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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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15 * accompanied this code).
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28 import sun.misc.FloatingDecimal;
29 import java.util.Arrays;
32 * A mutable sequence of characters.
34 * Implements a modifiable string. At any point in time it contains some
35 * particular sequence of characters, but the length and content of the
36 * sequence can be changed through certain method calls.
38 * @author Michael McCloskey
39 * @author Martin Buchholz
43 abstract class AbstractStringBuilder implements Appendable, CharSequence {
45 * The value is used for character storage.
50 * The count is the number of characters used.
55 * This no-arg constructor is necessary for serialization of subclasses.
57 AbstractStringBuilder() {
61 * Creates an AbstractStringBuilder of the specified capacity.
63 AbstractStringBuilder(int capacity) {
64 value = new char[capacity];
68 * Returns the length (character count).
70 * @return the length of the sequence of characters currently
71 * represented by this object
78 * Returns the current capacity. The capacity is the amount of storage
79 * available for newly inserted characters, beyond which an allocation
82 * @return the current capacity
84 public int capacity() {
89 * Ensures that the capacity is at least equal to the specified minimum.
90 * If the current capacity is less than the argument, then a new internal
91 * array is allocated with greater capacity. The new capacity is the
94 * <li>The <code>minimumCapacity</code> argument.
95 * <li>Twice the old capacity, plus <code>2</code>.
97 * If the <code>minimumCapacity</code> argument is nonpositive, this
98 * method takes no action and simply returns.
100 * @param minimumCapacity the minimum desired capacity.
102 public void ensureCapacity(int minimumCapacity) {
103 if (minimumCapacity > 0)
104 ensureCapacityInternal(minimumCapacity);
108 * This method has the same contract as ensureCapacity, but is
109 * never synchronized.
111 private void ensureCapacityInternal(int minimumCapacity) {
112 // overflow-conscious code
113 if (minimumCapacity - value.length > 0)
114 expandCapacity(minimumCapacity);
118 * This implements the expansion semantics of ensureCapacity with no
119 * size check or synchronization.
121 void expandCapacity(int minimumCapacity) {
122 int newCapacity = value.length * 2 + 2;
123 if (newCapacity - minimumCapacity < 0)
124 newCapacity = minimumCapacity;
125 if (newCapacity < 0) {
126 if (minimumCapacity < 0) // overflow
127 throw new OutOfMemoryError();
128 newCapacity = Integer.MAX_VALUE;
130 value = Arrays.copyOf(value, newCapacity);
134 * Attempts to reduce storage used for the character sequence.
135 * If the buffer is larger than necessary to hold its current sequence of
136 * characters, then it may be resized to become more space efficient.
137 * Calling this method may, but is not required to, affect the value
138 * returned by a subsequent call to the {@link #capacity()} method.
140 public void trimToSize() {
141 if (count < value.length) {
142 value = Arrays.copyOf(value, count);
147 * Sets the length of the character sequence.
148 * The sequence is changed to a new character sequence
149 * whose length is specified by the argument. For every nonnegative
150 * index <i>k</i> less than <code>newLength</code>, the character at
151 * index <i>k</i> in the new character sequence is the same as the
152 * character at index <i>k</i> in the old sequence if <i>k</i> is less
153 * than the length of the old character sequence; otherwise, it is the
154 * null character <code>'\u0000'</code>.
156 * In other words, if the <code>newLength</code> argument is less than
157 * the current length, the length is changed to the specified length.
159 * If the <code>newLength</code> argument is greater than or equal
160 * to the current length, sufficient null characters
161 * (<code>'\u0000'</code>) are appended so that
162 * length becomes the <code>newLength</code> argument.
164 * The <code>newLength</code> argument must be greater than or equal
167 * @param newLength the new length
168 * @throws IndexOutOfBoundsException if the
169 * <code>newLength</code> argument is negative.
171 public void setLength(int newLength) {
173 throw new StringIndexOutOfBoundsException(newLength);
174 ensureCapacityInternal(newLength);
176 if (count < newLength) {
177 for (; count < newLength; count++)
185 * Returns the <code>char</code> value in this sequence at the specified index.
186 * The first <code>char</code> value is at index <code>0</code>, the next at index
187 * <code>1</code>, and so on, as in array indexing.
189 * The index argument must be greater than or equal to
190 * <code>0</code>, and less than the length of this sequence.
192 * <p>If the <code>char</code> value specified by the index is a
193 * <a href="Character.html#unicode">surrogate</a>, the surrogate
196 * @param index the index of the desired <code>char</code> value.
197 * @return the <code>char</code> value at the specified index.
198 * @throws IndexOutOfBoundsException if <code>index</code> is
199 * negative or greater than or equal to <code>length()</code>.
201 public char charAt(int index) {
202 if ((index < 0) || (index >= count))
203 throw new StringIndexOutOfBoundsException(index);
208 * Returns the character (Unicode code point) at the specified
209 * index. The index refers to <code>char</code> values
210 * (Unicode code units) and ranges from <code>0</code> to
211 * {@link #length()}<code> - 1</code>.
213 * <p> If the <code>char</code> value specified at the given index
214 * is in the high-surrogate range, the following index is less
215 * than the length of this sequence, and the
216 * <code>char</code> value at the following index is in the
217 * low-surrogate range, then the supplementary code point
218 * corresponding to this surrogate pair is returned. Otherwise,
219 * the <code>char</code> value at the given index is returned.
