1 /* DragSourceContext.java -- 2 Copyright (C) 2002 Free Software Foundation 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 java.awt.dnd; 40 41 import java.awt.Component; 42 import java.awt.Cursor; 43 import java.awt.Image; 44 import java.awt.Point; 45 import java.awt.datatransfer.Transferable; 46 import java.awt.dnd.peer.DragSourceContextPeer; 47 import java.io.Serializable; 48 import java.util.TooManyListenersException; 49 50 /** 51 * @since 1.2 52 */ 53 public class DragSourceContext 54 implements DragSourceListener, DragSourceMotionListener, Serializable 55 { 56 /** 57 * Compatible with JDK 1.2+ 58 */ 59 static final long serialVersionUID = -115407898692194719L; 60 61 protected static final int DEFAULT = 0; 62 protected static final int ENTER = 1; 63 protected static final int OVER = 2; 64 protected static final int CHANGED = 3; 65 66 private DragSourceContextPeer peer; 67 private Cursor cursor; 68 private Transferable transferable; 69 private DragGestureEvent trigger; 70 private DragSourceListener dragSourceListener; 71 private boolean useCustomCursor; 72 private int sourceActions; 73 private Image image; 74 private Point offset; 75 76 /** 77 * Initializes a drag source context. 78 * 79 * @exception IllegalArgumentException If Component or DragSource of trigger 80 * are null, the drag action for the trigger event is DnDConstants.ACTION_NONE 81 * or if the source actions for the DragGestureRecognizer associated with the 82 * trigger event are equal to DnDConstants.ACTION_NONE. 83 * @exception NullPointerException If peer, trans or trigger is null or if the 84 * image is not null but the offset is. 85 */ DragSourceContext(DragSourceContextPeer peer, DragGestureEvent trigger, Cursor cursor, Image image, Point offset, Transferable trans, DragSourceListener dsl)86 public DragSourceContext (DragSourceContextPeer peer, 87 DragGestureEvent trigger, Cursor cursor, 88 Image image, Point offset, Transferable trans, 89 DragSourceListener dsl) 90 { 91 if (peer == null 92 || trigger == null || trans == null 93 || (image != null && offset == null)) 94 throw new NullPointerException (); 95 96 if (trigger.getComponent () == null 97 || trigger.getDragSource () == null 98 || trigger.getDragAction () == DnDConstants.ACTION_NONE 99 || trigger.getSourceAsDragGestureRecognizer () 100 .getSourceActions () == DnDConstants.ACTION_NONE) 101 throw new IllegalArgumentException (); 102 103 this.peer = peer; 104 this.trigger = trigger; 105 this.cursor = cursor; 106 this.image = image; 107 this.offset = offset; 108 this.transferable = trans; 109 this.dragSourceListener = dsl; 110 this.sourceActions = trigger.getSourceAsDragGestureRecognizer().getSourceActions(); 111 112 setCursor(cursor); 113 updateCurrentCursor(trigger.getDragAction(), sourceActions, DEFAULT); 114 } 115 116 /** 117 * Returns the DragSource object associated with the 118 * DragGestureEvent. 119 * 120 * @return the DragSource associated with the trigger. 121 */ getDragSource()122 public DragSource getDragSource() 123 { 124 return trigger.getDragSource (); 125 } 126 127 /** 128 * Returns the component associated with this. 129 * 130 * @return the component associated with the trigger. 131 */ getComponent()132 public Component getComponent() 133 { 134 return trigger.getComponent (); 135 } 136 137 /** 138 * Gets the trigger associated with this. 139 * 140 * @return the trigger. 