1 /*
2 * Copyright 2003-2008 Sun Microsystems, Inc. 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. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package java.lang;
27
28 import sun.misc.FloatingDecimal;
29 import java.util.Arrays;
30 import java.util.Iterator;
31
32 /**
33 * A mutable sequence of characters.
34 * <p>
35 * Implements a modifiable string. At any point in time it contains some
36 * particular sequence of characters, but the length and content of the
37 * sequence can be changed through certain method calls.
38 *
39 * @author Michael McCloskey
40 * @since 1.5
41 */
42 abstract class AbstractStringBuilder implements Appendable, CharSequence {
43 /**
44 * The value is used for character storage.
45 */
46 char[] value;
47
48 /**
49 * The count is the number of characters used.
50 */
51 int count;
52
53 /**
54 * This no-arg constructor is necessary for serialization of subclasses.
55 */
56 AbstractStringBuilder() {
57 }
58
59 /**
60 * Creates an AbstractStringBuilder of the specified capacity.
61 */
62 AbstractStringBuilder(int capacity) {
63 value = new char[capacity];
64 }
65
66 /**
67 * Returns the length (character count).
68 *
69 * @return the length of the sequence of characters currently
70 * represented by this object
71 */
72 public int length() {
73 return count;
74 }
75
76 /**
77 * Returns the current capacity. The capacity is the amount of storage
78 * available for newly inserted characters, beyond which an allocation
79 * will occur.
80 *
81 * @return the current capacity
82 */
83 public int capacity() {
84 return value.length;
85 }
86
87 /**
88 * Ensures that the capacity is at least equal to the specified minimum.
89 * If the current capacity is less than the argument, then a new internal
90 * array is allocated with greater capacity. The new capacity is the
91 * larger of:
92 * <ul>
93 * <li>The <code>minimumCapacity</code> argument.
94 * <li>Twice the old capacity, plus <code>2</code>.
95 * </ul>
96 * If the <code>minimumCapacity</code> argument is nonpositive, this
97 * method takes no action and simply returns.
98 *
99 * @param minimumCapacity the minimum desired capacity.
100 */
101 public void ensureCapacity(int minimumCapacity) {
102 if (minimumCapacity > value.length) {
103 expandCapacity(minimumCapacity);
104 }
105 }
106
107 /**
108 * This implements the expansion semantics of ensureCapacity with no
109 * size check or synchronization.
110 */
111 void expandCapacity(int minimumCapacity) {
112 int newCapacity = (value.length + 1) * 2;
113 if (newCapacity < 0) {
114 newCapacity = Integer.MAX_VALUE;
115 } else if (minimumCapacity > newCapacity) {
116 newCapacity = minimumCapacity;
117 }
118 value = Arrays.copyOf(value, newCapacity);
119 }
120
121 /**
122 * Attempts to reduce storage used for the character sequence.
123 * If the buffer is larger than necessary to hold its current sequence of
124 * characters, then it may be resized to become more space efficient.
125 * Calling this method may, but is not required to, affect the value
126 * returned by a subsequent call to the {@link #capacity()} method.
127 */
128 public void trimToSize() {
129 if (count < value.length) {
130 value = Arrays.copyOf(value, count);
131 }
132 }
133
134 /**
135 * Sets the length of the character sequence.
136 * The sequence is changed to a new character sequence
137 * whose length is specified by the argument. For every nonnegative
138 * index <i>k</i> less than <code>newLength</code>, the character at
139 * index <i>k</i> in the new character sequence is the same as the
140 * character at index <i>k</i> in the old sequence if <i>k</i> is less
141 * than the length of the old character sequence; otherwise, it is the
142 * null character <code>'\u0000'</code>.
143 *
144 * In other words, if the <code>newLength</code> argument is less than
145 * the current length, the length is changed to the specified length.
146 * <p>
147 * If the <code>newLength</code> argument is greater than or equal
148 * to the current length, sufficient null characters
149 * (<code>'\u0000'</code>) are appended so that
150 * length becomes the <code>newLength</code> argument.
151 * <p>
152 * The <code>newLength</code> argument must be greater than or equal
153 * to <code>0</code>.
154 *
155 * @param newLength the new length
156 * @throws IndexOutOfBoundsException if the
157 * <code>newLength</code> argument is negative.
158 */
159 public void setLength(int newLength) {
160 if (newLength < 0)
161 throw new StringIndexOutOfBoundsException(newLength);
162 if (newLength > value.length)
163 expandCapacity(newLength);
164
165 if (count < newLength) {
166 for (; count < newLength; count++)
167 value[count] = '\0';
168 } else {
169 count = newLength;
170 }
171 }
172
173 /**
174 * Returns the <code>char</code> value in this sequence at the specified index.
175 * The first <code>char</code> value is at index <code>0</code>, the next at index
176 * <code>1</code>, and so on, as in array indexing.
177 * <p>
178 * The index argument must be greater than or equal to
179 * <code>0</code>, and less than the length of this sequence.
180 *
181 * <p>If the <code>char</code> value specified by the index is a
182 * <a href="Character.html#unicode">surrogate</a>, the surrogate
183 * value is returned.
184 *
185 * @param index the index of the desired <code>char</code> value.
186 * @return the <code>char</code> value at the specified index.
187 * @throws IndexOutOfBoundsException if <code>index</code> is
188 * negative or greater than or equal to <code>length()</code>.
189 */
190 public char charAt(int index) {
191 if ((index < 0) || (index >= count))
192 throw new StringIndexOutOfBoundsException(index);
193 return value[index];
194 }
195
196 /**
197 * Returns the character (Unicode code point) at the specified
198 * index. The index refers to <code>char</code> values
199 * (Unicode code units) and ranges from <code>0</code> to
200 * {@link #length()}<code> - 1</code>.
201 *
202 * <p> If the <code>char</code> value specified at the given index
203 * is in the high-surrogate range, the following index is less
204 * than the length of this sequence, and the
205 * <code>char</code> value at the following index is in the
206 * low-surrogate range, then the supplementary code point
207 * corresponding to this surrogate pair is returned. Otherwise,
208 * the <code>char</code> value at the given index is returned.
209 *
210 * @param index the index to the <code>char</code> values
211 * @return the code point value of the character at the
212 * <code>index</code>
213 * @exception IndexOutOfBoundsException if the <code>index</code>
214 * argument is negative or not less than the length of this
215 * sequence.
216 */
217 public int codePointAt(int index) {
218 if ((index < 0) || (index >= count)) {
219 throw new StringIndexOutOfBoundsException(index);
220 }
221 return Character.codePointAt(value, index);
222 }
223
224 /**
225 * Returns the character (Unicode code point) before the specified
226 * index. The index refers to <code>char</code> values
227 * (Unicode code units) and ranges from <code>1</code> to {@link
228 * #length()}.
