1 /*
2 * Copyright (c) 2003, 2015, 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 import java.util.Spliterator;
31 import java.util.stream.IntStream;
32 import java.util.stream.StreamSupport;
33
34 /**
35 * A mutable sequence of characters.
36 * <p>
37 * Implements a modifiable string. At any point in time it contains some
38 * particular sequence of characters, but the length and content of the
39 * sequence can be changed through certain method calls.
40 *
41 * <p>Unless otherwise noted, passing a {@code null} argument to a constructor
42 * or method in this class will cause a {@link NullPointerException} to be
43 * thrown.
44 *
45 * @author Michael McCloskey
46 * @author Martin Buchholz
47 * @author Ulf Zibis
48 * @since 1.5
49 */
50 abstract class AbstractStringBuilder implements Appendable, CharSequence {
51 /**
52 * The value is used for character storage.
53 */
54 char[] value;
55
56 /**
57 * The count is the number of characters used.
58 */
59 int count;
60
61 /**
62 * This no-arg constructor is necessary for serialization of subclasses.
63 */
64 AbstractStringBuilder() {
65 }
66
67 /**
68 * Creates an AbstractStringBuilder of the specified capacity.
69 */
70 AbstractStringBuilder(int capacity) {
71 value = new char[capacity];
72 }
73
74 /**
75 * Returns the length (character count).
76 *
77 * @return the length of the sequence of characters currently
78 * represented by this object
79 */
80 @Override
81 public int length() {
82 return count;
83 }
84
85 /**
86 * Returns the current capacity. The capacity is the amount of storage
87 * available for newly inserted characters, beyond which an allocation
88 * will occur.
89 *
90 * @return the current capacity
91 */
92 public int capacity() {
93 return value.length;
94 }
95
96 /**
97 * Ensures that the capacity is at least equal to the specified minimum.
98 * If the current capacity is less than the argument, then a new internal
99 * array is allocated with greater capacity. The new capacity is the
100 * larger of:
101 * <ul>
102 * <li>The {@code minimumCapacity} argument.
103 * <li>Twice the old capacity, plus {@code 2}.
104 * </ul>
105 * If the {@code minimumCapacity} argument is nonpositive, this
106 * method takes no action and simply returns.
107 * Note that subsequent operations on this object can reduce the
108 * actual capacity below that requested here.
109 *
110 * @param minimumCapacity the minimum desired capacity.
111 */
112 public void ensureCapacity(int minimumCapacity) {
113 if (minimumCapacity > 0)
114 ensureCapacityInternal(minimumCapacity);
115 }
116
117 /**
118 * This method has the same contract as ensureCapacity, but is
119 * never synchronized.
120 */
121 private void ensureCapacityInternal(int minimumCapacity) {
122 // overflow-conscious code
123 if (minimumCapacity - value.length > 0)
124 expandCapacity(minimumCapacity);
125 }
126
127 /**
128 * This implements the expansion semantics of ensureCapacity with no
129 * size check or synchronization.
130 */
131 void expandCapacity(int minimumCapacity) {
132 int newCapacity = value.length * 2 + 2;
133 if (newCapacity - minimumCapacity < 0)
134 newCapacity = minimumCapacity;
135 if (newCapacity < 0) {
136 if (minimumCapacity < 0) // overflow
137 throw new OutOfMemoryError();
138 newCapacity = Integer.MAX_VALUE;
139 }
140 value = Arrays.copyOf(value, newCapacity);
141 }
142
143 /**
144 * Attempts to reduce storage used for the character sequence.
145 * If the buffer is larger than necessary to hold its current sequence of
146 * characters, then it may be resized to become more space efficient.
147 * Calling this method may, but is not required to, affect the value
148 * returned by a subsequent call to the {@link #capacity()} method.
149 */
150 public void trimToSize() {
151 if (count < value.length) {
152 value = Arrays.copyOf(value, count);
153 }
154 }
155
156 /**
157 * Sets the length of the character sequence.
158 * The sequence is changed to a new character sequence
159 * whose length is specified by the argument. For every nonnegative
160 * index <i>k</i> less than {@code newLength}, the character at
161 * index <i>k</i> in the new character sequence is the same as the
162 * character at index <i>k</i> in the old sequence if <i>k</i> is less
163 * than the length of the old character sequence; otherwise, it is the
164 * null character {@code '\u005Cu0000'}.
165 *
166 * In other words, if the {@code newLength} argument is less than
167 * the current length, the length is changed to the specified length.
168 * <p>
169 * If the {@code newLength} argument is greater than or equal
170 * to the current length, sufficient null characters
171 * ({@code '\u005Cu0000'}) are appended so that
172 * length becomes the {@code newLength} argument.
173 * <p>
174 * The {@code newLength} argument must be greater than or equal
175 * to {@code 0}.
176 *
177 * @param newLength the new length
178 * @throws IndexOutOfBoundsException if the
179 * {@code newLength} argument is negative.
180 */
181 public void setLength(int newLength) {
182 if (newLength < 0)
183 throw new StringIndexOutOfBoundsException(newLength);
184 ensureCapacityInternal(newLength);
185
186 if (count < newLength) {
187 Arrays.fill(value, count, newLength, '\0');
188 }
189
190 count = newLength;
191 }
192
193 /**
194 * Returns the {@code char} value in this sequence at the specified index.
195 * The first {@code char} value is at index {@code 0}, the next at index
196 * {@code 1}, and so on, as in array indexing.
197 * <p>
198 * The index argument must be greater than or equal to
199 * {@code 0}, and less than the length of this sequence.
200 *
201 * <p>If the {@code char} value specified by the index is a
202 * <a href="Character.html#unicode">surrogate</a>, the surrogate
203 * value is returned.
204 *
205 * @param index the index of the desired {@code char} value.
206 * @return the {@code char} value at the specified index.
207 * @throws IndexOutOfBoundsException if {@code index} is
208 * negative or greater than or equal to {@code length()}.
209 */
210 @Override
211 public char charAt(int index) {
212 if ((index < 0) || (index >= count))
213 throw new StringIndexOutOfBoundsException(index);
214 return value[index];
215 }
216
217 /**
218 * Returns the character (Unicode code point) at the specified
219 * index. The index refers to {@code char} values
220 * (Unicode code units) and ranges from {@code 0} to
221 * {@link #length()}{@code - 1}.
