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| 1 | /* | ||
| 2 | * Copyright (c) 1997, 2008, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 9 | * by Oracle in the LICENSE file that accompanied this code. | ||
| 10 | * | ||
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT | ||
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
| 14 | * version 2 for more details (a copy is included in the LICENSE file that | ||
| 15 | * accompanied this code). | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU General Public License version | ||
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, | ||
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 20 | * | ||
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 22 | * or visit www.oracle.com if you need additional information or have any | ||
| 23 | * questions. | ||
| 24 | */ | ||
| 25 | |||
| 26 | package java.awt.dnd; | ||
| 27 | |||
| 28 | import java.awt.Component; | ||
| 29 | import java.awt.Cursor; | ||
| 30 | import java.awt.Image; | ||
| 31 | import java.awt.Point; | ||
| 32 | |||
| 33 | import java.awt.datatransfer.DataFlavor; | ||
| 34 | import java.awt.datatransfer.Transferable; | ||
| 35 | import java.awt.datatransfer.UnsupportedFlavorException; | ||
| 36 | |||
| 37 | import java.awt.dnd.peer.DragSourceContextPeer; | ||
| 38 | |||
| 39 | import java.io.IOException; | ||
| 40 | import java.io.ObjectOutputStream; | ||
| 41 | import java.io.ObjectInputStream; | ||
| 42 | import java.io.Serializable; | ||
| 43 | |||
| 44 | import java.util.TooManyListenersException; | ||
| 45 | |||
| 46 | /** | ||
| 47 | * The <code>DragSourceContext</code> class is responsible for managing the | ||
| 48 | * initiator side of the Drag and Drop protocol. In particular, it is responsible | ||
| 49 | * for managing drag event notifications to the | ||
| 50 | * {@linkplain DragSourceListener DragSourceListeners} | ||
| 51 | * and {@linkplain DragSourceMotionListener DragSourceMotionListeners}, and providing the | ||
| 52 | * {@link Transferable} representing the source data for the drag operation. | ||
| 53 | * <p> | ||
| 54 | * Note that the <code>DragSourceContext</code> itself | ||
| 55 | * implements the <code>DragSourceListener</code> and | ||
| 56 | * <code>DragSourceMotionListener</code> interfaces. | ||
| 57 | * This is to allow the platform peer | ||
| 58 | * (the {@link DragSourceContextPeer} instance) | ||
| 59 | * created by the {@link DragSource} to notify | ||
| 60 | * the <code>DragSourceContext</code> of | ||
| 61 | * state changes in the ongoing operation. This allows the | ||
| 62 | * <code>DragSourceContext</code> object to interpose | ||
| 63 | * itself between the platform and the | ||
| 64 | * listeners provided by the initiator of the drag operation. | ||
| 65 | * <p> | ||
| 66 | * <a name="defaultCursor" /> | ||
| 67 | * By default, {@code DragSourceContext} sets the cursor as appropriate | ||
| 68 | * for the current state of the drag and drop operation. For example, if | ||
| 69 | * the user has chosen {@linkplain DnDConstants#ACTION_MOVE the move action}, | ||
| 70 | * and the pointer is over a target that accepts | ||
| 71 | * the move action, the default move cursor is shown. When | ||
| 72 | * the pointer is over an area that does not accept the transfer, | ||
| 73 | * the default "no drop" cursor is shown. | ||
| 74 | * <p> | ||