221 * @param index the index to the <code>char</code> values
222 * @return the code point value of the character at the
224 * @exception IndexOutOfBoundsException if the <code>index</code>
225 * argument is negative or not less than the length of this
228 public int codePointAt(int index) {
229 if ((index < 0) || (index >= count)) {
230 throw new StringIndexOutOfBoundsException(index);
232 return Character.codePointAt(value, index);
236 * Returns the character (Unicode code point) before the specified
237 * index. The index refers to <code>char</code> values
238 * (Unicode code units) and ranges from <code>1</code> to {@link
241 * <p> If the <code>char</code> value at <code>(index - 1)</code>
242 * is in the low-surrogate range, <code>(index - 2)</code> is not
243 * negative, and the <code>char</code> value at <code>(index -
244 * 2)</code> is in the high-surrogate range, then the
245 * supplementary code point value of the surrogate pair is
246 * returned. If the <code>char</code> value at <code>index -
247 * 1</code> is an unpaired low-surrogate or a high-surrogate, the
248 * surrogate value is returned.
250 * @param index the index following the code point that should be returned
251 * @return the Unicode code point value before the given index.
252 * @exception IndexOutOfBoundsException if the <code>index</code>
253 * argument is less than 1 or greater than the length
256 public int codePointBefore(int index) {
258 if ((i < 0) || (i >= count)) {
259 throw new StringIndexOutOfBoundsException(index);
261 return Character.codePointBefore(value, index);
265 * Returns the number of Unicode code points in the specified text
266 * range of this sequence. The text range begins at the specified
267 * <code>beginIndex</code> and extends to the <code>char</code> at
268 * index <code>endIndex - 1</code>. Thus the length (in
269 * <code>char</code>s) of the text range is
270 * <code>endIndex-beginIndex</code>. Unpaired surrogates within
271 * this sequence count as one code point each.
273 * @param beginIndex the index to the first <code>char</code> of
275 * @param endIndex the index after the last <code>char</code> of
277 * @return the number of Unicode code points in the specified text
279 * @exception IndexOutOfBoundsException if the
280 * <code>beginIndex</code> is negative, or <code>endIndex</code>
281 * is larger than the length of this sequence, or
282 * <code>beginIndex</code> is larger than <code>endIndex</code>.
284 public int codePointCount(int beginIndex, int endIndex) {
285 if (beginIndex < 0 || endIndex > count || beginIndex > endIndex) {
286 throw new IndexOutOfBoundsException();
288 return Character.codePointCountImpl(value, beginIndex, endIndex-beginIndex);
292 * Returns the index within this sequence that is offset from the
293 * given <code>index</code> by <code>codePointOffset</code> code
294 * points. Unpaired surrogates within the text range given by
295 * <code>index</code> and <code>codePointOffset</code> count as
296 * one code point each.
298 * @param index the index to be offset
299 * @param codePointOffset the offset in code points
300 * @return the index within this sequence
301 * @exception IndexOutOfBoundsException if <code>index</code>
302 * is negative or larger then the length of this sequence,
303 * or if <code>codePointOffset</code> is positive and the subsequence
304 * starting with <code>index</code> has fewer than
305 * <code>codePointOffset</code> code points,
306 * or if <code>codePointOffset</code> is negative and the subsequence
307 * before <code>index</code> has fewer than the absolute value of
308 * <code>codePointOffset</code> code points.
310 public int offsetByCodePoints(int index, int codePointOffset) {
311 if (index < 0 || index > count) {
312 throw new IndexOutOfBoundsException();
314 return Character.offsetByCodePointsImpl(value, 0, count,
315 index, codePointOffset);
319 * Characters are copied from this sequence into the
320 * destination character array <code>dst</code>. The first character to
321 * be copied is at index <code>srcBegin</code>; the last character to
322 * be copied is at index <code>srcEnd-1</code>. The total number of
323 * characters to be copied is <code>srcEnd-srcBegin</code>. The
324 * characters are copied into the subarray of <code>dst</code> starting
325 * at index <code>dstBegin</code> and ending at index:
326 * <p><blockquote><pre>
327 * dstbegin + (srcEnd-srcBegin) - 1
328 * </pre></blockquote>
330 * @param srcBegin start copying at this offset.
331 * @param srcEnd stop copying at this offset.
332 * @param dst the array to copy the data into.
333 * @param dstBegin offset into <code>dst</code>.
334 * @throws NullPointerException if <code>dst</code> is
336 * @throws IndexOutOfBoundsException if any of the following is true:
338 * <li><code>srcBegin</code> is negative
339 * <li><code>dstBegin</code> is negative
340 * <li>the <code>srcBegin</code> argument is greater than
341 * the <code>srcEnd</code> argument.
342 * <li><code>srcEnd</code> is greater than
343 * <code>this.length()</code>.
344 * <li><code>dstBegin+srcEnd-srcBegin</code> is greater than
345 * <code>dst.length</code>
348 public void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)
351 throw new StringIndexOutOfBoundsException(srcBegin);
352 if ((srcEnd < 0) || (srcEnd > count))
353 throw new StringIndexOutOfBoundsException(srcEnd);
354 if (srcBegin > srcEnd)
355 throw new StringIndexOutOfBoundsException("srcBegin > srcEnd");
356 System.arraycopy(value, srcBegin, dst, dstBegin, srcEnd - srcBegin);
360 * The character at the specified index is set to <code>ch</code>. This
361 * sequence is altered to represent a new character sequence that is
362 * identical to the old character sequence, except that it contains the
363 * character <code>ch</code> at position <code>index</code>.