222 *
223 * <p> If the {@code char} value specified at the given index
224 * is in the high-surrogate range, the following index is less
225 * than the length of this sequence, and the
226 * {@code char} value at the following index is in the
227 * low-surrogate range, then the supplementary code point
228 * corresponding to this surrogate pair is returned. Otherwise,
229 * the {@code char} value at the given index is returned.
230 *
231 * @param index the index to the {@code char} values
232 * @return the code point value of the character at the
233 * {@code index}
234 * @exception IndexOutOfBoundsException if the {@code index}
235 * argument is negative or not less than the length of this
236 * sequence.
237 */
238 public int codePointAt(int index) {
239 if ((index < 0) || (index >= count)) {
240 throw new StringIndexOutOfBoundsException(index);
241 }
242 return Character.codePointAtImpl(value, index, count);
243 }
244
245 /**
246 * Returns the character (Unicode code point) before the specified
247 * index. The index refers to {@code char} values
248 * (Unicode code units) and ranges from {@code 1} to {@link
249 * #length()}.
250 *
251 * <p> If the {@code char} value at {@code (index - 1)}
252 * is in the low-surrogate range, {@code (index - 2)} is not
253 * negative, and the {@code char} value at {@code (index -
254 * 2)} is in the high-surrogate range, then the
255 * supplementary code point value of the surrogate pair is
256 * returned. If the {@code char} value at {@code index -
257 * 1} is an unpaired low-surrogate or a high-surrogate, the
258 * surrogate value is returned.
259 *
260 * @param index the index following the code point that should be returned
261 * @return the Unicode code point value before the given index.
262 * @exception IndexOutOfBoundsException if the {@code index}
263 * argument is less than 1 or greater than the length
264 * of this sequence.
265 */
266 public int codePointBefore(int index) {
267 int i = index - 1;
268 if ((i < 0) || (i >= count)) {
269 throw new StringIndexOutOfBoundsException(index);
270 }
271 return Character.codePointBeforeImpl(value, index, 0);
272 }
273
274 /**
275 * Returns the number of Unicode code points in the specified text
276 * range of this sequence. The text range begins at the specified
277 * {@code beginIndex} and extends to the {@code char} at
278 * index {@code endIndex - 1}. Thus the length (in
279 * {@code char}s) of the text range is
280 * {@code endIndex-beginIndex}. Unpaired surrogates within
281 * this sequence count as one code point each.
282 *
283 * @param beginIndex the index to the first {@code char} of
284 * the text range.
285 * @param endIndex the index after the last {@code char} of
286 * the text range.
287 * @return the number of Unicode code points in the specified text
288 * range
289 * @exception IndexOutOfBoundsException if the
290 * {@code beginIndex} is negative, or {@code endIndex}
291 * is larger than the length of this sequence, or
292 * {@code beginIndex} is larger than {@code endIndex}.
293 */
294 public int codePointCount(int beginIndex, int endIndex) {
295 if (beginIndex < 0 || endIndex > count || beginIndex > endIndex) {
296 throw new IndexOutOfBoundsException();
297 }
298 return Character.codePointCountImpl(value, beginIndex, endIndex - beginIndex);
299 }
300
301 /**
302 * Returns the index within this sequence that is offset from the
303 * given {@code index} by {@code codePointOffset} code
304 * points. Unpaired surrogates within the text range given by
305 * {@code index} and {@code codePointOffset} count as
306 * one code point each.
307 *
308 * @param index the index to be offset
309 * @param codePointOffset the offset in code points
310 * @return the index within this sequence
311 * @exception IndexOutOfBoundsException if {@code index}
312 * is negative or larger then the length of this sequence,
313 * or if {@code codePointOffset} is positive and the subsequence
314 * starting with {@code index} has fewer than
315 * {@code codePointOffset} code points,
316 * or if {@code codePointOffset} is negative and the subsequence
317 * before {@code index} has fewer than the absolute value of
318 * {@code codePointOffset} code points.
319 */
320 public int offsetByCodePoints(int index, int codePointOffset) {
321 if (index < 0 || index > count) {
322 throw new IndexOutOfBoundsException();
323 }
324 return Character.offsetByCodePointsImpl(value, 0, count,
325 index, codePointOffset);
326 }
327
328 /**
329 * Characters are copied from this sequence into the
330 * destination character array {@code dst}. The first character to
331 * be copied is at index {@code srcBegin}; the last character to
332 * be copied is at index {@code srcEnd-1}. The total number of
333 * characters to be copied is {@code srcEnd-srcBegin}. The
334 * characters are copied into the subarray of {@code dst} starting
335 * at index {@code dstBegin} and ending at index:
336 * <pre>{@code
337 * dstbegin + (srcEnd-srcBegin) - 1
338 * }</pre>
339 *
340 * @param srcBegin start copying at this offset.
341 * @param srcEnd stop copying at this offset.
342 * @param dst the array to copy the data into.
343 * @param dstBegin offset into {@code dst}.
344 * @throws IndexOutOfBoundsException if any of the following is true:
345 * <ul>
346 * <li>{@code srcBegin} is negative
347 * <li>{@code dstBegin} is negative
348 * <li>the {@code srcBegin} argument is greater than
349 * the {@code srcEnd} argument.
350 * <li>{@code srcEnd} is greater than
351 * {@code this.length()}.
352 * <li>{@code dstBegin+srcEnd-srcBegin} is greater than
353 * {@code dst.length}
354 * </ul>
355 */
356 public void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)
357 {
358 if (srcBegin < 0)
359 throw new StringIndexOutOfBoundsException(srcBegin);
360 if ((srcEnd < 0) || (srcEnd > count))
361 throw new StringIndexOutOfBoundsException(srcEnd);
362 if (srcBegin > srcEnd)
363 throw new StringIndexOutOfBoundsException("srcBegin > srcEnd");
364 System.arraycopy(value, srcBegin, dst, dstBegin, srcEnd - srcBegin);
365 }
366
367 /**
368 * The character at the specified index is set to {@code ch}. This
369 * sequence is altered to represent a new character sequence that is
370 * identical to the old character sequence, except that it contains the
371 * character {@code ch} at position {@code index}.
372 * <p>
373 * The index argument must be greater than or equal to
374 * {@code 0}, and less than the length of this sequence.
375 *
376 * @param index the index of the character to modify.
377 * @param ch the new character.
378 * @throws IndexOutOfBoundsException if {@code index} is
379 * negative or greater than or equal to {@code length()}.
380 */
381 public void setCharAt(int index, char ch) {
382 if ((index < 0) || (index >= count))
383 throw new StringIndexOutOfBoundsException(index);
384 value[index] = ch;
385 }
386
387 /**
388 * Appends the string representation of the {@code Object} argument.