| 75 | * This default handling mechanism is disabled when a custom cursor is set | ||
| 76 | * by the {@link #setCursor} method. When the default handling is disabled, | ||
| 77 | * it becomes the responsibility | ||
| 78 | * of the developer to keep the cursor up to date, by listening | ||
| 79 | * to the {@code DragSource} events and calling the {@code setCursor()} method. | ||
| 80 | * Alternatively, you can provide custom cursor behavior by providing | ||
| 81 | * custom implementations of the {@code DragSource} | ||
| 82 | * and the {@code DragSourceContext} classes. | ||
| 83 | * | ||
| 84 | * @see DragSourceListener | ||
| 85 | * @see DragSourceMotionListener | ||
| 86 | * @see DnDConstants | ||
| 87 | * @since 1.2 | ||
| 88 | */ | ||
| 89 | |||
| 90 | public class DragSourceContext | ||
| 91 | implements DragSourceListener, DragSourceMotionListener, Serializable { | ||
| 92 | |||
| 93 | private static final long serialVersionUID = -115407898692194719L; | ||
| 94 | |||
| 95 | // used by updateCurrentCursor | ||
| 96 | |||
| 97 | /** | ||
| 98 | * An <code>int</code> used by updateCurrentCursor() | ||
| 99 | * indicating that the <code>Cursor</code> should change | ||
| 100 | * to the default (no drop) <code>Cursor</code>. | ||
| 101 | */ | ||
| 102 | protected static final int DEFAULT = 0; | ||
| 103 | |||
| 104 | /** | ||
| 105 | * An <code>int</code> used by updateCurrentCursor() | ||
| 106 | * indicating that the <code>Cursor</code> | ||
| 107 | * has entered a <code>DropTarget</code>. | ||
| 108 | */ | ||
| 109 | protected static final int ENTER = 1; | ||
| 110 | |||
| 111 | /** | ||
| 112 | * An <code>int</code> used by updateCurrentCursor() | ||
| 113 | * indicating that the <code>Cursor</code> is | ||
| 114 | * over a <code>DropTarget</code>. | ||
| 115 | */ | ||
| 116 | protected static final int OVER = 2; | ||
| 117 | |||
| 118 | /** | ||
| 119 | * An <code>int</code> used by updateCurrentCursor() | ||
| 120 | * indicating that the user operation has changed. | ||
| 121 | */ | ||
| 122 | |||
| 123 | protected static final int CHANGED = 3; | ||
| 124 | |||
| 125 | /** | ||
| 126 | * Called from <code>DragSource</code>, this constructor creates a new | ||
| 127 | * <code>DragSourceContext</code> given the | ||
| 128 | * <code>DragSourceContextPeer</code> for this Drag, the | ||
| 129 | * <code>DragGestureEvent</code> that triggered the Drag, the initial | ||
| 130 | * <code>Cursor</code> to use for the Drag, an (optional) | ||
| 131 | * <code>Image</code> to display while the Drag is taking place, the offset | ||
| 132 | * of the <code>Image</code> origin from the hotspot at the instant of the | ||
| 133 | * triggering event, the <code>Transferable</code> subject data, and the | ||
| 134 | * <code>DragSourceListener</code> to use during the Drag and Drop | ||
| 135 | * operation. | ||
| 136 | * <br> | ||
| 137 | * If <code>DragSourceContextPeer</code> is <code>null</code> | ||
| 138 | * <code>NullPointerException</code> is thrown. | ||
| 139 | * <br> | ||
| 140 | * If <code>DragGestureEvent</code> is <code>null</code> | ||
| 141 | * <code>NullPointerException</code> is thrown. | ||
| 142 | * <br> | ||
| 143 | * If <code>Cursor</code> is <code>null</code> no exception is thrown and | ||
| 144 | * the default drag cursor behavior is activated for this drag operation. | ||
| 145 | * <br> | ||
| 146 | * If <code>Image</code> is <code>null</code> no exception is thrown. | ||
