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| 1 | /* | ||
| 2 | * Copyright (c) 1998, 2006, 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.event.InputEvent; | ||
| 29 | import java.awt.Component; | ||
| 30 | import java.awt.Point; | ||
| 31 | |||
| 32 | import java.util.TooManyListenersException; | ||
| 33 | import java.util.ArrayList; | ||
| 34 | |||
| 35 | import java.io.IOException; | ||
| 36 | import java.io.ObjectInputStream; | ||
| 37 | import java.io.ObjectOutputStream; | ||
| 38 | import java.io.Serializable; | ||
| 39 | |||
| 40 | /** | ||
| 41 | * The <code>DragGestureRecognizer</code> is an | ||
| 42 | * abstract base class for the specification | ||
| 43 | * of a platform-dependent listener that can be associated with a particular | ||
| 44 | * <code>Component</code> in order to | ||
| 45 | * identify platform-dependent drag initiating gestures. | ||
| 46 | * <p> | ||
| 47 | * The appropriate <code>DragGestureRecognizer</code> | ||
| 48 | * subclass instance is obtained from the | ||
| 49 | * {@link DragSource} asssociated with | ||
| 50 | * a particular <code>Component</code>, or from the <code>Toolkit</code> object via its | ||
| 51 | * {@link java.awt.Toolkit#createDragGestureRecognizer createDragGestureRecognizer()} | ||
| 52 | * method. | ||
| 53 | * <p> | ||
| 54 | * Once the <code>DragGestureRecognizer</code> | ||
| 55 | * is associated with a particular <code>Component</code> | ||
| 56 | * it will register the appropriate listener interfaces on that | ||
| 57 | * <code>Component</code> | ||
| 58 | * in order to track the input events delivered to the <code>Component</code>. | ||
| 59 | * <p> | ||
| 60 | * Once the <code>DragGestureRecognizer</code> identifies a sequence of events | ||
| 61 | * on the <code>Component</code> as a drag initiating gesture, it will notify | ||
| 62 | * its unicast <code>DragGestureListener</code> by | ||
| 63 | * invoking its | ||
| 64 | * {@link java.awt.dnd.DragGestureListener#dragGestureRecognized gestureRecognized()} | ||
| 65 | * method. | ||
| 66 | * <P> | ||
| 67 | * When a concrete <code>DragGestureRecognizer</code> | ||
| 68 | * instance detects a drag initiating | ||
| 69 | * gesture on the <code>Component</code> it is associated with, | ||
| 70 | * it fires a {@link DragGestureEvent} to | ||
| 71 | * the <code>DragGestureListener</code> registered on | ||
| 72 | * its unicast event source for <code>DragGestureListener</code> | ||
| 73 | * events. This <code>DragGestureListener</code> is responsible | ||
| 74 | * for causing the associated | ||
| 75 | * <code>DragSource</code> to start the Drag and Drop operation (if | ||
| 76 | * appropriate). | ||
| 77 | * <P> | ||
| 78 | * @author Laurence P. G. Cable | ||
| 79 | * @see java.awt.dnd.DragGestureListener | ||
| 80 | * @see java.awt.dnd.DragGestureEvent | ||
| 81 | * @see java.awt.dnd.DragSource | ||
| 82 | */ | ||
| 83 | |||
| 84 | public abstract class DragGestureRecognizer implements Serializable { | ||
| 85 | |||
| 86 | private static final long serialVersionUID = 8996673345831063337L; | ||
| 87 | |||
| 88 | /** | ||
| 89 | * Construct a new <code>DragGestureRecognizer</code> | ||
| 90 | * given the <code>DragSource</code> to be used | ||
| 91 | * in this Drag and Drop operation, the <code>Component</code> | ||
| 92 | * this <code>DragGestureRecognizer</code> should "observe" | ||
| 93 | * for drag initiating gestures, the action(s) supported | ||
| 94 | * for this Drag and Drop operation, and the | ||
| 95 | * <code>DragGestureListener</code> to notify | ||
| 96 | * once a drag initiating gesture has been detected. | ||
| 97 | * <P> | ||
| 98 | * @param ds the <code>DragSource</code> this | ||
| 99 | * <code>DragGestureRecognizer</code> | ||