389 * <p>
390 * The overall effect is exactly as if the argument were converted
391 * to a string by the method {@link String#valueOf(Object)},
392 * and the characters of that string were then
393 * {@link #append(String) appended} to this character sequence.
394 *
395 * @param obj an {@code Object}.
396 * @return a reference to this object.
397 */
398 public AbstractStringBuilder append(Object obj) {
399 return append(String.valueOf(obj));
400 }
401
402 /**
403 * Appends the specified string to this character sequence.
404 * <p>
405 * The characters of the {@code String} argument are appended, in
406 * order, increasing the length of this sequence by the length of the
407 * argument. If {@code str} is {@code null}, then the four
408 * characters {@code "null"} are appended.
409 * <p>
410 * Let <i>n</i> be the length of this character sequence just prior to
411 * execution of the {@code append} method. Then the character at
412 * index <i>k</i> in the new character sequence is equal to the character
413 * at index <i>k</i> in the old character sequence, if <i>k</i> is less
414 * than <i>n</i>; otherwise, it is equal to the character at index
415 * <i>k-n</i> in the argument {@code str}.
416 *
417 * @param str a string.
418 * @return a reference to this object.
419 */
420 public AbstractStringBuilder append(String str) {
421 if (str == null)
422 return appendNull();
423 int len = str.length();
424 ensureCapacityInternal(count + len);
425 str.getChars(0, len, value, count);
426 count += len;
427 return this;
428 }
429
430 // Documentation in subclasses because of synchro difference
431 public AbstractStringBuilder append(StringBuffer sb) {
432 if (sb == null)
433 return appendNull();
434 int len = sb.length();
435 ensureCapacityInternal(count + len);
436 sb.getChars(0, len, value, count);
437 count += len;
438 return this;
439 }
440
441 /**
442 * @since 1.8
443 */
444 AbstractStringBuilder append(AbstractStringBuilder asb) {
445 if (asb == null)
446 return appendNull();
447 int len = asb.length();
448 ensureCapacityInternal(count + len);
449 asb.getChars(0, len, value, count);
450 count += len;
451 return this;
452 }
453
454 // Documentation in subclasses because of synchro difference
455 @Override
456 public AbstractStringBuilder append(CharSequence s) {
457 if (s == null)
458 return appendNull();
459 if (s instanceof String)
460 return this.append((String)s);
461 if (s instanceof AbstractStringBuilder)
462 return this.append((AbstractStringBuilder)s);
463
464 return this.append(s, 0, s.length());
465 }
466
467 private AbstractStringBuilder appendNull() {
468 int c = count;
469 ensureCapacityInternal(c + 4);
470 final char[] value = this.value;
471 value[c++] = 'n';
472 value[c++] = 'u';
473 value[c++] = 'l';
474 value[c++] = 'l';
475 count = c;
476 return this;
477 }
478
479 /**
480 * Appends a subsequence of the specified {@code CharSequence} to this
481 * sequence.
482 * <p>
483 * Characters of the argument {@code s}, starting at
484 * index {@code start}, are appended, in order, to the contents of
485 * this sequence up to the (exclusive) index {@code end}. The length
486 * of this sequence is increased by the value of {@code end - start}.
487 * <p>
488 * Let <i>n</i> be the length of this character sequence just prior to
489 * execution of the {@code append} method. Then the character at
490 * index <i>k</i> in this character sequence becomes equal to the
491 * character at index <i>k</i> in this sequence, if <i>k</i> is less than
492 * <i>n</i>; otherwise, it is equal to the character at index
493 * <i>k+start-n</i> in the argument {@code s}.
494 * <p>
495 * If {@code s} is {@code null}, then this method appends
496 * characters as if the s parameter was a sequence containing the four
497 * characters {@code "null"}.
498 *
499 * @param s the sequence to append.
500 * @param start the starting index of the subsequence to be appended.
501 * @param end the end index of the subsequence to be appended.
502 * @return a reference to this object.
503 * @throws IndexOutOfBoundsException if
504 * {@code start} is negative, or
505 * {@code start} is greater than {@code end} or
506 * {@code end} is greater than {@code s.length()}
507 */
508 @Override
509 public AbstractStringBuilder append(CharSequence s, int start, int end) {
510 if (s == null)
511 s = "null";
512 if ((start < 0) || (start > end) || (end > s.length()))
513 throw new IndexOutOfBoundsException(
514 "start " + start + ", end " + end + ", s.length() "
515 + s.length());
516 int len = end - start;
517 ensureCapacityInternal(count + len);
518 if (s instanceof String) {
519 ((String)s).getChars(start, end, value, count);
520 } else {
521 for (int i = start, j = count; i < end; i++, j++)
522 value[j] = s.charAt(i);
523 }
524 count += len;
525 return this;
526 }
527
528 /**
529 * Appends the string representation of the {@code char} array
530 * argument to this sequence.
531 * <p>
532 * The characters of the array argument are appended, in order, to
533 * the contents of this sequence. The length of this sequence
534 * increases by the length of the argument.
535 * <p>
536 * The overall effect is exactly as if the argument were converted
537 * to a string by the method {@link String#valueOf(char[])},
538 * and the characters of that string were then
539 * {@link #append(String) appended} to this character sequence.
540 *
541 * @param str the characters to be appended.
542 * @return a reference to this object.
543 */
544 public AbstractStringBuilder append(char[] str) {
545 int len = str.length;
546 ensureCapacityInternal(count + len);
547 System.arraycopy(str, 0, value, count, len);
548 count += len;
549 return this;
550 }
551
552 /**
553 * Appends the string representation of a subarray of the
554 * {@code char} array argument to this sequence.
555 * <p>
556 * Characters of the {@code char} array {@code str}, starting at
557 * index {@code offset}, are appended, in order, to the contents
558 * of this sequence. The length of this sequence increases
559 * by the value of {@code len}.
560 * <p>
561 * The overall effect is exactly as if the arguments were converted
562 * to a string by the method {@link String#valueOf(char[],int,int)},
563 * and the characters of that string were then
564 * {@link #append(String) appended} to this character sequence.
565 *
566 * @param str the characters to be appended.
567 * @param offset the index of the first {@code char} to append.
568 * @param len the number of {@code char}s to append.
569 * @return a reference to this object.
