J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1995-2006 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | package java.awt; |
| 26 | |
| 27 | import java.util.*; |
| 28 | import java.awt.peer.ChoicePeer; |
| 29 | import java.awt.event.*; |
| 30 | import java.util.EventListener; |
| 31 | import java.io.ObjectOutputStream; |
| 32 | import java.io.ObjectInputStream; |
| 33 | import java.io.IOException; |
| 34 | |
| 35 | import javax.accessibility.*; |
| 36 | |
| 37 | /** |
| 38 | * The <code>Choice</code> class presents a pop-up menu of choices. |
| 39 | * The current choice is displayed as the title of the menu. |
| 40 | * <p> |
| 41 | * The following code example produces a pop-up menu: |
| 42 | * <p> |
| 43 | * <hr><blockquote><pre> |
| 44 | * Choice ColorChooser = new Choice(); |
| 45 | * ColorChooser.add("Green"); |
| 46 | * ColorChooser.add("Red"); |
| 47 | * ColorChooser.add("Blue"); |
| 48 | * </pre></blockquote><hr> |
| 49 | * <p> |
| 50 | * After this choice menu has been added to a panel, |
| 51 | * it appears as follows in its normal state: |
| 52 | * <p> |
| 53 | * <img src="doc-files/Choice-1.gif" alt="The following text describes the graphic" |
| 54 | * ALIGN=center HSPACE=10 VSPACE=7> |
| 55 | * <p> |
| 56 | * In the picture, <code>"Green"</code> is the current choice. |
| 57 | * Pushing the mouse button down on the object causes a menu to |
| 58 | * appear with the current choice highlighted. |
| 59 | * <p> |
| 60 | * Some native platforms do not support arbitrary resizing of |
| 61 | * <code>Choice</code> components and the behavior of |
| 62 | * <code>setSize()/getSize()</code> is bound by |
| 63 | * such limitations. |
| 64 | * Native GUI <code>Choice</code> components' size are often bound by such |
| 65 | * attributes as font size and length of items contained within |
| 66 | * the <code>Choice</code>. |
| 67 | * <p> |
| 68 | * @author Sami Shaio |
| 69 | * @author Arthur van Hoff |
| 70 | * @since JDK1.0 |
| 71 | */ |
| 72 | public class Choice extends Component implements ItemSelectable, Accessible { |
| 73 | /** |
| 74 | * The items for the <code>Choice</code>. |
| 75 | * This can be a <code>null</code> value. |
| 76 | * @serial |
| 77 | * @see #add(String) |
| 78 | * @see #addItem(String) |
| 79 | * @see #getItem(int) |
| 80 | * @see #getItemCount() |
| 81 | * @see #insert(String, int) |
| 82 | * @see #remove(String) |
| 83 | */ |
| 84 | Vector pItems; |
| 85 | |
| 86 | /** |
| 87 | * The index of the current choice for this <code>Choice</code> |
| 88 | * or -1 if nothing is selected. |
| 89 | * @serial |
| 90 | * @see #getSelectedItem() |
| 91 | * @see #select(int) |
| 92 | */ |
| 93 | int selectedIndex = -1; |
| 94 | |
| 95 | transient ItemListener itemListener; |
| 96 | |
| 97 | private static final String base = "choice"; |
| 98 | private static int nameCounter = 0; |
| 99 | |
| 100 | /* |
| 101 | * JDK 1.1 serialVersionUID |
| 102 | */ |
| 103 | private static final long serialVersionUID = -4075310674757313071L; |
| 104 | |
| 105 | /** |
| 106 | * Creates a new choice menu. The menu initially has no items in it. |
| 107 | * <p> |
| 108 | * By default, the first item added to the choice menu becomes the |
| 109 | * selected item, until a different selection is made by the user |
| 110 | * by calling one of the <code>select</code> methods. |
| 111 | * @exception HeadlessException if GraphicsEnvironment.isHeadless() |
| 112 | * returns true |
| 113 | * @see java.awt.GraphicsEnvironment#isHeadless |
| 114 | * @see #select(int) |
| 115 | * @see #select(java.lang.String) |
| 116 | */ |
| 117 | public Choice() throws HeadlessException { |
| 118 | GraphicsEnvironment.checkHeadless(); |
| 119 | pItems = new Vector(); |
| 120 | } |