365 * The index argument must be greater than or equal to
366 * <code>0</code>, and less than the length of this sequence.
368 * @param index the index of the character to modify.
369 * @param ch the new character.
370 * @throws IndexOutOfBoundsException if <code>index</code> is
371 * negative or greater than or equal to <code>length()</code>.
373 public void setCharAt(int index, char ch) {
374 if ((index < 0) || (index >= count))
375 throw new StringIndexOutOfBoundsException(index);
380 * Appends the string representation of the {@code Object} argument.
382 * The overall effect is exactly as if the argument were converted
383 * to a string by the method {@link String#valueOf(Object)},
384 * and the characters of that string were then
385 * {@link #append(String) appended} to this character sequence.
387 * @param obj an {@code Object}.
388 * @return a reference to this object.
390 public AbstractStringBuilder append(Object obj) {
391 return append(String.valueOf(obj));
395 * Appends the specified string to this character sequence.
397 * The characters of the {@code String} argument are appended, in
398 * order, increasing the length of this sequence by the length of the
399 * argument. If {@code str} is {@code null}, then the four
400 * characters {@code "null"} are appended.
402 * Let <i>n</i> be the length of this character sequence just prior to
403 * execution of the {@code append} method. Then the character at
404 * index <i>k</i> in the new character sequence is equal to the character
405 * at index <i>k</i> in the old character sequence, if <i>k</i> is less
406 * than <i>n</i>; otherwise, it is equal to the character at index
407 * <i>k-n</i> in the argument {@code str}.
409 * @param str a string.
410 * @return a reference to this object.
412 public AbstractStringBuilder append(String str) {
413 if (str == null) str = "null";
414 int len = str.length();
415 ensureCapacityInternal(count + len);
416 str.getChars(0, len, value, count);
421 // Documentation in subclasses because of synchro difference
422 public AbstractStringBuilder append(StringBuffer sb) {
424 return append("null");
425 int len = sb.length();
426 ensureCapacityInternal(count + len);
427 sb.getChars(0, len, value, count);
432 // Documentation in subclasses because of synchro difference
433 public AbstractStringBuilder append(CharSequence s) {
436 if (s instanceof String)
437 return this.append((String)s);
438 if (s instanceof StringBuffer)
439 return this.append((StringBuffer)s);
440 return this.append(s, 0, s.length());
444 * Appends a subsequence of the specified {@code CharSequence} to this
447 * Characters of the argument {@code s}, starting at
448 * index {@code start}, are appended, in order, to the contents of
449 * this sequence up to the (exclusive) index {@code end}. The length
450 * of this sequence is increased by the value of {@code end - start}.
452 * Let <i>n</i> be the length of this character sequence just prior to
453 * execution of the {@code append} method. Then the character at
454 * index <i>k</i> in this character sequence becomes equal to the
455 * character at index <i>k</i> in this sequence, if <i>k</i> is less than
456 * <i>n</i>; otherwise, it is equal to the character at index
457 * <i>k+start-n</i> in the argument {@code s}.
459 * If {@code s} is {@code null}, then this method appends
460 * characters as if the s parameter was a sequence containing the four
461 * characters {@code "null"}.
463 * @param s the sequence to append.
464 * @param start the starting index of the subsequence to be appended.
465 * @param end the end index of the subsequence to be appended.
466 * @return a reference to this object.
467 * @throws IndexOutOfBoundsException if
468 * {@code start} is negative, or
469 * {@code start} is greater than {@code end} or
470 * {@code end} is greater than {@code s.length()}
472 public AbstractStringBuilder append(CharSequence s, int start, int end) {
475 if ((start < 0) || (start > end) || (end > s.length()))
476 throw new IndexOutOfBoundsException(
477 "start " + start + ", end " + end + ", s.length() "
479 int len = end - start;
480 ensureCapacityInternal(count + len);
481 for (int i = start, j = count; i < end; i++, j++)
482 value[j] = s.charAt(i);
488 * Appends the string representation of the {@code char} array
489 * argument to this sequence.
491 * The characters of the array argument are appended, in order, to
492 * the contents of this sequence. The length of this sequence
493 * increases by the length of the argument.
495 * The overall effect is exactly as if the argument were converted
496 * to a string by the method {@link String#valueOf(char[])},
497 * and the characters of that string were then
498 * {@link #append(String) appended} to this character sequence.
500 * @param str the characters to be appended.
501 * @return a reference to this object.
503 public AbstractStringBuilder append(char[] str) {
504 int len = str.length;
505 ensureCapacityInternal(count + len);
506 System.arraycopy(str, 0, value, count, len);
512 * Appends the string representation of a subarray of the
513 * {@code char} array argument to this sequence.
515 * Characters of the {@code char} array {@code str}, starting at
516 * index {@code offset}, are appended, in order, to the contents
517 * of this sequence. The length of this sequence increases
518 * by the value of {@code len}.
520 * The overall effect is exactly as if the arguments were converted
521 * to a string by the method {@link String#valueOf(char[],int,int)},
522 * and the characters of that string were then
523 * {@link #append(String) appended} to this character sequence.
525 * @param str the characters to be appended.
526 * @param offset the index of the first {@code char} to append.
527 * @param len the number of {@code char}s to append.
528 * @return a reference to this object.