570 * @throws IndexOutOfBoundsException
571 * if {@code offset < 0} or {@code len < 0}
572 * or {@code offset+len > str.length}
573 */
574 public AbstractStringBuilder append(char str[], int offset, int len) {
575 if (len > 0) // let arraycopy report AIOOBE for len < 0
576 ensureCapacityInternal(count + len);
577 System.arraycopy(str, offset, value, count, len);
578 count += len;
579 return this;
580 }
581
582 /**
583 * Appends the string representation of the {@code boolean}
584 * argument to the sequence.
585 * <p>
586 * The overall effect is exactly as if the argument were converted
587 * to a string by the method {@link String#valueOf(boolean)},
588 * and the characters of that string were then
589 * {@link #append(String) appended} to this character sequence.
590 *
591 * @param b a {@code boolean}.
592 * @return a reference to this object.
593 */
594 public AbstractStringBuilder append(boolean b) {
595 if (b) {
596 ensureCapacityInternal(count + 4);
597 value[count++] = 't';
598 value[count++] = 'r';
599 value[count++] = 'u';
600 value[count++] = 'e';
601 } else {
602 ensureCapacityInternal(count + 5);
603 value[count++] = 'f';
604 value[count++] = 'a';
605 value[count++] = 'l';
606 value[count++] = 's';
607 value[count++] = 'e';
608 }
609 return this;
610 }
611
612 /**
613 * Appends the string representation of the {@code char}
614 * argument to this sequence.
615 * <p>
616 * The argument is appended to the contents of this sequence.
617 * The length of this sequence increases by {@code 1}.
618 * <p>
619 * The overall effect is exactly as if the argument were converted
620 * to a string by the method {@link String#valueOf(char)},
621 * and the character in that string were then
622 * {@link #append(String) appended} to this character sequence.
623 *
624 * @param c a {@code char}.
625 * @return a reference to this object.
626 */
627 @Override
628 public AbstractStringBuilder append(char c) {
629 ensureCapacityInternal(count + 1);
630 value[count++] = c;
631 return this;
632 }
633
634 /**
635 * Appends the string representation of the {@code int}
636 * argument to this sequence.
637 * <p>
638 * The overall effect is exactly as if the argument were converted
639 * to a string by the method {@link String#valueOf(int)},
640 * and the characters of that string were then
641 * {@link #append(String) appended} to this character sequence.
642 *
643 * @param i an {@code int}.
644 * @return a reference to this object.
645 */
646 public AbstractStringBuilder append(int i) {
647 if (i == Integer.MIN_VALUE) {
648 append("-2147483648");
649 return this;
650 }
651 int appendedLength = (i < 0) ? Integer.stringSize(-i) + 1
652 : Integer.stringSize(i);
653 int spaceNeeded = count + appendedLength;
654 ensureCapacityInternal(spaceNeeded);
655 Integer.getChars(i, spaceNeeded, value);
656 count = spaceNeeded;
657 return this;
658 }
659
660 /**
661 * Appends the string representation of the {@code long}
662 * argument to this sequence.
663 * <p>
664 * The overall effect is exactly as if the argument were converted
665 * to a string by the method {@link String#valueOf(long)},
666 * and the characters of that string were then
667 * {@link #append(String) appended} to this character sequence.
668 *
669 * @param l a {@code long}.
670 * @return a reference to this object.
671 */
672 public AbstractStringBuilder append(long l) {
673 if (l == Long.MIN_VALUE) {
674 append("-9223372036854775808");
675 return this;
676 }
677 int appendedLength = (l < 0) ? Long.stringSize(-l) + 1
678 : Long.stringSize(l);
679 int spaceNeeded = count + appendedLength;
680 ensureCapacityInternal(spaceNeeded);
681 Long.getChars(l, spaceNeeded, value);
682 count = spaceNeeded;
683 return this;
684 }
685
686 /**
687 * Appends the string representation of the {@code float}
688 * argument to this sequence.
689 * <p>
690 * The overall effect is exactly as if the argument were converted
691 * to a string by the method {@link String#valueOf(float)},
692 * and the characters of that string were then
693 * {@link #append(String) appended} to this character sequence.
694 *
695 * @param f a {@code float}.
696 * @return a reference to this object.
697 */
698 public AbstractStringBuilder append(float f) {
699 FloatingDecimal.appendTo(f,this);
700 return this;
701 }
702
703 /**
704 * Appends the string representation of the {@code double}
705 * argument to this sequence.
706 * <p>
707 * The overall effect is exactly as if the argument were converted
708 * to a string by the method {@link String#valueOf(double)},
709 * and the characters of that string were then
710 * {@link #append(String) appended} to this character sequence.
711 *
712 * @param d a {@code double}.
713 * @return a reference to this object.
714 */
715 public AbstractStringBuilder append(double d) {
716 FloatingDecimal.appendTo(d,this);
717 return this;
718 }
719
720 /**
721 * Removes the characters in a substring of this sequence.
722 * The substring begins at the specified {@code start} and extends to
723 * the character at index {@code end - 1} or to the end of the
724 * sequence if no such character exists. If
725 * {@code start} is equal to {@code end}, no changes are made.
726 *
727 * @param start The beginning index, inclusive.
728 * @param end The ending index, exclusive.
729 * @return This object.
730 * @throws StringIndexOutOfBoundsException if {@code start}
731 * is negative, greater than {@code length()}, or
732 * greater than {@code end}.
733 */
734 public AbstractStringBuilder delete(int start, int end) {
735 if (start < 0)
736 throw new StringIndexOutOfBoundsException(start);
737 if (end > count)
738 end = count;
739 if (start > end)
740 throw new StringIndexOutOfBoundsException();
741 int len = end - start;
742 if (len > 0) {
743 System.arraycopy(value, start+len, value, start, count-end);
744 count -= len;
745 }
746 return this;
747 }
748
749 /**
750 * Appends the string representation of the {@code codePoint}
751 * argument to this sequence.
752 *
753 * <p> The argument is appended to the contents of this sequence.
754 * The length of this sequence increases by
755 * {@link Character#charCount(int) Character.charCount(codePoint)}.
756 *
757 * <p> The overall effect is exactly as if the argument were
758 * converted to a {@code char} array by the method
759 * {@link Character#toChars(int)} and the character in that array
760 * were then {@link #append(char[]) appended} to this character
761 * sequence.
762 *
763 * @param codePoint a Unicode code point
764 * @return a reference to this object.
