1 /*
2 * Copyright (c) 2003, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang;
27
28 import sun.misc.FloatingDecimal;
29 import java.util.Arrays;
30
31 /**
32 * A mutable sequence of characters.
33 * <p>
34 * Implements a modifiable string. At any point in time it contains some
35 * particular sequence of characters, but the length and content of the
36 * sequence can be changed through certain method calls.
37 *
38 * @author Michael McCloskey
39 * @author Martin Buchholz
40 * @author Ulf Zibis
41 * @since 1.5
42 */
43 abstract class AbstractStringBuilder implements Appendable, CharSequence {
44 /**
45 * The value is used for character storage.
46 */
47 char[] value;
48
49 /**
50 * The count is the number of characters used.
51 */
52 int count;
53
54 /**
55 * This no-arg constructor is necessary for serialization of subclasses.
56 */
57 AbstractStringBuilder() {
58 }
59
60 /**
61 * Creates an AbstractStringBuilder of the specified capacity.
62 */
63 AbstractStringBuilder(int capacity) {
64 value = new char[capacity];
65 }
66
67 /**
68 * Returns the length (character count).
69 *
70 * @return the length of the sequence of characters currently
71 * represented by this object
72 */
73 public int length() {
74 return count;
75 }
76
77 /**
78 * Returns the current capacity. The capacity is the amount of storage
79 * available for newly inserted characters, beyond which an allocation
80 * will occur.
81 *
82 * @return the current capacity
83 */
84 public int capacity() {
85 return value.length;
86 }
87
88 /**
89 * Ensures that the capacity is at least equal to the specified minimum.
90 * If the current capacity is less than the argument, then a new internal
91 * array is allocated with greater capacity. The new capacity is the
92 * larger of:
93 * <ul>
94 * <li>The {@code minimumCapacity} argument.
95 * <li>Twice the old capacity, plus {@code 2}.
96 * </ul>
97 * If the {@code minimumCapacity} argument is nonpositive, this
98 * method takes no action and simply returns.
99 * Note that subsequent operations on this object can reduce the
100 * actual capacity below that requested here.
101 *
102 * @param minimumCapacity the minimum desired capacity.
103 */
104 public void ensureCapacity(int minimumCapacity) {
105 if (minimumCapacity > 0)
106 ensureCapacityInternal(minimumCapacity);
107 }
108
109 /**
110 * This method has the same contract as ensureCapacity, but is
111 * never synchronized.
112 */
113 private void ensureCapacityInternal(int minimumCapacity) {
114 // overflow-conscious code
115 if (minimumCapacity - value.length > 0)
116 expandCapacity(minimumCapacity);
117 }
118
119 /**
120 * This implements the expansion semantics of ensureCapacity with no
121 * size check or synchronization.
122 */
123 void expandCapacity(int minimumCapacity) {
124 int newCapacity = value.length * 2 + 2;
125 if (newCapacity - minimumCapacity < 0)
126 newCapacity = minimumCapacity;
127 if (newCapacity < 0) {
128 if (minimumCapacity < 0) // overflow
129 throw new OutOfMemoryError();
130 newCapacity = Integer.MAX_VALUE;
131 }
132 value = Arrays.copyOf(value, newCapacity);
133 }
134
135 /**
136 * Attempts to reduce storage used for the character sequence.
137 * If the buffer is larger than necessary to hold its current sequence of
138 * characters, then it may be resized to become more space efficient.
139 * Calling this method may, but is not required to, affect the value
140 * returned by a subsequent call to the {@link #capacity()} method.
141 */
142 public void trimToSize() {
143 if (count < value.length) {
144 value = Arrays.copyOf(value, count);
145 }
146 }
147
148 /**
149 * Sets the length of the character sequence.
150 * The sequence is changed to a new character sequence
151 * whose length is specified by the argument. For every nonnegative
152 * index <i>k</i> less than {@code newLength}, the character at
153 * index <i>k</i> in the new character sequence is the same as the
154 * character at index <i>k</i> in the old sequence if <i>k</i> is less
155 * than the length of the old character sequence; otherwise, it is the
156 * null character {@code '\u005Cu0000'}.
157 *
158 * In other words, if the {@code newLength} argument is less than
159 * the current length, the length is changed to the specified length.
160 * <p>
161 * If the {@code newLength} argument is greater than or equal
162 * to the current length, sufficient null characters
163 * ({@code '\u005Cu0000'}) are appended so that
164 * length becomes the {@code newLength} argument.
165 * <p>
166 * The {@code newLength} argument must be greater than or equal
167 * to {@code 0}.
168 *
169 * @param newLength the new length
170 * @throws IndexOutOfBoundsException if the
171 * {@code newLength} argument is negative.
172 */
173 public void setLength(int newLength) {
174 if (newLength < 0)
175 throw new StringIndexOutOfBoundsException(newLength);
176 ensureCapacityInternal(newLength);
177
178 if (count < newLength) {
179 for (; count < newLength; count++)
180 value[count] = '\0';
181 } else {
182 count = newLength;
183 }
184 }
185
186 /**
187 * Returns the {@code char} value in this sequence at the specified index.
188 * The first {@code char} value is at index {@code 0}, the next at index
189 * {@code 1}, and so on, as in array indexing.
190 * <p>
191 * The index argument must be greater than or equal to
192 * {@code 0}, and less than the length of this sequence.
193 *
194 * <p>If the {@code char} value specified by the index is a
195 * <a href="Character.html#unicode">surrogate</a>, the surrogate
196 * value is returned.
197 *
198 * @param index the index of the desired {@code char} value.
199 * @return the {@code char} value at the specified index.
200 * @throws IndexOutOfBoundsException if {@code index} is
201 * negative or greater than or equal to {@code length()}.
202 */
203 public char charAt(int index) {
204 if ((index < 0) || (index >= count))
205 throw new StringIndexOutOfBoundsException(index);
206 return value[index];
207 }
208
209 /**
210 * Returns the character (Unicode code point) at the specified
211 * index. The index refers to {@code char} values
212 * (Unicode code units) and ranges from {@code 0} to
213 * {@link #length()}{@code - 1}.
214 *
215 * <p> If the {@code char} value specified at the given index
216 * is in the high-surrogate range, the following index is less
217 * than the length of this sequence, and the
218 * {@code char} value at the following index is in the
219 * low-surrogate range, then the supplementary code point
220 * corresponding to this surrogate pair is returned. Otherwise,
221 * the {@code char} value at the given index is returned.
