1 /* 2 * Copyright (c) 2003, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.lang; 27 28 import jdk.internal.math.FloatingDecimal; 29 import java.util.Arrays; 30 31 /** 32 * A mutable sequence of characters. 33 * <p> 34 * Implements a modifiable string. At any point in time it contains some 35 * particular sequence of characters, but the length and content of the 36 * sequence can be changed through certain method calls. 37 * 38 * <p>Unless otherwise noted, passing a {@code null} argument to a constructor 39 * or method in this class will cause a {@link NullPointerException} to be 40 * thrown. 41 * 42 * @author Michael McCloskey 43 * @author Martin Buchholz 44 * @author Ulf Zibis 45 * @since 1.5 46 */ 47 abstract class AbstractStringBuilder implements Appendable, CharSequence { 48 // TODO: remove java.lang.Integer.getChars(int, int, char[]) once updated to byte[] from 11. 49 /** 50 * The value is used for character storage. 51 */ 52 char[] value; 53 54 /** 55 * The count is the number of characters used. 56 */ 57 int count; 58 59 /** 60 * This no-arg constructor is necessary for serialization of subclasses. 61 */ AbstractStringBuilder()62 AbstractStringBuilder() { 63 } 64 65 /** 66 * Creates an AbstractStringBuilder of the specified capacity. 67 */ AbstractStringBuilder(int capacity)68 AbstractStringBuilder(int capacity) { 69 value = new char[capacity]; 70 } 71 72 /** 73 * Returns the length (character count). 74 * 75 * @return the length of the sequence of characters currently 76 * represented by this object 77 */ 78 @Override length()79 public int length() { 80 return count; 81 } 82 83 /** 84 * Returns the current capacity. The capacity is the amount of storage 85 * available for newly inserted characters, beyond which an allocation 86 * will occur. 87 * 88 * @return the current capacity 89 */ capacity()90 public int capacity() { 91 return value.length; 92 } 93 94 /** 95 * Ensures that the capacity is at least equal to the specified minimum. 96 * If the current capacity is less than the argument, then a new internal 97 * array is allocated with greater capacity. The new capacity is the 98 * larger of: 99 * <ul> 100 * <li>The {@code minimumCapacity} argument. 101 * <li>Twice the old capacity, plus {@code 2}. 102 * </ul> 103 * If the {@code minimumCapacity} argument is nonpositive, this 104 * method takes no action and simply returns. 105 * Note that subsequent operations on this object can reduce the 106 * actual capacity below that requested here. 107 * 108 * @param minimumCapacity the minimum desired capacity. 109 */ ensureCapacity(int minimumCapacity)110 public void ensureCapacity(int minimumCapacity) { 111 if (minimumCapacity > 0) 112 ensureCapacityInternal(minimumCapacity); 113 } 114 115 /** 116 * For positive values of {@code minimumCapacity}, this method 117 * behaves like {@code ensureCapacity}, however it is never 118 * synchronized. 119 * If {@code minimumCapacity} is non positive due to numeric 120 * overflow, this method throws {@code OutOfMemoryError}. 121 */ ensureCapacityInternal(int minimumCapacity)122 private void ensureCapacityInternal(int minimumCapacity) { 123 // overflow-conscious code 124 if (minimumCapacity - value.length > 0) { 125 value = Arrays.copyOf(value, 126 newCapacity(minimumCapacity)); 127 } 128 } 129 130 /** 131 * The maximum size of array to allocate (unless necessary). 132 * Some VMs reserve some header words in an array. 133 * Attempts to allocate larger arrays may result in 134 * OutOfMemoryError: Requested array size exceeds VM limit 135 */ 136 private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8; 137 138 /** 139 * Returns a capacity at least as large as the given minimum capacity. 140 * Returns the current capacity increased by the same amount + 2 if 141 * that suffices. 142 * Will not return a capacity greater than {@code MAX_ARRAY_SIZE} 143 * unless the given minimum capacity is greater than that. 144 * 145 * @param minCapacity the desired minimum capacity 146 * @throws OutOfMemoryError if minCapacity is less than zero or 147 * greater than Integer.MAX_VALUE 148 */ newCapacity(int minCapacity)149 private int newCapacity(int minCapacity) { 150 // overflow-conscious code 151 int newCapacity = (value.length << 1) + 2; 152 if (newCapacity - minCapacity < 0) { 153 newCapacity = minCapacity; 154 } 155 return (newCapacity <= 0 || MAX_ARRAY_SIZE - newCapacity < 0) 156 ? hugeCapacity(minCapacity) 157 : newCapacity; 158 } 159 hugeCapacity(int minCapacity)160 private int hugeCapacity(int minCapacity) { 161 if (Integer.MAX_VALUE - minCapacity < 0) { // overflow 162 throw new OutOfMemoryError(); 163 } 164 return (minCapacity > MAX_ARRAY_SIZE) 165 ? minCapacity : MAX_ARRAY_SIZE; 166 } 167 168 /** 169 * Attempts to reduce storage used for the character sequence. 170 * If the buffer is larger than necessary to hold its current sequence of 171 * characters, then it may be resized to become more space efficient. 172 * Calling this method may, but is not required to, affect the value 173 * returned by a subsequent call to the {@link #capacity()} method. 174 */ trimToSize()175 public void trimToSize() { 176 if (count < value.length) { 177 value = Arrays.copyOf(value, count); 178 } 179 } 180 181 /** 182 * Sets the length of the character sequence. 183 * The sequence is changed to a new character sequence 184 * whose length is specified by the argument. For every nonnegative 185 * index <i>k</i> less than {@code newLength}, the character at 186 * index <i>k</i> in the new character sequence is the same as the 187 * character at index <i>k</i> in the old sequence if <i>k</i> is less 188 * than the length of the old character sequence; otherwise, it is the 189 * null character {@code '\u005Cu0000'}. 