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