1 /*
2 * Copyright (c) 1995, 2014, 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 java.text.BreakIterator;
34 import javax.swing.text.AttributeSet;
35 import javax.accessibility.*;
36 import java.awt.im.InputMethodRequests;
37 import sun.awt.AWTPermissions;
38 import sun.awt.InputMethodSupport;
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 1.0
59 */
60 public class TextComponent extends Component implements Accessible {
61
62 /**
63 * The value of the text.
64 * A <code>null</code> value is the same as "".
65 *
66 * @serial
67 * @see #setText(String)
68 * @see #getText()
69 */
70 String text;
71
72 /**
73 * A boolean indicating whether or not this
74 * <code>TextComponent</code> is editable.
75 * It will be <code>true</code> if the text component
76 * is editable and <code>false</code> if not.
77 *
78 * @serial
79 * @see #isEditable()
80 */
81 boolean editable = true;
82
83 /**
84 * The selection refers to the selected text, and the
85 * <code>selectionStart</code> is the start position
86 * of the selected text.
87 *
88 * @serial
89 * @see #getSelectionStart()
90 * @see #setSelectionStart(int)
91 */
92 int selectionStart;
93
94 /**
95 * The selection refers to the selected text, and the
96 * <code>selectionEnd</code>
97 * is the end position of the selected text.
98 *
99 * @serial
100 * @see #getSelectionEnd()
101 * @see #setSelectionEnd(int)
102 */
103 int selectionEnd;
104
105 // A flag used to tell whether the background has been set by
106 // developer code (as opposed to AWT code). Used to determine
107 // the background color of non-editable TextComponents.
108 boolean backgroundSetByClientCode = false;
109
110 /**
111 * A list of listeners that will receive events from this object.
112 */
113 protected transient TextListener textListener;
114
115 /*
116 * JDK 1.1 serialVersionUID
117 */
118 private static final long serialVersionUID = -2214773872412987419L;
119
120 /**
121 * Constructs a new text component initialized with the
122 * specified text. Sets the value of the cursor to
123 * <code>Cursor.TEXT_CURSOR</code>.
124 * @param text the text to be displayed; if
125 * <code>text</code> is <code>null</code>, the empty
126 * string <code>""</code> will be displayed
127 * @exception HeadlessException if
128 * <code>GraphicsEnvironment.isHeadless</code>
129 * returns true
130 * @see java.awt.GraphicsEnvironment#isHeadless
131 * @see java.awt.Cursor
132 */
133 TextComponent(String text) throws HeadlessException {
134 GraphicsEnvironment.checkHeadless();
135 this.text = (text != null) ? text : "";
136 setCursor(Cursor.getPredefinedCursor(Cursor.TEXT_CURSOR));
137 }
138
139 private void enableInputMethodsIfNecessary() {
140 if (checkForEnableIM) {
141 checkForEnableIM = false;
142 try {
143 Toolkit toolkit = Toolkit.getDefaultToolkit();
144 boolean shouldEnable = false;
145 if (toolkit instanceof InputMethodSupport) {
146 shouldEnable = ((InputMethodSupport)toolkit)
147 .enableInputMethodsForTextComponent();
148 }
149 enableInputMethods(shouldEnable);
150 } catch (Exception e) {
151 // if something bad happens, just don't enable input methods
152 }
153 }
154 }
155
156 /**
157 * Enables or disables input method support for this text component. If input
158 * method support is enabled and the text component also processes key events,
159 * incoming events are offered to the current input method and will only be
160 * processed by the component or dispatched to its listeners if the input method
161 * does not consume them. Whether and how input method support for this text
162 * component is enabled or disabled by default is implementation dependent.
163 *
164 * @param enable true to enable, false to disable
165 * @see #processKeyEvent
166 * @since 1.2
167 */
168 public void enableInputMethods(boolean enable) {
169 checkForEnableIM = false;
170 super.enableInputMethods(enable);
171 }
172
173 boolean areInputMethodsEnabled() {
174 // moved from the constructor above to here and addNotify below,
175 // this call will initialize the toolkit if not already initialized.