765 * @exception IllegalArgumentException if the specified
766 * {@code codePoint} isn't a valid Unicode code point
767 */
768 public AbstractStringBuilder appendCodePoint(int codePoint) {
769 final int count = this.count;
770
771 if (Character.isBmpCodePoint(codePoint)) {
772 ensureCapacityInternal(count + 1);
773 value[count] = (char) codePoint;
774 this.count = count + 1;
775 } else if (Character.isValidCodePoint(codePoint)) {
776 ensureCapacityInternal(count + 2);
777 Character.toSurrogates(codePoint, value, count);
778 this.count = count + 2;
779 } else {
780 throw new IllegalArgumentException();
781 }
782 return this;
783 }
784
785 /**
786 * Removes the {@code char} at the specified position in this
787 * sequence. This sequence is shortened by one {@code char}.
788 *
789 * <p>Note: If the character at the given index is a supplementary
790 * character, this method does not remove the entire character. If
791 * correct handling of supplementary characters is required,
792 * determine the number of {@code char}s to remove by calling
793 * {@code Character.charCount(thisSequence.codePointAt(index))},
794 * where {@code thisSequence} is this sequence.
795 *
796 * @param index Index of {@code char} to remove
797 * @return This object.
798 * @throws StringIndexOutOfBoundsException if the {@code index}
799 * is negative or greater than or equal to
800 * {@code length()}.
801 */
802 public AbstractStringBuilder deleteCharAt(int index) {
803 if ((index < 0) || (index >= count))
804 throw new StringIndexOutOfBoundsException(index);
805 System.arraycopy(value, index+1, value, index, count-index-1);
806 count--;
807 return this;
808 }
809
810 /**
811 * Replaces the characters in a substring of this sequence
812 * with characters in the specified {@code String}. The substring
813 * begins at the specified {@code start} and extends to the character
814 * at index {@code end - 1} or to the end of the
815 * sequence if no such character exists. First the
816 * characters in the substring are removed and then the specified
817 * {@code String} is inserted at {@code start}. (This
818 * sequence will be lengthened to accommodate the
819 * specified String if necessary.)
820 *
821 * @param start The beginning index, inclusive.
822 * @param end The ending index, exclusive.
823 * @param str String that will replace previous contents.
824 * @return This object.
825 * @throws StringIndexOutOfBoundsException if {@code start}
826 * is negative, greater than {@code length()}, or
827 * greater than {@code end}.
828 */
829 public AbstractStringBuilder replace(int start, int end, String str) {
830 if (start < 0)
831 throw new StringIndexOutOfBoundsException(start);
832 if (start > count)
833 throw new StringIndexOutOfBoundsException("start > length()");
834 if (start > end)
835 throw new StringIndexOutOfBoundsException("start > end");
836
837 if (end > count)
838 end = count;
839 int len = str.length();
840 int newCount = count + len - (end - start);
841 ensureCapacityInternal(newCount);
842
843 System.arraycopy(value, end, value, start + len, count - end);
844 str.getChars(value, start);
845 count = newCount;
846 return this;
847 }
848
849 /**
850 * Returns a new {@code String} that contains a subsequence of
851 * characters currently contained in this character sequence. The
852 * substring begins at the specified index and extends to the end of
853 * this sequence.
854 *
855 * @param start The beginning index, inclusive.
856 * @return The new string.
857 * @throws StringIndexOutOfBoundsException if {@code start} is
858 * less than zero, or greater than the length of this object.
859 */
860 public String substring(int start) {
861 return substring(start, count);
862 }
863
864 /**
865 * Returns a new character sequence that is a subsequence of this sequence.
866 *
867 * <p> An invocation of this method of the form
868 *
869 * <pre>{@code
870 * sb.subSequence(begin, end)}</pre>
871 *
872 * behaves in exactly the same way as the invocation
873 *
874 * <pre>{@code
875 * sb.substring(begin, end)}</pre>
876 *
877 * This method is provided so that this class can
878 * implement the {@link CharSequence} interface.
879 *
880 * @param start the start index, inclusive.
881 * @param end the end index, exclusive.
882 * @return the specified subsequence.
883 *
884 * @throws IndexOutOfBoundsException
885 * if {@code start} or {@code end} are negative,
886 * if {@code end} is greater than {@code length()},
887 * or if {@code start} is greater than {@code end}
888 * @spec JSR-51
889 */
890 @Override
891 public CharSequence subSequence(int start, int end) {
892 return substring(start, end);
893 }
894
895 /**
896 * Returns a new {@code String} that contains a subsequence of
897 * characters currently contained in this sequence. The
898 * substring begins at the specified {@code start} and
899 * extends to the character at index {@code end - 1}.
900 *
901 * @param start The beginning index, inclusive.
902 * @param end The ending index, exclusive.
903 * @return The new string.
904 * @throws StringIndexOutOfBoundsException if {@code start}
905 * or {@code end} are negative or greater than
906 * {@code length()}, or {@code start} is
907 * greater than {@code end}.
908 */
909 public String substring(int start, int end) {
910 if (start < 0)
911 throw new StringIndexOutOfBoundsException(start);
912 if (end > count)
913 throw new StringIndexOutOfBoundsException(end);
914 if (start > end)
915 throw new StringIndexOutOfBoundsException(end - start);
916 return new String(value, start, end - start);
917 }
918
919 /**
920 * Inserts the string representation of a subarray of the {@code str}
921 * array argument into this sequence. The subarray begins at the
922 * specified {@code offset} and extends {@code len} {@code char}s.
923 * The characters of the subarray are inserted into this sequence at
924 * the position indicated by {@code index}. The length of this
925 * sequence increases by {@code len} {@code char}s.
926 *
927 * @param index position at which to insert subarray.
928 * @param str A {@code char} array.
929 * @param offset the index of the first {@code char} in subarray to
930 * be inserted.
931 * @param len the number of {@code char}s in the subarray to
932 * be inserted.
933 * @return This object
934 * @throws StringIndexOutOfBoundsException if {@code index}
935 * is negative or greater than {@code length()}, or
936 * {@code offset} or {@code len} are negative, or
937 * {@code (offset+len)} is greater than
938 * {@code str.length}.
939 */
940 public AbstractStringBuilder insert(int index, char[] str, int offset,
941 int len)
942 {
943 if ((index < 0) || (index > length()))
944 throw new StringIndexOutOfBoundsException(index);
945 if ((offset < 0) || (len < 0) || (offset > str.length - len))
946 throw new StringIndexOutOfBoundsException(
947 "offset " + offset + ", len " + len + ", str.length "
948 + str.length);
949 ensureCapacityInternal(count + len);
950 System.arraycopy(value, index, value, index + len, count - index);
951 System.arraycopy(str, offset, value, index, len);
952 count += len;
953 return this;
954 }
955
956 /**
957 * Inserts the string representation of the {@code Object}
958 * argument into this character sequence.