| 121 | |
| 122 | /** |
| 123 | * Constructs a name for this component. Called by |
| 124 | * <code>getName</code> when the name is <code>null</code>. |
| 125 | */ |
| 126 | String constructComponentName() { |
| 127 | synchronized (Choice.class) { |
| 128 | return base + nameCounter++; |
| 129 | } |
| 130 | } |
| 131 | |
| 132 | /** |
| 133 | * Creates the <code>Choice</code>'s peer. This peer allows us |
| 134 | * to change the look |
| 135 | * of the <code>Choice</code> without changing its functionality. |
| 136 | * @see java.awt.Toolkit#createChoice(java.awt.Choice) |
| 137 | * @see java.awt.Component#getToolkit() |
| 138 | */ |
| 139 | public void addNotify() { |
| 140 | synchronized (getTreeLock()) { |
| 141 | if (peer == null) |
| 142 | peer = getToolkit().createChoice(this); |
| 143 | super.addNotify(); |
| 144 | } |
| 145 | } |
| 146 | |
| 147 | /** |
| 148 | * Returns the number of items in this <code>Choice</code> menu. |
| 149 | * @return the number of items in this <code>Choice</code> menu |
| 150 | * @see #getItem |
| 151 | * @since JDK1.1 |
| 152 | */ |
| 153 | public int getItemCount() { |
| 154 | return countItems(); |
| 155 | } |
| 156 | |
| 157 | /** |
| 158 | * @deprecated As of JDK version 1.1, |
| 159 | * replaced by <code>getItemCount()</code>. |
| 160 | */ |
| 161 | @Deprecated |
| 162 | public int countItems() { |
| 163 | return pItems.size(); |
| 164 | } |
| 165 | |
| 166 | /** |
| 167 | * Gets the string at the specified index in this |
| 168 | * <code>Choice</code> menu. |
| 169 | * @param index the index at which to begin |
| 170 | * @see #getItemCount |
| 171 | */ |
| 172 | public String getItem(int index) { |
| 173 | return getItemImpl(index); |
| 174 | } |
| 175 | |
| 176 | /* |
| 177 | * This is called by the native code, so client code can't |
| 178 | * be called on the toolkit thread. |
| 179 | */ |
| 180 | final String getItemImpl(int index) { |
| 181 | return (String)pItems.elementAt(index); |
| 182 | } |
| 183 | |
| 184 | /** |
| 185 | * Adds an item to this <code>Choice</code> menu. |
| 186 | * @param item the item to be added |
| 187 | * @exception NullPointerException if the item's value is |
| 188 | * <code>null</code> |
| 189 | * @since JDK1.1 |
| 190 | */ |
| 191 | public void add(String item) { |
| 192 | addItem(item); |
| 193 | } |
| 194 | |
| 195 | /** |
| 196 | * Obsolete as of Java 2 platform v1.1. Please use the |
| 197 | * <code>add</code> method instead. |
| 198 | * <p> |
| 199 | * Adds an item to this <code>Choice</code> menu. |
| 200 | * @param item the item to be added |
| 201 | * @exception NullPointerException if the item's value is equal to |
| 202 | * <code>null</code> |
| 203 | */ |
| 204 | public void addItem(String item) { |
| 205 | synchronized (this) { |
| 206 | insertNoInvalidate(item, pItems.size()); |
| 207 | } |
| 208 | |
| 209 | // This could change the preferred size of the Component. |
| 210 | if (valid) { |
| 211 | invalidate(); |
| 212 | } |
| 213 | } |
| 214 | |
| 215 | /** |
| 216 | * Inserts an item to this <code>Choice</code>, |
| 217 | * but does not invalidate the <code>Choice</code>. |
| 218 | * Client methods must provide their own synchronization before |
| 219 | * invoking this method. |
| 220 | * @param item the item to be added |
| 221 | * @param index the new item position |
| 222 | * @exception NullPointerException if the item's value is equal to |
| 223 | * <code>null</code> |
| 224 | */ |
| 225 | private void insertNoInvalidate(String item, int index) { |
| 226 | if (item == null) { |
| 227 | throw new |
| 228 | NullPointerException("cannot add null item to Choice"); |
| 229 | } |
| 230 | pItems.insertElementAt(item, index); |
| 231 | ChoicePeer peer = (ChoicePeer)this.peer; |