229 *
230 * <p> If the <code>char</code> value at <code>(index - 1)</code>
231 * is in the low-surrogate range, <code>(index - 2)</code> is not
232 * negative, and the <code>char</code> value at <code>(index -
233 * 2)</code> is in the high-surrogate range, then the
234 * supplementary code point value of the surrogate pair is
235 * returned. If the <code>char</code> value at <code>index -
236 * 1</code> is an unpaired low-surrogate or a high-surrogate, the
237 * surrogate value is returned.
238 *
239 * @param index the index following the code point that should be returned
240 * @return the Unicode code point value before the given index.
241 * @exception IndexOutOfBoundsException if the <code>index</code>
242 * argument is less than 1 or greater than the length
243 * of this sequence.
244 */
245 public int codePointBefore(int index) {
246 int i = index - 1;
247 if ((i < 0) || (i >= count)) {
248 throw new StringIndexOutOfBoundsException(index);
249 }
250 return Character.codePointBefore(value, index);
251 }
252
253 /**
254 * Returns the number of Unicode code points in the specified text
255 * range of this sequence. The text range begins at the specified
256 * <code>beginIndex</code> and extends to the <code>char</code> at
257 * index <code>endIndex - 1</code>. Thus the length (in
258 * <code>char</code>s) of the text range is
259 * <code>endIndex-beginIndex</code>. Unpaired surrogates within
260 * this sequence count as one code point each.
261 *
262 * @param beginIndex the index to the first <code>char</code> of
263 * the text range.
264 * @param endIndex the index after the last <code>char</code> of
265 * the text range.
266 * @return the number of Unicode code points in the specified text
267 * range
268 * @exception IndexOutOfBoundsException if the
269 * <code>beginIndex</code> is negative, or <code>endIndex</code>
270 * is larger than the length of this sequence, or
271 * <code>beginIndex</code> is larger than <code>endIndex</code>.
272 */
273 public int codePointCount(int beginIndex, int endIndex) {
274 if (beginIndex < 0 || endIndex > count || beginIndex > endIndex) {
275 throw new IndexOutOfBoundsException();
276 }
277 return Character.codePointCountImpl(value, beginIndex, endIndex-beginIndex);
278 }
279
280 /**
281 * Returns the index within this sequence that is offset from the
282 * given <code>index</code> by <code>codePointOffset</code> code
283 * points. Unpaired surrogates within the text range given by
284 * <code>index</code> and <code>codePointOffset</code> count as
285 * one code point each.
286 *
287 * @param index the index to be offset
288 * @param codePointOffset the offset in code points
289 * @return the index within this sequence
290 * @exception IndexOutOfBoundsException if <code>index</code>
291 * is negative or larger then the length of this sequence,
292 * or if <code>codePointOffset</code> is positive and the subsequence
293 * starting with <code>index</code> has fewer than
294 * <code>codePointOffset</code> code points,
295 * or if <code>codePointOffset</code> is negative and the subsequence
296 * before <code>index</code> has fewer than the absolute value of
297 * <code>codePointOffset</code> code points.
298 */
299 public int offsetByCodePoints(int index, int codePointOffset) {
300 if (index < 0 || index > count) {
301 throw new IndexOutOfBoundsException();
302 }
303 return Character.offsetByCodePointsImpl(value, 0, count,
304 index, codePointOffset);
305 }
306
307 /**
308 * Characters are copied from this sequence into the
309 * destination character array <code>dst</code>. The first character to
310 * be copied is at index <code>srcBegin</code>; the last character to
311 * be copied is at index <code>srcEnd-1</code>. The total number of
312 * characters to be copied is <code>srcEnd-srcBegin</code>. The
313 * characters are copied into the subarray of <code>dst</code> starting
314 * at index <code>dstBegin</code> and ending at index:
315 * <p><blockquote><pre>
316 * dstbegin + (srcEnd-srcBegin) - 1
317 * </pre></blockquote>
318 *
319 * @param srcBegin start copying at this offset.
320 * @param srcEnd stop copying at this offset.
321 * @param dst the array to copy the data into.
322 * @param dstBegin offset into <code>dst</code>.
323 * @throws NullPointerException if <code>dst</code> is
324 * <code>null</code>.
325 * @throws IndexOutOfBoundsException if any of the following is true:
326 * <ul>
327 * <li><code>srcBegin</code> is negative
328 * <li><code>dstBegin</code> is negative
329 * <li>the <code>srcBegin</code> argument is greater than
330 * the <code>srcEnd</code> argument.
331 * <li><code>srcEnd</code> is greater than
332 * <code>this.length()</code>.
333 * <li><code>dstBegin+srcEnd-srcBegin</code> is greater than
334 * <code>dst.length</code>
335 * </ul>
336 */
337 public void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)
338 {
339 if (srcBegin < 0)
340 throw new StringIndexOutOfBoundsException(srcBegin);
341 if ((srcEnd < 0) || (srcEnd > count))
342 throw new StringIndexOutOfBoundsException(srcEnd);
343 if (srcBegin > srcEnd)
344 throw new StringIndexOutOfBoundsException("srcBegin > srcEnd");
345 System.arraycopy(value, srcBegin, dst, dstBegin, srcEnd - srcBegin);
346 }
347
348 /**
349 * The character at the specified index is set to <code>ch</code>. This
350 * sequence is altered to represent a new character sequence that is
351 * identical to the old character sequence, except that it contains the
352 * character <code>ch</code> at position <code>index</code>.
353 * <p>
354 * The index argument must be greater than or equal to
355 * <code>0</code>, and less than the length of this sequence.
356 *
357 * @param index the index of the character to modify.
358 * @param ch the new character.
359 * @throws IndexOutOfBoundsException if <code>index</code> is
360 * negative or greater than or equal to <code>length()</code>.
361 */
362 public void setCharAt(int index, char ch) {
363 if ((index < 0) || (index >= count))
364 throw new StringIndexOutOfBoundsException(index);
365 value[index] = ch;
366 }
367
368 /**
369 * Appends the string representation of the {@code Object} argument.
370 * <p>
371 * The overall effect is exactly as if the argument were converted
372 * to a string by the method {@link String#valueOf(Object)},
373 * and the characters of that string were then
374 * {@link #append(String) appended} to this character sequence.
375 *
376 * @param obj an {@code Object}.
377 * @return a reference to this object.
378 */
379 public AbstractStringBuilder append(Object obj) {
380 return append(String.valueOf(obj));
381 }
382
383 /**
384 * Appends the specified string to this character sequence.
