libjava/java/awt/dnd/DragSource.java

   1 /* DragSource.java --
   2    Copyright (C) 2002 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., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 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 java.awt.dnd;
  40
  41 import java.awt.Component;
  42 import java.awt.Cursor;
  43 import java.awt.GraphicsEnvironment;
  44 import java.awt.HeadlessException;
  45 import java.awt.Image;
  46 import java.awt.Point;
  47 import java.awt.Toolkit;
  48 import java.awt.datatransfer.FlavorMap;
  49 import java.awt.datatransfer.SystemFlavorMap;
  50 import java.awt.datatransfer.Transferable;
  51 import java.awt.dnd.peer.DragSourceContextPeer;
  52 import java.io.Serializable;
  53 import java.util.EventListener;
  54
  55 /**
  56  * @since 1.2
  57  */
  58 public class DragSource implements Serializable
  59 {
  60   /**
  61    * Compatible with JDK 1.2+.
  62    */
  63   private static final long serialVersionUID = 6236096958971414066L;
  64
  65   public static final Cursor DefaultCopyDrop = null;
  66   public static final Cursor DefaultMoveDrop = null;
  67   public static final Cursor DefaultLinkDrop = null;
  68   public static final Cursor DefaultCopyNoDrop = null;
  69   public static final Cursor DefaultMoveNoDrop = null;
  70   public static final Cursor DefaultLinkNoDrop = null;
  71
  72   private transient FlavorMap flavorMap = SystemFlavorMap.getDefaultFlavorMap ();
  73
  74   private transient DragSourceListener dragSourceListener;
  75   private transient DragSourceMotionListener dragSourceMotionListener;
  76
  77   /**
  78    * Initializes the drag source.
  79    *
  80    * @exception HeadlessException If GraphicsEnvironment.isHeadless() is true.
  81    */
  82   public DragSource()
  83   {
  84     if (GraphicsEnvironment.isHeadless())
  85       throw new HeadlessException ();
  86   }
  87
  88   /**
  89    * @exception HeadlessException If GraphicsEnvironment.isHeadless() is true.
  90    */
  91   public static DragSource getDefaultDragSource()
  92   {
  93     return null;
  94   }
  95
  96   public static boolean isDragImageSupported()
  97   {
  98     return false;
  99   }
 100
 101   /**
 102    * Start a drag, given the DragGestureEvent that initiated the drag.
 103    *
 104    * @exception InvalidDnDOperationException If the Drag and Drop system is
 105    * unable to initiate a drag operation, or if the user attempts to start
 106    * a drag while an existing drag operation is still executing.
 107    */
 108   public void startDrag(DragGestureEvent trigger, Cursor dragCursor,
 109                         Image dragImage, Point imageOffset,
 110                         Transferable trans, DragSourceListener dsl,
 111                         FlavorMap map)
 112   {
 113   }
 114
 115   /**
 116    * Start a drag, given the DragGestureEvent that initiated the drag.
 117    *
 118    * @exception InvalidDnDOperationException If the Drag and Drop system is
 119    * unable to initiate a drag operation, or if the user attempts to start
 120    * a drag while an existing drag operation is still executing.
 121    */
 122   public void startDrag(DragGestureEvent trigger, Cursor dragCursor,
 123                         Transferable trans, DragSourceListener dsl,
 124                         FlavorMap map)
 125   {
 126     startDrag(trigger, dragCursor, null, null, trans, dsl, map);
 127   }
 128
 129   /**
 130    * Start a drag, given the DragGestureEvent that initiated the drag.
 131    *
 132    * @exception InvalidDnDOperationException If the Drag and Drop system is
 133    * unable to initiate a drag operation, or if the user attempts to start
 134    * a drag while an existing drag operation is still executing.
 135    */
 136   public void startDrag(DragGestureEvent trigger, Cursor dragCursor,
 137                         Image dragImage, Point imageOffset,
 138                         Transferable trans, DragSourceListener dsl)
 139   {
 140     startDrag(trigger, dragCursor, dragImage, imageOffset, trans, dsl, null);
 141   }
 142
 143   /**
 144    * Start a drag, given the DragGestureEvent that initiated the drag.