222 *
223 * @param index the index to the {@code char} values
224 * @return the code point value of the character at the
225 * {@code index}
226 * @exception IndexOutOfBoundsException if the {@code index}
227 * argument is negative or not less than the length of this
228 * sequence.
229 */
230 public int codePointAt(int index) {
231 if ((index < 0) || (index >= count)) {
232 throw new StringIndexOutOfBoundsException(index);
233 }
234 return Character.codePointAt(value, index);
235 }
236
237 /**
238 * Returns the character (Unicode code point) before the specified
239 * index. The index refers to {@code char} values
240 * (Unicode code units) and ranges from {@code 1} to {@link
241 * #length()}.
242 *
243 * <p> If the {@code char} value at {@code (index - 1)}
244 * is in the low-surrogate range, {@code (index - 2)} is not
245 * negative, and the {@code char} value at {@code (index -
246 * 2)} is in the high-surrogate range, then the
247 * supplementary code point value of the surrogate pair is
248 * returned. If the {@code char} value at {@code index -
249 * 1} is an unpaired low-surrogate or a high-surrogate, the
250 * surrogate value is returned.
251 *
252 * @param index the index following the code point that should be returned
253 * @return the Unicode code point value before the given index.
254 * @exception IndexOutOfBoundsException if the {@code index}
255 * argument is less than 1 or greater than the length
256 * of this sequence.
257 */
258 public int codePointBefore(int index) {
259 int i = index - 1;
260 if ((i < 0) || (i >= count)) {
261 throw new StringIndexOutOfBoundsException(index);
262 }
263 return Character.codePointBefore(value, index);
264 }
265
266 /**
267 * Returns the number of Unicode code points in the specified text
268 * range of this sequence. The text range begins at the specified
269 * {@code beginIndex} and extends to the {@code char} at
270 * index {@code endIndex - 1}. Thus the length (in
271 * {@code char}s) of the text range is
272 * {@code endIndex-beginIndex}. Unpaired surrogates within
273 * this sequence count as one code point each.
274 *
275 * @param beginIndex the index to the first {@code char} of
276 * the text range.
277 * @param endIndex the index after the last {@code char} of
278 * the text range.
279 * @return the number of Unicode code points in the specified text
280 * range
281 * @exception IndexOutOfBoundsException if the
282 * {@code beginIndex} is negative, or {@code endIndex}
283 * is larger than the length of this sequence, or
284 * {@code beginIndex} is larger than {@code endIndex}.
285 */
286 public int codePointCount(int beginIndex, int endIndex) {
287 if (beginIndex < 0 || endIndex > count || beginIndex > endIndex) {
288 throw new IndexOutOfBoundsException();
289 }
290 return Character.codePointCountImpl(value, beginIndex, endIndex-beginIndex);
291 }
292
293 /**
294 * Returns the index within this sequence that is offset from the
295 * given {@code index} by {@code codePointOffset} code
296 * points. Unpaired surrogates within the text range given by
297 * {@code index} and {@code codePointOffset} count as
298 * one code point each.
299 *
300 * @param index the index to be offset
301 * @param codePointOffset the offset in code points
302 * @return the index within this sequence
303 * @exception IndexOutOfBoundsException if {@code index}
304 * is negative or larger then the length of this sequence,
305 * or if {@code codePointOffset} is positive and the subsequence
306 * starting with {@code index} has fewer than
307 * {@code codePointOffset} code points,
308 * or if {@code codePointOffset} is negative and the subsequence
309 * before {@code index} has fewer than the absolute value of
310 * {@code codePointOffset} code points.
311 */
312 public int offsetByCodePoints(int index, int codePointOffset) {
313 if (index < 0 || index > count) {
314 throw new IndexOutOfBoundsException();
315 }
316 return Character.offsetByCodePointsImpl(value, 0, count,
317 index, codePointOffset);
318 }
319
320 /**
321 * Characters are copied from this sequence into the
322 * destination character array {@code dst}. The first character to
323 * be copied is at index {@code srcBegin}; the last character to
324 * be copied is at index {@code srcEnd-1}. The total number of
325 * characters to be copied is {@code srcEnd-srcBegin}. The
326 * characters are copied into the subarray of {@code dst} starting
327 * at index {@code dstBegin} and ending at index:
328 * <p><blockquote><pre>
329 * dstbegin + (srcEnd-srcBegin) - 1
330 * </pre></blockquote>
331 *
332 * @param srcBegin start copying at this offset.
333 * @param srcEnd stop copying at this offset.
334 * @param dst the array to copy the data into.
335 * @param dstBegin offset into {@code dst}.
336 * @throws NullPointerException if {@code dst} is
337 * {@code null}.
338 * @throws IndexOutOfBoundsException if any of the following is true:
339 * <ul>
340 * <li>{@code srcBegin} is negative
341 * <li>{@code dstBegin} is negative
342 * <li>the {@code srcBegin} argument is greater than
343 * the {@code srcEnd} argument.
344 * <li>{@code srcEnd} is greater than
345 * {@code this.length()}.
346 * <li>{@code dstBegin+srcEnd-srcBegin} is greater than
347 * {@code dst.length}
348 * </ul>
349 */
350 public void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)
351 {
352 if (srcBegin < 0)
353 throw new StringIndexOutOfBoundsException(srcBegin);
354 if ((srcEnd < 0) || (srcEnd > count))
355 throw new StringIndexOutOfBoundsException(srcEnd);
356 if (srcBegin > srcEnd)
357 throw new StringIndexOutOfBoundsException("srcBegin > srcEnd");
358 System.arraycopy(value, srcBegin, dst, dstBegin, srcEnd - srcBegin);
359 }
360
361 /**
362 * The character at the specified index is set to {@code ch}. This
363 * sequence is altered to represent a new character sequence that is
364 * identical to the old character sequence, except that it contains the
365 * character {@code ch} at position {@code index}.
366 * <p>
367 * The index argument must be greater than or equal to
368 * {@code 0}, and less than the length of this sequence.
369 *
370 * @param index the index of the character to modify.
371 * @param ch the new character.
372 * @throws IndexOutOfBoundsException if {@code index} is
373 * negative or greater than or equal to {@code length()}.