| 147 | * <br> | ||
| 148 | * If <code>Image</code> is not <code>null</code> and the offset is | ||
| 149 | * <code>null</code> <code>NullPointerException</code> is thrown. | ||
| 150 | * <br> | ||
| 151 | * If <code>Transferable</code> is <code>null</code> | ||
| 152 | * <code>NullPointerException</code> is thrown. | ||
| 153 | * <br> | ||
| 154 | * If <code>DragSourceListener</code> is <code>null</code> no exception | ||
| 155 | * is thrown. | ||
| 156 | * | ||
| 157 | * @param dscp the <code>DragSourceContextPeer</code> for this drag | ||
| 158 | * @param trigger the triggering event | ||
| 159 | * @param dragCursor the initial {@code Cursor} for this drag operation | ||
| 160 | * or {@code null} for the default cursor handling; | ||
| 161 | * see <a href="DragSourceContext.html#defaultCursor">class level documentation</a> | ||
| 162 | * for more details on the cursor handling mechanism during drag and drop | ||
| 163 | * @param dragImage the <code>Image</code> to drag (or <code>null</code>) | ||
| 164 | * @param offset the offset of the image origin from the hotspot at the | ||
| 165 | * instant of the triggering event | ||
| 166 | * @param t the <code>Transferable</code> | ||
| 167 | * @param dsl the <code>DragSourceListener</code> | ||
| 168 | * | ||
| 169 | * @throws IllegalArgumentException if the <code>Component</code> associated | ||
| 170 | * with the trigger event is <code>null</code>. | ||
| 171 | * @throws IllegalArgumentException if the <code>DragSource</code> for the | ||
| 172 | * trigger event is <code>null</code>. | ||
| 173 | * @throws IllegalArgumentException if the drag action for the | ||
| 174 | * trigger event is <code>DnDConstants.ACTION_NONE</code>. | ||
| 175 | * @throws IllegalArgumentException if the source actions for the | ||
| 176 | * <code>DragGestureRecognizer</code> associated with the trigger | ||
| 177 | * event are equal to <code>DnDConstants.ACTION_NONE</code>. | ||
| 178 | * @throws NullPointerException if dscp, trigger, or t are null, or | ||
| 179 | * if dragImage is non-null and offset is null | ||
| 180 | */ | ||
| 181 | public DragSourceContext(DragSourceContextPeer dscp, | ||
| 182 | DragGestureEvent trigger, Cursor dragCursor, | ||
| 183 | Image dragImage, Point offset, Transferable t, | ||
| 184 | DragSourceListener dsl) { | ||
| 185 | if (dscp == null) { | ||
| 186 | throw new NullPointerException("DragSourceContextPeer"); | ||
| 187 | } | ||
| 188 | |||
| 189 | if (trigger == null) { | ||
| 190 | throw new NullPointerException("Trigger"); | ||
| 191 | } | ||
| 192 | |||
| 193 | if (trigger.getDragSource() == null) { | ||
| 194 | throw new IllegalArgumentException("DragSource"); | ||
| 195 | } | ||
| 196 | |||
| 197 | if (trigger.getComponent() == null) { | ||
| 198 | throw new IllegalArgumentException("Component"); | ||
| 199 | } | ||
| 200 | |||
| 201 | if (trigger.getSourceAsDragGestureRecognizer().getSourceActions() == | ||
| 202 | DnDConstants.ACTION_NONE) { | ||
| 203 | throw new IllegalArgumentException("source actions"); | ||
| 204 | } | ||
| 205 | |||
| 206 | if (trigger.getDragAction() == DnDConstants.ACTION_NONE) { | ||
| 207 | throw new IllegalArgumentException("no drag action"); | ||
| 208 | } | ||
| 209 | |||
| 210 | if (t == null) { | ||
| 211 | throw new NullPointerException("Transferable"); | ||
| 212 | } | ||
| 213 | |||