959 * <p>
960 * The overall effect is exactly as if the second argument were
961 * converted to a string by the method {@link String#valueOf(Object)},
962 * and the characters of that string were then
963 * {@link #insert(int,String) inserted} into this character
964 * sequence at the indicated offset.
965 * <p>
966 * The {@code offset} argument must be greater than or equal to
967 * {@code 0}, and less than or equal to the {@linkplain #length() length}
968 * of this sequence.
969 *
970 * @param offset the offset.
971 * @param obj an {@code Object}.
972 * @return a reference to this object.
973 * @throws StringIndexOutOfBoundsException if the offset is invalid.
974 */
975 public AbstractStringBuilder insert(int offset, Object obj) {
976 return insert(offset, String.valueOf(obj));
977 }
978
979 /**
980 * Inserts the string into this character sequence.
981 * <p>
982 * The characters of the {@code String} argument are inserted, in
983 * order, into this sequence at the indicated offset, moving up any
984 * characters originally above that position and increasing the length
985 * of this sequence by the length of the argument. If
986 * {@code str} is {@code null}, then the four characters
987 * {@code "null"} are inserted into this sequence.
988 * <p>
989 * The character at index <i>k</i> in the new character sequence is
990 * equal to:
991 * <ul>
992 * <li>the character at index <i>k</i> in the old character sequence, if
993 * <i>k</i> is less than {@code offset}
994 * <li>the character at index <i>k</i>{@code -offset} in the
995 * argument {@code str}, if <i>k</i> is not less than
996 * {@code offset} but is less than {@code offset+str.length()}
997 * <li>the character at index <i>k</i>{@code -str.length()} in the
998 * old character sequence, if <i>k</i> is not less than
999 * {@code offset+str.length()}
1000 * </ul><p>
1001 * The {@code offset} argument must be greater than or equal to
1002 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1003 * of this sequence.
1004 *
1005 * @param offset the offset.
1006 * @param str a string.
1007 * @return a reference to this object.
1008 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1009 */
1010 public AbstractStringBuilder insert(int offset, String str) {
1011 if ((offset < 0) || (offset > length()))
1012 throw new StringIndexOutOfBoundsException(offset);
1013 if (str == null)
1014 str = "null";
1015 int len = str.length();
1016 ensureCapacityInternal(count + len);
1017 System.arraycopy(value, offset, value, offset + len, count - offset);
1018 str.getChars(value, offset);
1019 count += len;
1020 return this;
1021 }
1022
1023 /**
1024 * Inserts the string representation of the {@code char} array
1025 * argument into this sequence.
1026 * <p>
1027 * The characters of the array argument are inserted into the
1028 * contents of this sequence at the position indicated by
1029 * {@code offset}. The length of this sequence increases by
1030 * the length of the argument.
1031 * <p>
1032 * The overall effect is exactly as if the second argument were
1033 * converted to a string by the method {@link String#valueOf(char[])},
1034 * and the characters of that string were then
1035 * {@link #insert(int,String) inserted} into this character
1036 * sequence at the indicated offset.
1037 * <p>
1038 * The {@code offset} argument must be greater than or equal to
1039 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1040 * of this sequence.
1041 *
1042 * @param offset the offset.
1043 * @param str a character array.
1044 * @return a reference to this object.
1045 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1046 */
1047 public AbstractStringBuilder insert(int offset, char[] str) {
1048 if ((offset < 0) || (offset > length()))
1049 throw new StringIndexOutOfBoundsException(offset);
1050 int len = str.length;
1051 ensureCapacityInternal(count + len);
1052 System.arraycopy(value, offset, value, offset + len, count - offset);
1053 System.arraycopy(str, 0, value, offset, len);
1054 count += len;
1055 return this;
1056 }
1057
1058 /**
1059 * Inserts the specified {@code CharSequence} into this sequence.
1060 * <p>
1061 * The characters of the {@code CharSequence} argument are inserted,
1062 * in order, into this sequence at the indicated offset, moving up
1063 * any characters originally above that position and increasing the length
1064 * of this sequence by the length of the argument s.
1065 * <p>
1066 * The result of this method is exactly the same as if it were an
1067 * invocation of this object's
1068 * {@link #insert(int,CharSequence,int,int) insert}(dstOffset, s, 0, s.length())
1069 * method.
1070 *
1071 * <p>If {@code s} is {@code null}, then the four characters
1072 * {@code "null"} are inserted into this sequence.
1073 *
1074 * @param dstOffset the offset.
1075 * @param s the sequence to be inserted
1076 * @return a reference to this object.
1077 * @throws IndexOutOfBoundsException if the offset is invalid.
1078 */
1079 public AbstractStringBuilder insert(int dstOffset, CharSequence s) {
1080 if (s == null)
1081 s = "null";
1082 if (s instanceof String)
1083 return this.insert(dstOffset, (String)s);
1084 return this.insert(dstOffset, s, 0, s.length());
1085 }
1086
1087 /**
1088 * Inserts a subsequence of the specified {@code CharSequence} into
1089 * this sequence.
1090 * <p>
1091 * The subsequence of the argument {@code s} specified by
1092 * {@code start} and {@code end} are inserted,
1093 * in order, into this sequence at the specified destination offset, moving
1094 * up any characters originally above that position. The length of this
1095 * sequence is increased by {@code end - start}.
1096 * <p>
1097 * The character at index <i>k</i> in this sequence becomes equal to:
1098 * <ul>
1099 * <li>the character at index <i>k</i> in this sequence, if
1100 * <i>k</i> is less than {@code dstOffset}
1101 * <li>the character at index <i>k</i>{@code +start-dstOffset} in
1102 * the argument {@code s}, if <i>k</i> is greater than or equal to
1103 * {@code dstOffset} but is less than {@code dstOffset+end-start}
1104 * <li>the character at index <i>k</i>{@code -(end-start)} in this
1105 * sequence, if <i>k</i> is greater than or equal to
1106 * {@code dstOffset+end-start}
1107 * </ul><p>
1108 * The {@code dstOffset} argument must be greater than or equal to
1109 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1110 * of this sequence.
1111 * <p>The start argument must be nonnegative, and not greater than
1112 * {@code end}.
1113 * <p>The end argument must be greater than or equal to
1114 * {@code start}, and less than or equal to the length of s.
