1 /* 2 * Copyright (c) 1995, 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 package java.awt; 26 27 import java.awt.peer.TextComponentPeer; 28 import java.awt.event.*; 29 import java.util.EventListener; 30 import java.io.ObjectOutputStream; 31 import java.io.ObjectInputStream; 32 import java.io.IOException; 33 import sun.awt.InputMethodSupport; 34 import java.text.BreakIterator; 35 import javax.swing.text.AttributeSet; 36 import javax.accessibility.*; 37 import java.awt.im.InputMethodRequests; 38 import javax.tools.annotation.GenerateNativeHeader; 39 40 /** 41 * The <code>TextComponent</code> class is the superclass of 42 * any component that allows the editing of some text. 43 * <p> 44 * A text component embodies a string of text. The 45 * <code>TextComponent</code> class defines a set of methods 46 * that determine whether or not this text is editable. If the 47 * component is editable, it defines another set of methods 48 * that supports a text insertion caret. 49 * <p> 50 * In addition, the class defines methods that are used 51 * to maintain a current <em>selection</em> from the text. 52 * The text selection, a substring of the component's text, 53 * is the target of editing operations. It is also referred 54 * to as the <em>selected text</em>. 55 * 56 * @author Sami Shaio 57 * @author Arthur van Hoff 58 * @since JDK1.0 59 */ 60 /* No native methods here, but the constants are needed in the supporting JNI code */ 61 @GenerateNativeHeader 62 public class TextComponent extends Component implements Accessible { 63 64 /** 65 * The value of the text. 66 * A <code>null</code> value is the same as "". 67 * 68 * @serial 69 * @see #setText(String) 70 * @see #getText() 71 */ 72 String text; 73 74 /** 75 * A boolean indicating whether or not this 76 * <code>TextComponent</code> is editable. 77 * It will be <code>true</code> if the text component 78 * is editable and <code>false</code> if not. 79 * 80 * @serial 81 * @see #isEditable() 82 */ 83 boolean editable = true; 84 85 /** 86 * The selection refers to the selected text, and the 87 * <code>selectionStart</code> is the start position 88 * of the selected text. 89 * 90 * @serial 91 * @see #getSelectionStart() 92 * @see #setSelectionStart(int) 93 */ 94 int selectionStart; 95 96 /** 97 * The selection refers to the selected text, and the 98 * <code>selectionEnd</code> 99 * is the end position of the selected text. 100 * 101 * @serial 102 * @see #getSelectionEnd() 103 * @see #setSelectionEnd(int) 104 */ 105 int selectionEnd; 106 107 // A flag used to tell whether the background has been set by 108 // developer code (as opposed to AWT code). Used to determine 109 // the background color of non-editable TextComponents. 110 boolean backgroundSetByClientCode = false; 111 112 /** 113 * True if this <code>TextComponent</code> has access 114 * to the System clipboard. 115 */ 116 transient private boolean canAccessClipboard; 117 118 transient protected TextListener textListener; 119 120 /* 121 * JDK 1.1 serialVersionUID 122 */ 123 private static final long serialVersionUID = -2214773872412987419L; 124 125 /** 126 * Constructs a new text component initialized with the 127 * specified text. Sets the value of the cursor to 128 * <code>Cursor.TEXT_CURSOR</code>. 129 * @param text the text to be displayed; if 130 * <code>text</code> is <code>null</code>, the empty 131 * string <code>""</code> will be displayed 132 * @exception HeadlessException if 133 * <code>GraphicsEnvironment.isHeadless</code> 134 * returns true 135 * @see java.awt.GraphicsEnvironment#isHeadless 136 * @see java.awt.Cursor 137 */ 138 TextComponent(String text) throws HeadlessException { 139 GraphicsEnvironment.checkHeadless(); 140 this.text = (text != null) ? text : ""; 141 setCursor(Cursor.getPredefinedCursor(Cursor.TEXT_CURSOR)); 142 checkSystemClipboardAccess(); 143 } 144 145 private void enableInputMethodsIfNecessary() { 146 if (checkForEnableIM) { 147 checkForEnableIM = false; 148 try { 149 Toolkit toolkit = Toolkit.getDefaultToolkit(); 150 boolean shouldEnable = false; 151 if (toolkit instanceof InputMethodSupport) { 152 shouldEnable = ((InputMethodSupport)toolkit) 153 .enableInputMethodsForTextComponent(); 154 } 155 enableInputMethods(shouldEnable); 156 } catch (Exception e) { 157 // if something bad happens, just don't enable input methods 158 } 159 } 160 } 161 162 /** 163 * Enables or disables input method support for this text component. If input 164 * method support is enabled and the text component also processes key events, 165 * incoming events are offered to the current input method and will only be 166 * processed by the component or dispatched to its listeners if the input method 167 * does not consume them. Whether and how input method support for this text 168 * component is enabled or disabled by default is implementation dependent. 