| 100 | * will use to process the Drag and Drop operation | ||
| 101 | * | ||
| 102 | * @param c the <code>Component</code> | ||
| 103 | * this <code>DragGestureRecognizer</code> | ||
| 104 | * should "observe" the event stream to, | ||
| 105 | * in order to detect a drag initiating gesture. | ||
| 106 | * If this value is <code>null</code>, the | ||
| 107 | * <code>DragGestureRecognizer</code> | ||
| 108 | * is not associated with any <code>Component</code>. | ||
| 109 | * | ||
| 110 | * @param sa the set (logical OR) of the | ||
| 111 | * <code>DnDConstants</code> | ||
| 112 | * that this Drag and Drop operation will support | ||
| 113 | * | ||
| 114 | * @param dgl the <code>DragGestureRecognizer</code> | ||
| 115 | * to notify when a drag gesture is detected | ||
| 116 | * <P> | ||
| 117 | * @throws <code>IllegalArgumentException</code> | ||
| 118 | * if ds is <code>null</code>. | ||
| 119 | */ | ||
| 120 | |||
| 121 | protected DragGestureRecognizer(DragSource ds, Component c, int sa, DragGestureListener dgl) { | ||
| 122 | super(); | ||
| 123 | |||
| 124 | if (ds == null) throw new IllegalArgumentException("null DragSource"); | ||
| 125 | |||
| 126 | dragSource = ds; | ||
| 127 | component = c; | ||
| 128 | sourceActions = sa & (DnDConstants.ACTION_COPY_OR_MOVE | DnDConstants.ACTION_LINK); | ||
| 129 | |||
| 130 | try { | ||
| 131 | if (dgl != null) addDragGestureListener(dgl); | ||
| 132 | } catch (TooManyListenersException tmle) { | ||
| 133 | // cant happen ... | ||
| 134 | } | ||
| 135 | } | ||
| 136 | |||
| 137 | /** | ||
| 138 | * Construct a new <code>DragGestureRecognizer</code> | ||
| 139 | * given the <code>DragSource</code> to be used in this | ||
| 140 | * Drag and Drop | ||
| 141 | * operation, the <code>Component</code> this | ||
| 142 | * <code>DragGestureRecognizer</code> should "observe" | ||
| 143 | * for drag initiating gestures, and the action(s) | ||
| 144 | * supported for this Drag and Drop operation. | ||
| 145 | * <P> | ||
| 146 | * @param ds the <code>DragSource</code> this | ||
| 147 | * <code>DragGestureRecognizer</code> will use to | ||
| 148 | * process the Drag and Drop operation | ||
| 149 | * | ||
| 150 | * @param c the <code>Component</code> this | ||
| 151 | * <code>DragGestureRecognizer</code> should "observe" the event | ||
| 152 | * stream to, in order to detect a drag initiating gesture. | ||
| 153 | * If this value is <code>null</code>, the | ||
| 154 | * <code>DragGestureRecognizer</code> | ||
| 155 | * is not associated with any <code>Component</code>. | ||
| 156 | * | ||
| 157 | * @param sa the set (logical OR) of the <code>DnDConstants</code> | ||
| 158 | * that this Drag and Drop operation will support | ||
| 159 | * <P> | ||
| 160 | * @throws <code>IllegalArgumentException</code> | ||
| 161 | * if ds is <code>null</code>. | ||
| 162 | */ | ||
| 163 | |||
| 164 | protected DragGestureRecognizer(DragSource ds, Component c, int sa) { | ||
| 165 | this(ds, c, sa, null); | ||
| 166 | } | ||
| 167 | |||
| 168 | /** | ||
| 169 | * Construct a new <code>DragGestureRecognizer</code> | ||
| 170 | * given the <code>DragSource</code> to be used | ||
| 171 | * in this Drag and Drop operation, and | ||
| 172 | * the <code>Component</code> this | ||
| 173 | * <code>DragGestureRecognizer</code> | ||
| 174 | * should "observe" for drag initiating gestures. | ||
| 175 | * <P> | ||
| 176 | * @param ds the <code>DragSource</code> this | ||
| 177 | * <code>DragGestureRecognizer</code> | ||
| 178 | * will use to process the Drag and Drop operation | ||
| 179 | * | ||
| 180 | * @param c the <code>Component</code> | ||
| 181 | * this <code>DragGestureRecognizer</code> | ||
| 182 | * should "observe" the event stream to, | ||