| 232 | if (peer != null) { |
| 233 | peer.addItem(item, index); |
| 234 | } |
| 235 | // no selection or selection shifted up |
| 236 | if (selectedIndex < 0 || selectedIndex >= index) { |
| 237 | select(0); |
| 238 | } |
| 239 | } |
| 240 | |
| 241 | |
| 242 | /** |
| 243 | * Inserts the item into this choice at the specified position. |
| 244 | * Existing items at an index greater than or equal to |
| 245 | * <code>index</code> are shifted up by one to accommodate |
| 246 | * the new item. If <code>index</code> is greater than or |
| 247 | * equal to the number of items in this choice, |
| 248 | * <code>item</code> is added to the end of this choice. |
| 249 | * <p> |
| 250 | * If the item is the first one being added to the choice, |
| 251 | * then the item becomes selected. Otherwise, if the |
| 252 | * selected item was one of the items shifted, the first |
| 253 | * item in the choice becomes the selected item. If the |
| 254 | * selected item was no among those shifted, it remains |
| 255 | * the selected item. |
| 256 | * @param item the non-<code>null</code> item to be inserted |
| 257 | * @param index the position at which the item should be inserted |
| 258 | * @exception IllegalArgumentException if index is less than 0 |
| 259 | */ |
| 260 | public void insert(String item, int index) { |
| 261 | synchronized (this) { |
| 262 | if (index < 0) { |
| 263 | throw new IllegalArgumentException("index less than zero."); |
| 264 | } |
| 265 | /* if the index greater than item count, add item to the end */ |
| 266 | index = Math.min(index, pItems.size()); |
| 267 | |
| 268 | insertNoInvalidate(item, index); |
| 269 | } |
| 270 | |
| 271 | // This could change the preferred size of the Component. |
| 272 | if (valid) { |
| 273 | invalidate(); |
| 274 | } |
| 275 | } |
| 276 | |
| 277 | /** |
| 278 | * Removes the first occurrence of <code>item</code> |
| 279 | * from the <code>Choice</code> menu. If the item |
| 280 | * being removed is the currently selected item, |
| 281 | * then the first item in the choice becomes the |
| 282 | * selected item. Otherwise, the currently selected |
| 283 | * item remains selected (and the selected index is |
| 284 | * updated accordingly). |
| 285 | * @param item the item to remove from this <code>Choice</code> menu |
| 286 | * @exception IllegalArgumentException if the item doesn't |
| 287 | * exist in the choice menu |
| 288 | * @since JDK1.1 |
| 289 | */ |
| 290 | public void remove(String item) { |
| 291 | synchronized (this) { |
| 292 | int index = pItems.indexOf(item); |
| 293 | if (index < 0) { |
| 294 | throw new IllegalArgumentException("item " + item + |
| 295 | " not found in choice"); |
| 296 | } else { |
| 297 | removeNoInvalidate(index); |
| 298 | } |
| 299 | } |
| 300 | |
| 301 | // This could change the preferred size of the Component. |
| 302 | if (valid) { |
| 303 | invalidate(); |
| 304 | } |
| 305 | } |
| 306 | |
| 307 | /** |
| 308 | * Removes an item from the choice menu |
| 309 | * at the specified position. If the item |
| 310 | * being removed is the currently selected item, |
| 311 | * then the first item in the choice becomes the |
| 312 | * selected item. Otherwise, the currently selected |
| 313 | * item remains selected (and the selected index is |
| 314 | * updated accordingly). |
| 315 | * @param position the position of the item |
| 316 | * @throws IndexOutOfBoundsException if the specified |
| 317 | * position is out of bounds |
| 318 | * @since JDK1.1 |
| 319 | */ |
| 320 | public void remove(int position) { |
| 321 | synchronized (this) { |
| 322 | removeNoInvalidate(position); |
| 323 | } |
| 324 | |
| 325 | // This could change the preferred size of the Component. |
| 326 | if (valid) { |