176 if (checkForEnableIM) {
177 enableInputMethodsIfNecessary();
178 }
179
180 // TextComponent handles key events without touching the eventMask or
181 // having a key listener, so just check whether the flag is set
182 return (eventMask & AWTEvent.INPUT_METHODS_ENABLED_MASK) != 0;
183 }
184
185 public InputMethodRequests getInputMethodRequests() {
186 TextComponentPeer peer = (TextComponentPeer)this.peer;
187 if (peer != null) return peer.getInputMethodRequests();
188 else return null;
189 }
190
191
192
193 /**
194 * Makes this Component displayable by connecting it to a
195 * native screen resource.
196 * This method is called internally by the toolkit and should
197 * not be called directly by programs.
198 * @see java.awt.TextComponent#removeNotify
199 */
200 public void addNotify() {
201 super.addNotify();
202 enableInputMethodsIfNecessary();
203 }
204
205 /**
206 * Removes the <code>TextComponent</code>'s peer.
207 * The peer allows us to modify the appearance of the
208 * <code>TextComponent</code> without changing its
209 * functionality.
210 */
211 public void removeNotify() {
212 synchronized (getTreeLock()) {
213 TextComponentPeer peer = (TextComponentPeer)this.peer;
214 if (peer != null) {
215 text = peer.getText();
216 selectionStart = peer.getSelectionStart();
217 selectionEnd = peer.getSelectionEnd();
218 }
219 super.removeNotify();
220 }
221 }
222
223 /**
224 * Sets the text that is presented by this
225 * text component to be the specified text.
226 * @param t the new text;
227 * if this parameter is <code>null</code> then
228 * the text is set to the empty string ""
229 * @see java.awt.TextComponent#getText
230 */
231 public synchronized void setText(String t) {
232 if (t == null) {
233 t = "";
234 }
235 TextComponentPeer peer = (TextComponentPeer)this.peer;
236 if (peer != null) {
237 text = peer.getText();
238 // Please note that we do not want to post an event
239 // if TextArea.setText() or TextField.setText() replaces text
240 // by same text, that is, if component's text remains unchanged.
241 if (!t.equals(text)) {
242 text = t;
243 peer.setText(text);
244 }
245 } else {
246 text = t;
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 1.0
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 1.0
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 1.0
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 1.0
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 1.1
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 1.1
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 1.1
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 1.1
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 1.1
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 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 boolean canAccessClipboard() {
738 SecurityManager sm = System.getSecurityManager();
739 if (sm == null) return true;
740 try {
741 sm.checkPermission(AWTPermissions.ACCESS_CLIPBOARD_PERMISSION);
742 return true;
743 } catch (SecurityException e) {}
744 return false;
745 }
746
747 /*
748 * Serialization support.
749 */
750 /**
751 * The textComponent SerializedDataVersion.
752 *
753 * @serial
754 */
755 private int textComponentSerializedDataVersion = 1;
756
757 /**
758 * Writes default serializable fields to stream. Writes
759 * a list of serializable TextListener(s) as optional data.
760 * The non-serializable TextListener(s) are detected and
761 * no attempt is made to serialize them.
762 *
763 * @serialData Null terminated sequence of zero or more pairs.
764 * A pair consists of a String and Object.
765 * The String indicates the type of object and
766 * is one of the following :
767 * textListenerK indicating and TextListener object.
768 *
769 * @see AWTEventMulticaster#save(ObjectOutputStream, String, EventListener)
770 * @see java.awt.Component#textListenerK
771 */
772 private void writeObject(java.io.ObjectOutputStream s)
773 throws IOException
774 {
775 // Serialization support. Since the value of the fields
776 // selectionStart, selectionEnd, and text aren't necessarily
777 // up to date, we sync them up with the peer before serializing.
778 TextComponentPeer peer = (TextComponentPeer)this.peer;
779 if (peer != null) {
780 text = peer.getText();
781 selectionStart = peer.getSelectionStart();
782 selectionEnd = peer.getSelectionEnd();
783 }
784
785 s.defaultWriteObject();
786
787 AWTEventMulticaster.save(s, textListenerK, textListener);
788 s.writeObject(null);
789 }
790
791 /**
792 * Read the ObjectInputStream, and if it isn't null,
793 * add a listener to receive text events fired by the
794 * TextComponent. Unrecognized keys or values will be
795 * ignored.