1115 *
1116 * <p>If {@code s} is {@code null}, then this method inserts
1117 * characters as if the s parameter was a sequence containing the four
1118 * characters {@code "null"}.
1119 *
1120 * @param dstOffset the offset in this sequence.
1121 * @param s the sequence to be inserted.
1122 * @param start the starting index of the subsequence to be inserted.
1123 * @param end the end index of the subsequence to be inserted.
1124 * @return a reference to this object.
1125 * @throws IndexOutOfBoundsException if {@code dstOffset}
1126 * is negative or greater than {@code this.length()}, or
1127 * {@code start} or {@code end} are negative, or
1128 * {@code start} is greater than {@code end} or
1129 * {@code end} is greater than {@code s.length()}
1130 */
1131 public AbstractStringBuilder insert(int dstOffset, CharSequence s,
1132 int start, int end) {
1133 if (s == null)
1134 s = "null";
1135 if ((dstOffset < 0) || (dstOffset > this.length()))
1136 throw new IndexOutOfBoundsException("dstOffset "+dstOffset);
1137 if ((start < 0) || (end < 0) || (start > end) || (end > s.length()))
1138 throw new IndexOutOfBoundsException(
1139 "start " + start + ", end " + end + ", s.length() "
1140 + s.length());
1141 int len = end - start;
1142 ensureCapacityInternal(count + len);
1143 System.arraycopy(value, dstOffset, value, dstOffset + len,
1144 count - dstOffset);
1145 for (int i=start; i<end; i++)
1146 value[dstOffset++] = s.charAt(i);
1147 count += len;
1148 return this;
1149 }
1150
1151 /**
1152 * Inserts the string representation of the {@code boolean}
1153 * argument into this sequence.
1154 * <p>
1155 * The overall effect is exactly as if the second argument were
1156 * converted to a string by the method {@link String#valueOf(boolean)},
1157 * and the characters of that string were then
1158 * {@link #insert(int,String) inserted} into this character
1159 * sequence at the indicated offset.
1160 * <p>
1161 * The {@code offset} argument must be greater than or equal to
1162 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1163 * of this sequence.
1164 *
1165 * @param offset the offset.
1166 * @param b a {@code boolean}.
1167 * @return a reference to this object.
1168 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1169 */
1170 public AbstractStringBuilder insert(int offset, boolean b) {
1171 return insert(offset, String.valueOf(b));
1172 }
1173
1174 /**
1175 * Inserts the string representation of the {@code char}
1176 * argument into this sequence.
1177 * <p>
1178 * The overall effect is exactly as if the second argument were
1179 * converted to a string by the method {@link String#valueOf(char)},
1180 * and the character in that string were then
1181 * {@link #insert(int,String) inserted} into this character
1182 * sequence at the indicated offset.
1183 * <p>
1184 * The {@code offset} argument must be greater than or equal to
1185 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1186 * of this sequence.
1187 *
1188 * @param offset the offset.
1189 * @param c a {@code char}.
1190 * @return a reference to this object.
1191 * @throws IndexOutOfBoundsException if the offset is invalid.
1192 */
1193 public AbstractStringBuilder insert(int offset, char c) {
1194 ensureCapacityInternal(count + 1);
1195 System.arraycopy(value, offset, value, offset + 1, count - offset);
1196 value[offset] = c;
1197 count += 1;
1198 return this;
1199 }
1200
1201 /**
1202 * Inserts the string representation of the second {@code int}
1203 * argument into this sequence.
1204 * <p>
1205 * The overall effect is exactly as if the second argument were
1206 * converted to a string by the method {@link String#valueOf(int)},
1207 * and the characters of that string were then
1208 * {@link #insert(int,String) inserted} into this character
1209 * sequence at the indicated offset.
1210 * <p>
1211 * The {@code offset} argument must be greater than or equal to
1212 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1213 * of this sequence.
1214 *
1215 * @param offset the offset.
1216 * @param i an {@code int}.
1217 * @return a reference to this object.
1218 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1219 */
1220 public AbstractStringBuilder insert(int offset, int i) {
1221 return insert(offset, String.valueOf(i));
1222 }
1223
1224 /**
1225 * Inserts the string representation of the {@code long}
1226 * argument into this sequence.
1227 * <p>
1228 * The overall effect is exactly as if the second argument were
1229 * converted to a string by the method {@link String#valueOf(long)},
1230 * and the characters of that string were then
1231 * {@link #insert(int,String) inserted} into this character
1232 * sequence at the indicated offset.
1233 * <p>
1234 * The {@code offset} argument must be greater than or equal to
1235 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1236 * of this sequence.
1237 *
1238 * @param offset the offset.
1239 * @param l a {@code long}.
1240 * @return a reference to this object.
1241 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1242 */
1243 public AbstractStringBuilder insert(int offset, long l) {
1244 return insert(offset, String.valueOf(l));
1245 }
1246
1247 /**
1248 * Inserts the string representation of the {@code float}
1249 * argument into this sequence.
1250 * <p>
1251 * The overall effect is exactly as if the second argument were
1252 * converted to a string by the method {@link String#valueOf(float)},
1253 * and the characters of that string were then
1254 * {@link #insert(int,String) inserted} into this character
1255 * sequence at the indicated offset.
1256 * <p>
1257 * The {@code offset} argument must be greater than or equal to
1258 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1259 * of this sequence.
1260 *
1261 * @param offset the offset.
1262 * @param f a {@code float}.
1263 * @return a reference to this object.
1264 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1265 */
1266 public AbstractStringBuilder insert(int offset, float f) {
1267 return insert(offset, String.valueOf(f));
1268 }
1269
1270 /**
1271 * Inserts the string representation of the {@code double}
1272 * argument into this sequence.
1273 * <p>
1274 * The overall effect is exactly as if the second argument were
1275 * converted to a string by the method {@link String#valueOf(double)},
1276 * and the characters of that string were then
1277 * {@link #insert(int,String) inserted} into this character
1278 * sequence at the indicated offset.
1279 * <p>
1280 * The {@code offset} argument must be greater than or equal to
1281 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1282 * of this sequence.
1283 *
1284 * @param offset the offset.
1285 * @param d a {@code double}.
1286 * @return a reference to this object.
1287 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1288 */
1289 public AbstractStringBuilder insert(int offset, double d) {
1290 return insert(offset, String.valueOf(d));
1291 }
1292
1293 /**
1294 * Returns the index within this string of the first occurrence of the
1295 * specified substring.