385 * <p>
386 * The characters of the {@code String} argument are appended, in
387 * order, increasing the length of this sequence by the length of the
388 * argument. If {@code str} is {@code null}, then the four
389 * characters {@code "null"} are appended.
390 * <p>
391 * Let <i>n</i> be the length of this character sequence just prior to
392 * execution of the {@code append} method. Then the character at
393 * index <i>k</i> in the new character sequence is equal to the character
394 * at index <i>k</i> in the old character sequence, if <i>k</i> is less
395 * than <i>n</i>; otherwise, it is equal to the character at index
396 * <i>k-n</i> in the argument {@code str}.
397 *
398 * @param str a string.
399 * @return a reference to this object.
400 */
401 public AbstractStringBuilder append(String str) {
402 if (str == null) str = "null";
403 int len = str.length();
404 if (len == 0) return this;
405 int newCount = count + len;
406 if (newCount > value.length)
407 expandCapacity(newCount);
408 str.getChars(0, len, value, count);
409 count = newCount;
410 return this;
411 }
412
413 // Documentation in subclasses because of synchro difference
414 public AbstractStringBuilder append(StringBuffer sb) {
415 if (sb == null)
416 return append("null");
417 int len = sb.length();
418 int newCount = count + len;
419 if (newCount > value.length)
420 expandCapacity(newCount);
421 sb.getChars(0, len, value, count);
422 count = newCount;
423 return this;
424 }
425
426 // Documentation in subclasses because of synchro difference
427 public AbstractStringBuilder append(CharSequence s) {
428 if (s == null)
429 s = "null";
430 if (s instanceof String)
431 return this.append((String)s);
432 if (s instanceof StringBuffer)
433 return this.append((StringBuffer)s);
434 return this.append(s, 0, s.length());
435 }
436
437 /**
438 * Appends a subsequence of the specified {@code CharSequence} to this
439 * sequence.
440 * <p>
441 * Characters of the argument {@code s}, starting at
442 * index {@code start}, are appended, in order, to the contents of
443 * this sequence up to the (exclusive) index {@code end}. The length
444 * of this sequence is increased by the value of {@code end - start}.
445 * <p>
446 * Let <i>n</i> be the length of this character sequence just prior to
447 * execution of the {@code append} method. Then the character at
448 * index <i>k</i> in this character sequence becomes equal to the
449 * character at index <i>k</i> in this sequence, if <i>k</i> is less than
450 * <i>n</i>; otherwise, it is equal to the character at index
451 * <i>k+start-n</i> in the argument {@code s}.
452 * <p>
453 * If {@code s} is {@code null}, then this method appends
454 * characters as if the s parameter was a sequence containing the four
455 * characters {@code "null"}.
456 *
457 * @param s the sequence to append.
458 * @param start the starting index of the subsequence to be appended.
459 * @param end the end index of the subsequence to be appended.
460 * @return a reference to this object.
461 * @throws IndexOutOfBoundsException if
462 * {@code start} is negative, or
463 * {@code start} is greater than {@code end} or
464 * {@code end} is greater than {@code s.length()}
465 */
466 public AbstractStringBuilder append(CharSequence s, int start, int end) {
467 if (s == null)
468 s = "null";
469 if ((start < 0) || (end < 0) || (start > end) || (end > s.length()))
470 throw new IndexOutOfBoundsException(
471 "start " + start + ", end " + end + ", s.length() "
472 + s.length());
473 int len = end - start;
474 if (len == 0)
475 return this;
476 int newCount = count + len;
477 if (newCount > value.length)
478 expandCapacity(newCount);
479 for (int i=start; i<end; i++)
480 value[count++] = s.charAt(i);
481 count = newCount;
482 return this;
483 }
484
485 /**
486 * Appends the string representation of the {@code char} array
487 * argument to this sequence.
488 * <p>
489 * The characters of the array argument are appended, in order, to
490 * the contents of this sequence. The length of this sequence
491 * increases by the length of the argument.
492 * <p>
493 * The overall effect is exactly as if the argument were converted
494 * to a string by the method {@link String#valueOf(char[])},
495 * and the characters of that string were then
496 * {@link #append(String) appended} to this character sequence.
497 *
498 * @param str the characters to be appended.
499 * @return a reference to this object.
500 */
501 public AbstractStringBuilder append(char[] str) {
502 int newCount = count + str.length;
503 if (newCount > value.length)
504 expandCapacity(newCount);
505 System.arraycopy(str, 0, value, count, str.length);
506 count = newCount;
507 return this;
508 }
509
510 /**
511 * Appends the string representation of a subarray of the
512 * {@code char} array argument to this sequence.
513 * <p>
514 * Characters of the {@code char} array {@code str}, starting at
515 * index {@code offset}, are appended, in order, to the contents
516 * of this sequence. The length of this sequence increases
517 * by the value of {@code len}.
518 * <p>
519 * The overall effect is exactly as if the arguments were converted
520 * to a string by the method {@link String#valueOf(char[],int,int)},
521 * and the characters of that string were then
522 * {@link #append(String) appended} to this character sequence.
523 *
524 * @param str the characters to be appended.
525 * @param offset the index of the first {@code char} to append.
526 * @param len the number of {@code char}s to append.
527 * @return a reference to this object.
528 * @throws IndexOutOfBoundsException
529 * if {@code offset < 0} or {@code len < 0}
530 * or {@code offset+len > str.length}
531 */
532 public AbstractStringBuilder append(char str[], int offset, int len) {
533 int newCount = count + len;
534 if (newCount > value.length)
535 expandCapacity(newCount);
536 System.arraycopy(str, offset, value, count, len);
537 count = newCount;
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 int newCount = count + 4;
556 if (newCount > value.length)
557 expandCapacity(newCount);
558 value[count++] = 't';
559 value[count++] = 'r';
560 value[count++] = 'u';
561 value[count++] = 'e';
562 } else {
563 int newCount = count + 5;
564 if (newCount > value.length)
565 expandCapacity(newCount);
566 value[count++] = 'f';
567 value[count++] = 'a';
568 value[count++] = 'l';
569 value[count++] = 's';
570 value[count++] = 'e';
571 }
572 return this;
573 }
574
575 /**
576 * Appends the string representation of the {@code char}
577 * argument to this sequence.
578 * <p>
579 * The argument is appended to the contents of this sequence.
580 * The length of this sequence increases by {@code 1}.
581 * <p>
582 * The overall effect is exactly as if the argument were converted
583 * to a string by the method {@link String#valueOf(char)},
584 * and the character in that string were then
585 * {@link #append(String) appended} to this character sequence.
586 *
587 * @param c a {@code char}.
588 * @return a reference to this object.