374 */
375 public void setCharAt(int index, char ch) {
376 if ((index < 0) || (index >= count))
377 throw new StringIndexOutOfBoundsException(index);
378 value[index] = ch;
379 }
380
381 /**
382 * Appends the string representation of the {@code Object} argument.
383 * <p>
384 * The overall effect is exactly as if the argument were converted
385 * to a string by the method {@link String#valueOf(Object)},
386 * and the characters of that string were then
387 * {@link #append(String) appended} to this character sequence.
388 *
389 * @param obj an {@code Object}.
390 * @return a reference to this object.
391 */
392 public AbstractStringBuilder append(Object obj) {
393 return append(String.valueOf(obj));
394 }
395
396 /**
397 * Appends the specified string to this character sequence.
398 * <p>
399 * The characters of the {@code String} argument are appended, in
400 * order, increasing the length of this sequence by the length of the
401 * argument. If {@code str} is {@code null}, then the four
402 * characters {@code "null"} are appended.
403 * <p>
404 * Let <i>n</i> be the length of this character sequence just prior to
405 * execution of the {@code append} method. Then the character at
406 * index <i>k</i> in the new character sequence is equal to the character
407 * at index <i>k</i> in the old character sequence, if <i>k</i> is less
408 * than <i>n</i>; otherwise, it is equal to the character at index
409 * <i>k-n</i> in the argument {@code str}.
410 *
411 * @param str a string.
412 * @return a reference to this object.
413 */
414 public AbstractStringBuilder append(String str) {
415 if (str == null) str = "null";
416 int len = str.length();
417 ensureCapacityInternal(count + len);
418 str.getChars(0, len, value, count);
419 count += len;
420 return this;
421 }
422
423 // Documentation in subclasses because of synchro difference
424 public AbstractStringBuilder append(StringBuffer sb) {
425 if (sb == null)
426 return append("null");
427 int len = sb.length();
428 ensureCapacityInternal(count + len);
429 sb.getChars(0, len, value, count);
430 count += len;
431 return this;
432 }
433
434 // Documentation in subclasses because of synchro difference
435 public AbstractStringBuilder append(CharSequence s) {
436 if (s == null)
437 s = "null";
438 if (s instanceof String)
439 return this.append((String)s);
440 if (s instanceof StringBuffer)
441 return this.append((StringBuffer)s);
442 return this.append(s, 0, s.length());
443 }
444
445 /**
446 * Appends a subsequence of the specified {@code CharSequence} to this
447 * sequence.
448 * <p>
449 * Characters of the argument {@code s}, starting at
450 * index {@code start}, are appended, in order, to the contents of
451 * this sequence up to the (exclusive) index {@code end}. The length
452 * of this sequence is increased by the value of {@code end - start}.
453 * <p>
454 * Let <i>n</i> be the length of this character sequence just prior to
455 * execution of the {@code append} method. Then the character at
456 * index <i>k</i> in this character sequence becomes equal to the
457 * character at index <i>k</i> in this sequence, if <i>k</i> is less than
458 * <i>n</i>; otherwise, it is equal to the character at index
459 * <i>k+start-n</i> in the argument {@code s}.
460 * <p>
461 * If {@code s} is {@code null}, then this method appends
462 * characters as if the s parameter was a sequence containing the four
463 * characters {@code "null"}.
464 *
465 * @param s the sequence to append.
466 * @param start the starting index of the subsequence to be appended.
467 * @param end the end index of the subsequence to be appended.
468 * @return a reference to this object.
469 * @throws IndexOutOfBoundsException if
470 * {@code start} is negative, or
471 * {@code start} is greater than {@code end} or
472 * {@code end} is greater than {@code s.length()}
473 */
474 public AbstractStringBuilder append(CharSequence s, int start, int end) {
475 if (s == null)
476 s = "null";
477 if ((start < 0) || (start > end) || (end > s.length()))
478 throw new IndexOutOfBoundsException(
479 "start " + start + ", end " + end + ", s.length() "
480 + s.length());
481 int len = end - start;
482 ensureCapacityInternal(count + len);
483 for (int i = start, j = count; i < end; i++, j++)
484 value[j] = s.charAt(i);
485 count += len;
486 return this;
487 }
488
489 /**
490 * Appends the string representation of the {@code char} array
491 * argument to this sequence.
492 * <p>
493 * The characters of the array argument are appended, in order, to
494 * the contents of this sequence. The length of this sequence
495 * increases by the length of the argument.
496 * <p>
497 * The overall effect is exactly as if the argument were converted
498 * to a string by the method {@link String#valueOf(char[])},
499 * and the characters of that string were then
500 * {@link #append(String) appended} to this character sequence.
501 *
502 * @param str the characters to be appended.
503 * @return a reference to this object.
504 */
505 public AbstractStringBuilder append(char[] str) {
506 int len = str.length;
507 ensureCapacityInternal(count + len);
508 System.arraycopy(str, 0, value, count, len);
509 count += len;
510 return this;
511 }
512
513 /**
514 * Appends the string representation of a subarray of the
515 * {@code char} array argument to this sequence.
516 * <p>
517 * Characters of the {@code char} array {@code str}, starting at
518 * index {@code offset}, are appended, in order, to the contents
519 * of this sequence. The length of this sequence increases
520 * by the value of {@code len}.
521 * <p>
522 * The overall effect is exactly as if the arguments were converted
523 * to a string by the method {@link String#valueOf(char[],int,int)},
524 * and the characters of that string were then
525 * {@link #append(String) appended} to this character sequence.
526 *
527 * @param str the characters to be appended.
528 * @param offset the index of the first {@code char} to append.
529 * @param len the number of {@code char}s to append.
530 * @return a reference to this object.
531 * @throws IndexOutOfBoundsException
532 * if {@code offset < 0} or {@code len < 0}
533 * or {@code offset+len > str.length}
534 */
535 public AbstractStringBuilder append(char str[], int offset, int len) {
536 if (len > 0) // let arraycopy report AIOOBE for len < 0
537 ensureCapacityInternal(count + len);
538 System.arraycopy(str, offset, value, count, len);
539 count += len;
540 return this;
541 }
542
543 /**
544 * Appends the string representation of the {@code boolean}
545 * argument to the sequence.