190 * 191 * In other words, if the {@code newLength} argument is less than 192 * the current length, the length is changed to the specified length. 193 * <p> 194 * If the {@code newLength} argument is greater than or equal 195 * to the current length, sufficient null characters 196 * ({@code '\u005Cu0000'}) are appended so that 197 * length becomes the {@code newLength} argument. 198 * <p> 199 * The {@code newLength} argument must be greater than or equal 200 * to {@code 0}. 201 * 202 * @param newLength the new length 203 * @throws IndexOutOfBoundsException if the 204 * {@code newLength} argument is negative. 205 */ setLength(int newLength)206 public void setLength(int newLength) { 207 if (newLength < 0) 208 throw new StringIndexOutOfBoundsException(newLength); 209 ensureCapacityInternal(newLength); 210 211 if (count < newLength) { 212 Arrays.fill(value, count, newLength, '\0'); 213 } 214 215 count = newLength; 216 } 217 218 /** 219 * Returns the {@code char} value in this sequence at the specified index. 220 * The first {@code char} value is at index {@code 0}, the next at index 221 * {@code 1}, and so on, as in array indexing. 222 * <p> 223 * The index argument must be greater than or equal to 224 * {@code 0}, and less than the length of this sequence. 225 * 226 * <p>If the {@code char} value specified by the index is a 227 * <a href="Character.html#unicode">surrogate</a>, the surrogate 228 * value is returned. 229 * 230 * @param index the index of the desired {@code char} value. 231 * @return the {@code char} value at the specified index. 232 * @throws IndexOutOfBoundsException if {@code index} is 233 * negative or greater than or equal to {@code length()}. 234 */ 235 @Override charAt(int index)236 public char charAt(int index) { 237 if ((index < 0) || (index >= count)) 238 throw new StringIndexOutOfBoundsException(index); 239 return value[index]; 240 } 241 242 /** 243 * Returns the character (Unicode code point) at the specified 244 * index. The index refers to {@code char} values 245 * (Unicode code units) and ranges from {@code 0} to 246 * {@link #length()}{@code - 1}. 247 * 248 * <p> If the {@code char} value specified at the given index 249 * is in the high-surrogate range, the following index is less 250 * than the length of this sequence, and the 251 * {@code char} value at the following index is in the 252 * low-surrogate range, then the supplementary code point 253 * corresponding to this surrogate pair is returned. Otherwise, 254 * the {@code char} value at the given index is returned. 255 * 256 * @param index the index to the {@code char} values 257 * @return the code point value of the character at the 258 * {@code index} 259 * @exception IndexOutOfBoundsException if the {@code index} 260 * argument is negative or not less than the length of this 261 * sequence. 262 */ codePointAt(int index)263 public int codePointAt(int index) { 264 if ((index < 0) || (index >= count)) { 265 throw new StringIndexOutOfBoundsException(index); 266 } 267 return Character.codePointAtImpl(value, index, count); 268 } 269 270 /** 271 * Returns the character (Unicode code point) before the specified 272 * index. The index refers to {@code char} values 273 * (Unicode code units) and ranges from {@code 1} to {@link 274 * #length()}. 275 * 276 * <p> If the {@code char} value at {@code (index - 1)} 277 * is in the low-surrogate range, {@code (index - 2)} is not 278 * negative, and the {@code char} value at {@code (index - 279 * 2)} is in the high-surrogate range, then the 280 * supplementary code point value of the surrogate pair is 281 * returned. If the {@code char} value at {@code index - 282 * 1} is an unpaired low-surrogate or a high-surrogate, the 283 * surrogate value is returned. 284 * 285 * @param index the index following the code point that should be returned 286 * @return the Unicode code point value before the given index. 287 * @exception IndexOutOfBoundsException if the {@code index} 288 * argument is less than 1 or greater than the length 289 * of this sequence. 290 */ codePointBefore(int index)291 public int codePointBefore(int index) { 292 int i = index - 1; 293 if ((i < 0) || (i >= count)) { 294 throw new StringIndexOutOfBoundsException(index); 295 } 296 return Character.codePointBeforeImpl(value, index, 0); 297 } 298 299 /** 300 * Returns the number of Unicode code points in the specified text 301 * range of this sequence. The text range begins at the specified 302 * {@code beginIndex} and extends to the {@code char} at 303 * index {@code endIndex - 1}. Thus the length (in 304 * {@code char}s) of the text range is 305 * {@code endIndex-beginIndex}. Unpaired surrogates within 306 * this sequence count as one code point each. 307 * 308 * @param beginIndex the index to the first {@code char} of 309 * the text range. 310 * @param endIndex the index after the last {@code char} of 311 * the text range. 312 * @return the number of Unicode code points in the specified text 313 * range 314 * @exception IndexOutOfBoundsException if the 315 * {@code beginIndex} is negative, or {@code endIndex} 316 * is larger than the length of this sequence, or 317 * {@code beginIndex} is larger than {@code endIndex}. 