| 214 | if (dragImage != null && offset == null) { | ||
| 215 | throw new NullPointerException("offset"); | ||
| 216 | } | ||
| 217 | |||
| 218 | peer = dscp; | ||
| 219 | this.trigger = trigger; | ||
| 220 | cursor = dragCursor; | ||
| 221 | transferable = t; | ||
| 222 | listener = dsl; | ||
| 223 | sourceActions = | ||
| 224 | trigger.getSourceAsDragGestureRecognizer().getSourceActions(); | ||
| 225 | |||
| 226 | useCustomCursor = (dragCursor != null); | ||
| 227 | |||
| 228 | updateCurrentCursor(trigger.getDragAction(), getSourceActions(), DEFAULT); | ||
| 229 | } | ||
| 230 | |||
| 231 | /** | ||
| 232 | * Returns the <code>DragSource</code> | ||
| 233 | * that instantiated this <code>DragSourceContext</code>. | ||
| 234 | * | ||
| 235 | * @return the <code>DragSource</code> that | ||
| 236 | * instantiated this <code>DragSourceContext</code> | ||
| 237 | */ | ||
| 238 | |||
| 239 | public DragSource getDragSource() { return trigger.getDragSource(); } | ||
| 240 | |||
| 241 | /** | ||
| 242 | * Returns the <code>Component</code> associated with this | ||
| 243 | * <code>DragSourceContext</code>. | ||
| 244 | * | ||
| 245 | * @return the <code>Component</code> that started the drag | ||
| 246 | */ | ||
| 247 | |||
| 248 | public Component getComponent() { return trigger.getComponent(); } | ||
| 249 | |||
| 250 | /** | ||
| 251 | * Returns the <code>DragGestureEvent</code> | ||
| 252 | * that initially triggered the drag. | ||
| 253 | * | ||
| 254 | * @return the Event that triggered the drag | ||
| 255 | */ | ||
| 256 | |||
| 257 | public DragGestureEvent getTrigger() { return trigger; } | ||
| 258 | |||
| 259 | /** | ||
| 260 | * Returns a bitwise mask of <code>DnDConstants</code> that | ||
| 261 | * represent the set of drop actions supported by the drag source for the | ||
| 262 | * drag operation associated with this <code>DragSourceContext</code>. | ||
| 263 | * | ||
| 264 | * @return the drop actions supported by the drag source | ||
| 265 | */ | ||
| 266 | public int getSourceActions() { | ||
| 267 | return sourceActions; | ||
| 268 | } | ||
| 269 | |||
| 270 | /** | ||
| 271 | * Sets the cursor for this drag operation to the specified | ||
| 272 | * <code>Cursor</code>. If the specified <code>Cursor</code> | ||
| 273 | * is <code>null</code>, the default drag cursor behavior is | ||
| 274 | * activated for this drag operation, otherwise it is deactivated. | ||
| 275 | * | ||
| 276 | * @param c the initial {@code Cursor} for this drag operation, | ||
| 277 | * or {@code null} for the default cursor handling; | ||
| 278 | * see {@linkplain Cursor class | ||
| 279 | * level documentation} for more details | ||
| 280 | * on the cursor handling during drag and drop | ||
| 281 | * | ||
| 282 | */ | ||
| 283 | |||
| 284 | public synchronized void setCursor(Cursor c) { | ||
| 285 | useCustomCursor = (c != null); | ||
| 286 | setCursorImpl(c); | ||
| 287 | } | ||
| 288 | |||
| 289 | /** | ||
| 290 | * Returns the current drag <code>Cursor</code>. | ||
| 291 | * <P> | ||
| 292 | * @return the current drag <code>Cursor</code> | ||
| 293 | */ | ||
| 294 | |||
| 295 | public Cursor getCursor() { return cursor; } | ||
| 296 | |||
| 297 | /** | ||
| 298 | * Add a <code>DragSourceListener</code> to this | ||
| 299 | * <code>DragSourceContext</code> if one has not already been added. | ||
| 300 | * If a <code>DragSourceListener</code> already exists, | ||