546 * <p>
547 * The overall effect is exactly as if the argument were converted
548 * to a string by the method {@link String#valueOf(boolean)},
549 * and the characters of that string were then
550 * {@link #append(String) appended} to this character sequence.
551 *
552 * @param b a {@code boolean}.
553 * @return a reference to this object.
554 */
555 public AbstractStringBuilder append(boolean b) {
556 if (b) {
557 ensureCapacityInternal(count + 4);
558 value[count++] = 't';
559 value[count++] = 'r';
560 value[count++] = 'u';
561 value[count++] = 'e';
562 } else {
563 ensureCapacityInternal(count + 5);
564 value[count++] = 'f';
565 value[count++] = 'a';
566 value[count++] = 'l';
567 value[count++] = 's';
568 value[count++] = 'e';
569 }
570 return this;
571 }
572
573 /**
574 * Appends the string representation of the {@code char}
575 * argument to this sequence.
576 * <p>
577 * The argument is appended to the contents of this sequence.
578 * The length of this sequence increases by {@code 1}.
579 * <p>
580 * The overall effect is exactly as if the argument were converted
581 * to a string by the method {@link String#valueOf(char)},
582 * and the character in that string were then
583 * {@link #append(String) appended} to this character sequence.
584 *
585 * @param c a {@code char}.
586 * @return a reference to this object.
587 */
588 public AbstractStringBuilder append(char c) {
589 ensureCapacityInternal(count + 1);
590 value[count++] = c;
591 return this;
592 }
593
594 /**
595 * Appends the string representation of the {@code int}
596 * argument to this sequence.
597 * <p>
598 * The overall effect is exactly as if the argument were converted
599 * to a string by the method {@link String#valueOf(int)},
600 * and the characters of that string were then
601 * {@link #append(String) appended} to this character sequence.
602 *
603 * @param i an {@code int}.
604 * @return a reference to this object.
605 */
606 public AbstractStringBuilder append(int i) {
607 if (i == Integer.MIN_VALUE) {
608 append("-2147483648");
609 return this;
610 }
611 int appendedLength = (i < 0) ? Integer.stringSize(-i) + 1
612 : Integer.stringSize(i);
613 int spaceNeeded = count + appendedLength;
614 ensureCapacityInternal(spaceNeeded);
615 Integer.getChars(i, spaceNeeded, value);
616 count = spaceNeeded;
617 return this;
618 }
619
620 /**
621 * Appends the string representation of the {@code long}
622 * argument to this sequence.
623 * <p>
624 * The overall effect is exactly as if the argument were converted
625 * to a string by the method {@link String#valueOf(long)},
626 * and the characters of that string were then
627 * {@link #append(String) appended} to this character sequence.
628 *
629 * @param l a {@code long}.
630 * @return a reference to this object.
631 */
632 public AbstractStringBuilder append(long l) {
633 if (l == Long.MIN_VALUE) {
634 append("-9223372036854775808");
635 return this;
636 }
637 int appendedLength = (l < 0) ? Long.stringSize(-l) + 1
638 : Long.stringSize(l);
639 int spaceNeeded = count + appendedLength;
640 ensureCapacityInternal(spaceNeeded);
641 Long.getChars(l, spaceNeeded, value);
642 count = spaceNeeded;
643 return this;
644 }
645
646 /**
647 * Appends the string representation of the {@code float}
648 * argument to this sequence.
649 * <p>
650 * The overall effect is exactly as if the argument were converted
651 * to a string by the method {@link String#valueOf(float)},
652 * and the characters of that string were then
653 * {@link #append(String) appended} to this character sequence.
654 *
655 * @param f a {@code float}.
656 * @return a reference to this object.
657 */
658 public AbstractStringBuilder append(float f) {
659 new FloatingDecimal(f).appendTo(this);
660 return this;
661 }
662
663 /**
664 * Appends the string representation of the {@code double}
665 * argument to this sequence.
666 * <p>
667 * The overall effect is exactly as if the argument were converted
668 * to a string by the method {@link String#valueOf(double)},
669 * and the characters of that string were then
670 * {@link #append(String) appended} to this character sequence.
671 *
672 * @param d a {@code double}.
673 * @return a reference to this object.
674 */
675 public AbstractStringBuilder append(double d) {
676 new FloatingDecimal(d).appendTo(this);
677 return this;
678 }
679
680 /**
681 * Removes the characters in a substring of this sequence.
682 * The substring begins at the specified {@code start} and extends to
683 * the character at index {@code end - 1} or to the end of the
684 * sequence if no such character exists. If
685 * {@code start} is equal to {@code end}, no changes are made.
686 *
687 * @param start The beginning index, inclusive.
688 * @param end The ending index, exclusive.
689 * @return This object.
690 * @throws StringIndexOutOfBoundsException if {@code start}
691 * is negative, greater than {@code length()}, or
692 * greater than {@code end}.
693 */
694 public AbstractStringBuilder delete(int start, int end) {
695 if (start < 0)
696 throw new StringIndexOutOfBoundsException(start);
697 if (end > count)
698 end = count;
699 if (start > end)
700 throw new StringIndexOutOfBoundsException();
701 int len = end - start;
702 if (len > 0) {
703 System.arraycopy(value, start+len, value, start, count-end);
704 count -= len;
705 }
706 return this;
707 }
708
709 /**
710 * Appends the string representation of the {@code codePoint}
711 * argument to this sequence.
712 *
713 * <p> The argument is appended to the contents of this sequence.
714 * The length of this sequence increases by
715 * {@link Character#charCount(int) Character.charCount(codePoint)}.
716 *
717 * <p> The overall effect is exactly as if the argument were
718 * converted to a {@code char} array by the method
719 * {@link Character#toChars(int)} and the character in that array
720 * were then {@link #append(char[]) appended} to this character
721 * sequence.
722 *
723 * @param codePoint a Unicode code point
724 * @return a reference to this object.
725 * @exception IllegalArgumentException if the specified
726 * {@code codePoint} isn't a valid Unicode code point
727 */
728 public AbstractStringBuilder appendCodePoint(int codePoint) {
729 final int count = this.count;
730
731 if (Character.isBmpCodePoint(codePoint)) {
732 ensureCapacityInternal(count + 1);
733 value[count] = (char) codePoint;
734 this.count = count + 1;
735 } else if (Character.isValidCodePoint(codePoint)) {
736 ensureCapacityInternal(count + 2);
737 Character.toSurrogates(codePoint, value, count);
738 this.count = count + 2;
739 } else {
740 throw new IllegalArgumentException();
741 }
742 return this;
743 }
744
745 /**
746 * Removes the {@code char} at the specified position in this
747 * sequence. This sequence is shortened by one {@code char}.