318 */ codePointCount(int beginIndex, int endIndex)319 public int codePointCount(int beginIndex, int endIndex) { 320 if (beginIndex < 0 || endIndex > count || beginIndex > endIndex) { 321 throw new IndexOutOfBoundsException(); 322 } 323 return Character.codePointCountImpl(value, beginIndex, endIndex-beginIndex); 324 } 325 326 /** 327 * Returns the index within this sequence that is offset from the 328 * given {@code index} by {@code codePointOffset} code 329 * points. Unpaired surrogates within the text range given by 330 * {@code index} and {@code codePointOffset} count as 331 * one code point each. 332 * 333 * @param index the index to be offset 334 * @param codePointOffset the offset in code points 335 * @return the index within this sequence 336 * @exception IndexOutOfBoundsException if {@code index} 337 * is negative or larger then the length of this sequence, 338 * or if {@code codePointOffset} is positive and the subsequence 339 * starting with {@code index} has fewer than 340 * {@code codePointOffset} code points, 341 * or if {@code codePointOffset} is negative and the subsequence 342 * before {@code index} has fewer than the absolute value of 343 * {@code codePointOffset} code points. 344 */ offsetByCodePoints(int index, int codePointOffset)345 public int offsetByCodePoints(int index, int codePointOffset) { 346 if (index < 0 || index > count) { 347 throw new IndexOutOfBoundsException(); 348 } 349 return Character.offsetByCodePointsImpl(value, 0, count, 350 index, codePointOffset); 351 } 352 353 /** 354 * Characters are copied from this sequence into the 355 * destination character array {@code dst}. The first character to 356 * be copied is at index {@code srcBegin}; the last character to 357 * be copied is at index {@code srcEnd-1}. The total number of 358 * characters to be copied is {@code srcEnd-srcBegin}. The 359 * characters are copied into the subarray of {@code dst} starting 360 * at index {@code dstBegin} and ending at index: 361 * <pre>{@code 362 * dstbegin + (srcEnd-srcBegin) - 1 363 * }</pre> 364 * 365 * @param srcBegin start copying at this offset. 366 * @param srcEnd stop copying at this offset. 367 * @param dst the array to copy the data into. 368 * @param dstBegin offset into {@code dst}. 369 * @throws IndexOutOfBoundsException if any of the following is true: 370 * <ul> 371 * <li>{@code srcBegin} is negative 372 * <li>{@code dstBegin} is negative 373 * <li>the {@code srcBegin} argument is greater than 374 * the {@code srcEnd} argument. 375 * <li>{@code srcEnd} is greater than 376 * {@code this.length()}. 377 * <li>{@code dstBegin+srcEnd-srcBegin} is greater than 378 * {@code dst.length} 379 * </ul> 380 */ getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)381 public void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin) 382 { 383 if (srcBegin < 0) 384 throw new StringIndexOutOfBoundsException(srcBegin); 385 if ((srcEnd < 0) || (srcEnd > count)) 386 throw new StringIndexOutOfBoundsException(srcEnd); 387 if (srcBegin > srcEnd) 388 throw new StringIndexOutOfBoundsException("srcBegin > srcEnd"); 389 System.arraycopy(value, srcBegin, dst, dstBegin, srcEnd - srcBegin); 390 } 391 392 /** 393 * The character at the specified index is set to {@code ch}. This 394 * sequence is altered to represent a new character sequence that is 395 * identical to the old character sequence, except that it contains the 396 * character {@code ch} at position {@code index}. 397 * <p> 398 * The index argument must be greater than or equal to 399 * {@code 0}, and less than the length of this sequence. 400 * 401 * @param index the index of the character to modify. 402 * @param ch the new character. 403 * @throws IndexOutOfBoundsException if {@code index} is 404 * negative or greater than or equal to {@code length()}. 405 */ setCharAt(int index, char ch)406 public void setCharAt(int index, char ch) { 407 if ((index < 0) || (index >= count)) 408 throw new StringIndexOutOfBoundsException(index); 409 value[index] = ch; 410 } 411 412 /** 413 * Appends the string representation of the {@code Object} argument. 414 * <p> 415 * The overall effect is exactly as if the argument were converted 416 * to a string by the method {@link String#valueOf(Object)}, 417 * and the characters of that string were then 418 * {@link #append(String) appended} to this character sequence. 419 * 420 * @param obj an {@code Object}. 421 * @return a reference to this object. 422 */ append(Object obj)423 public AbstractStringBuilder append(Object obj) { 424 return append(String.valueOf(obj)); 425 } 426 427 /** 428 * Appends the specified string to this character sequence. 429 * <p> 430 * The characters of the {@code String} argument are appended, in 431 * order, increasing the length of this sequence by the length of the 432 * argument. If {@code str} is {@code null}, then the four 433 * characters {@code "null"} are appended. 434 * <p> 435 * Let <i>n</i> be the length of this character sequence just prior to 436 * execution of the {@code append} method. Then the character at 437 * index <i>k</i> in the new character sequence is equal to the character 438 * at index <i>k</i> in the old character sequence, if <i>k</i> is less 439 * than <i>n</i>; otherwise, it is equal to the character at index 440 * <i>k-n</i> in the argument {@code str}. 441 * 442 * @param str a string. 443 * @return a reference to this object. 