java.awt.KeyEventPostProcessor Maven / Gradle / Ivy
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*/
package java.awt;
import java.awt.event.KeyEvent;
/**
* A KeyEventPostProcessor cooperates with the current KeyboardFocusManager
* in the final resolution of all unconsumed KeyEvents. KeyEventPostProcessors
* registered with the current KeyboardFocusManager will receive KeyEvents
* after the KeyEvents have been dispatched to and handled by their targets.
* KeyEvents that would have been otherwise discarded because no Component in
* the application currently owns the focus will also be forwarded to
* registered KeyEventPostProcessors. This will allow applications to implement
* features that require global KeyEvent post-handling, such as menu shortcuts.
*
* Note that the KeyboardFocusManager itself implements KeyEventPostProcessor.
* By default, the current KeyboardFocusManager will be the final
* KeyEventPostProcessor in the chain. The current KeyboardFocusManager cannot
* be completely deregistered as a KeyEventPostProcessor. However, if a
* KeyEventPostProcessor reports that no further post-processing of the
* KeyEvent should take place, the AWT will consider the event fully handled
* and will take no additional action with regard to the event. (While it is
* possible for client code to register the current KeyboardFocusManager as
* a KeyEventPostProcessor one or more times, this is usually unnecessary and
* not recommended.)
*
* @author David Mendenhall
* @version 1.4, 01/23/03
*
* @see KeyboardFocusManager#addKeyEventPostProcessor
* @see KeyboardFocusManager#removeKeyEventPostProcessor
* @since 1.4
*/
public interface KeyEventPostProcessor
{
/**
* This method is called by the current KeyboardFocusManager, requesting
* that this KeyEventPostProcessor perform any necessary post-processing
* which should be part of the KeyEvent's final resolution. At the time
* this method is invoked, typically the KeyEvent has already been
* dispatched to and handled by its target. However, if no Component in
* the application currently owns the focus, then the KeyEvent has not
* been dispatched to any Component. Typically, KeyEvent post-processing
* will be used to implement features which require global KeyEvent
* post-handling, such as menu shortcuts. Note that if a
* KeyEventPostProcessor wishes to dispatch the KeyEvent, it must use
* redispatchEvent to prevent the AWT from recursively
* requesting that this KeyEventPostProcessor perform post-processing
* of the event again.
*
* If an implementation of this method returns false, then the
* KeyEvent is passed to the next KeyEventPostProcessor in the chain,
* ending with the current KeyboardFocusManager. If an implementation
* returns true, the KeyEvent is assumed to have been fully
* handled (although this need not be the case), and the AWT will take no
* further action with regard to the KeyEvent. If an implementation
* consumes the KeyEvent but returns false, the consumed
* event will still be passed to the next KeyEventPostProcessor in the
* chain. It is important for developers to check whether the KeyEvent has
* been consumed before performing any post-processing of the KeyEvent. By
* default, the current KeyboardFocusManager will perform no post-
* processing in response to a consumed KeyEvent.
*
* @param e the KeyEvent to post-process
* @return true if the AWT should take no further action with
* regard to the KeyEvent; false otherwise
* @see KeyboardFocusManager#redispatchEvent
*/
public boolean postProcessKeyEvent(KeyEvent e);
}