589 */
590 public AbstractStringBuilder append(char c) {
591 int newCount = count + 1;
592 if (newCount > value.length)
593 expandCapacity(newCount);
594 value[count++] = c;
595 return this;
596 }
597
598 /**
599 * Appends the string representation of the {@code int}
600 * argument to this sequence.
601 * <p>
602 * The overall effect is exactly as if the argument were converted
603 * to a string by the method {@link String#valueOf(int)},
604 * and the characters of that string were then
605 * {@link #append(String) appended} to this character sequence.
606 *
607 * @param i an {@code int}.
608 * @return a reference to this object.
609 */
610 public AbstractStringBuilder append(int i) {
611 if (i == Integer.MIN_VALUE) {
612 append("-2147483648");
613 return this;
614 }
615 int appendedLength = (i < 0) ? Integer.stringSize(-i) + 1
616 : Integer.stringSize(i);
617 int spaceNeeded = count + appendedLength;
618 if (spaceNeeded > value.length)
619 expandCapacity(spaceNeeded);
620 Integer.getChars(i, spaceNeeded, value);
621 count = spaceNeeded;
622 return this;
623 }
624
625 /**
626 * Appends the string representation of the {@code long}
627 * argument to this sequence.
628 * <p>
629 * The overall effect is exactly as if the argument were converted
630 * to a string by the method {@link String#valueOf(long)},
631 * and the characters of that string were then
632 * {@link #append(String) appended} to this character sequence.
633 *
634 * @param l a {@code long}.
635 * @return a reference to this object.
636 */
637 public AbstractStringBuilder append(long l) {
638 if (l == Long.MIN_VALUE) {
639 append("-9223372036854775808");
640 return this;
641 }
642 int appendedLength = (l < 0) ? Long.stringSize(-l) + 1
643 : Long.stringSize(l);
644 int spaceNeeded = count + appendedLength;
645 if (spaceNeeded > value.length)
646 expandCapacity(spaceNeeded);
647 Long.getChars(l, spaceNeeded, value);
648 count = spaceNeeded;
649 return this;
650 }
651
652 /**
653 * Appends the string representation of the {@code float}
654 * argument to this sequence.
655 * <p>
656 * The overall effect is exactly as if the argument were converted
657 * to a string by the method {@link String#valueOf(float)},
658 * and the characters of that string were then
659 * {@link #append(String) appended} to this character sequence.
660 *
661 * @param f a {@code float}.
662 * @return a reference to this object.
663 */
664 public AbstractStringBuilder append(float f) {
665 new FloatingDecimal(f).appendTo(this);
666 return this;
667 }
668
669 /**
670 * Appends the string representation of the {@code double}
671 * argument to this sequence.
672 * <p>
673 * The overall effect is exactly as if the argument were converted
674 * to a string by the method {@link String#valueOf(double)},
675 * and the characters of that string were then
676 * {@link #append(String) appended} to this character sequence.
677 *
678 * @param d a {@code double}.
679 * @return a reference to this object.
680 */
681 public AbstractStringBuilder append(double d) {
682 new FloatingDecimal(d).appendTo(this);
683 return this;
684 }
685
686 /**
687 * Removes the characters in a substring of this sequence.
688 * The substring begins at the specified {@code start} and extends to
689 * the character at index {@code end - 1} or to the end of the
690 * sequence if no such character exists. If
691 * {@code start} is equal to {@code end}, no changes are made.
692 *
693 * @param start The beginning index, inclusive.
694 * @param end The ending index, exclusive.
695 * @return This object.
696 * @throws StringIndexOutOfBoundsException if {@code start}
697 * is negative, greater than {@code length()}, or
698 * greater than {@code end}.
699 */
700 public AbstractStringBuilder delete(int start, int end) {
701 if (start < 0)
702 throw new StringIndexOutOfBoundsException(start);
703 if (end > count)
704 end = count;
705 if (start > end)
706 throw new StringIndexOutOfBoundsException();
707 int len = end - start;
708 if (len > 0) {
709 System.arraycopy(value, start+len, value, start, count-end);
710 count -= len;
711 }
712 return this;
713 }
714
715 /**
716 * Appends the string representation of the {@code codePoint}
717 * argument to this sequence.
718 *
719 * <p> The argument is appended to the contents of this sequence.
720 * The length of this sequence increases by
721 * {@link Character#charCount(int) Character.charCount(codePoint)}.
722 *
723 * <p> The overall effect is exactly as if the argument were
724 * converted to a {@code char} array by the method
725 * {@link Character#toChars(int)} and the character in that array
726 * were then {@link #append(char[]) appended} to this character
727 * sequence.
728 *
729 * @param codePoint a Unicode code point
730 * @return a reference to this object.
731 * @exception IllegalArgumentException if the specified
732 * {@code codePoint} isn't a valid Unicode code point
733 */
734 public AbstractStringBuilder appendCodePoint(int codePoint) {
735 if (!Character.isValidCodePoint(codePoint)) {
736 throw new IllegalArgumentException();
737 }
738 int n = 1;
739 if (codePoint >= Character.MIN_SUPPLEMENTARY_CODE_POINT) {
740 n++;
741 }
742 int newCount = count + n;
743 if (newCount > value.length) {
744 expandCapacity(newCount);
745 }
746 if (n == 1) {
747 value[count++] = (char) codePoint;
748 } else {
749 Character.toSurrogates(codePoint, value, count);
750 count += n;
751 }
752 return this;
753 }
754
755 /**
756 * Removes the <code>char</code> at the specified position in this
757 * sequence. This sequence is shortened by one <code>char</code>.
758 *
759 * <p>Note: If the character at the given index is a supplementary
760 * character, this method does not remove the entire character. If
761 * correct handling of supplementary characters is required,
762 * determine the number of <code>char</code>s to remove by calling
763 * <code>Character.charCount(thisSequence.codePointAt(index))</code>,
764 * where <code>thisSequence</code> is this sequence.
765 *
766 * @param index Index of <code>char</code> to remove
767 * @return This object.
768 * @throws StringIndexOutOfBoundsException if the <code>index</code>
769 * is negative or greater than or equal to
770 * <code>length()</code>.
771 */
772 public AbstractStringBuilder deleteCharAt(int index) {
773 if ((index < 0) || (index >= count))
774 throw new StringIndexOutOfBoundsException(index);
775 System.arraycopy(value, index+1, value, index, count-index-1);
776 count--;
777 return this;
778 }
779
780 /**
781 * Replaces the characters in a substring of this sequence
782 * with characters in the specified <code>String</code>. The substring
783 * begins at the specified <code>start</code> and extends to the character
784 * at index <code>end - 1</code> or to the end of the
785 * sequence if no such character exists. First the
786 * characters in the substring are removed and then the specified
787 * <code>String</code> is inserted at <code>start</code>. (This
788 * sequence will be lengthened to accommodate the
789 * specified String if necessary.)