| 327 | invalidate(); |
| 328 | } |
| 329 | } |
| 330 | |
| 331 | /** |
| 332 | * Removes an item from the <code>Choice</code> at the |
| 333 | * specified position, but does not invalidate the <code>Choice</code>. |
| 334 | * Client methods must provide their |
| 335 | * own synchronization before invoking this method. |
| 336 | * @param position the position of the item |
| 337 | */ |
| 338 | private void removeNoInvalidate(int position) { |
| 339 | pItems.removeElementAt(position); |
| 340 | ChoicePeer peer = (ChoicePeer)this.peer; |
| 341 | if (peer != null) { |
| 342 | peer.remove(position); |
| 343 | } |
| 344 | /* Adjust selectedIndex if selected item was removed. */ |
| 345 | if (pItems.size() == 0) { |
| 346 | selectedIndex = -1; |
| 347 | } else if (selectedIndex == position) { |
| 348 | select(0); |
| 349 | } else if (selectedIndex > position) { |
| 350 | select(selectedIndex-1); |
| 351 | } |
| 352 | } |
| 353 | |
| 354 | |
| 355 | /** |
| 356 | * Removes all items from the choice menu. |
| 357 | * @see #remove |
| 358 | * @since JDK1.1 |
| 359 | */ |
| 360 | public void removeAll() { |
| 361 | synchronized (this) { |
| 362 | if (peer != null) { |
| 363 | ((ChoicePeer)peer).removeAll(); |
| 364 | } |
| 365 | pItems.removeAllElements(); |
| 366 | selectedIndex = -1; |
| 367 | } |
| 368 | |
| 369 | // This could change the preferred size of the Component. |
| 370 | if (valid) { |
| 371 | invalidate(); |
| 372 | } |
| 373 | } |
| 374 | |
| 375 | /** |
| 376 | * Gets a representation of the current choice as a string. |
| 377 | * @return a string representation of the currently |
| 378 | * selected item in this choice menu |
| 379 | * @see #getSelectedIndex |
| 380 | */ |
| 381 | public synchronized String getSelectedItem() { |
| 382 | return (selectedIndex >= 0) ? getItem(selectedIndex) : null; |
| 383 | } |
| 384 | |
| 385 | /** |
| 386 | * Returns an array (length 1) containing the currently selected |
| 387 | * item. If this choice has no items, returns <code>null</code>. |
| 388 | * @see ItemSelectable |
| 389 | */ |
| 390 | public synchronized Object[] getSelectedObjects() { |
| 391 | if (selectedIndex >= 0) { |
| 392 | Object[] items = new Object[1]; |
| 393 | items[0] = getItem(selectedIndex); |
| 394 | return items; |
| 395 | } |
| 396 | return null; |
| 397 | } |
| 398 | |
| 399 | /** |
| 400 | * Returns the index of the currently selected item. |
| 401 | * If nothing is selected, returns -1. |
| 402 | * |
| 403 | * @return the index of the currently selected item, or -1 if nothing |
| 404 | * is currently selected |
| 405 | * @see #getSelectedItem |
| 406 | */ |
| 407 | public int getSelectedIndex() { |
| 408 | return selectedIndex; |
| 409 | } |
| 410 | |
| 411 | /** |
| 412 | * Sets the selected item in this <code>Choice</code> menu to be the |
| 413 | * item at the specified position. |
| 414 | * |
| 415 | * <p>Note that this method should be primarily used to |
| 416 | * initially select an item in this component. |
| 417 | * Programmatically calling this method will <i>not</i> trigger |
| 418 | * an <code>ItemEvent</code>. The only way to trigger an |
| 419 | * <code>ItemEvent</code> is by user interaction. |
| 420 | * |
| 421 | * @param pos the positon of the selected item |
| 422 | * @exception IllegalArgumentException if the specified |
| 423 | * position is greater than the |
| 424 | * number of items or less than zero |
| 425 | * @see #getSelectedItem |
| 426 | * @see #getSelectedIndex |
| 427 | */ |
| 428 | public synchronized void select(int pos) { |
| 429 | if ((pos >= pItems.size()) || (pos < 0)) { |
| 430 | throw new IllegalArgumentException("illegal Choice item position: " + pos); |
| 431 | } |
| 432 | if (pItems.size() > 0) { |