| 301 | * this method throws a <code>TooManyListenersException</code>. | ||
| 302 | * <P> | ||
| 303 | * @param dsl the <code>DragSourceListener</code> to add. | ||
| 304 | * Note that while <code>null</code> is not prohibited, | ||
| 305 | * it is not acceptable as a parameter. | ||
| 306 | * <P> | ||
| 307 | * @throws TooManyListenersException if | ||
| 308 | * a <code>DragSourceListener</code> has already been added | ||
| 309 | */ | ||
| 310 | |||
| 311 | public synchronized void addDragSourceListener(DragSourceListener dsl) throws TooManyListenersException { | ||
| 312 | if (dsl == null) return; | ||
| 313 | |||
| 314 | if (equals(dsl)) throw new IllegalArgumentException("DragSourceContext may not be its own listener"); | ||
| 315 | |||
| 316 | if (listener != null) | ||
| 317 | throw new TooManyListenersException(); | ||
| 318 | else | ||
| 319 | listener = dsl; | ||
| 320 | } | ||
| 321 | |||
| 322 | /** | ||
| 323 | * Removes the specified <code>DragSourceListener</code> | ||
| 324 | * from this <code>DragSourceContext</code>. | ||
| 325 | * | ||
| 326 | * @param dsl the <code>DragSourceListener</code> to remove; | ||
| 327 | * note that while <code>null</code> is not prohibited, | ||
| 328 | * it is not acceptable as a parameter | ||
| 329 | */ | ||
| 330 | |||
| 331 | public synchronized void removeDragSourceListener(DragSourceListener dsl) { | ||
| 332 | if (listener != null && listener.equals(dsl)) { | ||
| 333 | listener = null; | ||
| 334 | } else | ||
| 335 | throw new IllegalArgumentException(); | ||
| 336 | } | ||
| 337 | |||
| 338 | /** | ||
| 339 | * Notifies the peer that the <code>Transferable</code>'s | ||
| 340 | * <code>DataFlavor</code>s have changed. | ||
| 341 | */ | ||
| 342 | |||
| 343 | public void transferablesFlavorsChanged() { | ||
| 344 | if (peer != null) peer.transferablesFlavorsChanged(); | ||
| 345 | } | ||
| 346 | |||
| 347 | /** | ||
| 348 | * Calls <code>dragEnter</code> on the | ||
| 349 | * <code>DragSourceListener</code>s registered with this | ||
| 350 | * <code>DragSourceContext</code> and with the associated | ||
| 351 | * <code>DragSource</code>, and passes them the specified | ||
| 352 | * <code>DragSourceDragEvent</code>. | ||
| 353 | * | ||
| 354 | * @param dsde the <code>DragSourceDragEvent</code> | ||
| 355 | */ | ||
| 356 | public void dragEnter(DragSourceDragEvent dsde) { | ||
| 357 | DragSourceListener dsl = listener; | ||
| 358 | if (dsl != null) { | ||
| 359 | dsl.dragEnter(dsde); | ||
| 360 | } | ||
| 361 | getDragSource().processDragEnter(dsde); | ||
| 362 | |||
| 363 | updateCurrentCursor(getSourceActions(), dsde.getTargetActions(), ENTER); | ||
| 364 | } | ||
| 365 | |||
| 366 | /** | ||
| 367 | * Calls <code>dragOver</code> on the | ||
| 368 | * <code>DragSourceListener</code>s registered with this | ||
| 369 | * <code>DragSourceContext</code> and with the associated | ||
| 370 | * <code>DragSource</code>, and passes them the specified | ||
| 371 | * <code>DragSourceDragEvent</code>. | ||
| 372 | * | ||
| 373 | * @param dsde the <code>DragSourceDragEvent</code> | ||
| 374 | */ | ||
| 375 | public void dragOver(DragSourceDragEvent dsde) { | ||
| 376 | DragSourceListener dsl = listener; | ||
| 377 | if (dsl != null) { | ||
| 378 | dsl.dragOver(dsde); | ||
| 379 | } | ||
| 380 | getDragSource().processDragOver(dsde); | ||
| 381 | |||