444 */ append(String str)445 public AbstractStringBuilder append(String str) { 446 if (str == null) 447 return appendNull(); 448 int len = str.length(); 449 ensureCapacityInternal(count + len); 450 str.getChars(0, len, value, count); 451 count += len; 452 return this; 453 } 454 455 // Documentation in subclasses because of synchro difference append(StringBuffer sb)456 public AbstractStringBuilder append(StringBuffer sb) { 457 if (sb == null) 458 return appendNull(); 459 int len = sb.length(); 460 ensureCapacityInternal(count + len); 461 sb.getChars(0, len, value, count); 462 count += len; 463 return this; 464 } 465 466 /** 467 * @since 1.8 468 */ append(AbstractStringBuilder asb)469 AbstractStringBuilder append(AbstractStringBuilder asb) { 470 if (asb == null) 471 return appendNull(); 472 int len = asb.length(); 473 ensureCapacityInternal(count + len); 474 asb.getChars(0, len, value, count); 475 count += len; 476 return this; 477 } 478 479 // Documentation in subclasses because of synchro difference 480 @Override append(CharSequence s)481 public AbstractStringBuilder append(CharSequence s) { 482 if (s == null) 483 return appendNull(); 484 if (s instanceof String) 485 return this.append((String)s); 486 if (s instanceof AbstractStringBuilder) 487 return this.append((AbstractStringBuilder)s); 488 489 return this.append(s, 0, s.length()); 490 } 491 appendNull()492 private AbstractStringBuilder appendNull() { 493 int c = count; 494 ensureCapacityInternal(c + 4); 495 final char[] value = this.value; 496 value[c++] = 'n'; 497 value[c++] = 'u'; 498 value[c++] = 'l'; 499 value[c++] = 'l'; 500 count = c; 501 return this; 502 } 503 504 /** 505 * Appends a subsequence of the specified {@code CharSequence} to this 506 * sequence. 507 * <p> 508 * Characters of the argument {@code s}, starting at 509 * index {@code start}, are appended, in order, to the contents of 510 * this sequence up to the (exclusive) index {@code end}. The length 511 * of this sequence is increased by the value of {@code end - start}. 512 * <p> 513 * Let <i>n</i> be the length of this character sequence just prior to 514 * execution of the {@code append} method. Then the character at 515 * index <i>k</i> in this character sequence becomes equal to the 516 * character at index <i>k</i> in this sequence, if <i>k</i> is less than 517 * <i>n</i>; otherwise, it is equal to the character at index 518 * <i>k+start-n</i> in the argument {@code s}. 519 * <p> 520 * If {@code s} is {@code null}, then this method appends 521 * characters as if the s parameter was a sequence containing the four 522 * characters {@code "null"}. 523 * 524 * @param s the sequence to append. 525 * @param start the starting index of the subsequence to be appended. 526 * @param end the end index of the subsequence to be appended. 527 * @return a reference to this object. 528 * @throws IndexOutOfBoundsException if 529 * {@code start} is negative, or 530 * {@code start} is greater than {@code end} or 531 * {@code end} is greater than {@code s.length()} 532 */ 533 @Override append(CharSequence s, int start, int end)534 public AbstractStringBuilder append(CharSequence s, int start, int end) { 535 if (s == null) 536 s = "null"; 537 if ((start < 0) || (start > end) || (end > s.length())) 538 throw new IndexOutOfBoundsException( 539 "start " + start + ", end " + end + ", s.length() " 540 + s.length()); 541 int len = end - start; 542 ensureCapacityInternal(count + len); 543 for (int i = start, j = count; i < end; i++, j++) 544 value[j] = s.charAt(i); 545 count += len; 546 return this; 547 } 548 549 /** 550 * Appends the string representation of the {@code char} array 551 * argument to this sequence. 552 * <p> 553 * The characters of the array argument are appended, in order, to 554 * the contents of this sequence. The length of this sequence 555 * increases by the length of the argument. 556 * <p> 557 * The overall effect is exactly as if the argument were converted 558 * to a string by the method {@link String#valueOf(char[])}, 559 * and the characters of that string were then 560 * {@link #append(String) appended} to this character sequence. 561 * 562 * @param str the characters to be appended. 563 * @return a reference to this object. 564 */ append(char[] str)565 public AbstractStringBuilder append(char[] str) { 566 int len = str.length; 567 ensureCapacityInternal(count + len); 568 System.arraycopy(str, 0, value, count, len); 569 count += len; 570 return this; 571 } 572 573 /** 574 * Appends the string representation of a subarray of the 575 * {@code char} array argument to this sequence. 576 * <p> 577 * Characters of the {@code char} array {@code str}, starting at 578 * index {@code offset}, are appended, in order, to the contents 579 * of this sequence. The length of this sequence increases 580 * by the value of {@code len}. 581 * <p> 582 * The overall effect is exactly as if the arguments were converted 583 * to a string by the method {@link String#valueOf(char[],int,int)}, 584 * and the characters of that string were then 585 * {@link #append(String) appended} to this character sequence. 586 * 587 * @param str the characters to be appended. 588 * @param offset the index of the first {@code char} to append. 589 * @param len the number of {@code char}s to append. 590 * @return a reference to this object. 591 * @throws IndexOutOfBoundsException 592 * if {@code offset < 0} or {@code len < 0} 593 * or {@code offset+len > str.length} 594 */ append(char str[], int offset, int len)595 public AbstractStringBuilder append(char str[], int offset, int len) { 596 if (len > 0) // let arraycopy report AIOOBE for len < 0 597 ensureCapacityInternal(count + len); 598 System.arraycopy(str, offset, value, count, len); 599 count += len; 600 return this; 601 } 602 603 /** 604 * Appends the string representation of the {@code boolean} 605 * argument to the sequence. 606 * <p> 607 * The overall effect is exactly as if the argument were converted 608 * to a string by the method {@link String#valueOf(boolean)}, 609 * and the characters of that string were then 610 * {@link #append(String) appended} to this character sequence. 611 * 612 * @param b a {@code boolean}. 613 * @return a reference to this object. 