defaultkeyboardfocusmanager.java

gcc的组建

/* DefaultKeyboardFocusManager.java -- 
   Copyright (C) 2002, 2004  Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version. */


package java.awt;

import java.awt.event.ActionEvent;
import java.awt.event.FocusEvent;
import java.awt.event.KeyEvent;
import java.awt.event.WindowEvent;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Set;
import java.util.SortedSet;
import java.util.TreeSet;

// FIXME: finish documentation
public class DefaultKeyboardFocusManager extends KeyboardFocusManager
{
  /**
   * This class models a request to delay the dispatch of events that
   * arrive after a certain time, until a certain component becomes
   * the focus owner.
   */
  private class EventDelayRequest implements Comparable
  {
    /** A {@link java.util.List} of {@link java.awt.event.KeyEvent}s
        that are being delayed, pending this request's {@link
        Component} receiving the keyboard focus. */
    private LinkedList enqueuedKeyEvents = new LinkedList ();

    /** An event timestamp.  All events that arrive after this time
        should be queued in the {@link #enqueuedKeyEvents} {@link
        java.util.List}. */
    public long timestamp;
    /** When this {@link Component} becomes focused, all events
        between this EventDelayRequest and the next one in will be
        dispatched from {@link #enqueuedKeyEvents}. */
    public Component focusedComp;

    /**
     * Construct a new EventDelayRequest.
     *
     * @param timestamp events that arrive after this time will be
     * delayed
     * @param focusedComp the Component that needs to receive focus
     * before events are dispatched
     */
    public EventDelayRequest (long timestamp, Component focusedComp)
    {
      this.timestamp = timestamp;
      this.focusedComp = focusedComp;
    }

    public int compareTo (Object o)
    {
      if (!(o instanceof EventDelayRequest))
        throw new ClassCastException ();

      EventDelayRequest request = (EventDelayRequest) o;

      if (request.timestamp < timestamp)
        return -1;
      else if (request.timestamp == timestamp)
        return 0;
      else
        return 1;
    }

    public boolean equals (Object o)
    {
      if (!(o instanceof EventDelayRequest) || o == null)
        return false;

      EventDelayRequest request = (EventDelayRequest) o;

      return (request.timestamp == timestamp
              && request.focusedComp == focusedComp);
    }

    public void enqueueEvent (KeyEvent e)
    {
      KeyEvent last = (KeyEvent) enqueuedKeyEvents.getLast ();
      if (last != null && e.getWhen () < last.getWhen ())
        throw new RuntimeException ("KeyEvents enqueued out-of-order");

      if (e.getWhen () <= timestamp)
        throw new RuntimeException ("KeyEvents enqueued before starting timestamp");

      enqueuedKeyEvents.add (e);
    }

    public void dispatchEvents ()
    {
      int size = enqueuedKeyEvents.size ();
      for (int i = 0; i < size; i++)
        {
          KeyEvent e = (KeyEvent) enqueuedKeyEvents.remove (0);
          dispatchKeyEvent (e);
        }
    }

    public void discardEvents ()
    {
      enqueuedKeyEvents.clear ();
    }
  }

  /**
   * This flag indicates for which focus traversal key release event we
   * possibly wait, before letting any more KEY_TYPED events through.
   */
  private AWTKeyStroke waitForKeyStroke = null;

  /** The {@link java.util.SortedSet} of current 
   * {@link EventDelayRequest}s. */
  private SortedSet delayRequests = new TreeSet ();

  public DefaultKeyboardFocusManager ()
  {
  }

  public boolean dispatchEvent (AWTEvent e)
  {
    if (e instanceof WindowEvent)
      {
        Window target = (Window) e.getSource ();

        if (e.id == WindowEvent.WINDOW_ACTIVATED)
          setGlobalActiveWindow (target);
        else if (e.id == WindowEvent.WINDOW_GAINED_FOCUS)
          setGlobalFocusedWindow (target);
        else if (e.id != WindowEvent.WINDOW_LOST_FOCUS
                 && e.id != WindowEvent.WINDOW_DEACTIVATED)
          return false;

        redispatchEvent(target, e);
        return true;
      }
    else if (e instanceof FocusEvent)
      {
        Component target = (Component) e.getSource ();

        if (e.id == FocusEvent.FOCUS_GAINED)
          {
            if (! (target instanceof Window))
              {
                if (((FocusEvent) e).isTemporary ())
                  setGlobalFocusOwner (target);
                else
                  setGlobalPermanentFocusOwner (target);
              }

            // Keep track of this window's focus owner.

            // Find the target Component's top-level ancestor.  target
            // may be a window.
            Container parent = target.getParent ();

            while (parent != null
                   && !(parent instanceof Window))
              parent = parent.getParent ();

            // If the parent is null and target is not a window, then target is an
            // unanchored component and so we don't want to set the focus owner.
            if (! (parent == null && ! (target instanceof Window)))
              {
                Window toplevel = parent == null ?
                  (Window) target : (Window) parent;

                Component focusOwner = getFocusOwner ();
                if (focusOwner != null
                    && ! (focusOwner instanceof Window))
                  toplevel.setFocusOwner (focusOwner);
              }
          }
        else if (e.id == FocusEvent.FOCUS_LOST)
          {
            if (((FocusEvent) e).isTemporary ())
              setGlobalFocusOwner (null);
            else
              setGlobalPermanentFocusOwner (null);
          }

        redispatchEvent(target, e);

        return true;
      }
    else if (e instanceof KeyEvent)
      {
        // Loop through all registered KeyEventDispatchers, giving
        // each a chance to handle this event.
        Iterator i = getKeyEventDispatchers().iterator();

        while (i.hasNext ())
          {
            KeyEventDispatcher dispatcher = (KeyEventDispatcher) i.next ();
            if (dispatcher.dispatchKeyEvent ((KeyEvent) e))
              return true;
          }

        // processKeyEvent checks if this event represents a focus
        // traversal key stroke.
        Component focusOwner = getGlobalPermanentFocusOwner ();

        if (focusOwner != null)
          processKeyEvent (focusOwner, (KeyEvent) e);

        if (e.isConsumed ())
          return true;

        if (enqueueKeyEvent ((KeyEvent) e))
          // This event was enqueued for dispatch at a later time.
          return true;
        else
          // This event wasn't handled by any of the registered
          // KeyEventDispatchers, and wasn't enqueued for dispatch
          // later, so send it to the default dispatcher.
          return dispatchKeyEvent ((KeyEvent) e);
      }

    return false;
  }

  private boolean enqueueKeyEvent (KeyEvent e)
  {
    Iterator i = delayRequests.iterator ();
    boolean oneEnqueued = false;
    while (i.hasNext ())
      {
        EventDelayRequest request = (EventDelayRequest) i.next ();
        if (e.getWhen () > request.timestamp)
          {
            request.enqueueEvent (e);
            oneEnqueued = true;