790 *
791 * @param start The beginning index, inclusive.
792 * @param end The ending index, exclusive.
793 * @param str String that will replace previous contents.
794 * @return This object.
795 * @throws StringIndexOutOfBoundsException if <code>start</code>
796 * is negative, greater than <code>length()</code>, or
797 * greater than <code>end</code>.
798 */
799 public AbstractStringBuilder replace(int start, int end, String str) {
800 if (start < 0)
801 throw new StringIndexOutOfBoundsException(start);
802 if (start > count)
803 throw new StringIndexOutOfBoundsException("start > length()");
804 if (start > end)
805 throw new StringIndexOutOfBoundsException("start > end");
806
807 if (end > count)
808 end = count;
809 int len = str.length();
810 int newCount = count + len - (end - start);
811 if (newCount > value.length)
812 expandCapacity(newCount);
813
814 System.arraycopy(value, end, value, start + len, count - end);
815 str.getChars(value, start);
816 count = newCount;
817 return this;
818 }
819
820 /**
821 * Returns a new <code>String</code> that contains a subsequence of
822 * characters currently contained in this character sequence. The
823 * substring begins at the specified index and extends to the end of
824 * this sequence.
825 *
826 * @param start The beginning index, inclusive.
827 * @return The new string.
828 * @throws StringIndexOutOfBoundsException if <code>start</code> is
829 * less than zero, or greater than the length of this object.
830 */
831 public String substring(int start) {
832 return substring(start, count);
833 }
834
835 /**
836 * Returns a new character sequence that is a subsequence of this sequence.
837 *
838 * <p> An invocation of this method of the form
839 *
840 * <blockquote><pre>
841 * sb.subSequence(begin, end)</pre></blockquote>
842 *
843 * behaves in exactly the same way as the invocation
844 *
845 * <blockquote><pre>
846 * sb.substring(begin, end)</pre></blockquote>
847 *
848 * This method is provided so that this class can
849 * implement the {@link CharSequence} interface. </p>
850 *
851 * @param start the start index, inclusive.
852 * @param end the end index, exclusive.
853 * @return the specified subsequence.
854 *
855 * @throws IndexOutOfBoundsException
856 * if <tt>start</tt> or <tt>end</tt> are negative,
857 * if <tt>end</tt> is greater than <tt>length()</tt>,
858 * or if <tt>start</tt> is greater than <tt>end</tt>
859 * @spec JSR-51
860 */
861 public CharSequence subSequence(int start, int end) {
862 return substring(start, end);
863 }
864
865 /**
866 * Returns a new <code>String</code> that contains a subsequence of
867 * characters currently contained in this sequence. The
868 * substring begins at the specified <code>start</code> and
869 * extends to the character at index <code>end - 1</code>.
870 *
871 * @param start The beginning index, inclusive.
872 * @param end The ending index, exclusive.
873 * @return The new string.
874 * @throws StringIndexOutOfBoundsException if <code>start</code>
875 * or <code>end</code> are negative or greater than
876 * <code>length()</code>, or <code>start</code> is
877 * greater than <code>end</code>.
878 */
879 public String substring(int start, int end) {
880 if (start < 0)
881 throw new StringIndexOutOfBoundsException(start);
882 if (end > count)
883 throw new StringIndexOutOfBoundsException(end);
884 if (start > end)
885 throw new StringIndexOutOfBoundsException(end - start);
886 return new String(value, start, end - start);
887 }
888
889 /**
890 * Inserts the string representation of a subarray of the {@code str}
891 * array argument into this sequence. The subarray begins at the
892 * specified {@code offset} and extends {@code len} {@code char}s.
893 * The characters of the subarray are inserted into this sequence at
894 * the position indicated by {@code index}. The length of this
895 * sequence increases by {@code len} {@code char}s.
896 *
897 * @param index position at which to insert subarray.
898 * @param str A {@code char} array.
899 * @param offset the index of the first {@code char} in subarray to
900 * be inserted.
901 * @param len the number of {@code char}s in the subarray to
902 * be inserted.
903 * @return This object
904 * @throws StringIndexOutOfBoundsException if {@code index}
905 * is negative or greater than {@code length()}, or
906 * {@code offset} or {@code len} are negative, or
907 * {@code (offset+len)} is greater than
908 * {@code str.length}.
909 */
910 public AbstractStringBuilder insert(int index, char[] str, int offset,
911 int len)
912 {
913 if ((index < 0) || (index > length()))
914 throw new StringIndexOutOfBoundsException(index);
915 if ((offset < 0) || (len < 0) || (offset > str.length - len))
916 throw new StringIndexOutOfBoundsException(
917 "offset " + offset + ", len " + len + ", str.length "
918 + str.length);
919 int newCount = count + len;
920 if (newCount > value.length)
921 expandCapacity(newCount);
922 System.arraycopy(value, index, value, index + len, count - index);
923 System.arraycopy(str, offset, value, index, len);
924 count = newCount;
925 return this;
926 }
927
928 /**
929 * Inserts the string representation of the {@code Object}
930 * argument into this character sequence.
931 * <p>
932 * The overall effect is exactly as if the second argument were
933 * converted to a string by the method {@link String#valueOf(Object)},
934 * and the characters of that string were then
935 * {@link #insert(int,String) inserted} into this character
936 * sequence at the indicated offset.
937 * <p>
938 * The {@code offset} argument must be greater than or equal to
939 * {@code 0}, and less than or equal to the {@linkplain #length() length}
940 * of this sequence.
941 *
942 * @param offset the offset.
943 * @param obj an {@code Object}.
944 * @return a reference to this object.
945 * @throws StringIndexOutOfBoundsException if the offset is invalid.
946 */
947 public AbstractStringBuilder insert(int offset, Object obj) {
948 return insert(offset, String.valueOf(obj));
949 }
950
951 /**
952 * Inserts the string into this character sequence.
953 * <p>
954 * The characters of the {@code String} argument are inserted, in
955 * order, into this sequence at the indicated offset, moving up any
956 * characters originally above that position and increasing the length
957 * of this sequence by the length of the argument. If
958 * {@code str} is {@code null}, then the four characters
959 * {@code "null"} are inserted into this sequence.
960 * <p>
961 * The character at index <i>k</i> in the new character sequence is
962 * equal to:
963 * <ul>
964 * <li>the character at index <i>k</i> in the old character sequence, if
965 * <i>k</i> is less than {@code offset}
966 * <li>the character at index <i>k</i>{@code -offset} in the
967 * argument {@code str}, if <i>k</i> is not less than
968 * {@code offset} but is less than {@code offset+str.length()}
969 * <li>the character at index <i>k</i>{@code -str.length()} in the
970 * old character sequence, if <i>k</i> is not less than
971 * {@code offset+str.length()}
972 * </ul><p>
973 * The {@code offset} argument must be greater than or equal to
974 * {@code 0}, and less than or equal to the {@linkplain #length() length}
975 * of this sequence.