141 */ getTrigger()142 public DragGestureEvent getTrigger() 143 { 144 return trigger; 145 } 146 147 /** 148 * Returns the source actions for the DragGestureRecognizer. 149 * 150 * @return the source actions for DragGestureRecognizer. 151 */ getSourceActions()152 public int getSourceActions() 153 { 154 if (sourceActions == 0) 155 sourceActions = trigger.getSourceAsDragGestureRecognizer().getSourceActions(); 156 return sourceActions; 157 } 158 159 /** 160 * Sets the cursor for this drag operation to the specified cursor. 161 * 162 * @param cursor c - the Cursor to use, or null to use the default drag 163 * cursor. 164 */ setCursor(Cursor cursor)165 public void setCursor(Cursor cursor) 166 { 167 if (cursor == null) 168 useCustomCursor = false; 169 else 170 useCustomCursor = true; 171 this.cursor = cursor; 172 peer.setCursor(cursor); 173 } 174 175 /** 176 * Returns the current cursor or null if the default 177 * drag cursor is used. 178 * 179 * @return the current cursor or null. 180 */ getCursor()181 public Cursor getCursor() 182 { 183 return cursor; 184 } 185 186 /** 187 * Adds a <code>DragSourceListener</code>. 188 * 189 * @exception TooManyListenersException If a <code>DragSourceListener</code> 190 * has already been added. 191 */ addDragSourceListener(DragSourceListener dsl)192 public void addDragSourceListener (DragSourceListener dsl) 193 throws TooManyListenersException 194 { 195 if (dragSourceListener != null) 196 throw new TooManyListenersException (); 197 198 dragSourceListener = dsl; 199 } 200 removeDragSourceListener(DragSourceListener dsl)201 public void removeDragSourceListener (DragSourceListener dsl) 202 { 203 if (dragSourceListener == dsl) 204 dragSourceListener = null; 205 } 206 207 /** 208 * This function tells the peer that the DataFlavors have been modified. 209 */ transferablesFlavorsChanged()210 public void transferablesFlavorsChanged() 211 { 212 peer.transferablesFlavorsChanged(); 213 } 214 215 /** 216 * Calls dragEnter on the listeners registered with this 217 * and with the DragSource. 218 * 219 * @param e - the DragSourceDragEvent 220 */ dragEnter(DragSourceDragEvent e)221 public void dragEnter(DragSourceDragEvent e) 222 { 223 if (dragSourceListener != null) 224 dragSourceListener.dragEnter(e); 225 226 DragSource ds = getDragSource(); 227 DragSourceListener[] dsl = ds.getDragSourceListeners(); 228 for (int i = 0; i < dsl.length; i++) 229 dsl[i].dragEnter(e); 230 231 updateCurrentCursor(e.getDropAction(), e.getTargetActions(), ENTER); 232 } 233 234 /** 235 * Calls dragOver on the listeners registered with this 236 * and with the DragSource. 237 * 238 * @param e - the DragSourceDragEvent 239 */ dragOver(DragSourceDragEvent e)240 public void dragOver(DragSourceDragEvent e) 241 { 242 if (dragSourceListener != null) 243 dragSourceListener.dragOver(e); 244 245 DragSource ds = getDragSource(); 246 DragSourceListener[] dsl = ds.getDragSourceListeners(); 247 for (int i = 0; i < dsl.length; i++) 248 dsl[i].dragOver(e); 249 250 updateCurrentCursor(e.getDropAction(), e.getTargetActions(), OVER); 251 } 252 253 /** 254 * Calls dragExit on the listeners registered with this 255 * and with the DragSource. 256 * 257 * @param e - the DragSourceEvent 258 */ dragExit(DragSourceEvent e)259 public void dragExit(DragSourceEvent e) 260 { 261 if (dragSourceListener != null) 262 dragSourceListener.dragExit(e); 263 264 DragSource ds = getDragSource(); 265 DragSourceListener[] dsl = ds.getDragSourceListeners(); 266 for (int i = 0; i < dsl.length; i++) 267 dsl[i].dragExit(e); 268 269 updateCurrentCursor(DnDConstants.ACTION_NONE, DnDConstants.ACTION_NONE, 270 DEFAULT); 271 } 272 273 /** 274 * Calls dropActionChanged on the listeners registered with this 275 * and with the DragSource. 