| 382 | updateCurrentCursor(getSourceActions(), dsde.getTargetActions(), OVER); | ||
| 383 | } | ||
| 384 | |||
| 385 | /** | ||
| 386 | * Calls <code>dragExit</code> on the | ||
| 387 | * <code>DragSourceListener</code>s registered with this | ||
| 388 | * <code>DragSourceContext</code> and with the associated | ||
| 389 | * <code>DragSource</code>, and passes them the specified | ||
| 390 | * <code>DragSourceEvent</code>. | ||
| 391 | * | ||
| 392 | * @param dse the <code>DragSourceEvent</code> | ||
| 393 | */ | ||
| 394 | public void dragExit(DragSourceEvent dse) { | ||
| 395 | DragSourceListener dsl = listener; | ||
| 396 | if (dsl != null) { | ||
| 397 | dsl.dragExit(dse); | ||
| 398 | } | ||
| 399 | getDragSource().processDragExit(dse); | ||
| 400 | |||
| 401 | updateCurrentCursor(DnDConstants.ACTION_NONE, DnDConstants.ACTION_NONE, DEFAULT); | ||
| 402 | } | ||
| 403 | |||
| 404 | /** | ||
| 405 | * Calls <code>dropActionChanged</code> on the | ||
| 406 | * <code>DragSourceListener</code>s registered with this | ||
| 407 | * <code>DragSourceContext</code> and with the associated | ||
| 408 | * <code>DragSource</code>, and passes them the specified | ||
| 409 | * <code>DragSourceDragEvent</code>. | ||
| 410 | * | ||
| 411 | * @param dsde the <code>DragSourceDragEvent</code> | ||
| 412 | */ | ||
| 413 | public void dropActionChanged(DragSourceDragEvent dsde) { | ||
| 414 | DragSourceListener dsl = listener; | ||
| 415 | if (dsl != null) { | ||
| 416 | dsl.dropActionChanged(dsde); | ||
| 417 | } | ||
| 418 | getDragSource().processDropActionChanged(dsde); | ||
| 419 | |||
| 420 | updateCurrentCursor(getSourceActions(), dsde.getTargetActions(), CHANGED); | ||
| 421 | } | ||
| 422 | |||
| 423 | /** | ||
| 424 | * Calls <code>dragDropEnd</code> on the | ||
| 425 | * <code>DragSourceListener</code>s registered with this | ||
| 426 | * <code>DragSourceContext</code> and with the associated | ||
| 427 | * <code>DragSource</code>, and passes them the specified | ||
| 428 | * <code>DragSourceDropEvent</code>. | ||
| 429 | * | ||
| 430 | * @param dsde the <code>DragSourceDropEvent</code> | ||
| 431 | */ | ||
| 432 | public void dragDropEnd(DragSourceDropEvent dsde) { | ||
| 433 | DragSourceListener dsl = listener; | ||
| 434 | if (dsl != null) { | ||
| 435 | dsl.dragDropEnd(dsde); | ||
| 436 | } | ||
| 437 | getDragSource().processDragDropEnd(dsde); | ||
| 438 | } | ||
| 439 | |||
| 440 | /** | ||
| 441 | * Calls <code>dragMouseMoved</code> on the | ||
| 442 | * <code>DragSourceMotionListener</code>s registered with the | ||
| 443 | * <code>DragSource</code> associated with this | ||
| 444 | * <code>DragSourceContext</code>, and them passes the specified | ||
| 445 | * <code>DragSourceDragEvent</code>. | ||
| 446 | * | ||
| 447 | * @param dsde the <code>DragSourceDragEvent</code> | ||
| 448 | * @since 1.4 | ||
| 449 | */ | ||
| 450 | public void dragMouseMoved(DragSourceDragEvent dsde) { | ||
| 451 | getDragSource().processDragMouseMoved(dsde); | ||
| 452 | } | ||
| 453 | |||
| 454 | /** | ||
| 455 | * Returns the <code>Transferable</code> associated with | ||
| 456 | * this <code>DragSourceContext</code>. | ||
| 457 | * | ||
| 458 | * @return the <code>Transferable</code> | ||
| 459 | */ | ||
| 460 | public Transferable getTransferable() { return transferable; } | ||
| 461 | |||
| 462 | /** | ||
| 463 | * If the default drag cursor behavior is active, this method | ||