748 *
749 * <p>Note: If the character at the given index is a supplementary
750 * character, this method does not remove the entire character. If
751 * correct handling of supplementary characters is required,
752 * determine the number of {@code char}s to remove by calling
753 * {@code Character.charCount(thisSequence.codePointAt(index))},
754 * where {@code thisSequence} is this sequence.
755 *
756 * @param index Index of {@code char} to remove
757 * @return This object.
758 * @throws StringIndexOutOfBoundsException if the {@code index}
759 * is negative or greater than or equal to
760 * {@code length()}.
761 */
762 public AbstractStringBuilder deleteCharAt(int index) {
763 if ((index < 0) || (index >= count))
764 throw new StringIndexOutOfBoundsException(index);
765 System.arraycopy(value, index+1, value, index, count-index-1);
766 count--;
767 return this;
768 }
769
770 /**
771 * Replaces the characters in a substring of this sequence
772 * with characters in the specified {@code String}. The substring
773 * begins at the specified {@code start} and extends to the character
774 * at index {@code end - 1} or to the end of the
775 * sequence if no such character exists. First the
776 * characters in the substring are removed and then the specified
777 * {@code String} is inserted at {@code start}. (This
778 * sequence will be lengthened to accommodate the
779 * specified String if necessary.)
780 *
781 * @param start The beginning index, inclusive.
782 * @param end The ending index, exclusive.
783 * @param str String that will replace previous contents.
784 * @return This object.
785 * @throws StringIndexOutOfBoundsException if {@code start}
786 * is negative, greater than {@code length()}, or
787 * greater than {@code end}.
788 */
789 public AbstractStringBuilder replace(int start, int end, String str) {
790 if (start < 0)
791 throw new StringIndexOutOfBoundsException(start);
792 if (start > count)
793 throw new StringIndexOutOfBoundsException("start > length()");
794 if (start > end)
795 throw new StringIndexOutOfBoundsException("start > end");
796
797 if (end > count)
798 end = count;
799 int len = str.length();
800 int newCount = count + len - (end - start);
801 ensureCapacityInternal(newCount);
802
803 System.arraycopy(value, end, value, start + len, count - end);
804 str.getChars(value, start);
805 count = newCount;
806 return this;
807 }
808
809 /**
810 * Returns a new {@code String} that contains a subsequence of
811 * characters currently contained in this character sequence. The
812 * substring begins at the specified index and extends to the end of
813 * this sequence.
814 *
815 * @param start The beginning index, inclusive.
816 * @return The new string.
817 * @throws StringIndexOutOfBoundsException if {@code start} is
818 * less than zero, or greater than the length of this object.
819 */
820 public String substring(int start) {
821 return substring(start, count);
822 }
823
824 /**
825 * Returns a new character sequence that is a subsequence of this sequence.
826 *
827 * <p> An invocation of this method of the form
828 *
829 * <blockquote><pre>
830 * sb.subSequence(begin, end)</pre></blockquote>
831 *
832 * behaves in exactly the same way as the invocation
833 *
834 * <blockquote><pre>
835 * sb.substring(begin, end)</pre></blockquote>
836 *
837 * This method is provided so that this class can
838 * implement the {@link CharSequence} interface. </p>
839 *
840 * @param start the start index, inclusive.
841 * @param end the end index, exclusive.
842 * @return the specified subsequence.
843 *
844 * @throws IndexOutOfBoundsException
845 * if <tt>start</tt> or <tt>end</tt> are negative,
846 * if <tt>end</tt> is greater than <tt>length()</tt>,
847 * or if <tt>start</tt> is greater than <tt>end</tt>
848 * @spec JSR-51
849 */
850 public CharSequence subSequence(int start, int end) {
851 return substring(start, end);
852 }
853
854 /**
855 * Returns a new {@code String} that contains a subsequence of
856 * characters currently contained in this sequence. The
857 * substring begins at the specified {@code start} and
858 * extends to the character at index {@code end - 1}.
859 *
860 * @param start The beginning index, inclusive.
861 * @param end The ending index, exclusive.
862 * @return The new string.
863 * @throws StringIndexOutOfBoundsException if {@code start}
864 * or {@code end} are negative or greater than
865 * {@code length()}, or {@code start} is
866 * greater than {@code end}.
867 */
868 public String substring(int start, int end) {
869 if (start < 0)
870 throw new StringIndexOutOfBoundsException(start);
871 if (end > count)
872 throw new StringIndexOutOfBoundsException(end);
873 if (start > end)
874 throw new StringIndexOutOfBoundsException(end - start);
875 return new String(value, start, end - start);
876 }
877
878 /**
879 * Inserts the string representation of a subarray of the {@code str}
880 * array argument into this sequence. The subarray begins at the
881 * specified {@code offset} and extends {@code len} {@code char}s.
882 * The characters of the subarray are inserted into this sequence at
883 * the position indicated by {@code index}. The length of this
884 * sequence increases by {@code len} {@code char}s.
885 *
886 * @param index position at which to insert subarray.
887 * @param str A {@code char} array.
888 * @param offset the index of the first {@code char} in subarray to
889 * be inserted.
890 * @param len the number of {@code char}s in the subarray to
891 * be inserted.
892 * @return This object
893 * @throws StringIndexOutOfBoundsException if {@code index}
894 * is negative or greater than {@code length()}, or
895 * {@code offset} or {@code len} are negative, or
896 * {@code (offset+len)} is greater than
897 * {@code str.length}.
898 */
899 public AbstractStringBuilder insert(int index, char[] str, int offset,
900 int len)
901 {
902 if ((index < 0) || (index > length()))
903 throw new StringIndexOutOfBoundsException(index);
904 if ((offset < 0) || (len < 0) || (offset > str.length - len))
905 throw new StringIndexOutOfBoundsException(
906 "offset " + offset + ", len " + len + ", str.length "
907 + str.length);
908 ensureCapacityInternal(count + len);
909 System.arraycopy(value, index, value, index + len, count - index);
910 System.arraycopy(str, offset, value, index, len);
911 count += len;
912 return this;
913 }
914
915 /**
916 * Inserts the string representation of the {@code Object}
917 * argument into this character sequence.