976 *
977 * @param offset the offset.
978 * @param str a string.
979 * @return a reference to this object.
980 * @throws StringIndexOutOfBoundsException if the offset is invalid.
981 */
982 public AbstractStringBuilder insert(int offset, String str) {
983 if ((offset < 0) || (offset > length()))
984 throw new StringIndexOutOfBoundsException(offset);
985 if (str == null)
986 str = "null";
987 int len = str.length();
988 int newCount = count + len;
989 if (newCount > value.length)
990 expandCapacity(newCount);
991 System.arraycopy(value, offset, value, offset + len, count - offset);
992 str.getChars(value, offset);
993 count = newCount;
994 return this;
995 }
996
997 /**
998 * Inserts the string representation of the {@code char} array
999 * argument into this sequence.
1000 * <p>
1001 * The characters of the array argument are inserted into the
1002 * contents of this sequence at the position indicated by
1003 * {@code offset}. The length of this sequence increases by
1004 * the length of the argument.
1005 * <p>
1006 * The overall effect is exactly as if the second argument were
1007 * converted to a string by the method {@link String#valueOf(char[])},
1008 * and the characters of that string were then
1009 * {@link #insert(int,String) inserted} into this character
1010 * sequence at the indicated offset.
1011 * <p>
1012 * The {@code offset} argument must be greater than or equal to
1013 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1014 * of this sequence.
1015 *
1016 * @param offset the offset.
1017 * @param str a character array.
1018 * @return a reference to this object.
1019 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1020 */
1021 public AbstractStringBuilder insert(int offset, char[] str) {
1022 if ((offset < 0) || (offset > length()))
1023 throw new StringIndexOutOfBoundsException(offset);
1024 int len = str.length;
1025 int newCount = count + len;
1026 if (newCount > value.length)
1027 expandCapacity(newCount);
1028 System.arraycopy(value, offset, value, offset + len, count - offset);
1029 System.arraycopy(str, 0, value, offset, len);
1030 count = newCount;
1031 return this;
1032 }
1033
1034 /**
1035 * Inserts the specified {@code CharSequence} into this sequence.
1036 * <p>
1037 * The characters of the {@code CharSequence} argument are inserted,
1038 * in order, into this sequence at the indicated offset, moving up
1039 * any characters originally above that position and increasing the length
1040 * of this sequence by the length of the argument s.
1041 * <p>
1042 * The result of this method is exactly the same as if it were an
1043 * invocation of this object's
1044 * {@link #insert(int,CharSequence,int,int) insert}(dstOffset, s, 0, s.length())
1045 * method.
1046 *
1047 * <p>If {@code s} is {@code null}, then the four characters
1048 * {@code "null"} are inserted into this sequence.
1049 *
1050 * @param dstOffset the offset.
1051 * @param s the sequence to be inserted
1052 * @return a reference to this object.
1053 * @throws IndexOutOfBoundsException if the offset is invalid.
1054 */
1055 public AbstractStringBuilder insert(int dstOffset, CharSequence s) {
1056 if (s == null)
1057 s = "null";
1058 if (s instanceof String)
1059 return this.insert(dstOffset, (String)s);
1060 return this.insert(dstOffset, s, 0, s.length());
1061 }
1062
1063 /**
1064 * Inserts a subsequence of the specified {@code CharSequence} into
1065 * this sequence.
1066 * <p>
1067 * The subsequence of the argument {@code s} specified by
1068 * {@code start} and {@code end} are inserted,
1069 * in order, into this sequence at the specified destination offset, moving
1070 * up any characters originally above that position. The length of this
1071 * sequence is increased by {@code end - start}.
1072 * <p>
1073 * The character at index <i>k</i> in this sequence becomes equal to:
1074 * <ul>
1075 * <li>the character at index <i>k</i> in this sequence, if
1076 * <i>k</i> is less than {@code dstOffset}
1077 * <li>the character at index <i>k</i>{@code +start-dstOffset} in
1078 * the argument {@code s}, if <i>k</i> is greater than or equal to
1079 * {@code dstOffset} but is less than {@code dstOffset+end-start}
1080 * <li>the character at index <i>k</i>{@code -(end-start)} in this
1081 * sequence, if <i>k</i> is greater than or equal to
1082 * {@code dstOffset+end-start}
1083 * </ul><p>
1084 * The {@code dstOffset} argument must be greater than or equal to
1085 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1086 * of this sequence.
1087 * <p>The start argument must be nonnegative, and not greater than
1088 * {@code end}.
1089 * <p>The end argument must be greater than or equal to
1090 * {@code start}, and less than or equal to the length of s.
1091 *
1092 * <p>If {@code s} is {@code null}, then this method inserts
1093 * characters as if the s parameter was a sequence containing the four
1094 * characters {@code "null"}.
1095 *
1096 * @param dstOffset the offset in this sequence.
1097 * @param s the sequence to be inserted.
1098 * @param start the starting index of the subsequence to be inserted.
1099 * @param end the end index of the subsequence to be inserted.
1100 * @return a reference to this object.
1101 * @throws IndexOutOfBoundsException if {@code dstOffset}
1102 * is negative or greater than {@code this.length()}, or
1103 * {@code start} or {@code end} are negative, or
1104 * {@code start} is greater than {@code end} or
1105 * {@code end} is greater than {@code s.length()}
1106 */
1107 public AbstractStringBuilder insert(int dstOffset, CharSequence s,
1108 int start, int end) {
1109 if (s == null)
1110 s = "null";
1111 if ((dstOffset < 0) || (dstOffset > this.length()))
1112 throw new IndexOutOfBoundsException("dstOffset "+dstOffset);
1113 if ((start < 0) || (end < 0) || (start > end) || (end > s.length()))
1114 throw new IndexOutOfBoundsException(
1115 "start " + start + ", end " + end + ", s.length() "
1116 + s.length());
1117 int len = end - start;
1118 if (len == 0)
1119 return this;
1120 int newCount = count + len;
1121 if (newCount > value.length)
1122 expandCapacity(newCount);
1123 System.arraycopy(value, dstOffset, value, dstOffset + len,
1124 count - dstOffset);
1125 for (int i=start; i<end; i++)
1126 value[dstOffset++] = s.charAt(i);
1127 count = newCount;
1128 return this;
1129 }
1130
1131 /**
1132 * Inserts the string representation of the {@code boolean}
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(boolean)},
1137 * and the characters of 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 b a {@code boolean}.
