defaultkeyboardfocusmanager.java

gcc的组建

          }
      }
    return oneEnqueued;
  }

  public boolean dispatchKeyEvent (KeyEvent e)
  {
    Component focusOwner = getGlobalPermanentFocusOwner ();

    if (focusOwner != null)
      redispatchEvent(focusOwner, e);

    // Loop through all registered KeyEventPostProcessors, giving
    // each a chance to process this event.
    Iterator i = getKeyEventPostProcessors().iterator();

    while (i.hasNext ())
      {
        KeyEventPostProcessor processor = (KeyEventPostProcessor) i.next ();
        if (processor.postProcessKeyEvent ((KeyEvent) e))
          return true;
      }

    // The event hasn't been consumed yet.  Check if it is an
    // MenuShortcut.
    if (postProcessKeyEvent (e))
      return true;

    // Always return true.
    return true;
  }

  public boolean postProcessKeyEvent (KeyEvent e)
  {
    // Check if this event represents a menu shortcut.

    // MenuShortcuts are activated by Ctrl- KeyEvents, only on KEY_PRESSED.
    int modifiers = e.getModifiersEx ();
    if (e.getID() == KeyEvent.KEY_PRESSED
        && (modifiers & KeyEvent.CTRL_DOWN_MASK) != 0)
      {
        Window focusedWindow = getGlobalFocusedWindow ();
        if (focusedWindow instanceof Frame)
          {
            MenuBar menubar = ((Frame) focusedWindow).getMenuBar ();

            if (menubar != null)
              {
                // If there's a menubar, loop through all menu items,
                // checking whether each one has a shortcut, and if
                // so, whether this key event should activate it.
                int numMenus = menubar.getMenuCount ();

                for (int i = 0; i < numMenus; i++)
                  {
                    Menu menu = menubar.getMenu (i);
                    int numItems = menu.getItemCount ();

                    for (int j = 0; j < numItems; j++)
                      {
                        MenuItem item = menu.getItem (j);
                        MenuShortcut shortcut = item.getShortcut ();

                        if (item.isEnabled() && shortcut != null)
                          {
                            // Dispatch a new ActionEvent if:
                            //
                            //     a) this is a Shift- KeyEvent, and the
                            //        shortcut requires the Shift modifier
                            //
                            // or, b) this is not a Shift- KeyEvent, and the
                            //        shortcut does not require the Shift
                            //        modifier.
                            if (shortcut.getKey () == e.getKeyCode ()
                                && ((shortcut.usesShiftModifier ()
                                     && (modifiers & KeyEvent.SHIFT_DOWN_MASK) != 0)
                                    || (! shortcut.usesShiftModifier ()
                                        && (modifiers & KeyEvent.SHIFT_DOWN_MASK) == 0)))
                              {
                                item.dispatchEvent (new ActionEvent (item,
                                                                     ActionEvent.ACTION_PERFORMED,
                                                                     item.getActionCommand (),
                                                                     modifiers));
                                // The event was dispatched.
                                return true;
                              }
                          }
                      }
                  }
              }
          }
      }
    return false;
  }

  public void processKeyEvent (Component comp, KeyEvent e)
  {
    AWTKeyStroke eventKeystroke = AWTKeyStroke.getAWTKeyStrokeForEvent (e);
    // For every focus traversal keystroke, we need to also consume
    // the other two key event types for the same key (e.g. if
    // KEY_PRESSED TAB is a focus traversal keystroke, we also need to
    // consume KEY_RELEASED and KEY_TYPED TAB key events).
    // consuming KEY_RELEASED is easy, because their keyCodes matches
    // the KEY_PRESSED event. Consuming the intermediate KEY_TYPED is
    // very difficult because their is no clean way that we can know
    // which KEY_TYPED belongs to a focusTraversalKey and which not.
    // To address this problem we swallow every KEY_TYPE between the
    // KEY_PRESSED event that matches a focusTraversalKey and the
    // corresponding KEY_RELEASED.
    AWTKeyStroke oppositeKeystroke = AWTKeyStroke.getAWTKeyStroke (e.getKeyCode (),
                                                                   e.getModifiersEx (),
                                                                   !(e.id == KeyEvent.KEY_RELEASED));

    // Here we check if we are currently waiting for a KEY_RELEASED and
    // swallow all KeyEvents that are to be delivered in between. This
    // should only be the KEY_TYPED events that correspond to the
    // focusTraversalKey's KEY_PRESSED event
    if (waitForKeyStroke != null)
      {
        if (eventKeystroke.equals(waitForKeyStroke))
          // release this lock
          waitForKeyStroke = null;

        // as long as we are waiting for the KEY_RELEASED, we swallow every
        // KeyEvent, including the KEY_RELEASED
        e.consume();
        return;
      }