614 */ append(boolean b)615 public AbstractStringBuilder append(boolean b) { 616 if (b) { 617 ensureCapacityInternal(count + 4); 618 value[count++] = 't'; 619 value[count++] = 'r'; 620 value[count++] = 'u'; 621 value[count++] = 'e'; 622 } else { 623 ensureCapacityInternal(count + 5); 624 value[count++] = 'f'; 625 value[count++] = 'a'; 626 value[count++] = 'l'; 627 value[count++] = 's'; 628 value[count++] = 'e'; 629 } 630 return this; 631 } 632 633 /** 634 * Appends the string representation of the {@code char} 635 * argument to this sequence. 636 * <p> 637 * The argument is appended to the contents of this sequence. 638 * The length of this sequence increases by {@code 1}. 639 * <p> 640 * The overall effect is exactly as if the argument were converted 641 * to a string by the method {@link String#valueOf(char)}, 642 * and the character in that string were then 643 * {@link #append(String) appended} to this character sequence. 644 * 645 * @param c a {@code char}. 646 * @return a reference to this object. 647 */ 648 @Override append(char c)649 public AbstractStringBuilder append(char c) { 650 ensureCapacityInternal(count + 1); 651 value[count++] = c; 652 return this; 653 } 654 655 /** 656 * Appends the string representation of the {@code int} 657 * argument to this sequence. 658 * <p> 659 * The overall effect is exactly as if the argument were converted 660 * to a string by the method {@link String#valueOf(int)}, 661 * and the characters of that string were then 662 * {@link #append(String) appended} to this character sequence. 663 * 664 * @param i an {@code int}. 665 * @return a reference to this object. 666 */ append(int i)667 public AbstractStringBuilder append(int i) { 668 if (i == Integer.MIN_VALUE) { 669 append("-2147483648"); 670 return this; 671 } 672 int appendedLength = (i < 0) ? Integer.stringSize(-i) + 1 673 : Integer.stringSize(i); 674 int spaceNeeded = count + appendedLength; 675 ensureCapacityInternal(spaceNeeded); 676 Integer.getChars(i, spaceNeeded, value); 677 count = spaceNeeded; 678 return this; 679 } 680 681 /** 682 * Appends the string representation of the {@code long} 683 * argument to this sequence. 684 * <p> 685 * The overall effect is exactly as if the argument were converted 686 * to a string by the method {@link String#valueOf(long)}, 687 * and the characters of that string were then 688 * {@link #append(String) appended} to this character sequence. 689 * 690 * @param l a {@code long}. 691 * @return a reference to this object. 692 */ append(long l)693 public AbstractStringBuilder append(long l) { 694 if (l == Long.MIN_VALUE) { 695 append("-9223372036854775808"); 696 return this; 697 } 698 int appendedLength = (l < 0) ? Long.stringSize(-l) + 1 699 : Long.stringSize(l); 700 int spaceNeeded = count + appendedLength; 701 ensureCapacityInternal(spaceNeeded); 702 Long.getChars(l, spaceNeeded, value); 703 count = spaceNeeded; 704 return this; 705 } 706 707 /** 708 * Appends the string representation of the {@code float} 709 * argument to this sequence. 710 * <p> 711 * The overall effect is exactly as if the argument were converted 712 * to a string by the method {@link String#valueOf(float)}, 713 * and the characters of that string were then 714 * {@link #append(String) appended} to this character sequence. 715 * 716 * @param f a {@code float}. 717 * @return a reference to this object. 718 */ append(float f)719 public AbstractStringBuilder append(float f) { 720 FloatingDecimal.appendTo(f,this); 721 return this; 722 } 723 724 /** 725 * Appends the string representation of the {@code double} 726 * argument to this sequence. 727 * <p> 728 * The overall effect is exactly as if the argument were converted 729 * to a string by the method {@link String#valueOf(double)}, 730 * and the characters of that string were then 731 * {@link #append(String) appended} to this character sequence. 732 * 733 * @param d a {@code double}. 734 * @return a reference to this object. 735 */ append(double d)736 public AbstractStringBuilder append(double d) { 737 FloatingDecimal.appendTo(d,this); 738 return this; 739 } 740 741 /** 742 * Removes the characters in a substring of this sequence. 743 * The substring begins at the specified {@code start} and extends to 744 * the character at index {@code end - 1} or to the end of the 745 * sequence if no such character exists. If 746 * {@code start} is equal to {@code end}, no changes are made. 747 * 748 * @param start The beginning index, inclusive. 749 * @param end The ending index, exclusive. 750 * @return This object. 751 * @throws StringIndexOutOfBoundsException if {@code start} 752 * is negative, greater than {@code length()}, or 753 * greater than {@code end}. 754 */ delete(int start, int end)755 public AbstractStringBuilder delete(int start, int end) { 756 if (start < 0) 757 throw new StringIndexOutOfBoundsException(start); 758 if (end > count) 759 end = count; 760 if (start > end) 761 throw new StringIndexOutOfBoundsException(); 762 int len = end - start; 763 if (len > 0) { 764 System.arraycopy(value, start+len, value, start, count-end); 765 count -= len; 766 } 767 return this; 768 } 769 770 /** 771 * Appends the string representation of the {@code codePoint} 772 * argument to this sequence. 773 * 774 * <p> The argument is appended to the contents of this sequence. 775 * The length of this sequence increases by 776 * {@link Character#charCount(int) Character.charCount(codePoint)}. 777 * 778 * <p> The overall effect is exactly as if the argument were 779 * converted to a {@code char} array by the method 780 * {@link Character#toChars(int)} and the character in that array 781 * were then {@link #append(char[]) appended} to this character 782 * sequence. 