276 * 277 * @param e - the DragSourceDragEvent 278 */ dropActionChanged(DragSourceDragEvent e)279 public void dropActionChanged(DragSourceDragEvent e) 280 { 281 if (dragSourceListener != null) 282 dragSourceListener.dropActionChanged(e); 283 284 DragSource ds = getDragSource(); 285 DragSourceListener[] dsl = ds.getDragSourceListeners(); 286 for (int i = 0; i < dsl.length; i++) 287 dsl[i].dropActionChanged(e); 288 289 updateCurrentCursor(e.getDropAction(), e.getTargetActions(), CHANGED); 290 } 291 292 /** 293 * Calls dragDropEnd on the listeners registered with this 294 * and with the DragSource. 295 * 296 * @param e - the DragSourceDropEvent 297 */ dragDropEnd(DragSourceDropEvent e)298 public void dragDropEnd(DragSourceDropEvent e) 299 { 300 if (dragSourceListener != null) 301 dragSourceListener.dragDropEnd(e); 302 303 DragSource ds = getDragSource(); 304 DragSourceListener[] dsl = ds.getDragSourceListeners(); 305 for (int i = 0; i < dsl.length; i++) 306 dsl[i].dragDropEnd(e); 307 } 308 309 /** 310 * Calls dragMouseMoved on the listeners registered with the DragSource. 311 * 312 * @param e - the DragSourceDragEvent 313 */ dragMouseMoved(DragSourceDragEvent e)314 public void dragMouseMoved(DragSourceDragEvent e) 315 { 316 DragSource ds = getDragSource(); 317 DragSourceMotionListener[] dsml = ds.getDragSourceMotionListeners(); 318 for (int i = 0; i < dsml.length; i++) 319 dsml[i].dragMouseMoved(e); 320 } 321 322 /** 323 * Returns the Transferable set with this object. 324 * 325 * @return the transferable. 326 */ getTransferable()327 public Transferable getTransferable() 328 { 329 return transferable; 330 } 331 332 /** 333 * This function sets the drag cursor for the specified operation, actions and 334 * status if the default drag cursor is active. Otherwise, the cursor is not 335 * updated in any way. 336 * 337 * @param dropOp - the current operation. 338 * @param targetAct - the supported actions. 339 * @param status - the status of the cursor (constant). 340 */ updateCurrentCursor(int dropOp, int targetAct, int status)341 protected void updateCurrentCursor(int dropOp, int targetAct, int status) 342 { 343 if (! useCustomCursor) 344 { 345 Cursor newCursor = null; 346 switch (status) 347 { 348 default: 349 targetAct = DnDConstants.ACTION_NONE; 350 case ENTER: 351 case CHANGED: 352 case OVER: 353 int action = dropOp & targetAct; 354 if (action == DnDConstants.ACTION_NONE) 355 { 356 if ((dropOp & DnDConstants.ACTION_LINK) != 0) 357 newCursor = DragSource.DefaultLinkNoDrop; 358 else if ((dropOp & DnDConstants.ACTION_MOVE) != 0) 359 newCursor = DragSource.DefaultMoveNoDrop; 360 else 361 newCursor = DragSource.DefaultCopyNoDrop; 362 } 363 else 364 { 365 if ((dropOp & DnDConstants.ACTION_LINK) != 0) 366 newCursor = DragSource.DefaultLinkDrop; 367 else if ((dropOp & DnDConstants.ACTION_MOVE) != 0) 368 newCursor = DragSource.DefaultMoveDrop; 369 else 370 newCursor = DragSource.DefaultCopyDrop; 371 } 372 } 373 374 if (cursor == null || ! cursor.equals(newCursor)) 375 { 376 cursor = newCursor; 377 DragSourceContextPeer p = peer; 378 if (p != null) 379 p.setCursor(cursor); 380 } 381 } 382 } 383 } // class DragSourceContext 384