796 *
797 * @exception HeadlessException if
798 * <code>GraphicsEnvironment.isHeadless()</code> returns
799 * <code>true</code>
800 * @see #removeTextListener
801 * @see #addTextListener
802 * @see java.awt.GraphicsEnvironment#isHeadless
803 */
804 private void readObject(ObjectInputStream s)
805 throws ClassNotFoundException, IOException, HeadlessException
806 {
807 GraphicsEnvironment.checkHeadless();
808 s.defaultReadObject();
809
810 // Make sure the state we just read in for text,
811 // selectionStart and selectionEnd has legal values
812 this.text = (text != null) ? text : "";
813 select(selectionStart, selectionEnd);
814
815 Object keyOrNull;
816 while(null != (keyOrNull = s.readObject())) {
817 String key = ((String)keyOrNull).intern();
818
819 if (textListenerK == key) {
820 addTextListener((TextListener)(s.readObject()));
821 } else {
822 // skip value for unrecognized key
823 s.readObject();
824 }
825 }
826 enableInputMethodsIfNecessary();
827 }
828
829
830 /////////////////
831 // Accessibility support
832 ////////////////
833
834 /**
835 * Gets the AccessibleContext associated with this TextComponent.
836 * For text components, the AccessibleContext takes the form of an
837 * AccessibleAWTTextComponent.
838 * A new AccessibleAWTTextComponent instance is created if necessary.
839 *
840 * @return an AccessibleAWTTextComponent that serves as the
841 * AccessibleContext of this TextComponent
842 * @since 1.3
843 */
844 public AccessibleContext getAccessibleContext() {
845 if (accessibleContext == null) {
846 accessibleContext = new AccessibleAWTTextComponent();
847 }
848 return accessibleContext;
849 }
850
851 /**
852 * This class implements accessibility support for the
853 * <code>TextComponent</code> class. It provides an implementation of the
854 * Java Accessibility API appropriate to text component user-interface
855 * elements.
856 * @since 1.3
857 */
858 protected class AccessibleAWTTextComponent extends AccessibleAWTComponent
859 implements AccessibleText, TextListener
860 {
861 /*
862 * JDK 1.3 serialVersionUID
863 */
864 private static final long serialVersionUID = 3631432373506317811L;
865
866 /**
867 * Constructs an AccessibleAWTTextComponent. Adds a listener to track
868 * caret change.
869 */
870 public AccessibleAWTTextComponent() {
871 TextComponent.this.addTextListener(this);
872 }
873
874 /**
875 * TextListener notification of a text value change.
876 */
877 public void textValueChanged(TextEvent textEvent) {
878 Integer cpos = Integer.valueOf(TextComponent.this.getCaretPosition());
879 firePropertyChange(ACCESSIBLE_TEXT_PROPERTY, null, cpos);
880 }
881
882 /**
883 * Gets the state set of the TextComponent.
884 * The AccessibleStateSet of an object is composed of a set of
885 * unique AccessibleStates. A change in the AccessibleStateSet
886 * of an object will cause a PropertyChangeEvent to be fired
887 * for the AccessibleContext.ACCESSIBLE_STATE_PROPERTY property.
888 *
889 * @return an instance of AccessibleStateSet containing the
890 * current state set of the object
891 * @see AccessibleStateSet
892 * @see AccessibleState
893 * @see #addPropertyChangeListener
894 */
895 public AccessibleStateSet getAccessibleStateSet() {
896 AccessibleStateSet states = super.getAccessibleStateSet();
897 if (TextComponent.this.isEditable()) {
898 states.add(AccessibleState.EDITABLE);
899 }
900 return states;
901 }
902
903
904 /**
905 * Gets the role of this object.
906 *
907 * @return an instance of AccessibleRole describing the role of the
908 * object (AccessibleRole.TEXT)
909 * @see AccessibleRole
910 */
911 public AccessibleRole getAccessibleRole() {
912 return AccessibleRole.TEXT;
913 }
914
915 /**
916 * Get the AccessibleText associated with this object. In the
917 * implementation of the Java Accessibility API for this class,
918 * return this object, which is responsible for implementing the
919 * AccessibleText interface on behalf of itself.
920 *
921 * @return this object
922 */
923 public AccessibleText getAccessibleText() {
924 return this;
925 }
926
927
928 // --- interface AccessibleText methods ------------------------
929
930 /**
931 * Many of these methods are just convenience methods; they
932 * just call the equivalent on the parent
933 */
934
935 /**
936 * Given a point in local coordinates, return the zero-based index
937 * of the character under that Point. If the point is invalid,
938 * this method returns -1.
939 *
940 * @param p the Point in local coordinates
941 * @return the zero-based index of the character under Point p.