169 * 170 * @param enable true to enable, false to disable 171 * @see #processKeyEvent 172 * @since 1.2 173 */ 174 public void enableInputMethods(boolean enable) { 175 checkForEnableIM = false; 176 super.enableInputMethods(enable); 177 } 178 179 boolean areInputMethodsEnabled() { 180 // moved from the constructor above to here and addNotify below, 181 // this call will initialize the toolkit if not already initialized. 182 if (checkForEnableIM) { 183 enableInputMethodsIfNecessary(); 184 } 185 186 // TextComponent handles key events without touching the eventMask or 187 // having a key listener, so just check whether the flag is set 188 return (eventMask & AWTEvent.INPUT_METHODS_ENABLED_MASK) != 0; 189 } 190 191 public InputMethodRequests getInputMethodRequests() { 192 TextComponentPeer peer = (TextComponentPeer)this.peer; 193 if (peer != null) return peer.getInputMethodRequests(); 194 else return null; 195 } 196 197 198 199 /** 200 * Makes this Component displayable by connecting it to a 201 * native screen resource. 202 * This method is called internally by the toolkit and should 203 * not be called directly by programs. 204 * @see java.awt.TextComponent#removeNotify 205 */ 206 public void addNotify() { 207 super.addNotify(); 208 enableInputMethodsIfNecessary(); 209 } 210 211 /** 212 * Removes the <code>TextComponent</code>'s peer. 213 * The peer allows us to modify the appearance of the 214 * <code>TextComponent</code> without changing its 215 * functionality. 216 */ 217 public void removeNotify() { 218 synchronized (getTreeLock()) { 219 TextComponentPeer peer = (TextComponentPeer)this.peer; 220 if (peer != null) { 221 text = peer.getText(); 222 selectionStart = peer.getSelectionStart(); 223 selectionEnd = peer.getSelectionEnd(); 224 } 225 super.removeNotify(); 226 } 227 } 228 229 /** 230 * Sets the text that is presented by this 231 * text component to be the specified text. 232 * @param t the new text; 233 * if this parameter is <code>null</code> then 234 * the text is set to the empty string "" 235 * @see java.awt.TextComponent#getText 236 */ 237 public synchronized void setText(String t) { 238 boolean skipTextEvent = (text == null || text.isEmpty()) 239 && (t == null || t.isEmpty()); 240 text = (t != null) ? t : ""; 241 TextComponentPeer peer = (TextComponentPeer)this.peer; 242 // Please note that we do not want to post an event 243 // if TextArea.setText() or TextField.setText() replaces an empty text 244 // by an empty text, that is, if component's text remains unchanged. 245 if (peer != null && !skipTextEvent) { 246 peer.setText(text); 247 } 248 } 249 250 /** 251 * Returns the text that is presented by this text component. 252 * By default, this is an empty string. 253 * 254 * @return the value of this <code>TextComponent</code> 255 * @see java.awt.TextComponent#setText 256 */ 257 public synchronized String getText() { 258 TextComponentPeer peer = (TextComponentPeer)this.peer; 259 if (peer != null) { 260 text = peer.getText(); 261 } 262 return text; 263 } 264 265 /** 266 * Returns the selected text from the text that is 267 * presented by this text component. 268 * @return the selected text of this text component 269 * @see java.awt.TextComponent#select 270 */ 271 public synchronized String getSelectedText() { 272 return getText().substring(getSelectionStart(), getSelectionEnd()); 273 } 274 275 /** 276 * Indicates whether or not this text component is editable. 277 * @return <code>true</code> if this text component is 278 * editable; <code>false</code> otherwise. 279 * @see java.awt.TextComponent#setEditable 280 * @since JDK1.0 281 */ 282 public boolean isEditable() { 283 return editable; 284 } 285 286 /** 287 * Sets the flag that determines whether or not this 288 * text component is editable. 289 * <p> 290 * If the flag is set to <code>true</code>, this text component 291 * becomes user editable. If the flag is set to <code>false</code>, 292 * the user cannot change the text of this text component. 293 * By default, non-editable text components have a background color 294 * of SystemColor.control. This default can be overridden by 295 * calling setBackground. 296 * 297 * @param b a flag indicating whether this text component 298 * is user editable. 299 * @see java.awt.TextComponent#isEditable 300 * @since JDK1.0 301 */ 302 public synchronized void setEditable(boolean b) { 303 if (editable == b) { 304 return; 305 } 306 307 editable = b; 308 TextComponentPeer peer = (TextComponentPeer)this.peer; 309 if (peer != null) { 310 peer.setEditable(b); 311 } 312 } 313 314 /** 315 * Gets the background color of this text component. 316 * 317 * By default, non-editable text components have a background color 318 * of SystemColor.control. This default can be overridden by 319 * calling setBackground. 320 * 321 * @return This text component's background color. 322 * If this text component does not have a background color, 323 * the background color of its parent is returned. 