| 433 | selectedIndex = pos; |
| 434 | ChoicePeer peer = (ChoicePeer)this.peer; |
| 435 | if (peer != null) { |
| 436 | peer.select(pos); |
| 437 | } |
| 438 | } |
| 439 | } |
| 440 | |
| 441 | /** |
| 442 | * Sets the selected item in this <code>Choice</code> menu |
| 443 | * to be the item whose name is equal to the specified string. |
| 444 | * If more than one item matches (is equal to) the specified string, |
| 445 | * the one with the smallest index is selected. |
| 446 | * |
| 447 | * <p>Note that this method should be primarily used to |
| 448 | * initially select an item in this component. |
| 449 | * Programmatically calling this method will <i>not</i> trigger |
| 450 | * an <code>ItemEvent</code>. The only way to trigger an |
| 451 | * <code>ItemEvent</code> is by user interaction. |
| 452 | * |
| 453 | * @param str the specified string |
| 454 | * @see #getSelectedItem |
| 455 | * @see #getSelectedIndex |
| 456 | */ |
| 457 | public synchronized void select(String str) { |
| 458 | int index = pItems.indexOf(str); |
| 459 | if (index >= 0) { |
| 460 | select(index); |
| 461 | } |
| 462 | } |
| 463 | |
| 464 | /** |
| 465 | * Adds the specified item listener to receive item events from |
| 466 | * this <code>Choice</code> menu. Item events are sent in response |
| 467 | * to user input, but not in response to calls to <code>select</code>. |
| 468 | * If l is <code>null</code>, no exception is thrown and no action |
| 469 | * is performed. |
| 470 | * <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads" |
| 471 | * >AWT Threading Issues</a> for details on AWT's threading model. |
| 472 | * @param l the item listener |
| 473 | * @see #removeItemListener |
| 474 | * @see #getItemListeners |
| 475 | * @see #select |
| 476 | * @see java.awt.event.ItemEvent |
| 477 | * @see java.awt.event.ItemListener |
| 478 | * @since JDK1.1 |
| 479 | */ |
| 480 | public synchronized void addItemListener(ItemListener l) { |
| 481 | if (l == null) { |
| 482 | return; |
| 483 | } |
| 484 | itemListener = AWTEventMulticaster.add(itemListener, l); |
| 485 | newEventsOnly = true; |
| 486 | } |
| 487 | |
| 488 | /** |
| 489 | * Removes the specified item listener so that it no longer receives |
| 490 | * item events from this <code>Choice</code> menu. |
| 491 | * If l is <code>null</code>, no exception is thrown and no |
| 492 | * action is performed. |
| 493 | * <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads" |
| 494 | * >AWT Threading Issues</a> for details on AWT's threading model. |
| 495 | * @param l the item listener |
| 496 | * @see #addItemListener |
| 497 | * @see #getItemListeners |
| 498 | * @see java.awt.event.ItemEvent |
| 499 | * @see java.awt.event.ItemListener |
| 500 | * @since JDK1.1 |
| 501 | */ |
| 502 | public synchronized void removeItemListener(ItemListener l) { |
| 503 | if (l == null) { |
| 504 | return; |
| 505 | } |
| 506 | itemListener = AWTEventMulticaster.remove(itemListener, l); |
| 507 | } |
| 508 | |
| 509 | /** |
| 510 | * Returns an array of all the item listeners |
| 511 | * registered on this choice. |
| 512 | * |
| 513 | * @return all of this choice's <code>ItemListener</code>s |
| 514 | * or an empty array if no item |
| 515 | * listeners are currently registered |
| 516 | * |
| 517 | * @see #addItemListener |
| 518 | * @see #removeItemListener |
| 519 | * @see java.awt.event.ItemEvent |
| 520 | * @see java.awt.event.ItemListener |
| 521 | * @since 1.4 |
| 522 | */ |
| 523 | public synchronized ItemListener[] getItemListeners() { |
| 524 | return (ItemListener[])(getListeners(ItemListener.class)); |
| 525 | } |
| 526 | |
| 527 | /** |
| 528 | * Returns an array of all the objects currently registered |
| 529 | * as <code><em>Foo</em>Listener</code>s |