529 * @throws IndexOutOfBoundsException
530 * if {@code offset < 0} or {@code len < 0}
531 * or {@code offset+len > str.length}
533 public AbstractStringBuilder append(char str[], int offset, int len) {
534 if (len > 0) // let arraycopy report AIOOBE for len < 0
535 ensureCapacityInternal(count + len);
536 System.arraycopy(str, offset, value, count, len);
542 * Appends the string representation of the {@code boolean}
543 * argument to the sequence.
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.
550 * @param b a {@code boolean}.
551 * @return a reference to this object.
553 public AbstractStringBuilder append(boolean b) {
555 ensureCapacityInternal(count + 4);
556 value[count++] = 't';
557 value[count++] = 'r';
558 value[count++] = 'u';
559 value[count++] = 'e';
561 ensureCapacityInternal(count + 5);
562 value[count++] = 'f';
563 value[count++] = 'a';
564 value[count++] = 'l';
565 value[count++] = 's';
566 value[count++] = 'e';
572 * Appends the string representation of the {@code char}
573 * argument to this sequence.
575 * The argument is appended to the contents of this sequence.
576 * The length of this sequence increases by {@code 1}.
578 * The overall effect is exactly as if the argument were converted
579 * to a string by the method {@link String#valueOf(char)},
580 * and the character in that string were then
581 * {@link #append(String) appended} to this character sequence.
583 * @param c a {@code char}.
584 * @return a reference to this object.
586 public AbstractStringBuilder append(char c) {
587 ensureCapacityInternal(count + 1);
593 * Appends the string representation of the {@code int}
594 * argument to this sequence.
596 * The overall effect is exactly as if the argument were converted
597 * to a string by the method {@link String#valueOf(int)},
598 * and the characters of that string were then
599 * {@link #append(String) appended} to this character sequence.
601 * @param i an {@code int}.
602 * @return a reference to this object.
604 public AbstractStringBuilder append(int i) {
605 if (i == Integer.MIN_VALUE) {
606 append("-2147483648");
609 int appendedLength = (i < 0) ? Integer.stringSize(-i) + 1
610 : Integer.stringSize(i);
611 int spaceNeeded = count + appendedLength;
612 ensureCapacityInternal(spaceNeeded);
613 Integer.getChars(i, spaceNeeded, value);
619 * Appends the string representation of the {@code long}
620 * argument to this sequence.
622 * The overall effect is exactly as if the argument were converted
623 * to a string by the method {@link String#valueOf(long)},
624 * and the characters of that string were then
625 * {@link #append(String) appended} to this character sequence.
627 * @param l a {@code long}.
628 * @return a reference to this object.
630 public AbstractStringBuilder append(long l) {
631 if (l == Long.MIN_VALUE) {
632 append("-9223372036854775808");
635 int appendedLength = (l < 0) ? Long.stringSize(-l) + 1
636 : Long.stringSize(l);
637 int spaceNeeded = count + appendedLength;
638 ensureCapacityInternal(spaceNeeded);
639 Long.getChars(l, spaceNeeded, value);
645 * Appends the string representation of the {@code float}
646 * argument to this sequence.
648 * The overall effect is exactly as if the argument were converted
649 * to a string by the method {@link String#valueOf(float)},
650 * and the characters of that string were then
651 * {@link #append(String) appended} to this character sequence.
653 * @param f a {@code float}.
654 * @return a reference to this object.
656 public AbstractStringBuilder append(float f) {
657 new FloatingDecimal(f).appendTo(this);
662 * Appends the string representation of the {@code double}
663 * argument to this sequence.
665 * The overall effect is exactly as if the argument were converted
666 * to a string by the method {@link String#valueOf(double)},
667 * and the characters of that string were then
668 * {@link #append(String) appended} to this character sequence.
670 * @param d a {@code double}.
671 * @return a reference to this object.
673 public AbstractStringBuilder append(double d) {
674 new FloatingDecimal(d).appendTo(this);
679 * Removes the characters in a substring of this sequence.
680 * The substring begins at the specified {@code start} and extends to
681 * the character at index {@code end - 1} or to the end of the
682 * sequence if no such character exists. If
683 * {@code start} is equal to {@code end}, no changes are made.
685 * @param start The beginning index, inclusive.
686 * @param end The ending index, exclusive.
687 * @return This object.
688 * @throws StringIndexOutOfBoundsException if {@code start}
689 * is negative, greater than {@code length()}, or
690 * greater than {@code end}.
692 public AbstractStringBuilder delete(int start, int end) {
694 throw new StringIndexOutOfBoundsException(start);
698 throw new StringIndexOutOfBoundsException();
699 int len = end - start;
701 System.arraycopy(value, start+len, value, start, count-end);
708 * Appends the string representation of the {@code codePoint}
709 * argument to this sequence.
711 * <p> The argument is appended to the contents of this sequence.
712 * The length of this sequence increases by
713 * {@link Character#charCount(int) Character.charCount(codePoint)}.
715 * <p> The overall effect is exactly as if the argument were
716 * converted to a {@code char} array by the method
717 * {@link Character#toChars(int)} and the character in that array
718 * were then {@link #append(char[]) appended} to this character
721 * @param codePoint a Unicode code point
722 * @return a reference to this object.
723 * @exception IllegalArgumentException if the specified
724 * {@code codePoint} isn't a valid Unicode code point
726 public AbstractStringBuilder appendCodePoint(int codePoint) {
727 final int count = this.count;
729 if (Character.isBmpCodePoint(codePoint)) {
730 ensureCapacityInternal(count + 1);
731 value[count] = (char) codePoint;
732 this.count = count + 1;
733 } else if (Character.isValidCodePoint(codePoint)) {
734 ensureCapacityInternal(count + 2);
735 Character.toSurrogates(codePoint, value, count);
736 this.count = count + 2;
738 throw new IllegalArgumentException();
744 * Removes the <code>char</code> at the specified position in this
745 * sequence. This sequence is shortened by one <code>char</code>.