    Set forwardKeystrokes = comp.getFocusTraversalKeys (KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS);
    Set backwardKeystrokes = comp.getFocusTraversalKeys (KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS);
    Set upKeystrokes = comp.getFocusTraversalKeys (KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS);
    Set downKeystrokes = null;
    if (comp instanceof Container)
      downKeystrokes = comp.getFocusTraversalKeys (KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS);

    if (forwardKeystrokes.contains (eventKeystroke))
      {
        waitForKeyStroke = oppositeKeystroke;        
        focusNextComponent (comp);
        e.consume ();
      }
    else if (backwardKeystrokes.contains (eventKeystroke))
      {
        waitForKeyStroke = oppositeKeystroke;        
        focusPreviousComponent (comp);
        e.consume ();
      }
    else if (upKeystrokes.contains (eventKeystroke))
      {
        waitForKeyStroke = oppositeKeystroke;        
        upFocusCycle (comp);
        e.consume ();
      }
    else if (comp instanceof Container
             && downKeystrokes.contains (eventKeystroke))
      {
        waitForKeyStroke = oppositeKeystroke;        
        downFocusCycle ((Container) comp);
        e.consume ();
      }
  }

  protected void enqueueKeyEvents (long after, Component untilFocused)
  {
    delayRequests.add (new EventDelayRequest (after, untilFocused));
  }

  protected void dequeueKeyEvents (long after, Component untilFocused)
  {
    // FIXME: need synchronization on delayRequests and enqueuedKeyEvents.

    // Remove the KeyEvent with the oldest timestamp, which should be
    // the first element in the SortedSet.
    if (after < 0)
      {
        int size = delayRequests.size ();
        if (size > 0)
          delayRequests.remove (delayRequests.first ());
      }
    else
      {
        EventDelayRequest template = new EventDelayRequest (after, untilFocused);
        if (delayRequests.contains (template))
          {
            EventDelayRequest actual = (EventDelayRequest) delayRequests.tailSet (template).first ();
            delayRequests.remove (actual);
            actual.dispatchEvents ();
          }
      }
  }

  protected void discardKeyEvents (Component comp)
  {
    // FIXME: need synchronization on delayRequests and enqueuedKeyEvents.

    Iterator i = delayRequests.iterator ();

    while (i.hasNext ())
      {
        EventDelayRequest request = (EventDelayRequest) i.next ();

        if (request.focusedComp == comp
            || (comp instanceof Container
                && ((Container) comp).isAncestorOf (request.focusedComp)))
          request.discardEvents ();
      }
  }

  public void focusPreviousComponent (Component comp)
  {
    Component focusComp = (comp == null) ? getGlobalFocusOwner () : comp;
    Container focusCycleRoot = focusComp.getFocusCycleRootAncestor ();
    FocusTraversalPolicy policy = focusCycleRoot.getFocusTraversalPolicy ();

    Component previous = policy.getComponentBefore (focusCycleRoot, focusComp);
    if (previous != null)
      previous.requestFocusInWindow ();
  }

  public void focusNextComponent (Component comp)
  {
    Component focusComp = (comp == null) ? getGlobalFocusOwner () : comp;
    Container focusCycleRoot = focusComp.getFocusCycleRootAncestor ();
    FocusTraversalPolicy policy = focusCycleRoot.getFocusTraversalPolicy ();

    Component next = policy.getComponentAfter (focusCycleRoot, focusComp);
    if (next != null)
      next.requestFocusInWindow ();
  }

  public void upFocusCycle (Component comp)
  {
    Component focusComp = (comp == null) ? getGlobalFocusOwner () : comp;
    Container focusCycleRoot = focusComp.getFocusCycleRootAncestor ();

    if (focusCycleRoot instanceof Window)
      {
        FocusTraversalPolicy policy = focusCycleRoot.getFocusTraversalPolicy ();
        Component defaultComponent = policy.getDefaultComponent (focusCycleRoot);
        if (defaultComponent != null)
          defaultComponent.requestFocusInWindow ();
      }
    else
      {
        Container parentFocusCycleRoot = focusCycleRoot.getFocusCycleRootAncestor ();

        focusCycleRoot.requestFocusInWindow ();
        setGlobalCurrentFocusCycleRoot (parentFocusCycleRoot);
      }
  }

  public void downFocusCycle (Container cont)
  {
    if (cont == null)
      return;

    if (cont.isFocusCycleRoot (cont))
      {
        FocusTraversalPolicy policy = cont.getFocusTraversalPolicy ();
        Component defaultComponent = policy.getDefaultComponent (cont);
        if (defaultComponent != null)
          defaultComponent.requestFocusInWindow ();        
        setGlobalCurrentFocusCycleRoot (cont);
      }
  }
} // class DefaultKeyboardFocusManager