942 */
943 public int getIndexAtPoint(Point p) {
944 return -1;
945 }
946
947 /**
948 * Determines the bounding box of the character at the given
949 * index into the string. The bounds are returned in local
950 * coordinates. If the index is invalid a null rectangle
951 * is returned.
952 *
953 * @param i the index into the String >= 0
954 * @return the screen coordinates of the character's bounding box
955 */
956 public Rectangle getCharacterBounds(int i) {
957 return null;
958 }
959
960 /**
961 * Returns the number of characters (valid indices)
962 *
963 * @return the number of characters >= 0
964 */
965 public int getCharCount() {
966 return TextComponent.this.getText().length();
967 }
968
969 /**
970 * Returns the zero-based offset of the caret.
971 *
972 * Note: The character to the right of the caret will have the
973 * same index value as the offset (the caret is between
974 * two characters).
975 *
976 * @return the zero-based offset of the caret.
977 */
978 public int getCaretPosition() {
979 return TextComponent.this.getCaretPosition();
980 }
981
982 /**
983 * Returns the AttributeSet for a given character (at a given index).
984 *
985 * @param i the zero-based index into the text
986 * @return the AttributeSet of the character
987 */
988 public AttributeSet getCharacterAttribute(int i) {
989 return null; // No attributes in TextComponent
990 }
991
992 /**
993 * Returns the start offset within the selected text.
994 * If there is no selection, but there is
995 * a caret, the start and end offsets will be the same.
996 * Return 0 if the text is empty, or the caret position
997 * if no selection.
998 *
999 * @return the index into the text of the start of the selection >= 0
1000 */
1001 public int getSelectionStart() {
1002 return TextComponent.this.getSelectionStart();
1003 }
1004
1005 /**
1006 * Returns the end offset within the selected text.
1007 * If there is no selection, but there is
1008 * a caret, the start and end offsets will be the same.
1009 * Return 0 if the text is empty, or the caret position
1010 * if no selection.
1011 *
1012 * @return the index into the text of the end of the selection >= 0
1013 */
1014 public int getSelectionEnd() {
1015 return TextComponent.this.getSelectionEnd();
1016 }
1017
1018 /**
1019 * Returns the portion of the text that is selected.
1020 *
1021 * @return the text, null if no selection
1022 */
1023 public String getSelectedText() {
1024 String selText = TextComponent.this.getSelectedText();
1025 // Fix for 4256662
1026 if (selText == null || selText.equals("")) {
1027 return null;
1028 }
1029 return selText;
1030 }
1031
1032 /**
1033 * Returns the String at a given index.
1034 *
1035 * @param part the AccessibleText.CHARACTER, AccessibleText.WORD,
1036 * or AccessibleText.SENTENCE to retrieve
1037 * @param index an index within the text >= 0
1038 * @return the letter, word, or sentence,
1039 * null for an invalid index or part
1040 */
1041 public String getAtIndex(int part, int index) {
1042 if (index < 0 || index >= TextComponent.this.getText().length()) {
1043 return null;
1044 }
1045 switch (part) {
1046 case AccessibleText.CHARACTER:
1047 return TextComponent.this.getText().substring(index, index+1);
1048 case AccessibleText.WORD: {
1049 String s = TextComponent.this.getText();
1050 BreakIterator words = BreakIterator.getWordInstance();
1051 words.setText(s);
1052 int end = words.following(index);
1053 return s.substring(words.previous(), end);
1054 }
1055 case AccessibleText.SENTENCE: {
1056 String s = TextComponent.this.getText();
1057 BreakIterator sentence = BreakIterator.getSentenceInstance();
1058 sentence.setText(s);
1059 int end = sentence.following(index);
1060 return s.substring(sentence.previous(), end);
1061 }
1062 default:
1063 return null;
1064 }
1065 }
1066
1067 private static final boolean NEXT = true;
1068 private static final boolean PREVIOUS = false;
1069
1070 /**
1071 * Needed to unify forward and backward searching.
1072 * The method assumes that s is the text assigned to words.
1073 */
1074 private int findWordLimit(int index, BreakIterator words, boolean direction,
1075 String s) {
1076 // Fix for 4256660 and 4256661.
1077 // Words iterator is different from character and sentence iterators
1078 // in that end of one word is not necessarily start of another word.
