gomp-20050608-branch/libjava/classpath/javax/swing/PopupFactory.java

   1 /* PopupFactory.java --
   2    Copyright (C) 2003 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package javax.swing;
  40
  41 import java.awt.Component;
  42 import java.awt.Dimension;
  43 import java.awt.Point;
  44
  45
  46 /**
  47  * A factory for <code>Popup</code> objects. These are used to
  48  * managed little windows that float over everything else,
  49  * typically containing a popup menu.
  50  *
  51  * @since 1.4
  52  *
  53  * @author Sascha Brawer (brawer@dandelis.ch)
  54  */
  55 public class PopupFactory
  56 {
  57   /**
  58    * The shared factory object.
  59    *
  60    * @see #getSharedInstance
  61    * @see #setSharedInstance
  62    */
  63   private static PopupFactory sharedFactory;
  64
  65
  66   /**
  67    * Constructs a new <code>PopupFactory</code>. Usually, a single
  68    * <code>PopupFactory</code> is shared among multiple consumers
  69    * of <code>Popup</code>. Use {@link #getSharedInstance} to retrieve
  70    * the current factory.
  71    */
  72   public PopupFactory()
  73   {
  74     // Nothing to do here.
  75   }
  76
  77
  78   /**
  79    * Sets the shared factory.
  80    *
  81    * @param factory the PopupFactory that future invocations of
  82    *        {@link #getSharedInstance} will return.
  83    *
  84    * @throws IllegalArgumentException if <code>factory</code>
  85    *         is <code>null</code>.
  86    */
  87   public static void setSharedInstance(PopupFactory factory)
  88   {
  89     if (factory == null)
  90       throw new IllegalArgumentException();
  91
  92     /* Swing is not designed to be thread-safe, so there is no
  93      * need to synchronize the access to the global variable.
  94      */
  95     sharedFactory = factory;
  96   }
  97
  98
  99   /**
 100    * Retrieves the shared factory, creating a new factory if
 101    * necessary.
 102    *
 103    * @return a <code>PopupFactory</code> that can be used
 104    *         to create <code>Popup</code> objects.
 105    */
 106   public static PopupFactory getSharedInstance()
 107   {
 108     /* Swing is not designed to be thread-safe, so there is no
 109      * need to synchronize the access to the global variable.
 110      */
 111     if (sharedFactory == null)
 112       sharedFactory = new PopupFactory();
 113
 114     return sharedFactory;
 115   }
 116
 117
 118   /**
 119    * Creates a new <code>Popup</code> given its owner,
 120    * contents and the screen position where the popup
 121    * will appear.
 122    *
 123    * @param owner the Component to which <code>x</code> and
 124    *        <code>y</code> are relative, or <code>null</code> for
 125    *        placing the popup relative to the origin of the screen.
 126    *
 127    * @param contents the contents that will be displayed inside
 128    *        the <code>Popup</code>.
 129    *
 130    * @param x the horizontal position where the Popup will appear.
 131    *
 132    * @param y the vertical position where the Popup will appear.
 133    *
 134    * @throws IllegalArgumentException if <code>contents</code>
 135    *         is <code>null</code>.
 136    */
 137   public Popup getPopup(Component owner, Component contents,
 138                         int x, int y)
 139   {
 140     Popup popup = null;
 141     // By default we enable lightweight popups since they are more efficient
 142     // than heavyweight popups.
 143     boolean lightweightEnabled = true;
 144     // Special case JPopupMenu here, since it supports a lightweightEnabled
 145     // flag that we must respect.
 146     if (contents instanceof JPopupMenu)
 147       {
 148         JPopupMenu menu = (JPopupMenu) contents;
 149         lightweightEnabled = menu.isLightWeightPopupEnabled();
 150       }
 151
 152     // If we have a root pane and the contents fits within the root pane and
 153     // lightweight popups are enabled, than we can use a lightweight popup.
 154     JRootPane root = SwingUtilities.getRootPane(owner);
 155     Point rootLoc = root.getLocationOnScreen();
 156     Dimension contentsSize = contents.getSize();
 157     Dimension rootSize = root.getSize();
 158     if (x >= rootLoc.x && y > rootLoc.y
 159         && (x - rootLoc.x) + contentsSize.width < rootSize.width
 160         && (y - rootLoc.y) + contentsSize.height < rootSize.height)
 161       popup = new Popup.LightweightPopup(owner, contents, x, y);
 162     else
 163       popup = new Popup.JWindowPopup(owner, contents, x, y);
 164     return popup;
 165   }
 166 }