| 183 | * in order to detect a drag initiating gesture. | ||
| 184 | * If this value is <code>null</code>, | ||
| 185 | * the <code>DragGestureRecognizer</code> | ||
| 186 | * is not associated with any <code>Component</code>. | ||
| 187 | * <P> | ||
| 188 | * @throws <code>IllegalArgumentException</code> | ||
| 189 | * if ds is <code>null</code>. | ||
| 190 | */ | ||
| 191 | |||
| 192 | protected DragGestureRecognizer(DragSource ds, Component c) { | ||
| 193 | this(ds, c, DnDConstants.ACTION_NONE); | ||
| 194 | } | ||
| 195 | |||
| 196 | /** | ||
| 197 | * Construct a new <code>DragGestureRecognizer</code> | ||
| 198 | * given the <code>DragSource</code> to be used in this | ||
| 199 | * Drag and Drop operation. | ||
| 200 | * <P> | ||
| 201 | * @param ds the <code>DragSource</code> this | ||
| 202 | * <code>DragGestureRecognizer</code> will | ||
| 203 | * use to process the Drag and Drop operation | ||
| 204 | * <P> | ||
| 205 | * @throws <code>IllegalArgumentException</code> | ||
| 206 | * if ds is <code>null</code>. | ||
| 207 | */ | ||
| 208 | |||
| 209 | protected DragGestureRecognizer(DragSource ds) { | ||
| 210 | this(ds, null); | ||
| 211 | } | ||
| 212 | |||
| 213 | /** | ||
| 214 | * register this DragGestureRecognizer's Listeners with the Component | ||
| 215 | * | ||
| 216 | * subclasses must override this method | ||
| 217 | */ | ||
| 218 | |||
| 219 | protected abstract void registerListeners(); | ||
| 220 | |||
| 221 | /** | ||
| 222 | * unregister this DragGestureRecognizer's Listeners with the Component | ||
| 223 | * | ||
| 224 | * subclasses must override this method | ||
| 225 | */ | ||
| 226 | |||
| 227 | protected abstract void unregisterListeners(); | ||
| 228 | |||
| 229 | /** | ||
| 230 | * This method returns the <code>DragSource</code> | ||
| 231 | * this <code>DragGestureRecognizer</code> | ||
| 232 | * will use in order to process the Drag and Drop | ||
| 233 | * operation. | ||
| 234 | * <P> | ||
| 235 | * @return the DragSource | ||
| 236 | */ | ||
| 237 | |||
| 238 | public DragSource getDragSource() { return dragSource; } | ||
| 239 | |||
| 240 | /** | ||
| 241 | * This method returns the <code>Component</code> | ||
| 242 | * that is to be "observed" by the | ||
| 243 | * <code>DragGestureRecognizer</code> | ||
| 244 | * for drag initiating gestures. | ||
| 245 | * <P> | ||
| 246 | * @return The Component this DragGestureRecognizer | ||
| 247 | * is associated with | ||
| 248 | */ | ||
| 249 | |||
| 250 | public synchronized Component getComponent() { return component; } | ||
| 251 | |||
| 252 | /** | ||
| 253 | * set the Component that the DragGestureRecognizer is associated with | ||
| 254 | * | ||
| 255 | * registerListeners() and unregisterListeners() are called as a side | ||
| 256 | * effect as appropriate. | ||
| 257 | * <P> | ||
| 258 | * @param c The <code>Component</code> or <code>null</code> | ||
| 259 | */ | ||
| 260 | |||
| 261 | public synchronized void setComponent(Component c) { | ||
| 262 | if (component != null && dragGestureListener != null) | ||
| 263 | unregisterListeners(); | ||
| 264 | |||
| 265 | component = c; | ||
| 266 | |||
| 267 | if (component != null && dragGestureListener != null) | ||
| 268 | registerListeners(); | ||
| 269 | } | ||
| 270 | |||
| 271 | /** | ||
| 272 | * This method returns an int representing the | ||
| 273 | * type of action(s) this Drag and Drop | ||
| 274 | * operation will support. | ||
| 275 | * <P> | ||
| 276 | * @return the currently permitted source action(s) | ||
| 277 | */ | ||
| 278 | |||
| 279 | public synchronized int getSourceActions() { return sourceActions; } | ||
| 280 | |||
| 281 | /** | ||
| 282 | * This method sets the permitted source drag action(s) | ||