747 * <p>Note: If the character at the given index is a supplementary
748 * character, this method does not remove the entire character. If
749 * correct handling of supplementary characters is required,
750 * determine the number of <code>char</code>s to remove by calling
751 * <code>Character.charCount(thisSequence.codePointAt(index))</code>,
752 * where <code>thisSequence</code> is this sequence.
754 * @param index Index of <code>char</code> to remove
755 * @return This object.
756 * @throws StringIndexOutOfBoundsException if the <code>index</code>
757 * is negative or greater than or equal to
758 * <code>length()</code>.
760 public AbstractStringBuilder deleteCharAt(int index) {
761 if ((index < 0) || (index >= count))
762 throw new StringIndexOutOfBoundsException(index);
763 System.arraycopy(value, index+1, value, index, count-index-1);
769 * Replaces the characters in a substring of this sequence
770 * with characters in the specified <code>String</code>. The substring
771 * begins at the specified <code>start</code> and extends to the character
772 * at index <code>end - 1</code> or to the end of the
773 * sequence if no such character exists. First the
774 * characters in the substring are removed and then the specified
775 * <code>String</code> is inserted at <code>start</code>. (This
776 * sequence will be lengthened to accommodate the
777 * specified String if necessary.)
779 * @param start The beginning index, inclusive.
780 * @param end The ending index, exclusive.
781 * @param str String that will replace previous contents.
782 * @return This object.
783 * @throws StringIndexOutOfBoundsException if <code>start</code>
784 * is negative, greater than <code>length()</code>, or
785 * greater than <code>end</code>.
787 public AbstractStringBuilder replace(int start, int end, String str) {
789 throw new StringIndexOutOfBoundsException(start);
791 throw new StringIndexOutOfBoundsException("start > length()");
793 throw new StringIndexOutOfBoundsException("start > end");
797 int len = str.length();
798 int newCount = count + len - (end - start);
799 ensureCapacityInternal(newCount);
801 System.arraycopy(value, end, value, start + len, count - end);
802 str.getChars(value, start);
808 * Returns a new <code>String</code> that contains a subsequence of
809 * characters currently contained in this character sequence. The
810 * substring begins at the specified index and extends to the end of
813 * @param start The beginning index, inclusive.
814 * @return The new string.
815 * @throws StringIndexOutOfBoundsException if <code>start</code> is
816 * less than zero, or greater than the length of this object.
818 public String substring(int start) {
819 return substring(start, count);
823 * Returns a new character sequence that is a subsequence of this sequence.
825 * <p> An invocation of this method of the form
828 * sb.subSequence(begin, end)</pre></blockquote>
830 * behaves in exactly the same way as the invocation
833 * sb.substring(begin, end)</pre></blockquote>
835 * This method is provided so that this class can
836 * implement the {@link CharSequence} interface. </p>
838 * @param start the start index, inclusive.
839 * @param end the end index, exclusive.
840 * @return the specified subsequence.
842 * @throws IndexOutOfBoundsException
843 * if <tt>start</tt> or <tt>end</tt> are negative,
844 * if <tt>end</tt> is greater than <tt>length()</tt>,
845 * or if <tt>start</tt> is greater than <tt>end</tt>
848 public CharSequence subSequence(int start, int end) {
849 return substring(start, end);
853 * Returns a new <code>String</code> that contains a subsequence of
854 * characters currently contained in this sequence. The
855 * substring begins at the specified <code>start</code> and
856 * extends to the character at index <code>end - 1</code>.
858 * @param start The beginning index, inclusive.
859 * @param end The ending index, exclusive.
860 * @return The new string.
861 * @throws StringIndexOutOfBoundsException if <code>start</code>
862 * or <code>end</code> are negative or greater than
863 * <code>length()</code>, or <code>start</code> is
864 * greater than <code>end</code>.
866 public String substring(int start, int end) {
868 throw new StringIndexOutOfBoundsException(start);
870 throw new StringIndexOutOfBoundsException(end);
872 throw new StringIndexOutOfBoundsException(end - start);
873 return new String(value, start, end - start);
877 * Inserts the string representation of a subarray of the {@code str}
878 * array argument into this sequence. The subarray begins at the
879 * specified {@code offset} and extends {@code len} {@code char}s.
880 * The characters of the subarray are inserted into this sequence at
881 * the position indicated by {@code index}. The length of this
882 * sequence increases by {@code len} {@code char}s.
884 * @param index position at which to insert subarray.
885 * @param str A {@code char} array.
886 * @param offset the index of the first {@code char} in subarray to
888 * @param len the number of {@code char}s in the subarray to
890 * @return This object
891 * @throws StringIndexOutOfBoundsException if {@code index}
892 * is negative or greater than {@code length()}, or
893 * {@code offset} or {@code len} are negative, or
894 * {@code (offset+len)} is greater than
895 * {@code str.length}.
897 public AbstractStringBuilder insert(int index, char[] str, int offset,
900 if ((index < 0) || (index > length()))
901 throw new StringIndexOutOfBoundsException(index);
902 if ((offset < 0) || (len < 0) || (offset > str.length - len))
903 throw new StringIndexOutOfBoundsException(
904 "offset " + offset + ", len " + len + ", str.length "
906 ensureCapacityInternal(count + len);
907 System.arraycopy(value, index, value, index + len, count - index);
908 System.arraycopy(str, offset, value, index, len);
914 * Inserts the string representation of the {@code Object}
915 * argument into this character sequence.