1147 * @return a reference to this object.
1148 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1149 */
1150 public AbstractStringBuilder insert(int offset, boolean b) {
1151 return insert(offset, String.valueOf(b));
1152 }
1153
1154 /**
1155 * Inserts the string representation of the {@code char}
1156 * argument into this sequence.
1157 * <p>
1158 * The overall effect is exactly as if the second argument were
1159 * converted to a string by the method {@link String#valueOf(char)},
1160 * and the character in that string were then
1161 * {@link #insert(int,String) inserted} into this character
1162 * sequence at the indicated offset.
1163 * <p>
1164 * The {@code offset} argument must be greater than or equal to
1165 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1166 * of this sequence.
1167 *
1168 * @param offset the offset.
1169 * @param c a {@code char}.
1170 * @return a reference to this object.
1171 * @throws IndexOutOfBoundsException if the offset is invalid.
1172 */
1173 public AbstractStringBuilder insert(int offset, char c) {
1174 int newCount = count + 1;
1175 if (newCount > value.length)
1176 expandCapacity(newCount);
1177 System.arraycopy(value, offset, value, offset + 1, count - offset);
1178 value[offset] = c;
1179 count = newCount;
1180 return this;
1181 }
1182
1183 /**
1184 * Inserts the string representation of the second {@code int}
1185 * argument into this sequence.
1186 * <p>
1187 * The overall effect is exactly as if the second argument were
1188 * converted to a string by the method {@link String#valueOf(int)},
1189 * and the characters of that string were then
1190 * {@link #insert(int,String) inserted} into this character
1191 * sequence at the indicated offset.
1192 * <p>
1193 * The {@code offset} argument must be greater than or equal to
1194 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1195 * of this sequence.
1196 *
1197 * @param offset the offset.
1198 * @param i an {@code int}.
1199 * @return a reference to this object.
1200 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1201 */
1202 public AbstractStringBuilder insert(int offset, int i) {
1203 return insert(offset, String.valueOf(i));
1204 }
1205
1206 /**
1207 * Inserts the string representation of the {@code long}
1208 * argument into this sequence.
1209 * <p>
1210 * The overall effect is exactly as if the second argument were
1211 * converted to a string by the method {@link String#valueOf(long)},
1212 * and the characters of that string were then
1213 * {@link #insert(int,String) inserted} into this character
1214 * sequence at the indicated offset.
1215 * <p>
1216 * The {@code offset} argument must be greater than or equal to
1217 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1218 * of this sequence.
1219 *
1220 * @param offset the offset.
1221 * @param l a {@code long}.
1222 * @return a reference to this object.
1223 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1224 */
1225 public AbstractStringBuilder insert(int offset, long l) {
1226 return insert(offset, String.valueOf(l));
1227 }
1228
1229 /**
1230 * Inserts the string representation of the {@code float}
1231 * argument into this sequence.
1232 * <p>
1233 * The overall effect is exactly as if the second argument were
1234 * converted to a string by the method {@link String#valueOf(float)},
1235 * and the characters of that string were then
1236 * {@link #insert(int,String) inserted} into this character
1237 * sequence at the indicated offset.
1238 * <p>
1239 * The {@code offset} argument must be greater than or equal to
1240 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1241 * of this sequence.
1242 *
1243 * @param offset the offset.
1244 * @param f a {@code float}.
1245 * @return a reference to this object.
1246 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1247 */
1248 public AbstractStringBuilder insert(int offset, float f) {
1249 return insert(offset, String.valueOf(f));
1250 }
1251
1252 /**
1253 * Inserts the string representation of the {@code double}
1254 * argument into this sequence.
1255 * <p>
1256 * The overall effect is exactly as if the second argument were
1257 * converted to a string by the method {@link String#valueOf(double)},
1258 * and the characters of that string were then
1259 * {@link #insert(int,String) inserted} into this character
1260 * sequence at the indicated offset.
1261 * <p>
1262 * The {@code offset} argument must be greater than or equal to
1263 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1264 * of this sequence.
1265 *
1266 * @param offset the offset.
1267 * @param d a {@code double}.
1268 * @return a reference to this object.
1269 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1270 */
1271 public AbstractStringBuilder insert(int offset, double d) {
1272 return insert(offset, String.valueOf(d));
1273 }
1274
1275 /**
1276 * Returns the index within this string of the first occurrence of the
1277 * specified substring. The integer returned is the smallest value
1278 * <i>k</i> such that:
1279 * <blockquote><pre>
1280 * this.toString().startsWith(str, <i>k</i>)
1281 * </pre></blockquote>
1282 * is <code>true</code>.
1283 *
1284 * @param str any string.
1285 * @return if the string argument occurs as a substring within this
1286 * object, then the index of the first character of the first
1287 * such substring is returned; if it does not occur as a
1288 * substring, <code>-1</code> is returned.
1289 * @throws java.lang.NullPointerException if <code>str</code> is
1290 * <code>null</code>.
1291 */
1292 public int indexOf(String str) {
1293 return indexOf(str, 0);
1294 }
1295
1296 /**
1297 * Returns the index within this string of the first occurrence of the
1298 * specified substring, starting at the specified index. The integer
1299 * returned is the smallest value <tt>k</tt> for which:
1300 * <blockquote><pre>
1301 * k >= Math.min(fromIndex, str.length()) &&
1302 * this.toString().startsWith(str, k)
1303 * </pre></blockquote>
1304 * If no such value of <i>k</i> exists, then -1 is returned.
1305 *
1306 * @param str the substring for which to search.
1307 * @param fromIndex the index from which to start the search.
1308 * @return the index within this string of the first occurrence of the
1309 * specified substring, starting at the specified index.
1310 * @throws java.lang.NullPointerException if <code>str</code> is
1311 * <code>null</code>.
1312 */
1313 public int indexOf(String str, int fromIndex) {
1314 return String.indexOf(value, 0, count,
1315 str.toCharArray(), 0, str.length(), fromIndex);
1316 }
1317
1318 /**
1319 * Returns the index within this string of the rightmost occurrence
1320 * of the specified substring. The rightmost empty string "" is
1321 * considered to occur at the index value <code>this.length()</code>.
1322 * The returned index is the largest value <i>k</i> such that
1323 * <blockquote><pre>
1324 * this.toString().startsWith(str, k)
1325 * </pre></blockquote>
1326 * is true.
1327 *
1328 * @param str the substring to search for.
1329 * @return if the string argument occurs one or more times as a substring
1330 * within this object, then the index of the first character of
1331 * the last such substring is returned. If it does not occur as
1332 * a substring, <code>-1</code> is returned.