| 283 | * for this Drag and Drop operation. | ||
| 284 | * <P> | ||
| 285 | * @param actions the permitted source drag action(s) | ||
| 286 | */ | ||
| 287 | |||
| 288 | public synchronized void setSourceActions(int actions) { | ||
| 289 | sourceActions = actions & (DnDConstants.ACTION_COPY_OR_MOVE | DnDConstants.ACTION_LINK); | ||
| 290 | } | ||
| 291 | |||
| 292 | /** | ||
| 293 | * This method returns the first event in the | ||
| 294 | * series of events that initiated | ||
| 295 | * the Drag and Drop operation. | ||
| 296 | * <P> | ||
| 297 | * @return the initial event that triggered the drag gesture | ||
| 298 | */ | ||
| 299 | |||
| 300 | public InputEvent getTriggerEvent() { return events.isEmpty() ? null : (InputEvent)events.get(0); } | ||
| 301 | |||
| 302 | /** | ||
| 303 | * Reset the Recognizer, if its currently recognizing a gesture, ignore | ||
| 304 | * it. | ||
| 305 | */ | ||
| 306 | |||
| 307 | public void resetRecognizer() { events.clear(); } | ||
| 308 | |||
| 309 | /** | ||
| 310 | * Register a new <code>DragGestureListener</code>. | ||
| 311 | * <P> | ||
| 312 | * @param dgl the <code>DragGestureListener</code> to register | ||
| 313 | * with this <code>DragGestureRecognizer</code>. | ||
| 314 | * <P> | ||
| 315 | * @throws java.util.TooManyListenersException if a | ||
| 316 | * <code>DragGestureListener</code> has already been added. | ||
| 317 | */ | ||
| 318 | |||
| 319 | public synchronized void addDragGestureListener(DragGestureListener dgl) throws TooManyListenersException { | ||
| 320 | if (dragGestureListener != null) | ||
| 321 | throw new TooManyListenersException(); | ||
| 322 | else { | ||
| 323 | dragGestureListener = dgl; | ||
| 324 | |||
| 325 | if (component != null) registerListeners(); | ||
| 326 | } | ||
| 327 | } | ||
| 328 | |||
| 329 | /** | ||
| 330 | * unregister the current DragGestureListener | ||
| 331 | * <P> | ||
| 332 | * @param dgl the <code>DragGestureListener</code> to unregister | ||
| 333 | * from this <code>DragGestureRecognizer</code> | ||
| 334 | * <P> | ||
| 335 | * @throws <code>IllegalArgumentException</code> if | ||
| 336 | * dgl is not (equal to) the currently registered <code>DragGestureListener</code>. | ||
| 337 | */ | ||
| 338 | |||
| 339 | public synchronized void removeDragGestureListener(DragGestureListener dgl) { | ||
| 340 | if (dragGestureListener == null || !dragGestureListener.equals(dgl)) | ||
| 341 | throw new IllegalArgumentException(); | ||
| 342 | else { | ||
| 343 | dragGestureListener = null; | ||
| 344 | |||
| 345 | if (component != null) unregisterListeners(); | ||
| 346 | } | ||
| 347 | } | ||
| 348 | |||
| 349 | /** | ||
| 350 | * Notify the DragGestureListener that a Drag and Drop initiating | ||
| 351 | * gesture has occurred. Then reset the state of the Recognizer. | ||
| 352 | * <P> | ||
| 353 | * @param dragAction The action initially selected by the users gesture | ||
| 354 | * @param p The point (in Component coords) where the gesture originated | ||
| 355 | */ | ||
| 356 | protected synchronized void fireDragGestureRecognized(int dragAction, Point p) { | ||
| 357 | try { | ||
| 358 | if (dragGestureListener != null) { | ||
| 359 | dragGestureListener.dragGestureRecognized(new DragGestureEvent(this, dragAction, p, events)); | ||
| 360 | } | ||
| 361 | } finally { | ||
| 362 | events.clear(); | ||
| 363 | } | ||
| 364 | } | ||
| 365 | |||
| 366 | /** | ||
| 367 | * Listeners registered on the Component by this Recognizer shall record | ||
| 368 | * all Events that are recognized as part of the series of Events that go | ||
| 369 | * to comprise a Drag and Drop initiating gesture via this API. | ||
| 370 | *<P> | ||
