalPolicy.

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:
FocusTraversalPolicy, Component.setFocusTraversalKeys(int, java.util.Set<? extends java.awt.AWTKeyStroke>), Component.getFocusTraversalKeys(int)

  • Constructor Details

  • Method Details

    • dispatchEvent

      public 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. DefaultKeyboardFocusManagers dispatch all FocusEvents, all WindowEvents related to focus, and all KeyEvents. These events are 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. If this method returns false, then the AWT event dispatcher will attempt to dispatch the event itself.
      Specified by:
      dispatchEvent in class KeyboardFocusManager
      Parameters:
      e - the AWTEvent to be dispatched
      Returns:
      true if this method dispatched the event; false otherwise
      See Also:
      KeyboardFocusManager.redispatchEvent(java.awt.Component, java.awt.AWTEvent), KeyboardFocusManager.dispatchKeyEvent(java.awt.event.KeyEvent)

    • dispatchKeyEvent

      public boolean dispatchKeyEvent​(KeyEvent e)
      Called by dispatchEvent if no other KeyEventDispatcher in the dispatcher chain dispatched the KeyEvent, or if no other KeyEventDispatchers are registered. If the event has not been consumed, its target is enabled, and the focus owner is not null, this method dispatches the event to its target. This method will also subsequently dispatch the event to all registered KeyEventPostProcessors. After all this operations are finished, the event is passed to peers for processing.

      In all cases, this method returns true, since DefaultKeyboardFocusManager is designed so that neither dispatchEvent, nor the AWT event dispatcher, should take further action on the event in any situation.

      Specified by:
      dispatchKeyEvent in interface KeyEventDispatcher
      Specified by:
      dispatchKeyEvent in class KeyboardFocusManager
      Parameters:
      e - the KeyEvent to be dispatched
      Returns:
      true
      See Also:
      Component.dispatchEvent(java.awt.AWTEvent)

    • postProcessKeyEvent

      public boolean postProcessKeyEvent​(KeyEvent e)
      This method will be called by dispatchKeyEvent. It 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
      Specified by:
      postProcessKeyEvent in class KeyboardFocusManager
      Parameters:
      e - the KeyEvent to post-process
      Returns:
      true
      See Also:
      dispatchKeyEvent(java.awt.event.KeyEvent), MenuShortcut

    • processKeyEvent

      public 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 focus owner.
      Specified by:
      processKeyEvent in class KeyboardFocusManager
      Parameters:
      focusedComponent - the Component that is 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 void enqueueKeyEvents​(long after, Component untilFocused)
      Delays dispatching of KeyEvents until the specified Component becomes the focus owner. KeyEvents with timestamps later than the specified timestamp will be enqueued until the specified Component receives a FOCUS_GAINED event, or the AWT cancels the delay request by invoking dequeueKeyEvents or discardKeyEvents.
      Specified by:
      enqueueKeyEvents in class KeyboardFocusManager
      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 will receive a FOCUS_GAINED event before any pending KeyEvents
      See Also:
      dequeueKeyEvents(long, java.awt.Component), discardKeyEvents(java.awt.Component)

    • dequeueKeyEvents

      protected void dequeueKeyEvents​(long after, Component untilFocused)
      Releases for normal dispatching to the current focus owner all KeyEvents which were enqueued because of a call to enqueueKeyEvents with the same timestamp and Component. 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.
      Specified by:
      dequeueKeyEvents in class KeyboardFocusManager
      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:
      enqueueKeyEvents(long, java.awt.Component), discardKeyEvents(java.awt.Component)

    • discardKeyEvents

      protected void discardKeyEvents​(Component comp)
      Discards all KeyEvents which were enqueued because of one or more calls to enqueueKeyEvents with the specified Component, or one of its descendants.
      Specified by:
      discardKeyEvents in class KeyboardFocusManager
      Parameters:
      comp - the Component specified in one or more calls to enqueueKeyEvents, or a parent of such a Component
      See Also:
      enqueueKeyEvents(long, java.awt.Component), dequeueKeyEvents(long, java.awt.Component)

    • focusPreviousComponent

      public void focusPreviousComponent​(Component aComponent)
      Focuses the Component before aComponent, typically based on a FocusTraversalPolicy.
      Specified by:
      focusPreviousComponent in class KeyboardFocusManager
      Parameters:
      aComponent - the Component that is the basis for the focus traversal operation
      See Also:
      FocusTraversalPolicy, Component.transferFocusBackward()

    • focusNextComponent

      public void focusNextComponent​(Component aComponent)
      Focuses the Component after aComponent, typically based on a FocusTraversalPolicy.
      Specified by:
      focusNextComponent in class KeyboardFocusManager
      Parameters:
      aComponent - the Component that is the basis for the focus traversal operation
      See Also:
      FocusTraversalPolicy, Component.transferFocus()

    • upFocusCycle

      public 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 the focus owner is set to the focus cycle root's default Component to focus, and the current focus cycle root is unchanged.
      Specified by:
      upFocusCycle in class KeyboardFocusManager
      Parameters:
      aComponent - the Component that is the basis for the focus traversal operation
      See Also:
      Component.transferFocusUpCycle()

    • downFocusCycle

      public void downFocusCycle​(Container aContainer)
      Moves the focus down one focus traversal cycle. 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.
      Specified by:
      downFocusCycle in class KeyboardFocusManager
      Parameters:
      aContainer - the Container that is the basis for the focus traversal operation
      See Also:
      Container.transferFocusDownCycle()