| 464 | * sets the default drag cursor for the specified actions | ||
| 465 | * supported by the drag source, the drop target action, | ||
| 466 | * and status, otherwise this method does nothing. | ||
| 467 | * | ||
| 468 | * @param sourceAct the actions supported by the drag source | ||
| 469 | * @param targetAct the drop target action | ||
| 470 | * @param status one of the fields <code>DEFAULT</code>, | ||
| 471 | * <code>ENTER</code>, <code>OVER</code>, | ||
| 472 | * <code>CHANGED</code> | ||
| 473 | */ | ||
| 474 | |||
| 475 | protected synchronized void updateCurrentCursor(int sourceAct, int targetAct, int status) { | ||
| 476 | |||
| 477 | // if the cursor has been previously set then dont do any defaults | ||
| 478 | // processing. | ||
| 479 | |||
| 480 | if (useCustomCursor) { | ||
| 481 | return; | ||
| 482 | } | ||
| 483 | |||
| 484 | // do defaults processing | ||
| 485 | |||
| 486 | Cursor c = null; | ||
| 487 | |||
| 488 | switch (status) { | ||
| 489 | default: | ||
| 490 | targetAct = DnDConstants.ACTION_NONE; | ||
| 491 | case ENTER: | ||
| 492 | case OVER: | ||
| 493 | case CHANGED: | ||
| 494 | int ra = sourceAct & targetAct; | ||
| 495 | |||
| 496 | if (ra == DnDConstants.ACTION_NONE) { // no drop possible | ||
| 497 | if ((sourceAct & DnDConstants.ACTION_LINK) == DnDConstants.ACTION_LINK) | ||
| 498 | c = DragSource.DefaultLinkNoDrop; | ||
| 499 | else if ((sourceAct & DnDConstants.ACTION_MOVE) == DnDConstants.ACTION_MOVE) | ||
| 500 | c = DragSource.DefaultMoveNoDrop; | ||
| 501 | else | ||
| 502 | c = DragSource.DefaultCopyNoDrop; | ||
| 503 | } else { // drop possible | ||
| 504 | if ((ra & DnDConstants.ACTION_LINK) == DnDConstants.ACTION_LINK) | ||
| 505 | c = DragSource.DefaultLinkDrop; | ||
| 506 | else if ((ra & DnDConstants.ACTION_MOVE) == DnDConstants.ACTION_MOVE) | ||
| 507 | c = DragSource.DefaultMoveDrop; | ||
| 508 | else | ||
| 509 | c = DragSource.DefaultCopyDrop; | ||
| 510 | } | ||
| 511 | } | ||
| 512 | |||
| 513 | setCursorImpl(c); | ||
| 514 | } | ||
| 515 | |||
| 516 | private void setCursorImpl(Cursor c) { | ||
| 517 | if (cursor == null || !cursor.equals(c)) { | ||
| 518 | cursor = c; | ||
| 519 | if (peer != null) peer.setCursor(cursor); | ||
| 520 | } | ||
| 521 | } | ||
| 522 | |||
| 523 | /** | ||
| 524 | * Serializes this <code>DragSourceContext</code>. This method first | ||
| 525 | * performs default serialization. Next, this object's | ||
| 526 | * <code>Transferable</code> is written out if and only if it can be | ||
| 527 | * serialized. If not, <code>null</code> is written instead. In this case, | ||
| 528 | * a <code>DragSourceContext</code> created from the resulting deserialized | ||
| 529 | * stream will contain a dummy <code>Transferable</code> which supports no | ||
| 530 | * <code>DataFlavor</code>s. Finally, this object's | ||
| 531 | * <code>DragSourceListener</code> is written out if and only if it can be | ||
| 532 | * serialized. If not, <code>null</code> is written instead. | ||
| 533 | * | ||
| 534 | * @serialData The default serializable fields, in alphabetical order, | ||
| 535 | * followed by either a <code>Transferable</code> instance, or | ||
| 536 | * <code>null</code>, followed by either a | ||
| 537 | * <code>DragSourceListener</code> instance, or | ||
| 538 | * <code>null</code>. | ||
| 539 | * @since 1.4 | ||
| 540 | */ | ||