324 * @see #setBackground(Color) 325 * @since JDK1.0 326 */ 327 public Color getBackground() { 328 if (!editable && !backgroundSetByClientCode) { 329 return SystemColor.control; 330 } 331 332 return super.getBackground(); 333 } 334 335 /** 336 * Sets the background color of this text component. 337 * 338 * @param c The color to become this text component's color. 339 * If this parameter is null then this text component 340 * will inherit the background color of its parent. 341 * @see #getBackground() 342 * @since JDK1.0 343 */ 344 public void setBackground(Color c) { 345 backgroundSetByClientCode = true; 346 super.setBackground(c); 347 } 348 349 /** 350 * Gets the start position of the selected text in 351 * this text component. 352 * @return the start position of the selected text 353 * @see java.awt.TextComponent#setSelectionStart 354 * @see java.awt.TextComponent#getSelectionEnd 355 */ 356 public synchronized int getSelectionStart() { 357 TextComponentPeer peer = (TextComponentPeer)this.peer; 358 if (peer != null) { 359 selectionStart = peer.getSelectionStart(); 360 } 361 return selectionStart; 362 } 363 364 /** 365 * Sets the selection start for this text component to 366 * the specified position. The new start point is constrained 367 * to be at or before the current selection end. It also 368 * cannot be set to less than zero, the beginning of the 369 * component's text. 370 * If the caller supplies a value for <code>selectionStart</code> 371 * that is out of bounds, the method enforces these constraints 372 * silently, and without failure. 373 * @param selectionStart the start position of the 374 * selected text 375 * @see java.awt.TextComponent#getSelectionStart 376 * @see java.awt.TextComponent#setSelectionEnd 377 * @since JDK1.1 378 */ 379 public synchronized void setSelectionStart(int selectionStart) { 380 /* Route through select method to enforce consistent policy 381 * between selectionStart and selectionEnd. 382 */ 383 select(selectionStart, getSelectionEnd()); 384 } 385 386 /** 387 * Gets the end position of the selected text in 388 * this text component. 389 * @return the end position of the selected text 390 * @see java.awt.TextComponent#setSelectionEnd 391 * @see java.awt.TextComponent#getSelectionStart 392 */ 393 public synchronized int getSelectionEnd() { 394 TextComponentPeer peer = (TextComponentPeer)this.peer; 395 if (peer != null) { 396 selectionEnd = peer.getSelectionEnd(); 397 } 398 return selectionEnd; 399 } 400 401 /** 402 * Sets the selection end for this text component to 403 * the specified position. The new end point is constrained 404 * to be at or after the current selection start. It also 405 * cannot be set beyond the end of the component's text. 406 * If the caller supplies a value for <code>selectionEnd</code> 407 * that is out of bounds, the method enforces these constraints 408 * silently, and without failure. 409 * @param selectionEnd the end position of the 410 * selected text 411 * @see java.awt.TextComponent#getSelectionEnd 412 * @see java.awt.TextComponent#setSelectionStart 413 * @since JDK1.1 414 */ 415 public synchronized void setSelectionEnd(int selectionEnd) { 416 /* Route through select method to enforce consistent policy 417 * between selectionStart and selectionEnd. 418 */ 419 select(getSelectionStart(), selectionEnd); 420 } 421 422 /** 423 * Selects the text between the specified start and end positions. 424 * <p> 425 * This method sets the start and end positions of the 426 * selected text, enforcing the restriction that the start position 427 * must be greater than or equal to zero. The end position must be 428 * greater than or equal to the start position, and less than or 429 * equal to the length of the text component's text. The 430 * character positions are indexed starting with zero. 431 * The length of the selection is 432 * <code>endPosition</code> - <code>startPosition</code>, so the 433 * character at <code>endPosition</code> is not selected. 434 * If the start and end positions of the selected text are equal, 435 * all text is deselected. 436 * <p> 437 * If the caller supplies values that are inconsistent or out of 438 * bounds, the method enforces these constraints silently, and 439 * without failure. Specifically, if the start position or end 440 * position is greater than the length of the text, it is reset to 441 * equal the text length. If the start position is less than zero, 442 * it is reset to zero, and if the end position is less than the 443 * start position, it is reset to the start position. 