917 * The overall effect is exactly as if the second argument were
918 * converted to a string by the method {@link String#valueOf(Object)},
919 * and the characters of that string were then
920 * {@link #insert(int,String) inserted} into this character
921 * sequence at the indicated offset.
923 * The {@code offset} argument must be greater than or equal to
924 * {@code 0}, and less than or equal to the {@linkplain #length() length}
927 * @param offset the offset.
928 * @param obj an {@code Object}.
929 * @return a reference to this object.
930 * @throws StringIndexOutOfBoundsException if the offset is invalid.
932 public AbstractStringBuilder insert(int offset, Object obj) {
933 return insert(offset, String.valueOf(obj));
937 * Inserts the string into this character sequence.
939 * The characters of the {@code String} argument are inserted, in
940 * order, into this sequence at the indicated offset, moving up any
941 * characters originally above that position and increasing the length
942 * of this sequence by the length of the argument. If
943 * {@code str} is {@code null}, then the four characters
944 * {@code "null"} are inserted into this sequence.
946 * The character at index <i>k</i> in the new character sequence is
949 * <li>the character at index <i>k</i> in the old character sequence, if
950 * <i>k</i> is less than {@code offset}
951 * <li>the character at index <i>k</i>{@code -offset} in the
952 * argument {@code str}, if <i>k</i> is not less than
953 * {@code offset} but is less than {@code offset+str.length()}
954 * <li>the character at index <i>k</i>{@code -str.length()} in the
955 * old character sequence, if <i>k</i> is not less than
956 * {@code offset+str.length()}
958 * The {@code offset} argument must be greater than or equal to
959 * {@code 0}, and less than or equal to the {@linkplain #length() length}
962 * @param offset the offset.
963 * @param str a string.
964 * @return a reference to this object.
965 * @throws StringIndexOutOfBoundsException if the offset is invalid.
967 public AbstractStringBuilder insert(int offset, String str) {
968 if ((offset < 0) || (offset > length()))
969 throw new StringIndexOutOfBoundsException(offset);
972 int len = str.length();
973 ensureCapacityInternal(count + len);
974 System.arraycopy(value, offset, value, offset + len, count - offset);
975 str.getChars(value, offset);
981 * Inserts the string representation of the {@code char} array
982 * argument into this sequence.
984 * The characters of the array argument are inserted into the
985 * contents of this sequence at the position indicated by
986 * {@code offset}. The length of this sequence increases by
987 * the length of the argument.
989 * The overall effect is exactly as if the second argument were
990 * converted to a string by the method {@link String#valueOf(char[])},
991 * and the characters of that string were then
992 * {@link #insert(int,String) inserted} into this character
993 * sequence at the indicated offset.
995 * The {@code offset} argument must be greater than or equal to
996 * {@code 0}, and less than or equal to the {@linkplain #length() length}
999 * @param offset the offset.
1000 * @param str a character array.
1001 * @return a reference to this object.
1002 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1004 public AbstractStringBuilder insert(int offset, char[] str) {
1005 if ((offset < 0) || (offset > length()))
1006 throw new StringIndexOutOfBoundsException(offset);
1007 int len = str.length;
1008 ensureCapacityInternal(count + len);
1009 System.arraycopy(value, offset, value, offset + len, count - offset);
1010 System.arraycopy(str, 0, value, offset, len);
1016 * Inserts the specified {@code CharSequence} into this sequence.
1018 * The characters of the {@code CharSequence} argument are inserted,
1019 * in order, into this sequence at the indicated offset, moving up
1020 * any characters originally above that position and increasing the length
1021 * of this sequence by the length of the argument s.
1023 * The result of this method is exactly the same as if it were an
1024 * invocation of this object's
1025 * {@link #insert(int,CharSequence,int,int) insert}(dstOffset, s, 0, s.length())
1028 * <p>If {@code s} is {@code null}, then the four characters
1029 * {@code "null"} are inserted into this sequence.
1031 * @param dstOffset the offset.
1032 * @param s the sequence to be inserted
1033 * @return a reference to this object.
1034 * @throws IndexOutOfBoundsException if the offset is invalid.
1036 public AbstractStringBuilder insert(int dstOffset, CharSequence s) {
1039 if (s instanceof String)
1040 return this.insert(dstOffset, (String)s);
1041 return this.insert(dstOffset, s, 0, s.length());
1045 * Inserts a subsequence of the specified {@code CharSequence} into
1048 * The subsequence of the argument {@code s} specified by
1049 * {@code start} and {@code end} are inserted,
1050 * in order, into this sequence at the specified destination offset, moving
1051 * up any characters originally above that position. The length of this
1052 * sequence is increased by {@code end - start}.
1054 * The character at index <i>k</i> in this sequence becomes equal to:
1056 * <li>the character at index <i>k</i> in this sequence, if
1057 * <i>k</i> is less than {@code dstOffset}
1058 * <li>the character at index <i>k</i>{@code +start-dstOffset} in
1059 * the argument {@code s}, if <i>k</i> is greater than or equal to
1060 * {@code dstOffset} but is less than {@code dstOffset+end-start}
1061 * <li>the character at index <i>k</i>{@code -(end-start)} in this
1062 * sequence, if <i>k</i> is greater than or equal to
1063 * {@code dstOffset+end-start}
1065 * The {@code dstOffset} argument must be greater than or equal to
1066 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1068 * <p>The start argument must be nonnegative, and not greater than
1070 * <p>The end argument must be greater than or equal to
1071 * {@code start}, and less than or equal to the length of s.