918 * <p>
919 * The overall effect is exactly as if the second argument were
920 * converted to a string by the method {@link String#valueOf(Object)},
921 * and the characters of that string were then
922 * {@link #insert(int,String) inserted} into this character
923 * sequence at the indicated offset.
924 * <p>
925 * The {@code offset} argument must be greater than or equal to
926 * {@code 0}, and less than or equal to the {@linkplain #length() length}
927 * of this sequence.
928 *
929 * @param offset the offset.
930 * @param obj an {@code Object}.
931 * @return a reference to this object.
932 * @throws StringIndexOutOfBoundsException if the offset is invalid.
933 */
934 public AbstractStringBuilder insert(int offset, Object obj) {
935 return insert(offset, String.valueOf(obj));
936 }
937
938 /**
939 * Inserts the string into this character sequence.
940 * <p>
941 * The characters of the {@code String} argument are inserted, in
942 * order, into this sequence at the indicated offset, moving up any
943 * characters originally above that position and increasing the length
944 * of this sequence by the length of the argument. If
945 * {@code str} is {@code null}, then the four characters
946 * {@code "null"} are inserted into this sequence.
947 * <p>
948 * The character at index <i>k</i> in the new character sequence is
949 * equal to:
950 * <ul>
951 * <li>the character at index <i>k</i> in the old character sequence, if
952 * <i>k</i> is less than {@code offset}
953 * <li>the character at index <i>k</i>{@code -offset} in the
954 * argument {@code str}, if <i>k</i> is not less than
955 * {@code offset} but is less than {@code offset+str.length()}
956 * <li>the character at index <i>k</i>{@code -str.length()} in the
957 * old character sequence, if <i>k</i> is not less than
958 * {@code offset+str.length()}
959 * </ul><p>
960 * The {@code offset} argument must be greater than or equal to
961 * {@code 0}, and less than or equal to the {@linkplain #length() length}
962 * of this sequence.
963 *
964 * @param offset the offset.
965 * @param str a string.
966 * @return a reference to this object.
967 * @throws StringIndexOutOfBoundsException if the offset is invalid.
968 */
969 public AbstractStringBuilder insert(int offset, String str) {
970 if ((offset < 0) || (offset > length()))
971 throw new StringIndexOutOfBoundsException(offset);
972 if (str == null)
973 str = "null";
974 int len = str.length();
975 ensureCapacityInternal(count + len);
976 System.arraycopy(value, offset, value, offset + len, count - offset);
977 str.getChars(value, offset);
978 count += len;
979 return this;
980 }
981
982 /**
983 * Inserts the string representation of the {@code char} array
984 * argument into this sequence.
985 * <p>
986 * The characters of the array argument are inserted into the
987 * contents of this sequence at the position indicated by
988 * {@code offset}. The length of this sequence increases by
989 * the length of the argument.
990 * <p>
991 * The overall effect is exactly as if the second argument were
992 * converted to a string by the method {@link String#valueOf(char[])},
993 * and the characters of that string were then
994 * {@link #insert(int,String) inserted} into this character
995 * sequence at the indicated offset.
996 * <p>
997 * The {@code offset} argument must be greater than or equal to
998 * {@code 0}, and less than or equal to the {@linkplain #length() length}
999 * of this sequence.
1000 *
1001 * @param offset the offset.
1002 * @param str a character array.
1003 * @return a reference to this object.
1004 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1005 */
1006 public AbstractStringBuilder insert(int offset, char[] str) {
1007 if ((offset < 0) || (offset > length()))
1008 throw new StringIndexOutOfBoundsException(offset);
1009 int len = str.length;
1010 ensureCapacityInternal(count + len);
1011 System.arraycopy(value, offset, value, offset + len, count - offset);
1012 System.arraycopy(str, 0, value, offset, len);
1013 count += len;
1014 return this;
1015 }
1016
1017 /**
1018 * Inserts the specified {@code CharSequence} into this sequence.
1019 * <p>
1020 * The characters of the {@code CharSequence} argument are inserted,
1021 * in order, into this sequence at the indicated offset, moving up
1022 * any characters originally above that position and increasing the length
1023 * of this sequence by the length of the argument s.
1024 * <p>
1025 * The result of this method is exactly the same as if it were an
1026 * invocation of this object's
1027 * {@link #insert(int,CharSequence,int,int) insert}(dstOffset, s, 0, s.length())
1028 * method.
1029 *
1030 * <p>If {@code s} is {@code null}, then the four characters
1031 * {@code "null"} are inserted into this sequence.
1032 *
1033 * @param dstOffset the offset.
1034 * @param s the sequence to be inserted
1035 * @return a reference to this object.
1036 * @throws IndexOutOfBoundsException if the offset is invalid.
1037 */
1038 public AbstractStringBuilder insert(int dstOffset, CharSequence s) {
1039 if (s == null)
1040 s = "null";
1041 if (s instanceof String)
1042 return this.insert(dstOffset, (String)s);
1043 return this.insert(dstOffset, s, 0, s.length());
1044 }
1045
1046 /**
1047 * Inserts a subsequence of the specified {@code CharSequence} into
1048 * this sequence.
1049 * <p>
1050 * The subsequence of the argument {@code s} specified by
1051 * {@code start} and {@code end} are inserted,
1052 * in order, into this sequence at the specified destination offset, moving
1053 * up any characters originally above that position. The length of this
1054 * sequence is increased by {@code end - start}.
1055 * <p>
1056 * The character at index <i>k</i> in this sequence becomes equal to:
1057 * <ul>
1058 * <li>the character at index <i>k</i> in this sequence, if
1059 * <i>k</i> is less than {@code dstOffset}
1060 * <li>the character at index <i>k</i>{@code +start-dstOffset} in
1061 * the argument {@code s}, if <i>k</i> is greater than or equal to
1062 * {@code dstOffset} but is less than {@code dstOffset+end-start}
1063 * <li>the character at index <i>k</i>{@code -(end-start)} in this
1064 * sequence, if <i>k</i> is greater than or equal to
1065 * {@code dstOffset+end-start}
1066 * </ul><p>
1067 * The {@code dstOffset} argument must be greater than or equal to
1068 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1069 * of this sequence.