444 * 445 * @param selectionStart the zero-based index of the first 446 character (<code>char</code> value) to be selected 447 * @param selectionEnd the zero-based end position of the 448 text to be selected; the character (<code>char</code> value) at 449 <code>selectionEnd</code> is not selected 450 * @see java.awt.TextComponent#setSelectionStart 451 * @see java.awt.TextComponent#setSelectionEnd 452 * @see java.awt.TextComponent#selectAll 453 */ 454 public synchronized void select(int selectionStart, int selectionEnd) { 455 String text = getText(); 456 if (selectionStart < 0) { 457 selectionStart = 0; 458 } 459 if (selectionStart > text.length()) { 460 selectionStart = text.length(); 461 } 462 if (selectionEnd > text.length()) { 463 selectionEnd = text.length(); 464 } 465 if (selectionEnd < selectionStart) { 466 selectionEnd = selectionStart; 467 } 468 469 this.selectionStart = selectionStart; 470 this.selectionEnd = selectionEnd; 471 472 TextComponentPeer peer = (TextComponentPeer)this.peer; 473 if (peer != null) { 474 peer.select(selectionStart, selectionEnd); 475 } 476 } 477 478 /** 479 * Selects all the text in this text component. 480 * @see java.awt.TextComponent#select 481 */ 482 public synchronized void selectAll() { 483 this.selectionStart = 0; 484 this.selectionEnd = getText().length(); 485 486 TextComponentPeer peer = (TextComponentPeer)this.peer; 487 if (peer != null) { 488 peer.select(selectionStart, selectionEnd); 489 } 490 } 491 492 /** 493 * Sets the position of the text insertion caret. 494 * The caret position is constrained to be between 0 495 * and the last character of the text, inclusive. 496 * If the passed-in value is greater than this range, 497 * the value is set to the last character (or 0 if 498 * the <code>TextComponent</code> contains no text) 499 * and no error is returned. If the passed-in value is 500 * less than 0, an <code>IllegalArgumentException</code> 501 * is thrown. 502 * 503 * @param position the position of the text insertion caret 504 * @exception IllegalArgumentException if <code>position</code> 505 * is less than zero 506 * @since JDK1.1 507 */ 508 public synchronized void setCaretPosition(int position) { 509 if (position < 0) { 510 throw new IllegalArgumentException("position less than zero."); 511 } 512 513 int maxposition = getText().length(); 514 if (position > maxposition) { 515 position = maxposition; 516 } 517 518 TextComponentPeer peer = (TextComponentPeer)this.peer; 519 if (peer != null) { 520 peer.setCaretPosition(position); 521 } else { 522 select(position, position); 523 } 524 } 525 526 /** 527 * Returns the position of the text insertion caret. 528 * The caret position is constrained to be between 0 529 * and the last character of the text, inclusive. 530 * If the text or caret have not been set, the default 531 * caret position is 0. 532 * 533 * @return the position of the text insertion caret 534 * @see #setCaretPosition(int) 535 * @since JDK1.1 536 */ 537 public synchronized int getCaretPosition() { 538 TextComponentPeer peer = (TextComponentPeer)this.peer; 539 int position = 0; 540 541 if (peer != null) { 542 position = peer.getCaretPosition(); 543 } else { 544 position = selectionStart; 545 } 546 int maxposition = getText().length(); 547 if (position > maxposition) { 548 position = maxposition; 549 } 550 return position; 551 } 552 553 /** 554 * Adds the specified text event listener to receive text events 555 * from this text component. 556 * If <code>l</code> is <code>null</code>, no exception is 557 * thrown and no action is performed. 558 * <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads" 559 * >AWT Threading Issues</a> for details on AWT's threading model. 560 * 561 * @param l the text event listener 562 * @see #removeTextListener 563 * @see #getTextListeners 564 * @see java.awt.event.TextListener 565 */ 566 public synchronized void addTextListener(TextListener l) { 567 if (l == null) { 568 return; 569 } 570 textListener = AWTEventMulticaster.add(textListener, l); 571 newEventsOnly = true; 572 } 573 574 /** 575 * Removes the specified text event listener so that it no longer 576 * receives text events from this text component 577 * If <code>l</code> is <code>null</code>, no exception is 578 * thrown and no action is performed. 579 * <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads" 580 * >AWT Threading Issues</a> for details on AWT's threading model. 581 * 582 * @param l the text listener 583 * @see #addTextListener 584 * @see #getTextListeners 585 * @see java.awt.event.TextListener 586 * @since JDK1.1 587 */ 588 public synchronized void removeTextListener(TextListener l) { 589 if (l == null) { 590 return; 591 } 592 textListener = AWTEventMulticaster.remove(textListener, l); 593 } 594 595 /** 596 * Returns an array of all the text listeners 597 * registered on this text component. 598 * 599 * @return all of this text component's <code>TextListener</code>s 600 * or an empty array if no text 601 * listeners are currently registered 602 * 603 * 604 * @see #addTextListener 605 * @see #removeTextListener 606 * @since 1.4 607 */ 608 public synchronized TextListener[] getTextListeners() { 609 return (TextListener[])(getListeners(TextListener.class)); 610 } 611 612 /** 613 * Returns an array of all the objects currently registered 614 * as <code><em>Foo</em>Listener</code>s 615 * upon this <code>TextComponent</code>. 