783 * 784 * @param codePoint a Unicode code point 785 * @return a reference to this object. 786 * @exception IllegalArgumentException if the specified 787 * {@code codePoint} isn't a valid Unicode code point 788 */ appendCodePoint(int codePoint)789 public AbstractStringBuilder appendCodePoint(int codePoint) { 790 final int count = this.count; 791 792 if (Character.isBmpCodePoint(codePoint)) { 793 ensureCapacityInternal(count + 1); 794 value[count] = (char) codePoint; 795 this.count = count + 1; 796 } else if (Character.isValidCodePoint(codePoint)) { 797 ensureCapacityInternal(count + 2); 798 Character.toSurrogates(codePoint, value, count); 799 this.count = count + 2; 800 } else { 801 throw new IllegalArgumentException(); 802 } 803 return this; 804 } 805 806 /** 807 * Removes the {@code char} at the specified position in this 808 * sequence. This sequence is shortened by one {@code char}. 809 * 810 * <p>Note: If the character at the given index is a supplementary 811 * character, this method does not remove the entire character. If 812 * correct handling of supplementary characters is required, 813 * determine the number of {@code char}s to remove by calling 814 * {@code Character.charCount(thisSequence.codePointAt(index))}, 815 * where {@code thisSequence} is this sequence. 816 * 817 * @param index Index of {@code char} to remove 818 * @return This object. 819 * @throws StringIndexOutOfBoundsException if the {@code index} 820 * is negative or greater than or equal to 821 * {@code length()}. 822 */ deleteCharAt(int index)823 public AbstractStringBuilder deleteCharAt(int index) { 824 if ((index < 0) || (index >= count)) 825 throw new StringIndexOutOfBoundsException(index); 826 System.arraycopy(value, index+1, value, index, count-index-1); 827 count--; 828 return this; 829 } 830 831 /** 832 * Replaces the characters in a substring of this sequence 833 * with characters in the specified {@code String}. The substring 834 * begins at the specified {@code start} and extends to the character 835 * at index {@code end - 1} or to the end of the 836 * sequence if no such character exists. First the 837 * characters in the substring are removed and then the specified 838 * {@code String} is inserted at {@code start}. (This 839 * sequence will be lengthened to accommodate the 840 * specified String if necessary.) 841 * 842 * @param start The beginning index, inclusive. 843 * @param end The ending index, exclusive. 844 * @param str String that will replace previous contents. 845 * @return This object. 846 * @throws StringIndexOutOfBoundsException if {@code start} 847 * is negative, greater than {@code length()}, or 848 * greater than {@code end}. 849 */ replace(int start, int end, String str)850 public AbstractStringBuilder replace(int start, int end, String str) { 851 if (start < 0) 852 throw new StringIndexOutOfBoundsException(start); 853 if (start > count) 854 throw new StringIndexOutOfBoundsException("start > length()"); 855 if (start > end) 856 throw new StringIndexOutOfBoundsException("start > end"); 857 858 if (end > count) 859 end = count; 860 int len = str.length(); 861 int newCount = count + len - (end - start); 862 ensureCapacityInternal(newCount); 863 864 System.arraycopy(value, end, value, start + len, count - end); 865 str.getChars(value, start); 866 count = newCount; 867 return this; 868 } 869 870 /** 871 * Returns a new {@code String} that contains a subsequence of 872 * characters currently contained in this character sequence. The 873 * substring begins at the specified index and extends to the end of 874 * this sequence. 875 * 876 * @param start The beginning index, inclusive. 877 * @return The new string. 878 * @throws StringIndexOutOfBoundsException if {@code start} is 879 * less than zero, or greater than the length of this object. 880 */ substring(int start)881 public String substring(int start) { 882 return substring(start, count); 883 } 884 885 /** 886 * Returns a new character sequence that is a subsequence of this sequence. 887 * 888 * <p> An invocation of this method of the form 889 * 890 * <pre>{@code 891 * sb.subSequence(begin, end)}</pre> 892 * 893 * behaves in exactly the same way as the invocation 894 * 895 * <pre>{@code 896 * sb.substring(begin, end)}</pre> 897 * 898 * This method is provided so that this class can 899 * implement the {@link CharSequence} interface. 900 * 901 * @param start the start index, inclusive. 902 * @param end the end index, exclusive. 903 * @return the specified subsequence. 904 * 905 * @throws IndexOutOfBoundsException 906 * if {@code start} or {@code end} are negative, 907 * if {@code end} is greater than {@code length()}, 908 * or if {@code start} is greater than {@code end} 909 * @spec JSR-51 910 */ 911 @Override subSequence(int start, int end)912 public CharSequence subSequence(int start, int end) { 913 return substring(start, end); 914 } 915 916 /** 917 * Returns a new {@code String} that contains a subsequence of 918 * characters currently contained in this sequence. The 919 * substring begins at the specified {@code start} and 920 * extends to the character at index {@code end - 1}. 921 * 922 * @param start The beginning index, inclusive. 923 * @param end The ending index, exclusive. 924 * @return The new string. 925 * @throws StringIndexOutOfBoundsException if {@code start} 926 * or {@code end} are negative or greater than 927 * {@code length()}, or {@code start} is 928 * greater than {@code end}. 