1333 * @throws java.lang.NullPointerException if <code>str</code> is
1334 * <code>null</code>.
1335 */
1336 public int lastIndexOf(String str) {
1337 return lastIndexOf(str, count);
1338 }
1339
1340 /**
1341 * Returns the index within this string of the last occurrence of the
1342 * specified substring. The integer returned is the largest value <i>k</i>
1343 * such that:
1344 * <blockquote><pre>
1345 * k <= Math.min(fromIndex, str.length()) &&
1346 * this.toString().startsWith(str, k)
1347 * </pre></blockquote>
1348 * If no such value of <i>k</i> exists, then -1 is returned.
1349 *
1350 * @param str the substring to search for.
1351 * @param fromIndex the index to start the search from.
1352 * @return the index within this sequence of the last occurrence of the
1353 * specified substring.
1354 * @throws java.lang.NullPointerException if <code>str</code> is
1355 * <code>null</code>.
1356 */
1357 public int lastIndexOf(String str, int fromIndex) {
1358 return String.lastIndexOf(value, 0, count,
1359 str.toCharArray(), 0, str.length(), fromIndex);
1360 }
1361
1362 /**
1363 * Causes this character sequence to be replaced by the reverse of
1364 * the sequence. If there are any surrogate pairs included in the
1365 * sequence, these are treated as single characters for the
1366 * reverse operation. Thus, the order of the high-low surrogates
1367 * is never reversed.
1368 *
1369 * Let <i>n</i> be the character length of this character sequence
1370 * (not the length in <code>char</code> values) just prior to
1371 * execution of the <code>reverse</code> method. Then the
1372 * character at index <i>k</i> in the new character sequence is
1373 * equal to the character at index <i>n-k-1</i> in the old
1374 * character sequence.
1375 *
1376 * <p>Note that the reverse operation may result in producing
1377 * surrogate pairs that were unpaired low-surrogates and
1378 * high-surrogates before the operation. For example, reversing
1379 * "\uDC00\uD800" produces "\uD800\uDC00" which is
1380 * a valid surrogate pair.
1381 *
1382 * @return a reference to this object.
1383 */
1384 public AbstractStringBuilder reverse() {
1385 boolean hasSurrogate = false;
1386 int n = count - 1;
1387 for (int j = (n-1) >> 1; j >= 0; --j) {
1388 char temp = value[j];
1389 char temp2 = value[n - j];
1390 if (!hasSurrogate) {
1391 hasSurrogate = (temp >= Character.MIN_SURROGATE && temp <= Character.MAX_SURROGATE)
1392 || (temp2 >= Character.MIN_SURROGATE && temp2 <= Character.MAX_SURROGATE);
1393 }
1394 value[j] = temp2;
1395 value[n - j] = temp;
1396 }
1397 if (hasSurrogate) {
1398 // Reverse back all valid surrogate pairs
1399 for (int i = 0; i < count - 1; i++) {
1400 char c2 = value[i];
1401 if (Character.isLowSurrogate(c2)) {
1402 char c1 = value[i + 1];
1403 if (Character.isHighSurrogate(c1)) {
1404 value[i++] = c1;
1405 value[i] = c2;
1406 }
1407 }
1408 }
1409 }
1410 return this;
1411 }
1412
1413 /**
1414 * Append to this sequence a composition of the values returned
1415 * by calling {@link String#valueOf(Object)} on each argument and joining them together
1416 * with the delimiter parameter.
1417 *
1418 * @param delimiter the String appended between each elements.
1419 * @param first the first element to append.
1420 * @param elements the other Object elements to join together with the first one.
1421 * @return a reference to this object.
1422 *
1423 * @throws NullPointerException
1424 * If <tt>delimiter</tt> or <tt>elements</tt> is <tt>null</tt>
1425 *
1426 * @since 1.7
1427 */
1428 public AbstractStringBuilder join(String delimiter, Object first, Object... elements) {
1429 if (delimiter == null) {
1430 throw new NullPointerException("delimiter is null");
1431 }
1432 append(first);
1433 for(Object o : elements) {
1434 append(delimiter).append(o);
1435 }
1436 return this;
1437 }
1438
1439 /**
1440 * Append to this sequence a composition of the values returned
1441 * by calling {@link String#valueOf(Object)} on each array element
1442 * and joining them together with the delimiter parameter.
1443 *
1444 * @param delimiter the String appended between each elements.
1445 * @param elements an array of Object element to join together.
1446 * @return a reference to this object.
1447 *
1448 * @throws NullPointerException
1449 * If <tt>delimiter</tt> or <tt>elements</tt> is <tt>null</tt>
1450 *
1451 * @since 1.7
1452 */
1453 public AbstractStringBuilder join(String delimiter, Object[] elements) {
1454 if (delimiter == null) {
1455 throw new NullPointerException("delimiter is null");
1456 }
1457 int length = elements.length;
1458 if (length == 0) {
1459 return this;
1460 }
1461 append(elements[0]);
1462 for(int i=1; i<length; i++) {
1463 append(delimiter).append(elements[i]);
1464 }
1465 return this;
1466 }
1467
1468 /**
1469 * Append to this sequence a composition of the values returned
1470 * by calling {@link String#valueOf(Object)} on each argument and joining them together
1471 * with the delimiter parameter.
1472 *
1473 * @param delimiter the String appended between each elements.
1474 * @param elements an Iterable that will have its elements joined together.
1475 * @return a reference to this object.
1476 *
1477 * @throws NullPointerException
1478 * If <tt>delimiter</tt> or <tt>elements</tt> is <tt>null</tt>
1479 *
1480 * @since 1.7
1481 */
1482 public AbstractStringBuilder join(String delimiter, Iterable<?> elements) {
1483 if (delimiter == null) {
1484 throw new NullPointerException("delimiter is null");
1485 }
1486 Iterator<?> iterator = elements.iterator();
1487 if (!iterator.hasNext()) {
1488 return this;
1489 }
1490 append(iterator.next());
1491 while(iterator.hasNext()) {
1492 append(delimiter).append(iterator.next());
1493 }
1494 return this;
1495 }
1496
1497 /**
1498 * Returns a string representing the data in this sequence.
1499 * A new <code>String</code> object is allocated and initialized to
1500 * contain the character sequence currently represented by this
1501 * object. This <code>String</code> is then returned. Subsequent
1502 * changes to this sequence do not affect the contents of the
1503 * <code>String</code>.
1504 *
1505 * @return a string representation of this sequence of characters.
1506 */
1507 public abstract String toString();
1508
1509 /**
1510 * Needed by <tt>String</tt> for the contentEquals method.
1511 */
1512 final char[] getValue() {
1513 return value;
1514 }
1515
1516 }