| 541 | private void writeObject(ObjectOutputStream s) throws IOException { | ||
| 542 | s.defaultWriteObject(); | ||
| 543 | |||
| 544 | s.writeObject(SerializationTester.test(transferable) | ||
| 545 | ? transferable : null); | ||
| 546 | s.writeObject(SerializationTester.test(listener) | ||
| 547 | ? listener : null); | ||
| 548 | } | ||
| 549 | |||
| 550 | /** | ||
| 551 | * Deserializes this <code>DragSourceContext</code>. This method first | ||
| 552 | * performs default deserialization for all non-<code>transient</code> | ||
| 553 | * fields. This object's <code>Transferable</code> and | ||
| 554 | * <code>DragSourceListener</code> are then deserialized as well by using | ||
| 555 | * the next two objects in the stream. If the resulting | ||
| 556 | * <code>Transferable</code> is <code>null</code>, this object's | ||
| 557 | * <code>Transferable</code> is set to a dummy <code>Transferable</code> | ||
| 558 | * which supports no <code>DataFlavor</code>s. | ||
| 559 | * | ||
| 560 | * @since 1.4 | ||
| 561 | */ | ||
| 562 | private void readObject(ObjectInputStream s) | ||
| 563 | throws ClassNotFoundException, IOException | ||
| 564 | { | ||
| 565 | s.defaultReadObject(); | ||
| 566 | |||
| 567 | transferable = (Transferable)s.readObject(); | ||
| 568 | listener = (DragSourceListener)s.readObject(); | ||
| 569 | |||
| 570 | // Implementation assumes 'transferable' is never null. | ||
| 571 | if (transferable == null) { | ||
| 572 | if (emptyTransferable == null) { | ||
| 573 | emptyTransferable = new Transferable() { | ||
| 574 | public DataFlavor[] getTransferDataFlavors() { | ||
| 575 | return new DataFlavor[0]; | ||
| 576 | } | ||
| 577 | public boolean isDataFlavorSupported(DataFlavor flavor) | ||
| 578 | { | ||
| 579 | return false; | ||
| 580 | } | ||
| 581 | public Object getTransferData(DataFlavor flavor) | ||
| 582 | throws UnsupportedFlavorException | ||
| 583 | { | ||
| 584 | throw new UnsupportedFlavorException(flavor); | ||
| 585 | } | ||
| 586 | }; | ||
| 587 | } | ||
| 588 | transferable = emptyTransferable; | ||
| 589 | } | ||
| 590 | } | ||
| 591 | |||
| 592 | private static Transferable emptyTransferable; | ||
| 593 | |||
| 594 | /* | ||
| 595 | * fields | ||
| 596 | */ | ||
| 597 | |||
| 598 | private transient DragSourceContextPeer peer; | ||
| 599 | |||
| 600 | /** | ||
| 601 | * The event which triggered the start of the drag. | ||
| 602 | * | ||
| 603 | * @serial | ||
| 604 | */ | ||
| 605 | private DragGestureEvent trigger; | ||
| 606 | |||
| 607 | /** | ||
| 608 | * The current drag cursor. | ||
| 609 | * | ||
| 610 | * @serial | ||
| 611 | */ | ||
| 612 | private Cursor cursor; | ||
| 613 | |||
| 614 | private transient Transferable transferable; | ||
| 615 | |||
| 616 | private transient DragSourceListener listener; | ||
| 617 | |||
| 618 | /** | ||
| 619 | * <code>true</code> if the custom drag cursor is used instead of the | ||
| 620 | * default one. | ||
| 621 | * | ||
| 622 | * @serial | ||
| 623 | */ | ||
| 624 | private boolean useCustomCursor; | ||
| 625 | |||
| 626 | /** | ||
| 627 | * A bitwise mask of <code>DnDConstants</code> that represents the set of | ||
| 628 | * drop actions supported by the drag source for the drag operation associated | ||
| 629 | * with this <code>DragSourceContext.</code> | ||
| 630 | * | ||
| 631 | * @serial | ||
| 632 | */ | ||
| 633 | private final int sourceActions; | ||
| 634 | } | ||