616 * <code><em>Foo</em>Listener</code>s are registered using the 617 * <code>add<em>Foo</em>Listener</code> method. 618 * 619 * <p> 620 * You can specify the <code>listenerType</code> argument 621 * with a class literal, such as 622 * <code><em>Foo</em>Listener.class</code>. 623 * For example, you can query a 624 * <code>TextComponent</code> <code>t</code> 625 * for its text listeners with the following code: 626 * 627 * <pre>TextListener[] tls = (TextListener[])(t.getListeners(TextListener.class));</pre> 628 * 629 * If no such listeners exist, this method returns an empty array. 630 * 631 * @param listenerType the type of listeners requested; this parameter 632 * should specify an interface that descends from 633 * <code>java.util.EventListener</code> 634 * @return an array of all objects registered as 635 * <code><em>Foo</em>Listener</code>s on this text component, 636 * or an empty array if no such 637 * listeners have been added 638 * @exception ClassCastException if <code>listenerType</code> 639 * doesn't specify a class or interface that implements 640 * <code>java.util.EventListener</code> 641 * 642 * @see #getTextListeners 643 * @since 1.3 644 */ 645 public <T extends EventListener> T[] getListeners(Class<T> listenerType) { 646 EventListener l = null; 647 if (listenerType == TextListener.class) { 648 l = textListener; 649 } else { 650 return super.getListeners(listenerType); 651 } 652 return AWTEventMulticaster.getListeners(l, listenerType); 653 } 654 655 // REMIND: remove when filtering is done at lower level 656 boolean eventEnabled(AWTEvent e) { 657 if (e.id == TextEvent.TEXT_VALUE_CHANGED) { 658 if ((eventMask & AWTEvent.TEXT_EVENT_MASK) != 0 || 659 textListener != null) { 660 return true; 661 } 662 return false; 663 } 664 return super.eventEnabled(e); 665 } 666 667 /** 668 * Processes events on this text component. If the event is a 669 * <code>TextEvent</code>, it invokes the <code>processTextEvent</code> 670 * method else it invokes its superclass's <code>processEvent</code>. 671 * <p>Note that if the event parameter is <code>null</code> 672 * the behavior is unspecified and may result in an 673 * exception. 674 * 675 * @param e the event 676 */ 677 protected void processEvent(AWTEvent e) { 678 if (e instanceof TextEvent) { 679 processTextEvent((TextEvent)e); 680 return; 681 } 682 super.processEvent(e); 683 } 684 685 /** 686 * Processes text events occurring on this text component by 687 * dispatching them to any registered <code>TextListener</code> objects. 688 * <p> 689 * NOTE: This method will not be called unless text events 690 * are enabled for this component. This happens when one of the 691 * following occurs: 692 * <ul> 693 * <li>A <code>TextListener</code> object is registered 694 * via <code>addTextListener</code> 695 * <li>Text events are enabled via <code>enableEvents</code> 696 * </ul> 697 * <p>Note that if the event parameter is <code>null</code> 698 * the behavior is unspecified and may result in an 699 * exception. 700 * 701 * @param e the text event 702 * @see Component#enableEvents 703 */ 704 protected void processTextEvent(TextEvent e) { 705 TextListener listener = textListener; 706 if (listener != null) { 707 int id = e.getID(); 708 switch (id) { 709 case TextEvent.TEXT_VALUE_CHANGED: 710 listener.textValueChanged(e); 711 break; 712 } 713 } 714 } 715 716 /** 717 * Returns a string representing the state of this 718 * <code>TextComponent</code>. This 719 * method is intended to be used only for debugging purposes, and the 720 * content and format of the returned string may vary between 721 * implementations. The returned string may be empty but may not be 722 * <code>null</code>. 723 * 724 * @return the parameter string of this text component 725 */ 726 protected String paramString() { 727 String str = super.paramString() + ",text=" + getText(); 728 if (editable) { 729 str += ",editable"; 730 } 731 return str + ",selection=" + getSelectionStart() + "-" + getSelectionEnd(); 732 } 733 734 /** 735 * Assigns a valid value to the canAccessClipboard instance variable. 736 */ 737 private void checkSystemClipboardAccess() { 738 canAccessClipboard = true; 739 SecurityManager sm = System.getSecurityManager(); 740 if (sm != null) { 741 try { 742 sm.checkSystemClipboardAccess(); 743 } 744 catch (SecurityException e) { 745 canAccessClipboard = false; 746 } 747 } 748 } 749 750 /* 751 * Serialization support. 752 */ 753 /** 754 * The textComponent SerializedDataVersion. 755 * 756 * @serial 757 */ 758 private int textComponentSerializedDataVersion = 1; 759 760 /** 761 * Writes default serializable fields to stream. Writes 762 * a list of serializable TextListener(s) as optional data. 763 * The non-serializable TextListener(s) are detected and 764 * no attempt is made to serialize them. 765 * 766 * @serialData Null terminated sequence of zero or more pairs. 