1073 * <p>If {@code s} is {@code null}, then this method inserts
1074 * characters as if the s parameter was a sequence containing the four
1075 * characters {@code "null"}.
1077 * @param dstOffset the offset in this sequence.
1078 * @param s the sequence to be inserted.
1079 * @param start the starting index of the subsequence to be inserted.
1080 * @param end the end index of the subsequence to be inserted.
1081 * @return a reference to this object.
1082 * @throws IndexOutOfBoundsException if {@code dstOffset}
1083 * is negative or greater than {@code this.length()}, or
1084 * {@code start} or {@code end} are negative, or
1085 * {@code start} is greater than {@code end} or
1086 * {@code end} is greater than {@code s.length()}
1088 public AbstractStringBuilder insert(int dstOffset, CharSequence s,
1089 int start, int end) {
1092 if ((dstOffset < 0) || (dstOffset > this.length()))
1093 throw new IndexOutOfBoundsException("dstOffset "+dstOffset);
1094 if ((start < 0) || (end < 0) || (start > end) || (end > s.length()))
1095 throw new IndexOutOfBoundsException(
1096 "start " + start + ", end " + end + ", s.length() "
1098 int len = end - start;
1099 ensureCapacityInternal(count + len);
1100 System.arraycopy(value, dstOffset, value, dstOffset + len,
1102 for (int i=start; i<end; i++)
1103 value[dstOffset++] = s.charAt(i);
1109 * Inserts the string representation of the {@code boolean}
1110 * argument into this sequence.
1112 * The overall effect is exactly as if the second argument were
1113 * converted to a string by the method {@link String#valueOf(boolean)},
1114 * and the characters of that string were then
1115 * {@link #insert(int,String) inserted} into this character
1116 * sequence at the indicated offset.
1118 * The {@code offset} argument must be greater than or equal to
1119 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1122 * @param offset the offset.
1123 * @param b a {@code boolean}.
1124 * @return a reference to this object.
1125 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1127 public AbstractStringBuilder insert(int offset, boolean b) {
1128 return insert(offset, String.valueOf(b));
1132 * Inserts the string representation of the {@code char}
1133 * argument into this sequence.
1135 * The overall effect is exactly as if the second argument were
1136 * converted to a string by the method {@link String#valueOf(char)},
1137 * and the character in that string were then
1138 * {@link #insert(int,String) inserted} into this character
1139 * sequence at the indicated offset.
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}
1145 * @param offset the offset.
1146 * @param c a {@code char}.
1147 * @return a reference to this object.
1148 * @throws IndexOutOfBoundsException if the offset is invalid.
1150 public AbstractStringBuilder insert(int offset, char c) {
1151 ensureCapacityInternal(count + 1);
1152 System.arraycopy(value, offset, value, offset + 1, count - offset);
1159 * Inserts the string representation of the second {@code int}
1160 * argument into this sequence.
1162 * The overall effect is exactly as if the second argument were
1163 * converted to a string by the method {@link String#valueOf(int)},
1164 * and the characters of that string were then
1165 * {@link #insert(int,String) inserted} into this character
1166 * sequence at the indicated offset.
1168 * The {@code offset} argument must be greater than or equal to
1169 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1172 * @param offset the offset.
1173 * @param i an {@code int}.
1174 * @return a reference to this object.
1175 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1177 public AbstractStringBuilder insert(int offset, int i) {
1178 return insert(offset, String.valueOf(i));
1182 * Inserts the string representation of the {@code long}
1183 * argument into this sequence.
1185 * The overall effect is exactly as if the second argument were
1186 * converted to a string by the method {@link String#valueOf(long)},
1187 * and the characters of that string were then
1188 * {@link #insert(int,String) inserted} into this character
1189 * sequence at the indicated offset.
1191 * The {@code offset} argument must be greater than or equal to
1192 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1195 * @param offset the offset.
1196 * @param l a {@code long}.
1197 * @return a reference to this object.
1198 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1200 public AbstractStringBuilder insert(int offset, long l) {
1201 return insert(offset, String.valueOf(l));
1205 * Inserts the string representation of the {@code float}
1206 * argument into this sequence.
1208 * The overall effect is exactly as if the second argument were
1209 * converted to a string by the method {@link String#valueOf(float)},
1210 * and the characters of that string were then
1211 * {@link #insert(int,String) inserted} into this character
1212 * sequence at the indicated offset.
1214 * The {@code offset} argument must be greater than or equal to
1215 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1218 * @param offset the offset.
1219 * @param f a {@code float}.
1220 * @return a reference to this object.
1221 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1223 public AbstractStringBuilder insert(int offset, float f) {
1224 return insert(offset, String.valueOf(f));
1228 * Inserts the string representation of the {@code double}
1229 * argument into this sequence.
1231 * The overall effect is exactly as if the second argument were
1232 * converted to a string by the method {@link String#valueOf(double)},
1233 * and the characters of that string were then
1234 * {@link #insert(int,String) inserted} into this character
1235 * sequence at the indicated offset.
1237 * The {@code offset} argument must be greater than or equal to
1238 * {@code 0}, and less than or equal to the {@linkplain #length() length}
1241 * @param offset the offset.
1242 * @param d a {@code double}.
1243 * @return a reference to this object.