1296 *
1297 * <p>The returned index is the smallest value {@code k} for which:
1298 * <pre>{@code
1299 * this.toString().startsWith(str, k)
1300 * }</pre>
1301 * If no such value of {@code k} exists, then {@code -1} is returned.
1302 *
1303 * @param str the substring to search for.
1304 * @return the index of the first occurrence of the specified substring,
1305 * or {@code -1} if there is no such occurrence.
1306 */
1307 public int indexOf(String str) {
1308 return indexOf(str, 0);
1309 }
1310
1311 /**
1312 * Returns the index within this string of the first occurrence of the
1313 * specified substring, starting at the specified index.
1314 *
1315 * <p>The returned index is the smallest value {@code k} for which:
1316 * <pre>{@code
1317 * k >= Math.min(fromIndex, this.length()) &&
1318 * this.toString().startsWith(str, k)
1319 * }</pre>
1320 * If no such value of {@code k} exists, then {@code -1} is returned.
1321 *
1322 * @param str the substring to search for.
1323 * @param fromIndex the index from which to start the search.
1324 * @return the index of the first occurrence of the specified substring,
1325 * starting at the specified index,
1326 * or {@code -1} if there is no such occurrence.
1327 */
1328 public int indexOf(String str, int fromIndex) {
1329 return String.indexOf(value, 0, count, str, fromIndex);
1330 }
1331
1332 /**
1333 * Returns the index within this string of the last occurrence of the
1334 * specified substring. The last occurrence of the empty string "" is
1335 * considered to occur at the index value {@code this.length()}.
1336 *
1337 * <p>The returned index is the largest value {@code k} for which:
1338 * <pre>{@code
1339 * this.toString().startsWith(str, k)
1340 * }</pre>
1341 * If no such value of {@code k} exists, then {@code -1} is returned.
1342 *
1343 * @param str the substring to search for.
1344 * @return the index of the last occurrence of the specified substring,
1345 * or {@code -1} if there is no such occurrence.
1346 */
1347 public int lastIndexOf(String str) {
1348 return lastIndexOf(str, count);
1349 }
1350
1351 /**
1352 * Returns the index within this string of the last occurrence of the
1353 * specified substring, searching backward starting at the specified index.
1354 *
1355 * <p>The returned index is the largest value {@code k} for which:
1356 * <pre>{@code
1357 * k <= Math.min(fromIndex, this.length()) &&
1358 * this.toString().startsWith(str, k)
1359 * }</pre>
1360 * If no such value of {@code k} exists, then {@code -1} is returned.
1361 *
1362 * @param str the substring to search for.
1363 * @param fromIndex the index to start the search from.
1364 * @return the index of the last occurrence of the specified substring,
1365 * searching backward from the specified index,
1366 * or {@code -1} if there is no such occurrence.
1367 */
1368 public int lastIndexOf(String str, int fromIndex) {
1369 return String.lastIndexOf(value, 0, count, str, fromIndex);
1370 }
1371
1372 /**
1373 * Causes this character sequence to be replaced by the reverse of
1374 * the sequence. If there are any surrogate pairs included in the
1375 * sequence, these are treated as single characters for the
1376 * reverse operation. Thus, the order of the high-low surrogates
1377 * is never reversed.
1378 *
1379 * Let <i>n</i> be the character length of this character sequence
1380 * (not the length in {@code char} values) just prior to
1381 * execution of the {@code reverse} method. Then the
1382 * character at index <i>k</i> in the new character sequence is
1383 * equal to the character at index <i>n-k-1</i> in the old
1384 * character sequence.
1385 *
1386 * <p>Note that the reverse operation may result in producing
1387 * surrogate pairs that were unpaired low-surrogates and
1388 * high-surrogates before the operation. For example, reversing
1389 * "\u005CuDC00\u005CuD800" produces "\u005CuD800\u005CuDC00" which is
1390 * a valid surrogate pair.
1391 *
1392 * @return a reference to this object.
1393 */
1394 public AbstractStringBuilder reverse() {
1395 boolean hasSurrogates = false;
1396 int n = count - 1;
1397 for (int j = (n-1) >> 1; j >= 0; j--) {
1398 int k = n - j;
1399 char cj = value[j];
1400 char ck = value[k];
1401 value[j] = ck;
1402 value[k] = cj;
1403 if (Character.isSurrogate(cj) ||
1404 Character.isSurrogate(ck)) {
1405 hasSurrogates = true;
1406 }
1407 }
1408 if (hasSurrogates) {
1409 reverseAllValidSurrogatePairs();
1410 }
1411 return this;
1412 }
1413
1414 /** Outlined helper method for reverse() */
1415 private void reverseAllValidSurrogatePairs() {
1416 for (int i = 0; i < count - 1; i++) {
1417 char c2 = value[i];
1418 if (Character.isLowSurrogate(c2)) {
1419 char c1 = value[i + 1];
1420 if (Character.isHighSurrogate(c1)) {
1421 value[i++] = c1;
1422 value[i] = c2;
1423 }
1424 }
1425 }
1426 }
1427
1428 /**
1429 * Returns a string representing the data in this sequence.
1430 * A new {@code String} object is allocated and initialized to
1431 * contain the character sequence currently represented by this
1432 * object. This {@code String} is then returned. Subsequent
1433 * changes to this sequence do not affect the contents of the
1434 * {@code String}.
1435 *
1436 * @return a string representation of this sequence of characters.
1437 */
1438 @Override
1439 public abstract String toString();
1440
1441 /**
1442 * {@inheritDoc}
1443 * @since 1.9
1444 */
1445 @Override
1446 public IntStream chars() {
1447 // Reuse String-based spliterator. This requires a supplier to
1448 // capture the value and count when the terminal operation is executed
1449 return StreamSupport.intStream(
1450 () -> new String.IntCharArraySpliterator(value, 0, count, 0),
1451 Spliterator.ORDERED | Spliterator.SIZED | Spliterator.SUBSIZED,
1452 false);
1453 }
1454
1455 /**
1456 * {@inheritDoc}
1457 * @since 1.9
1458 */
1459 @Override
1460 public IntStream codePoints() {
1461 // Reuse String-based spliterator. This requires a supplier to
1462 // capture the value and count when the terminal operation is executed
1463 return StreamSupport.intStream(
1464 () -> new String.CodePointsSpliterator(value, 0, count, 0),
1465 Spliterator.ORDERED,
1466 false);
1467 }
1468
1469 /**
1470 * Needed by {@code String} for the contentEquals method.
1471 */
1472 final char[] getValue() {
1473 return value;
1474 }
1475
1476 }