1070 * <p>The start argument must be nonnegative, and not greater than
1071 * {@code end}.
1072 * <p>The end argument must be greater than or equal to
1073 * {@code start}, and less than or equal to the length of s.
1074 *
1075 * <p>If {@code s} is {@code null}, then this method inserts
1076 * characters as if the s parameter was a sequence containing the four
1077 * characters {@code "null"}.
1078 *
1079 * @param dstOffset the offset in this sequence.
1080 * @param s the sequence to be inserted.
1081 * @param start the starting index of the subsequence to be inserted.
1082 * @param end the end index of the subsequence to be inserted.
1083 * @return a reference to this object.
1084 * @throws IndexOutOfBoundsException if {@code dstOffset}
1085 * is negative or greater than {@code this.length()}, or
1086 * {@code start} or {@code end} are negative, or
1087 * {@code start} is greater than {@code end} or
1088 * {@code end} is greater than {@code s.length()}
1089 */
1090 public AbstractStringBuilder insert(int dstOffset, CharSequence s,
1091 int start, int end) {
1092 if (s == null)
1093 s = "null";
1094 if ((dstOffset < 0) || (dstOffset > this.length()))
1095 throw new IndexOutOfBoundsException("dstOffset "+dstOffset);
1096 if ((start < 0) || (end < 0) || (start > end) || (end > s.length()))
1097 throw new IndexOutOfBoundsException(
1098 "start " + start + ", end " + end + ", s.length() "
1099 + s.length());
1100 int len = end - start;
1101 ensureCapacityInternal(count + len);
1102 System.arraycopy(value, dstOffset, value, dstOffset + len,
1103 count - dstOffset);
1104 for (int i=start; i<end; i++)
1105 value[dstOffset++] = s.charAt(i);
1106 count += len;
1107 return this;
1108 }
1109
1110 /**
1111 * Inserts the string representation of the {@code boolean}
1112 * argument into this sequence.
1113 * <p>
1114 * The overall effect is exactly as if the second argument were
1115 * converted to a string by the method {@link String#valueOf(boolean)},
1116 * and the characters of that string were then
1117 * {@link #insert(int,String) inserted} into this character
1118 * sequence at the indicated offset.
1119 * <p>
1120 * The {@code offset} argument must be greater than or equal to
1121 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1122 * of this sequence.
1123 *
1124 * @param offset the offset.
1125 * @param b a {@code boolean}.
1126 * @return a reference to this object.
1127 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1128 */
1129 public AbstractStringBuilder insert(int offset, boolean b) {
1130 return insert(offset, String.valueOf(b));
1131 }
1132
1133 /**
1134 * Inserts the string representation of the {@code char}
1135 * argument into this sequence.
1136 * <p>
1137 * The overall effect is exactly as if the second argument were
1138 * converted to a string by the method {@link String#valueOf(char)},
1139 * and the character in that string were then
1140 * {@link #insert(int,String) inserted} into this character
1141 * sequence at the indicated offset.
1142 * <p>
1143 * The {@code offset} argument must be greater than or equal to
1144 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1145 * of this sequence.
1146 *
1147 * @param offset the offset.
1148 * @param c a {@code char}.
1149 * @return a reference to this object.
1150 * @throws IndexOutOfBoundsException if the offset is invalid.
1151 */
1152 public AbstractStringBuilder insert(int offset, char c) {
1153 ensureCapacityInternal(count + 1);
1154 System.arraycopy(value, offset, value, offset + 1, count - offset);
1155 value[offset] = c;
1156 count += 1;
1157 return this;
1158 }
1159
1160 /**
1161 * Inserts the string representation of the second {@code int}
1162 * argument into this sequence.
1163 * <p>
1164 * The overall effect is exactly as if the second argument were
1165 * converted to a string by the method {@link String#valueOf(int)},
1166 * and the characters of that string were then
1167 * {@link #insert(int,String) inserted} into this character
1168 * sequence at the indicated offset.
1169 * <p>
1170 * The {@code offset} argument must be greater than or equal to
1171 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1172 * of this sequence.
1173 *
1174 * @param offset the offset.
1175 * @param i an {@code int}.
1176 * @return a reference to this object.
1177 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1178 */
1179 public AbstractStringBuilder insert(int offset, int i) {
1180 return insert(offset, String.valueOf(i));
1181 }
1182
1183 /**
1184 * Inserts the string representation of the {@code long}
1185 * argument into this sequence.
1186 * <p>
1187 * The overall effect is exactly as if the second argument were
1188 * converted to a string by the method {@link String#valueOf(long)},
1189 * and the characters of that string were then
1190 * {@link #insert(int,String) inserted} into this character
1191 * sequence at the indicated offset.
1192 * <p>
1193 * The {@code offset} argument must be greater than or equal to
1194 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1195 * of this sequence.
1196 *
1197 * @param offset the offset.
1198 * @param l a {@code long}.
1199 * @return a reference to this object.
1200 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1201 */
1202 public AbstractStringBuilder insert(int offset, long l) {
1203 return insert(offset, String.valueOf(l));
1204 }
1205
1206 /**
1207 * Inserts the string representation of the {@code float}
1208 * argument into this sequence.
1209 * <p>
1210 * The overall effect is exactly as if the second argument were
1211 * converted to a string by the method {@link String#valueOf(float)},
1212 * and the characters of that string were then
1213 * {@link #insert(int,String) inserted} into this character
1214 * sequence at the indicated offset.
1215 * <p>
1216 * The {@code offset} argument must be greater than or equal to
1217 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1218 * of this sequence.
1219 *
1220 * @param offset the offset.
1221 * @param f a {@code float}.
1222 * @return a reference to this object.
1223 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1224 */
1225 public AbstractStringBuilder insert(int offset, float f) {
1226 return insert(offset, String.valueOf(f));
1227 }
1228
1229 /**
1230 * Inserts the string representation of the {@code double}
1231 * argument into this sequence.
1232 * <p>
1233 * The overall effect is exactly as if the second argument were
1234 * converted to a string by the method {@link String#valueOf(double)},
1235 * and the characters of that string were then
1236 * {@link #insert(int,String) inserted} into this character
1237 * sequence at the indicated offset.
1238 * <p>
1239 * The {@code offset} argument must be greater than or equal to
1240 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1241 * of this sequence.
1242 *
1243 * @param offset the offset.
1244 * @param d a {@code double}.