767 * A pair consists of a String and Object. 768 * The String indicates the type of object and 769 * is one of the following : 770 * textListenerK indicating and TextListener object. 771 * 772 * @see AWTEventMulticaster#save(ObjectOutputStream, String, EventListener) 773 * @see java.awt.Component#textListenerK 774 */ 775 private void writeObject(java.io.ObjectOutputStream s) 776 throws IOException 777 { 778 // Serialization support. Since the value of the fields 779 // selectionStart, selectionEnd, and text aren't necessarily 780 // up to date, we sync them up with the peer before serializing. 781 TextComponentPeer peer = (TextComponentPeer)this.peer; 782 if (peer != null) { 783 text = peer.getText(); 784 selectionStart = peer.getSelectionStart(); 785 selectionEnd = peer.getSelectionEnd(); 786 } 787 788 s.defaultWriteObject(); 789 790 AWTEventMulticaster.save(s, textListenerK, textListener); 791 s.writeObject(null); 792 } 793 794 /** 795 * Read the ObjectInputStream, and if it isn't null, 796 * add a listener to receive text events fired by the 797 * TextComponent. Unrecognized keys or values will be 798 * ignored. 799 * 800 * @exception HeadlessException if 801 * <code>GraphicsEnvironment.isHeadless()</code> returns 802 * <code>true</code> 803 * @see #removeTextListener 804 * @see #addTextListener 805 * @see java.awt.GraphicsEnvironment#isHeadless 806 */ 807 private void readObject(ObjectInputStream s) 808 throws ClassNotFoundException, IOException, HeadlessException 809 { 810 GraphicsEnvironment.checkHeadless(); 811 s.defaultReadObject(); 812 813 // Make sure the state we just read in for text, 814 // selectionStart and selectionEnd has legal values 815 this.text = (text != null) ? text : ""; 816 select(selectionStart, selectionEnd); 817 818 Object keyOrNull; 819 while(null != (keyOrNull = s.readObject())) { 820 String key = ((String)keyOrNull).intern(); 821 822 if (textListenerK == key) { 823 addTextListener((TextListener)(s.readObject())); 824 } else { 825 // skip value for unrecognized key 826 s.readObject(); 827 } 828 } 829 enableInputMethodsIfNecessary(); 830 checkSystemClipboardAccess(); 831 } 832 833 834 ///////////////// 835 // Accessibility support 836 //////////////// 837 838 839 /** 840 * 841 */ 842 int getIndexAtPoint(Point p) { 843 return -1; 844 /* To be fully implemented in a future release 845 if (peer == null) { 846 return -1; 847 } 848 TextComponentPeer peer = (TextComponentPeer)this.peer; 849 return peer.getIndexAtPoint(p.x, p.y); 850 */ 851 } 852 853 854 /** 855 * 856 */ 857 Rectangle getCharacterBounds(int i) { 858 return null; 859 /* To be fully implemented in a future release 860 if (peer == null) { 861 return null; 862 } 863 TextComponentPeer peer = (TextComponentPeer)this.peer; 864 return peer.getCharacterBounds(i); 865 */ 866 } 867 868 869 /** 870 * Gets the AccessibleContext associated with this TextComponent. 871 * For text components, the AccessibleContext takes the form of an 872 * AccessibleAWTTextComponent. 873 * A new AccessibleAWTTextComponent instance is created if necessary. 874 * 875 * @return an AccessibleAWTTextComponent that serves as the 876 * AccessibleContext of this TextComponent 877 * @since 1.3 878 */ 879 public AccessibleContext getAccessibleContext() { 880 if (accessibleContext == null) { 881 accessibleContext = new AccessibleAWTTextComponent(); 882 } 883 return accessibleContext; 884 } 885 886 /** 887 * This class implements accessibility support for the 888 * <code>TextComponent</code> class. It provides an implementation of the 889 * Java Accessibility API appropriate to text component user-interface 890 * elements. 891 * @since 1.3 892 */ 893 protected class AccessibleAWTTextComponent extends AccessibleAWTComponent 894 implements AccessibleText, TextListener 895 { 896 /* 897 * JDK 1.3 serialVersionUID 898 */ 899 private static final long serialVersionUID = 3631432373506317811L; 900 901 /** 902 * Constructs an AccessibleAWTTextComponent. Adds a listener to track 903 * caret change. 904 */ 905 public AccessibleAWTTextComponent() { 906 TextComponent.this.addTextListener(this); 907 } 908 909 /** 910 * TextListener notification of a text value change. 911 */ 912 public void textValueChanged(TextEvent textEvent) { 913 Integer cpos = Integer.valueOf(TextComponent.this.getCaretPosition()); 914 firePropertyChange(ACCESSIBLE_TEXT_PROPERTY, null, cpos); 915 } 916 917 /** 918 * Gets the state set of the TextComponent. 919 * The AccessibleStateSet of an object is composed of a set of 920 * unique AccessibleStates. A change in the AccessibleStateSet 921 * of an object will cause a PropertyChangeEvent to be fired 922 * for the AccessibleContext.ACCESSIBLE_STATE_PROPERTY property. 