Source for javax.swing.PopupFactory

   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:     if (root != null)
 156:       {
 157:         Point rootLoc = root.getLocationOnScreen();
 158:         Dimension contentsSize = contents.getSize();
 159:         Dimension rootSize = root.getSize();
 160:         if (x >= rootLoc.x && y > rootLoc.y
 161:             && (x - rootLoc.x) + contentsSize.width < rootSize.width
 162:             && (y - rootLoc.y) + contentsSize.height < rootSize.height)
 163:           popup = new Popup.LightweightPopup(owner, contents, x, y);
 164:         else
 165:           popup = new Popup.JWindowPopup(owner, contents, x, y);
 166:       }
 167:     else
 168:       popup = new Popup.JWindowPopup(owner, contents, x, y);
 169:     return popup;
 170:   }
 171: }