 145    *
 146    * @exception InvalidDnDOperationException If the Drag and Drop system is
 147    * unable to initiate a drag operation, or if the user attempts to start
 148    * a drag while an existing drag operation is still executing.
 149    */
 150   public void startDrag(DragGestureEvent trigger, Cursor dragCursor,
 151                         Transferable trans, DragSourceListener dsl)
 152   {
 153     startDrag(trigger, dragCursor, null, null, trans, dsl, null);
 154   }
 155
 156   /**
 157    * Creates the DragSourceContext to handle this drag.
 158    *
 159    * @exception IllegalArgumentException FIXME
 160    * @exception NullPointerException If dscp, dgl, dragImage or t is null.
 161    */
 162   protected DragSourceContext
 163     createDragSourceContext(DragSourceContextPeer peer, DragGestureEvent dge,
 164                             Cursor cursor, Image image, Point offset,
 165                             Transferable t, DragSourceListener dsl)
 166   {
 167     return null;
 168   }
 169
 170   public FlavorMap getFlavorMap()
 171   {
 172     return flavorMap;
 173   }
 174
 175   public DragGestureRecognizer
 176     createDragGestureRecognizer(Class recognizer, Component c, int actions,
 177                                 DragGestureListener dgl)
 178   {
 179     return Toolkit.getDefaultToolkit ()
 180                   .createDragGestureRecognizer (recognizer, this, c, actions,
 181                                                 dgl);
 182   }
 183
 184   public DragGestureRecognizer
 185     createDefaultDragGestureRecognizer(Component c, int actions,
 186                                        DragGestureListener dgl)
 187   {
 188     return createDragGestureRecognizer (MouseDragGestureRecognizer.class, c,
 189                                         actions, dgl);
 190   }
 191
 192   /**
 193    * @since 1.4
 194    */
 195   public void addDragSourceListener(DragSourceListener l)
 196   {
 197     DnDEventMulticaster.add (dragSourceListener, l);
 198   }
 199
 200   /**
 201    * @since 1.4
 202    */
 203   public void removeDragSourceListener(DragSourceListener l)
 204   {
 205     DnDEventMulticaster.remove (dragSourceListener, l);
 206   }
 207
 208   /**
 209    * @since 1.4
 210    */
 211   public DragSourceListener[] getDragSourceListeners()
 212   {
 213     return (DragSourceListener[]) getListeners (DragSourceListener.class);
 214   }
 215
 216   /**
 217    * @since 1.4
 218    */
 219   public void addDragSourceMotionListener(DragSourceMotionListener l)
 220   {
 221     DnDEventMulticaster.add (dragSourceMotionListener, l);
 222   }
 223
 224   /**
 225    * @since 1.4
 226    */
 227   public void removeDragSourceMotionListener(DragSourceMotionListener l)
 228   {
 229     DnDEventMulticaster.remove (dragSourceMotionListener, l);
 230   }
 231
 232   /**
 233    * @since 1.4
 234    */
 235   public DragSourceMotionListener[] getDragSourceMotionListeners ()
 236   {
 237     return (DragSourceMotionListener[]) getListeners
 238                                          (DragSourceMotionListener.class);
 239   }
 240
 241   /**
 242    * @since 1.4
 243    */
 244   public EventListener[] getListeners (Class listenerType)
 245   {
 246     if (listenerType == DragSourceListener.class)
 247       return DnDEventMulticaster.getListeners (dragSourceListener,
 248                                                listenerType);
 249
 250     if (listenerType == DragSourceMotionListener.class)
 251       return DnDEventMulticaster.getListeners (dragSourceMotionListener,
 252                                                listenerType);
 253
 254     // Return an empty EventListener array.
 255     return new EventListener [0];
 256   }
 257 } // class DragSource