923 * 924 * @return an instance of AccessibleStateSet containing the 925 * current state set of the object 926 * @see AccessibleStateSet 927 * @see AccessibleState 928 * @see #addPropertyChangeListener 929 */ 930 public AccessibleStateSet getAccessibleStateSet() { 931 AccessibleStateSet states = super.getAccessibleStateSet(); 932 if (TextComponent.this.isEditable()) { 933 states.add(AccessibleState.EDITABLE); 934 } 935 return states; 936 } 937 938 939 /** 940 * Gets the role of this object. 941 * 942 * @return an instance of AccessibleRole describing the role of the 943 * object (AccessibleRole.TEXT) 944 * @see AccessibleRole 945 */ 946 public AccessibleRole getAccessibleRole() { 947 return AccessibleRole.TEXT; 948 } 949 950 /** 951 * Get the AccessibleText associated with this object. In the 952 * implementation of the Java Accessibility API for this class, 953 * return this object, which is responsible for implementing the 954 * AccessibleText interface on behalf of itself. 955 * 956 * @return this object 957 */ 958 public AccessibleText getAccessibleText() { 959 return this; 960 } 961 962 963 // --- interface AccessibleText methods ------------------------ 964 965 /** 966 * Many of these methods are just convenience methods; they 967 * just call the equivalent on the parent 968 */ 969 970 /** 971 * Given a point in local coordinates, return the zero-based index 972 * of the character under that Point. If the point is invalid, 973 * this method returns -1. 974 * 975 * @param p the Point in local coordinates 976 * @return the zero-based index of the character under Point p. 977 */ 978 public int getIndexAtPoint(Point p) { 979 return TextComponent.this.getIndexAtPoint(p); 980 } 981 982 /** 983 * Determines the bounding box of the character at the given 984 * index into the string. The bounds are returned in local 985 * coordinates. If the index is invalid a null rectangle 986 * is returned. 987 * 988 * @param i the index into the String >= 0 989 * @return the screen coordinates of the character's bounding box 990 */ 991 public Rectangle getCharacterBounds(int i) { 992 return TextComponent.this.getCharacterBounds(i); 993 } 994 995 /** 996 * Returns the number of characters (valid indicies) 997 * 998 * @return the number of characters >= 0 999 */ 1000 public int getCharCount() { 1001 return TextComponent.this.getText().length(); 1002 } 1003 1004 /** 1005 * Returns the zero-based offset of the caret. 1006 * 1007 * Note: The character to the right of the caret will have the 1008 * same index value as the offset (the caret is between 1009 * two characters). 1010 * 1011 * @return the zero-based offset of the caret. 1012 */ 1013 public int getCaretPosition() { 1014 return TextComponent.this.getCaretPosition(); 1015 } 1016 1017 /** 1018 * Returns the AttributeSet for a given character (at a given index). 1019 * 1020 * @param i the zero-based index into the text 1021 * @return the AttributeSet of the character 1022 */ 1023 public AttributeSet getCharacterAttribute(int i) { 1024 return null; // No attributes in TextComponent 1025 } 1026 1027 /** 1028 * Returns the start offset within the selected text. 1029 * If there is no selection, but there is 1030 * a caret, the start and end offsets will be the same. 1031 * Return 0 if the text is empty, or the caret position 1032 * if no selection. 1033 * 1034 * @return the index into the text of the start of the selection >= 0 1035 */ 1036 public int getSelectionStart() { 1037 return TextComponent.this.getSelectionStart(); 1038 } 1039 1040 /** 1041 * Returns the end offset within the selected text. 1042 * If there is no selection, but there is 1043 * a caret, the start and end offsets will be the same. 1044 * Return 0 if the text is empty, or the caret position 1045 * if no selection. 1046 * 1047 * @return the index into teh text of the end of the selection >= 0 1048 */ 1049 public int getSelectionEnd() { 1050 return TextComponent.this.getSelectionEnd(); 1051 } 1052 1053 /** 1054 * Returns the portion of the text that is selected. 1055 * 1056 * @return the text, null if no selection 1057 */ 1058 public String getSelectedText() { 1059 String selText = TextComponent.this.getSelectedText(); 1060 // Fix for 4256662 1061 if (selText == null || selText.equals("")) { 1062 return null; 1063 } 1064 return selText; 1065 } 1066 1067 /** 1068 * Returns the String at a given index. 1069 * 1070 * @param part the AccessibleText.CHARACTER, AccessibleText.WORD, 1071 * or AccessibleText.SENTENCE to retrieve 1072 * @param index an index within the text >= 0 1073 * @return the letter, word, or sentence, 1074 * null for an invalid index or part 1075 */ 1076 public String getAtIndex(int part, int index) { 1077 if (index < 0 || index >= TextComponent.this.getText().length()) { 1078 return null; 1079 } 1080 switch (part) { 1081 case AccessibleText.CHARACTER: 1082 return TextComponent.this.getText().substring(index, index+1); 1083 case AccessibleText.WORD: { 1084 String s = TextComponent.this.getText(); 1085 BreakIterator words = BreakIterator.getWordInstance(); 1086 words.setText(s); 1087 int end = words.following(index); 1088 return s.substring(words.previous(), end); 1089 } 1090 case AccessibleText.SENTENCE: { 1091 String s = TextComponent.this.getText(); 1092 BreakIterator sentence = BreakIterator.getSentenceInstance(); 1093 sentence.setText(s); 1094 int end = sentence.following(index); 1095 return s.substring(sentence.previous(), end); 1096 } 1097 default: 1098 return null; 1099 } 1100 } 1101 1102 private static final boolean NEXT = true; 1103 private static final boolean PREVIOUS = false; 1104 1105 /** 1106 * Needed to unify forward and backward searching. 