| 530 | * upon this <code>Choice</code>. |
| 531 | * <code><em>Foo</em>Listener</code>s are registered using the |
| 532 | * <code>add<em>Foo</em>Listener</code> method. |
| 533 | * |
| 534 | * <p> |
| 535 | * You can specify the <code>listenerType</code> argument |
| 536 | * with a class literal, such as |
| 537 | * <code><em>Foo</em>Listener.class</code>. |
| 538 | * For example, you can query a |
| 539 | * <code>Choice</code> <code>c</code> |
| 540 | * for its item listeners with the following code: |
| 541 | * |
| 542 | * <pre>ItemListener[] ils = (ItemListener[])(c.getListeners(ItemListener.class));</pre> |
| 543 | * |
| 544 | * If no such listeners exist, this method returns an empty array. |
| 545 | * |
| 546 | * @param listenerType the type of listeners requested; this parameter |
| 547 | * should specify an interface that descends from |
| 548 | * <code>java.util.EventListener</code> |
| 549 | * @return an array of all objects registered as |
| 550 | * <code><em>Foo</em>Listener</code>s on this choice, |
| 551 | * or an empty array if no such |
| 552 | * listeners have been added |
| 553 | * @exception ClassCastException if <code>listenerType</code> |
| 554 | * doesn't specify a class or interface that implements |
| 555 | * <code>java.util.EventListener</code> |
| 556 | * |
| 557 | * @see #getItemListeners |
| 558 | * @since 1.3 |
| 559 | */ |
| 560 | public <T extends EventListener> T[] getListeners(Class<T> listenerType) { |
| 561 | EventListener l = null; |
| 562 | if (listenerType == ItemListener.class) { |
| 563 | l = itemListener; |
| 564 | } else { |
| 565 | return super.getListeners(listenerType); |
| 566 | } |
| 567 | return AWTEventMulticaster.getListeners(l, listenerType); |
| 568 | } |
| 569 | |
| 570 | // REMIND: remove when filtering is done at lower level |
| 571 | boolean eventEnabled(AWTEvent e) { |
| 572 | if (e.id == ItemEvent.ITEM_STATE_CHANGED) { |
| 573 | if ((eventMask & AWTEvent.ITEM_EVENT_MASK) != 0 || |
| 574 | itemListener != null) { |
| 575 | return true; |
| 576 | } |
| 577 | return false; |
| 578 | } |
| 579 | return super.eventEnabled(e); |
| 580 | } |
| 581 | |
| 582 | /** |
| 583 | * Processes events on this choice. If the event is an |
| 584 | * instance of <code>ItemEvent</code>, it invokes the |
| 585 | * <code>processItemEvent</code> method. Otherwise, it calls its |
| 586 | * superclass's <code>processEvent</code> method. |
| 587 | * <p>Note that if the event parameter is <code>null</code> |
| 588 | * the behavior is unspecified and may result in an |
| 589 | * exception. |
| 590 | * |
| 591 | * @param e the event |
| 592 | * @see java.awt.event.ItemEvent |
| 593 | * @see #processItemEvent |
| 594 | * @since JDK1.1 |
| 595 | */ |
| 596 | protected void processEvent(AWTEvent e) { |
| 597 | if (e instanceof ItemEvent) { |
| 598 | processItemEvent((ItemEvent)e); |
| 599 | return; |
| 600 | } |
| 601 | super.processEvent(e); |
| 602 | } |
| 603 | |
| 604 | /** |
| 605 | * Processes item events occurring on this <code>Choice</code> |
| 606 | * menu by dispatching them to any registered |
| 607 | * <code>ItemListener</code> objects. |
| 608 | * <p> |
| 609 | * This method is not called unless item events are |
| 610 | * enabled for this component. Item events are enabled |
| 611 | * when one of the following occurs: |
| 612 | * <p><ul> |
| 613 | * <li>An <code>ItemListener</code> object is registered |
| 614 | * via <code>addItemListener</code>. |
| 615 | * <li>Item events are enabled via <code>enableEvents</code>. |
| 616 | * </ul> |
| 617 | * <p>Note that if the event parameter is <code>null</code> |
| 618 | * the behavior is unspecified and may result in an |
| 619 | * exception. |
| 620 | * |
| 621 | * @param e the item event |
