001/* PopupMenuUI.java --
002   Copyright (C) 2002, 2003, 2004  Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package javax.swing.plaf;
040
041import java.awt.event.MouseEvent;
042
043import javax.swing.JPopupMenu;
044import javax.swing.Popup;
045import javax.swing.PopupFactory;
046
047/**
048 * An abstract base class for delegates that implement the pluggable
049 * look and feel for a <code>JPopupMenu</code>.
050 *
051 * @see javax.swing.JPopupMenu
052 *
053 * @author Andrew Selkirk (aselkirk@sympatico.ca)
054 * @author Sascha Brawer (brawer@dandelis.ch)
055 */
056public abstract class PopupMenuUI extends ComponentUI
057{
058  /**
059   * Constructs a new <code>PopupMenuUI</code>.
060   */
061  public PopupMenuUI()
062  {
063    // Nothing to do here.
064  }
065
066
067  /**
068   * Tests whether or not a mouse event triggers a popup menu.
069   *
070   * <p>The default implementation calls
071   * <code>event.isPopupTrigger()</code>, which checks for the gesture
072   * that is common for the platform on which the application runs. If
073   * a look and feel wants to employ non-standard conventions for
074   * triggering a popup menu, it can override this method.
075   *
076   * @param event the event to check.
077   *
078   * @return <code>true</code> if the event triggers a popup menu;
079   *         <code>false</code> otherwise.
080   *
081   * @since 1.3
082   */
083  public boolean isPopupTrigger(MouseEvent event)
084  {
085    return event.isPopupTrigger();
086  }
087
088
089  /**
090   * Creates a <code>Popup</code> for displaying the popup menu.  The
091   * default implementation uses the {@link javax.swing.PopupFactory}
092   * for retrieving a suitable <code>Popup</code>, but subclasses
093   * might want to override this method if a LookAndFeel needs special
094   * Popups.
095   *
096   * @param popup the <code>JPopupMenu</code> for whose display
097   *        a <code>Popup</code> is needed.
098   *
099   * @param x the horizontal position where the popup will be
100   *        displayed.
101   *
102   * @param y the vertical position where the popup will be
103   *        displayed.
104   *
105   * @return a <code>Popup</code> for showing and hiding
106   *         the menu.
107   *
108   * @since 1.4
109   */
110  public Popup getPopup(JPopupMenu popup, int x, int y)
111  {
112    return PopupFactory.getSharedInstance().getPopup(
113      /* origin/owner of the popup */ popup.getInvoker(),
114      /* contents */                  popup,
115      x, y);
116  }
117}