1107 * The method assumes that s is the text assigned to words. 1108 */ 1109 private int findWordLimit(int index, BreakIterator words, boolean direction, 1110 String s) { 1111 // Fix for 4256660 and 4256661. 1112 // Words iterator is different from character and sentence iterators 1113 // in that end of one word is not necessarily start of another word. 1114 // Please see java.text.BreakIterator JavaDoc. The code below is 1115 // based on nextWordStartAfter example from BreakIterator.java. 1116 int last = (direction == NEXT) ? words.following(index) 1117 : words.preceding(index); 1118 int current = (direction == NEXT) ? words.next() 1119 : words.previous(); 1120 while (current != BreakIterator.DONE) { 1121 for (int p = Math.min(last, current); p < Math.max(last, current); p++) { 1122 if (Character.isLetter(s.charAt(p))) { 1123 return last; 1124 } 1125 } 1126 last = current; 1127 current = (direction == NEXT) ? words.next() 1128 : words.previous(); 1129 } 1130 return BreakIterator.DONE; 1131 } 1132 1133 /** 1134 * Returns the String after a given index. 1135 * 1136 * @param part the AccessibleText.CHARACTER, AccessibleText.WORD, 1137 * or AccessibleText.SENTENCE to retrieve 1138 * @param index an index within the text >= 0 1139 * @return the letter, word, or sentence, null for an invalid 1140 * index or part 1141 */ 1142 public String getAfterIndex(int part, int index) { 1143 if (index < 0 || index >= TextComponent.this.getText().length()) { 1144 return null; 1145 } 1146 switch (part) { 1147 case AccessibleText.CHARACTER: 1148 if (index+1 >= TextComponent.this.getText().length()) { 1149 return null; 1150 } 1151 return TextComponent.this.getText().substring(index+1, index+2); 1152 case AccessibleText.WORD: { 1153 String s = TextComponent.this.getText(); 1154 BreakIterator words = BreakIterator.getWordInstance(); 1155 words.setText(s); 1156 int start = findWordLimit(index, words, NEXT, s); 1157 if (start == BreakIterator.DONE || start >= s.length()) { 1158 return null; 1159 } 1160 int end = words.following(start); 1161 if (end == BreakIterator.DONE || end >= s.length()) { 1162 return null; 1163 } 1164 return s.substring(start, end); 1165 } 1166 case AccessibleText.SENTENCE: { 1167 String s = TextComponent.this.getText(); 1168 BreakIterator sentence = BreakIterator.getSentenceInstance(); 1169 sentence.setText(s); 1170 int start = sentence.following(index); 1171 if (start == BreakIterator.DONE || start >= s.length()) { 1172 return null; 1173 } 1174 int end = sentence.following(start); 1175 if (end == BreakIterator.DONE || end >= s.length()) { 1176 return null; 1177 } 1178 return s.substring(start, end); 1179 } 1180 default: 1181 return null; 1182 } 1183 } 1184 1185 1186 /** 1187 * Returns the String before a given index. 1188 * 1189 * @param part the AccessibleText.CHARACTER, AccessibleText.WORD, 1190 * or AccessibleText.SENTENCE to retrieve 1191 * @param index an index within the text >= 0 1192 * @return the letter, word, or sentence, null for an invalid index 1193 * or part 1194 */ 1195 public String getBeforeIndex(int part, int index) { 1196 if (index < 0 || index > TextComponent.this.getText().length()-1) { 1197 return null; 1198 } 1199 switch (part) { 1200 case AccessibleText.CHARACTER: 1201 if (index == 0) { 1202 return null; 1203 } 1204 return TextComponent.this.getText().substring(index-1, index); 1205 case AccessibleText.WORD: { 1206 String s = TextComponent.this.getText(); 1207 BreakIterator words = BreakIterator.getWordInstance(); 1208 words.setText(s); 1209 int end = findWordLimit(index, words, PREVIOUS, s); 1210 if (end == BreakIterator.DONE) { 1211 return null; 1212 } 1213 int start = words.preceding(end); 1214 if (start == BreakIterator.DONE) { 1215 return null; 1216 } 1217 return s.substring(start, end); 1218 } 1219 case AccessibleText.SENTENCE: { 1220 String s = TextComponent.this.getText(); 1221 BreakIterator sentence = BreakIterator.getSentenceInstance(); 1222 sentence.setText(s); 1223 int end = sentence.following(index); 1224 end = sentence.previous(); 1225 int start = sentence.previous(); 1226 if (start == BreakIterator.DONE) { 1227 return null; 1228 } 1229 return s.substring(start, end); 1230 } 1231 default: 1232 return null; 1233 } 1234 } 1235 } // end of AccessibleAWTTextComponent 1236 1237 private boolean checkForEnableIM = true; 1238 }