1244 * @throws StringIndexOutOfBoundsException if the offset is invalid.
1246 public AbstractStringBuilder insert(int offset, double d) {
1247 return insert(offset, String.valueOf(d));
1251 * Returns the index within this string of the first occurrence of the
1252 * specified substring. The integer returned is the smallest value
1253 * <i>k</i> such that:
1255 * this.toString().startsWith(str, <i>k</i>)
1256 * </pre></blockquote>
1257 * is <code>true</code>.
1259 * @param str any string.
1260 * @return if the string argument occurs as a substring within this
1261 * object, then the index of the first character of the first
1262 * such substring is returned; if it does not occur as a
1263 * substring, <code>-1</code> is returned.
1264 * @throws java.lang.NullPointerException if <code>str</code> is
1265 * <code>null</code>.
1267 public int indexOf(String str) {
1268 return indexOf(str, 0);
1272 * Returns the index within this string of the first occurrence of the
1273 * specified substring, starting at the specified index. The integer
1274 * returned is the smallest value <tt>k</tt> for which:
1276 * k >= Math.min(fromIndex, str.length()) &&
1277 * this.toString().startsWith(str, k)
1278 * </pre></blockquote>
1279 * If no such value of <i>k</i> exists, then -1 is returned.
1281 * @param str the substring for which to search.
1282 * @param fromIndex the index from which to start the search.
1283 * @return the index within this string of the first occurrence of the
1284 * specified substring, starting at the specified index.
1285 * @throws java.lang.NullPointerException if <code>str</code> is
1286 * <code>null</code>.
1288 public int indexOf(String str, int fromIndex) {
1289 return String.indexOf(value, 0, count,
1290 str.toCharArray(), 0, str.length(), fromIndex);
1294 * Returns the index within this string of the rightmost occurrence
1295 * of the specified substring. The rightmost empty string "" is
1296 * considered to occur at the index value <code>this.length()</code>.
1297 * The returned index is the largest value <i>k</i> such that
1299 * this.toString().startsWith(str, k)
1300 * </pre></blockquote>
1303 * @param str the substring to search for.
1304 * @return if the string argument occurs one or more times as a substring
1305 * within this object, then the index of the first character of
1306 * the last such substring is returned. If it does not occur as
1307 * a substring, <code>-1</code> is returned.
1308 * @throws java.lang.NullPointerException if <code>str</code> is
1309 * <code>null</code>.
1311 public int lastIndexOf(String str) {
1312 return lastIndexOf(str, count);
1316 * Returns the index within this string of the last occurrence of the
1317 * specified substring. The integer returned is the largest value <i>k</i>
1320 * k <= Math.min(fromIndex, str.length()) &&
1321 * this.toString().startsWith(str, k)
1322 * </pre></blockquote>
1323 * If no such value of <i>k</i> exists, then -1 is returned.
1325 * @param str the substring to search for.
1326 * @param fromIndex the index to start the search from.
1327 * @return the index within this sequence of the last occurrence of the
1328 * specified substring.
1329 * @throws java.lang.NullPointerException if <code>str</code> is
1330 * <code>null</code>.
1332 public int lastIndexOf(String str, int fromIndex) {
1333 return String.lastIndexOf(value, 0, count,
1334 str.toCharArray(), 0, str.length(), fromIndex);
1338 * Causes this character sequence to be replaced by the reverse of
1339 * the sequence. If there are any surrogate pairs included in the
1340 * sequence, these are treated as single characters for the
1341 * reverse operation. Thus, the order of the high-low surrogates
1342 * is never reversed.
1344 * Let <i>n</i> be the character length of this character sequence
1345 * (not the length in <code>char</code> values) just prior to
1346 * execution of the <code>reverse</code> method. Then the
1347 * character at index <i>k</i> in the new character sequence is
1348 * equal to the character at index <i>n-k-1</i> in the old
1349 * character sequence.
1351 * <p>Note that the reverse operation may result in producing
1352 * surrogate pairs that were unpaired low-surrogates and
1353 * high-surrogates before the operation. For example, reversing
1354 * "\uDC00\uD800" produces "\uD800\uDC00" which is
1355 * a valid surrogate pair.
1357 * @return a reference to this object.
1359 public AbstractStringBuilder reverse() {
1360 boolean hasSurrogate = false;
1362 for (int j = (n-1) >> 1; j >= 0; --j) {
1363 char temp = value[j];
1364 char temp2 = value[n - j];
1365 if (!hasSurrogate) {
1366 hasSurrogate = (temp >= Character.MIN_SURROGATE && temp <= Character.MAX_SURROGATE)
1367 || (temp2 >= Character.MIN_SURROGATE && temp2 <= Character.MAX_SURROGATE);
1370 value[n - j] = temp;
1373 // Reverse back all valid surrogate pairs
1374 for (int i = 0; i < count - 1; i++) {
1376 if (Character.isLowSurrogate(c2)) {
1377 char c1 = value[i + 1];
1378 if (Character.isHighSurrogate(c1)) {
1389 * Returns a string representing the data in this sequence.
1390 * A new <code>String</code> object is allocated and initialized to
1391 * contain the character sequence currently represented by this
1392 * object. This <code>String</code> is then returned. Subsequent
1393 * changes to this sequence do not affect the contents of the
1394 * <code>String</code>.
1396 * @return a string representation of this sequence of characters.
1398 public abstract String toString();
1401 * Needed by <tt>String</tt> for the contentEquals method.
1403 final char[] getValue() {