| 622 | * @see java.awt.event.ItemEvent |
| 623 | * @see java.awt.event.ItemListener |
| 624 | * @see #addItemListener(ItemListener) |
| 625 | * @see java.awt.Component#enableEvents |
| 626 | * @since JDK1.1 |
| 627 | */ |
| 628 | protected void processItemEvent(ItemEvent e) { |
| 629 | ItemListener listener = itemListener; |
| 630 | if (listener != null) { |
| 631 | listener.itemStateChanged(e); |
| 632 | } |
| 633 | } |
| 634 | |
| 635 | /** |
| 636 | * Returns a string representing the state of this <code>Choice</code> |
| 637 | * menu. This method is intended to be used only for debugging purposes, |
| 638 | * and the content and format of the returned string may vary between |
| 639 | * implementations. The returned string may be empty but may not be |
| 640 | * <code>null</code>. |
| 641 | * |
| 642 | * @return the parameter string of this <code>Choice</code> menu |
| 643 | */ |
| 644 | protected String paramString() { |
| 645 | return super.paramString() + ",current=" + getSelectedItem(); |
| 646 | } |
| 647 | |
| 648 | |
| 649 | /* Serialization support. |
| 650 | */ |
| 651 | |
| 652 | /* |
| 653 | * Choice Serial Data Version. |
| 654 | * @serial |
| 655 | */ |
| 656 | private int choiceSerializedDataVersion = 1; |
| 657 | |
| 658 | /** |
| 659 | * Writes default serializable fields to stream. Writes |
| 660 | * a list of serializable <code>ItemListeners</code> |
| 661 | * as optional data. The non-serializable |
| 662 | * <code>ItemListeners</code> are detected and |
| 663 | * no attempt is made to serialize them. |
| 664 | * |
| 665 | * @param s the <code>ObjectOutputStream</code> to write |
| 666 | * @serialData <code>null</code> terminated sequence of 0 |
| 667 | * or more pairs; the pair consists of a <code>String</code> |
| 668 | * and an <code>Object</code>; the <code>String</code> indicates |
| 669 | * the type of object and is one of the following: |
| 670 | * <code>itemListenerK</code> indicating an |
| 671 | * <code>ItemListener</code> object |
| 672 | * |
| 673 | * @see AWTEventMulticaster#save(ObjectOutputStream, String, EventListener) |
| 674 | * @see java.awt.Component#itemListenerK |
| 675 | * @see #readObject(ObjectInputStream) |
| 676 | */ |
| 677 | private void writeObject(ObjectOutputStream s) |
| 678 | throws java.io.IOException |
| 679 | { |
| 680 | s.defaultWriteObject(); |
| 681 | |
| 682 | AWTEventMulticaster.save(s, itemListenerK, itemListener); |
| 683 | s.writeObject(null); |
| 684 | } |
| 685 | |
| 686 | /** |
| 687 | * Reads the <code>ObjectInputStream</code> and if it |
| 688 | * isn't <code>null</code> adds a listener to receive |
| 689 | * item events fired by the <code>Choice</code> item. |
| 690 | * Unrecognized keys or values will be ignored. |
| 691 | * |
| 692 | * @param s the <code>ObjectInputStream</code> to read |
| 693 | * @exception HeadlessException if |
| 694 | * <code>GraphicsEnvironment.isHeadless</code> returns |
| 695 | * <code>true</code> |
| 696 | * @serial |
| 697 | * @see #removeItemListener(ItemListener) |
| 698 | * @see #addItemListener(ItemListener) |
| 699 | * @see java.awt.GraphicsEnvironment#isHeadless |
| 700 | * @see #writeObject(ObjectOutputStream) |
| 701 | */ |
| 702 | private void readObject(ObjectInputStream s) |
| 703 | throws ClassNotFoundException, IOException, HeadlessException |
| 704 | { |
| 705 | GraphicsEnvironment.checkHeadless(); |
| 706 | s.defaultReadObject(); |
| 707 | |
| 708 | Object keyOrNull; |
| 709 | while(null != (keyOrNull = s.readObject())) { |
| 710 | String key = ((String)keyOrNull).intern(); |
| 711 | |
| 712 | if (itemListenerK == key) |
| 713 | addItemListener((ItemListener)(s.readObject())); |
| 714 | |
| 715 | else // skip value for unrecognized key |