1079 // Please see java.text.BreakIterator JavaDoc. The code below is
1080 // based on nextWordStartAfter example from BreakIterator.java.
1081 int last = (direction == NEXT) ? words.following(index)
1082 : words.preceding(index);
1083 int current = (direction == NEXT) ? words.next()
1084 : words.previous();
1085 while (current != BreakIterator.DONE) {
1086 for (int p = Math.min(last, current); p < Math.max(last, current); p++) {
1087 if (Character.isLetter(s.charAt(p))) {
1088 return last;
1089 }
1090 }
1091 last = current;
1092 current = (direction == NEXT) ? words.next()
1093 : words.previous();
1094 }
1095 return BreakIterator.DONE;
1096 }
1097
1098 /**
1099 * Returns the String after a given index.
1100 *
1101 * @param part the AccessibleText.CHARACTER, AccessibleText.WORD,
1102 * or AccessibleText.SENTENCE to retrieve
1103 * @param index an index within the text >= 0
1104 * @return the letter, word, or sentence, null for an invalid
1105 * index or part
1106 */
1107 public String getAfterIndex(int part, int index) {
1108 if (index < 0 || index >= TextComponent.this.getText().length()) {
1109 return null;
1110 }
1111 switch (part) {
1112 case AccessibleText.CHARACTER:
1113 if (index+1 >= TextComponent.this.getText().length()) {
1114 return null;
1115 }
1116 return TextComponent.this.getText().substring(index+1, index+2);
1117 case AccessibleText.WORD: {
1118 String s = TextComponent.this.getText();
1119 BreakIterator words = BreakIterator.getWordInstance();
1120 words.setText(s);
1121 int start = findWordLimit(index, words, NEXT, s);
1122 if (start == BreakIterator.DONE || start >= s.length()) {
1123 return null;
1124 }
1125 int end = words.following(start);
1126 if (end == BreakIterator.DONE || end >= s.length()) {
1127 return null;
1128 }
1129 return s.substring(start, end);
1130 }
1131 case AccessibleText.SENTENCE: {
1132 String s = TextComponent.this.getText();
1133 BreakIterator sentence = BreakIterator.getSentenceInstance();
1134 sentence.setText(s);
1135 int start = sentence.following(index);
1136 if (start == BreakIterator.DONE || start >= s.length()) {
1137 return null;
1138 }
1139 int end = sentence.following(start);
1140 if (end == BreakIterator.DONE || end >= s.length()) {
1141 return null;
1142 }
1143 return s.substring(start, end);
1144 }
1145 default:
1146 return null;
1147 }
1148 }
1149
1150
1151 /**
1152 * Returns the String before a given index.
1153 *
1154 * @param part the AccessibleText.CHARACTER, AccessibleText.WORD,
1155 * or AccessibleText.SENTENCE to retrieve
1156 * @param index an index within the text >= 0
1157 * @return the letter, word, or sentence, null for an invalid index
1158 * or part
1159 */
1160 public String getBeforeIndex(int part, int index) {
1161 if (index < 0 || index > TextComponent.this.getText().length()-1) {
1162 return null;
1163 }
1164 switch (part) {
1165 case AccessibleText.CHARACTER:
1166 if (index == 0) {
1167 return null;
1168 }
1169 return TextComponent.this.getText().substring(index-1, index);
1170 case AccessibleText.WORD: {
1171 String s = TextComponent.this.getText();
1172 BreakIterator words = BreakIterator.getWordInstance();
1173 words.setText(s);
1174 int end = findWordLimit(index, words, PREVIOUS, s);
1175 if (end == BreakIterator.DONE) {
1176 return null;
1177 }
1178 int start = words.preceding(end);
1179 if (start == BreakIterator.DONE) {
1180 return null;
1181 }
1182 return s.substring(start, end);
1183 }
1184 case AccessibleText.SENTENCE: {
1185 String s = TextComponent.this.getText();
1186 BreakIterator sentence = BreakIterator.getSentenceInstance();
1187 sentence.setText(s);
1188 int end = sentence.following(index);
1189 end = sentence.previous();
1190 int start = sentence.previous();
1191 if (start == BreakIterator.DONE) {
1192 return null;
1193 }
1194 return s.substring(start, end);
1195 }
1196 default:
1197 return null;
1198 }
1199 }
1200 } // end of AccessibleAWTTextComponent
1201
1202 private boolean checkForEnableIM = true;
1203 }