| 371 | * This method is used by a <code>DragGestureRecognizer</code> | ||
| 372 | * implementation to add an <code>InputEvent</code> | ||
| 373 | * subclass (that it believes is one in a series | ||
| 374 | * of events that comprise a Drag and Drop operation) | ||
| 375 | * to the array of events that this | ||
| 376 | * <code>DragGestureRecognizer</code> maintains internally. | ||
| 377 | * <P> | ||
| 378 | * @param awtie the <code>InputEvent</code> | ||
| 379 | * to add to this <code>DragGestureRecognizer</code>'s | ||
| 380 | * internal array of events. Note that <code>null</code> | ||
| 381 | * is not a valid value, and will be ignored. | ||
| 382 | */ | ||
| 383 | |||
| 384 | protected synchronized void appendEvent(InputEvent awtie) { | ||
| 385 | events.add(awtie); | ||
| 386 | } | ||
| 387 | |||
| 388 | /** | ||
| 389 | * Serializes this <code>DragGestureRecognizer</code>. This method first | ||
| 390 | * performs default serialization. Then, this object's | ||
| 391 | * <code>DragGestureListener</code> is written out if and only if it can be | ||
| 392 | * serialized. If not, <code>null</code> is written instead. | ||
| 393 | * | ||
| 394 | * @serialData The default serializable fields, in alphabetical order, | ||
| 395 | * followed by either a <code>DragGestureListener</code>, or | ||
| 396 | * <code>null</code>. | ||
| 397 | * @since 1.4 | ||
| 398 | */ | ||
| 399 | private void writeObject(ObjectOutputStream s) throws IOException { | ||
| 400 | s.defaultWriteObject(); | ||
| 401 | |||
| 402 | s.writeObject(SerializationTester.test(dragGestureListener) | ||
| 403 | ? dragGestureListener : null); | ||
| 404 | } | ||
| 405 | |||
| 406 | /** | ||
| 407 | * Deserializes this <code>DragGestureRecognizer</code>. This method first | ||
| 408 | * performs default deserialization for all non-<code>transient</code> | ||
| 409 | * fields. This object's <code>DragGestureListener</code> is then | ||
| 410 | * deserialized as well by using the next object in the stream. | ||
| 411 | * | ||
| 412 | * @since 1.4 | ||
| 413 | */ | ||
| 414 | private void readObject(ObjectInputStream s) | ||
| 415 | throws ClassNotFoundException, IOException | ||
| 416 | { | ||
| 417 | s.defaultReadObject(); | ||
| 418 | |||
| 419 | dragGestureListener = (DragGestureListener)s.readObject(); | ||
| 420 | } | ||
| 421 | |||
| 422 | /* | ||
| 423 | * fields | ||
| 424 | */ | ||
| 425 | |||
| 426 | /** | ||
| 427 | * The <code>DragSource</code> | ||
| 428 | * associated with this | ||
| 429 | * <code>DragGestureRecognizer</code>. | ||
| 430 | * | ||
| 431 | * @serial | ||
| 432 | */ | ||
| 433 | protected DragSource dragSource; | ||
| 434 | |||
| 435 | /** | ||
| 436 | * The <code>Component</code> | ||
| 437 | * associated with this <code>DragGestureRecognizer</code>. | ||
| 438 | * | ||
| 439 | * @serial | ||
| 440 | */ | ||
| 441 | protected Component component; | ||
| 442 | |||
| 443 | /** | ||
| 444 | * The <code>DragGestureListener</code> | ||
| 445 | * associated with this <code>DragGestureRecognizer</code>. | ||
| 446 | */ | ||
| 447 | protected transient DragGestureListener dragGestureListener; | ||
| 448 | |||
| 449 | /** | ||
| 450 | * An <code>int</code> representing | ||
| 451 | * the type(s) of action(s) used | ||
| 452 | * in this Drag and Drop operation. | ||
| 453 | * | ||
| 454 | * @serial | ||
| 455 | */ | ||
| 456 | protected int sourceActions; | ||
| 457 | |||
| 458 | /** | ||
| 459 | * The list of events (in order) that | ||
| 460 | * the <code>DragGestureRecognizer</code> | ||
| 461 | * "recognized" as a "gesture" that triggers a drag. | ||
| 462 | * | ||
| 463 | * @serial | ||
| 464 | */ | ||
| 465 | protected ArrayList<InputEvent> events = new ArrayList<InputEvent>(1); | ||
| 466 | } | ||