929 */ substring(int start, int end)930 public String substring(int start, int end) { 931 if (start < 0) 932 throw new StringIndexOutOfBoundsException(start); 933 if (end > count) 934 throw new StringIndexOutOfBoundsException(end); 935 if (start > end) 936 throw new StringIndexOutOfBoundsException(end - start); 937 return new String(value, start, end - start); 938 } 939 940 /** 941 * Inserts the string representation of a subarray of the {@code str} 942 * array argument into this sequence. The subarray begins at the 943 * specified {@code offset} and extends {@code len} {@code char}s. 944 * The characters of the subarray are inserted into this sequence at 945 * the position indicated by {@code index}. The length of this 946 * sequence increases by {@code len} {@code char}s. 947 * 948 * @param index position at which to insert subarray. 949 * @param str A {@code char} array. 950 * @param offset the index of the first {@code char} in subarray to 951 * be inserted. 952 * @param len the number of {@code char}s in the subarray to 953 * be inserted. 954 * @return This object 955 * @throws StringIndexOutOfBoundsException if {@code index} 956 * is negative or greater than {@code length()}, or 957 * {@code offset} or {@code len} are negative, or 958 * {@code (offset+len)} is greater than 959 * {@code str.length}. 960 */ insert(int index, char[] str, int offset, int len)961 public AbstractStringBuilder insert(int index, char[] str, int offset, 962 int len) 963 { 964 if ((index < 0) || (index > length())) 965 throw new StringIndexOutOfBoundsException(index); 966 if ((offset < 0) || (len < 0) || (offset > str.length - len)) 967 throw new StringIndexOutOfBoundsException( 968 "offset " + offset + ", len " + len + ", str.length " 969 + str.length); 970 ensureCapacityInternal(count + len); 971 System.arraycopy(value, index, value, index + len, count - index); 972 System.arraycopy(str, offset, value, index, len); 973 count += len; 974 return this; 975 } 976 977 /** 978 * Inserts the string representation of the {@code Object} 979 * argument into this character sequence. 980 * <p> 981 * The overall effect is exactly as if the second argument were 982 * converted to a string by the method {@link String#valueOf(Object)}, 983 * and the characters of that string were then 984 * {@link #insert(int,String) inserted} into this character 985 * sequence at the indicated offset. 986 * <p> 987 * The {@code offset} argument must be greater than or equal to 988 * {@code 0}, and less than or equal to the {@linkplain #length() length} 989 * of this sequence. 990 * 991 * @param offset the offset. 992 * @param obj an {@code Object}. 993 * @return a reference to this object. 994 * @throws StringIndexOutOfBoundsException if the offset is invalid. 995 */ insert(int offset, Object obj)996 public AbstractStringBuilder insert(int offset, Object obj) { 997 return insert(offset, String.valueOf(obj)); 998 } 999 1000 /** 1001 * Inserts the string into this character sequence. 1002 * <p> 1003 * The characters of the {@code String} argument are inserted, in 1004 * order, into this sequence at the indicated offset, moving up any 1005 * characters originally above that position and increasing the length 1006 * of this sequence by the length of the argument. If 1007 * {@code str} is {@code null}, then the four characters 1008 * {@code "null"} are inserted into this sequence. 1009 * <p> 1010 * The character at index <i>k</i> in the new character sequence is 1011 * equal to: 1012 * <ul> 1013 * <li>the character at index <i>k</i> in the old character sequence, if 1014 * <i>k</i> is less than {@code offset} 1015 * <li>the character at index <i>k</i>{@code -offset} in the 1016 * argument {@code str}, if <i>k</i> is not less than 1017 * {@code offset} but is less than {@code offset+str.length()} 1018 * <li>the character at index <i>k</i>{@code -str.length()} in the 1019 * old character sequence, if <i>k</i> is not less than 1020 * {@code offset+str.length()} 1021 * </ul><p> 1022 * The {@code offset} argument must be greater than or equal to 1023 * {@code 0}, and less than or equal to the {@linkplain #length() length} 1024 * of this sequence. 1025 * 1026 * @param offset the offset. 1027 * @param str a string. 1028 * @return a reference to this object. 1029 * @throws StringIndexOutOfBoundsException if the offset is invalid. 1030 */ insert(int offset, String str)1031 public AbstractStringBuilder insert(int offset, String str) { 1032 if ((offset < 0) || (offset > length())) 1033 throw new StringIndexOutOfBoundsException(offset); 1034 if (str == null) 1035 str = "null"; 1036 int len = str.length(); 1037 ensureCapacityInternal(count + len); 1038 System.arraycopy(value, offset, value, offset + len, count - offset); 1039 str.getChars(value, offset); 1040 count += len; 1041 return this; 1042 } 1043 1044 /** 1045 * Inserts the string representation of the {@code char} array 1046 * argument into this sequence. 1047 * <p> 1048 * The characters of the array argument are inserted into the 1049 * contents of this sequence at the position indicated by 1050 * {@code offset}. The length of this sequence increases by 1051 * the length of the argument. 1052 * <p> 1053 * The overall effect is exactly as if the second argument were 1054 * converted to a string by the method {@link String#valueOf(char[])}, 1055 * and the characters of that string were then 1056 * {@link #insert(int,String) inserted} into this character 1057 * sequence at the indicated offset. 1058 * <p> 1059 * The {@code offset} argument must be greater than or equal to 1060 * {@code 0}, and less than or equal to the {@linkplain #length() length} 1061 * of this sequence. 1062 * 1063 * @param offset the offset. 1064 * @param str a character array. 1065 * @return a reference to this object. 1066 * @throws StringIndexOutOfBoundsException if the offset is invalid. 