1245 * @return a reference to this object.
1246 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1247 */
1248 public AbstractStringBuilder insert(int offset, double d) {
1249 return insert(offset, String.valueOf(d));
1250 }
1251
1252 /**
1253 * Returns the index within this string of the first occurrence of the
1254 * specified substring. The integer returned is the smallest value
1255 * <i>k</i> such that:
1256 * <blockquote><pre>
1257 * this.toString().startsWith(str, <i>k</i>)
1258 * </pre></blockquote>
1259 * is {@code true}.
1260 *
1261 * @param str any string.
1262 * @return if the string argument occurs as a substring within this
1263 * object, then the index of the first character of the first
1264 * such substring is returned; if it does not occur as a
1265 * substring, {@code -1} is returned.
1266 * @throws java.lang.NullPointerException if {@code str} is
1267 * {@code null}.
1268 */
1269 public int indexOf(String str) {
1270 return indexOf(str, 0);
1271 }
1272
1273 /**
1274 * Returns the index within this string of the first occurrence of the
1275 * specified substring, starting at the specified index. The integer
1276 * returned is the smallest value <tt>k</tt> for which:
1277 * <blockquote><pre>
1278 * k >= Math.min(fromIndex, str.length()) &&
1279 * this.toString().startsWith(str, k)
1280 * </pre></blockquote>
1281 * If no such value of <i>k</i> exists, then -1 is returned.
1282 *
1283 * @param str the substring for which to search.
1284 * @param fromIndex the index from which to start the search.
1285 * @return the index within this string of the first occurrence of the
1286 * specified substring, starting at the specified index.
1287 * @throws java.lang.NullPointerException if {@code str} is
1288 * {@code null}.
1289 */
1290 public int indexOf(String str, int fromIndex) {
1291 return String.indexOf(value, 0, count,
1292 str.toCharArray(), 0, str.length(), fromIndex);
1293 }
1294
1295 /**
1296 * Returns the index within this string of the rightmost occurrence
1297 * of the specified substring. The rightmost empty string "" is
1298 * considered to occur at the index value {@code this.length()}.
1299 * The returned index is the largest value <i>k</i> such that
1300 * <blockquote><pre>
1301 * this.toString().startsWith(str, k)
1302 * </pre></blockquote>
1303 * is true.
1304 *
1305 * @param str the substring to search for.
1306 * @return if the string argument occurs one or more times as a substring
1307 * within this object, then the index of the first character of
1308 * the last such substring is returned. If it does not occur as
1309 * a substring, {@code -1} is returned.
1310 * @throws java.lang.NullPointerException if {@code str} is
1311 * {@code null}.
1312 */
1313 public int lastIndexOf(String str) {
1314 return lastIndexOf(str, count);
1315 }
1316
1317 /**
1318 * Returns the index within this string of the last occurrence of the
1319 * specified substring. The integer returned is the largest value <i>k</i>
1320 * such that:
1321 * <blockquote><pre>
1322 * k <= Math.min(fromIndex, str.length()) &&
1323 * this.toString().startsWith(str, k)
1324 * </pre></blockquote>
1325 * If no such value of <i>k</i> exists, then -1 is returned.
1326 *
1327 * @param str the substring to search for.
1328 * @param fromIndex the index to start the search from.
1329 * @return the index within this sequence of the last occurrence of the
1330 * specified substring.
1331 * @throws java.lang.NullPointerException if {@code str} is
1332 * {@code null}.
1333 */
1334 public int lastIndexOf(String str, int fromIndex) {
1335 return String.lastIndexOf(value, 0, count,
1336 str.toCharArray(), 0, str.length(), fromIndex);
1337 }
1338
1339 /**
1340 * Causes this character sequence to be replaced by the reverse of
1341 * the sequence. If there are any surrogate pairs included in the
1342 * sequence, these are treated as single characters for the
1343 * reverse operation. Thus, the order of the high-low surrogates
1344 * is never reversed.
1345 *
1346 * Let <i>n</i> be the character length of this character sequence
1347 * (not the length in {@code char} values) just prior to
1348 * execution of the {@code reverse} method. Then the
1349 * character at index <i>k</i> in the new character sequence is
1350 * equal to the character at index <i>n-k-1</i> in the old
1351 * character sequence.
1352 *
1353 * <p>Note that the reverse operation may result in producing
1354 * surrogate pairs that were unpaired low-surrogates and
1355 * high-surrogates before the operation. For example, reversing
1356 * "\u005CuDC00\u005CuD800" produces "\u005CuD800\u005CuDC00" which is
1357 * a valid surrogate pair.
1358 *
1359 * @return a reference to this object.
1360 */
1361 public AbstractStringBuilder reverse() {
1362 boolean hasSurrogate = false;
1363 int n = count - 1;
1364 for (int j = (n-1) >> 1; j >= 0; --j) {
1365 char temp = value[j];
1366 char temp2 = value[n - j];
1367 if (!hasSurrogate) {
1368 hasSurrogate = (temp >= Character.MIN_SURROGATE && temp <= Character.MAX_SURROGATE)
1369 || (temp2 >= Character.MIN_SURROGATE && temp2 <= Character.MAX_SURROGATE);
1370 }
1371 value[j] = temp2;
1372 value[n - j] = temp;
1373 }
1374 if (hasSurrogate) {
1375 // Reverse back all valid surrogate pairs
1376 for (int i = 0; i < count - 1; i++) {
1377 char c2 = value[i];
1378 if (Character.isLowSurrogate(c2)) {
1379 char c1 = value[i + 1];
1380 if (Character.isHighSurrogate(c1)) {
1381 value[i++] = c1;
1382 value[i] = c2;
1383 }
1384 }
1385 }
1386 }
1387 return this;
1388 }
1389
1390 /**
1391 * Returns a string representing the data in this sequence.
1392 * A new {@code String} object is allocated and initialized to
1393 * contain the character sequence currently represented by this
1394 * object. This {@code String} is then returned. Subsequent
1395 * changes to this sequence do not affect the contents of the
1396 * {@code String}.
1397 *
1398 * @return a string representation of this sequence of characters.
1399 */
1400 public abstract String toString();
1401
1402 /**
1403 * Needed by <tt>String</tt> for the contentEquals method.
1404 */
1405 final char[] getValue() {
1406 return value;
1407 }
1408
1409 }