| 716 | s.readObject(); |
| 717 | } |
| 718 | } |
| 719 | |
| 720 | |
| 721 | ///////////////// |
| 722 | // Accessibility support |
| 723 | //////////////// |
| 724 | |
| 725 | |
| 726 | /** |
| 727 | * Gets the <code>AccessibleContext</code> associated with this |
| 728 | * <code>Choice</code>. For <code>Choice</code> components, |
| 729 | * the <code>AccessibleContext</code> takes the form of an |
| 730 | * <code>AccessibleAWTChoice</code>. A new <code>AccessibleAWTChoice</code> |
| 731 | * instance is created if necessary. |
| 732 | * |
| 733 | * @return an <code>AccessibleAWTChoice</code> that serves as the |
| 734 | * <code>AccessibleContext</code> of this <code>Choice</code> |
| 735 | * @since 1.3 |
| 736 | */ |
| 737 | public AccessibleContext getAccessibleContext() { |
| 738 | if (accessibleContext == null) { |
| 739 | accessibleContext = new AccessibleAWTChoice(); |
| 740 | } |
| 741 | return accessibleContext; |
| 742 | } |
| 743 | |
| 744 | /** |
| 745 | * This class implements accessibility support for the |
| 746 | * <code>Choice</code> class. It provides an implementation of the |
| 747 | * Java Accessibility API appropriate to choice user-interface elements. |
| 748 | * @since 1.3 |
| 749 | */ |
| 750 | protected class AccessibleAWTChoice extends AccessibleAWTComponent |
| 751 | implements AccessibleAction |
| 752 | { |
| 753 | /* |
| 754 | * JDK 1.3 serialVersionUID |
| 755 | */ |
| 756 | private static final long serialVersionUID = 7175603582428509322L; |
| 757 | |
| 758 | public AccessibleAWTChoice() { |
| 759 | super(); |
| 760 | } |
| 761 | |
| 762 | /** |
| 763 | * Get the AccessibleAction associated with this object. In the |
| 764 | * implementation of the Java Accessibility API for this class, |
| 765 | * return this object, which is responsible for implementing the |
| 766 | * AccessibleAction interface on behalf of itself. |
| 767 | * |
| 768 | * @return this object |
| 769 | * @see AccessibleAction |
| 770 | */ |
| 771 | public AccessibleAction getAccessibleAction() { |
| 772 | return this; |
| 773 | } |
| 774 | |
| 775 | /** |
| 776 | * Get the role of this object. |
| 777 | * |
| 778 | * @return an instance of AccessibleRole describing the role of the |
| 779 | * object |
| 780 | * @see AccessibleRole |
| 781 | */ |
| 782 | public AccessibleRole getAccessibleRole() { |
| 783 | return AccessibleRole.COMBO_BOX; |
| 784 | } |
| 785 | |
| 786 | /** |
| 787 | * Returns the number of accessible actions available in this object |
| 788 | * If there are more than one, the first one is considered the "default" |
| 789 | * action of the object. |
| 790 | * |
| 791 | * @return the zero-based number of Actions in this object |
| 792 | */ |
| 793 | public int getAccessibleActionCount() { |
| 794 | return 0; // To be fully implemented in a future release |
| 795 | } |
| 796 | |
| 797 | /** |
| 798 | * Returns a description of the specified action of the object. |
| 799 | * |
| 800 | * @param i zero-based index of the actions |
| 801 | * @return a String description of the action |
| 802 | * @see #getAccessibleActionCount |
| 803 | */ |
| 804 | public String getAccessibleActionDescription(int i) { |
| 805 | return null; // To be fully implemented in a future release |
| 806 | } |
| 807 | |
| 808 | /** |
| 809 | * Perform the specified Action on the object |
| 810 | * |
| 811 | * @param i zero-based index of actions |
| 812 | * @return true if the action was performed; otherwise false. |
| 813 | * @see #getAccessibleActionCount |
| 814 | */ |
| 815 | public boolean doAccessibleAction(int i) { |
| 816 | return false; // To be fully implemented in a future release |
| 817 | } |
| 818 | |
| 819 | } // inner class AccessibleAWTChoice |
| 820 | |
| 821 | } |