1067 */ insert(int offset, char[] str)1068 public AbstractStringBuilder insert(int offset, char[] str) { 1069 if ((offset < 0) || (offset > length())) 1070 throw new StringIndexOutOfBoundsException(offset); 1071 int len = str.length; 1072 ensureCapacityInternal(count + len); 1073 System.arraycopy(value, offset, value, offset + len, count - offset); 1074 System.arraycopy(str, 0, value, offset, len); 1075 count += len; 1076 return this; 1077 } 1078 1079 /** 1080 * Inserts the specified {@code CharSequence} into this sequence. 1081 * <p> 1082 * The characters of the {@code CharSequence} argument are inserted, 1083 * in order, into this sequence at the indicated offset, moving up 1084 * any characters originally above that position and increasing the length 1085 * of this sequence by the length of the argument s. 1086 * <p> 1087 * The result of this method is exactly the same as if it were an 1088 * invocation of this object's 1089 * {@link #insert(int,CharSequence,int,int) insert}(dstOffset, s, 0, s.length()) 1090 * method. 1091 * 1092 * <p>If {@code s} is {@code null}, then the four characters 1093 * {@code "null"} are inserted into this sequence. 1094 * 1095 * @param dstOffset the offset. 1096 * @param s the sequence to be inserted 1097 * @return a reference to this object. 1098 * @throws IndexOutOfBoundsException if the offset is invalid. 1099 */ insert(int dstOffset, CharSequence s)1100 public AbstractStringBuilder insert(int dstOffset, CharSequence s) { 1101 if (s == null) 1102 s = "null"; 1103 if (s instanceof String) 1104 return this.insert(dstOffset, (String)s); 1105 return this.insert(dstOffset, s, 0, s.length()); 1106 } 1107 1108 /** 1109 * Inserts a subsequence of the specified {@code CharSequence} into 1110 * this sequence. 1111 * <p> 1112 * The subsequence of the argument {@code s} specified by 1113 * {@code start} and {@code end} are inserted, 1114 * in order, into this sequence at the specified destination offset, moving 1115 * up any characters originally above that position. The length of this 1116 * sequence is increased by {@code end - start}. 1117 * <p> 1118 * The character at index <i>k</i> in this sequence becomes equal to: 1119 * <ul> 1120 * <li>the character at index <i>k</i> in this sequence, if 1121 * <i>k</i> is less than {@code dstOffset} 1122 * <li>the character at index <i>k</i>{@code +start-dstOffset} in 1123 * the argument {@code s}, if <i>k</i> is greater than or equal to 1124 * {@code dstOffset} but is less than {@code dstOffset+end-start} 1125 * <li>the character at index <i>k</i>{@code -(end-start)} in this 1126 * sequence, if <i>k</i> is greater than or equal to 1127 * {@code dstOffset+end-start} 1128 * </ul><p> 1129 * The {@code dstOffset} argument must be greater than or equal to 1130 * {@code 0}, and less than or equal to the {@linkplain #length() length} 1131 * of this sequence. 1132 * <p>The start argument must be nonnegative, and not greater than 1133 * {@code end}. 1134 * <p>The end argument must be greater than or equal to 1135 * {@code start}, and less than or equal to the length of s. 1136 * 1137 * <p>If {@code s} is {@code null}, then this method inserts 1138 * characters as if the s parameter was a sequence containing the four 1139 * characters {@code "null"}. 1140 * 1141 * @param dstOffset the offset in this sequence. 1142 * @param s the sequence to be inserted. 1143 * @param start the starting index of the subsequence to be inserted. 1144 * @param end the end index of the subsequence to be inserted. 1145 * @return a reference to this object. 1146 * @throws IndexOutOfBoundsException if {@code dstOffset} 1147 * is negative or greater than {@code this.length()}, or 1148 * {@code start} or {@code end} are negative, or 1149 * {@code start} is greater than {@code end} or 1150 * {@code end} is greater than {@code s.length()} 1151 */ insert(int dstOffset, CharSequence s, int start, int end)1152 public AbstractStringBuilder insert(int dstOffset, CharSequence s, 1153 int start, int end) { 1154 if (s == null) 1155 s = "null"; 1156 if ((dstOffset < 0) || (dstOffset > this.length())) 1157 throw new IndexOutOfBoundsException("dstOffset "+dstOffset); 1158 if ((start < 0) || (end < 0) || (start > end) || (end > s.length())) 1159 throw new IndexOutOfBoundsException( 1160 "start " + start + ", end " + end + ", s.length() " 1161 + s.length()); 1162 int len = end - start; 1163 ensureCapacityInternal(count + len); 1164 System.arraycopy(value, dstOffset, value, dstOffset + len, 1165 count - dstOffset); 1166 for (int i=start; i<end; i++) 1167 value[dstOffset++] = s.charAt(i); 1168 count += len; 1169 return this; 1170 } 1171 1172 /** 1173 * Inserts the string representation of the {@code boolean} 1174 * argument into this sequence. 1175 * <p> 1176 * The overall effect is exactly as if the second argument were 1177 * converted to a string by the method {@link String#valueOf(boolean)}, 1178 * and the characters of that string were then 1179 * {@link #insert(int,String) inserted} into this character 1180 * sequence at the indicated offset. 1181 * <p> 1182 * The {@code offset} argument must be greater than or equal to 1183 * {@code 0}, and less than or equal to the {@linkplain #length() length} 1184 * of this sequence. 1185 * 1186 * @param offset the offset. 1187 * @param b a {@code boolean}. 1188 * @return a reference to this object. 1189 * @throws StringIndexOutOfBoundsException if the offset is invalid. 1190 */ insert(int offset, boolean b)1191 public AbstractStringBuilder insert(int offset, boolean b) { 1192 return insert(offset, String.valueOf(b)); 1193 } 1194 1195 /** 1196 * Inserts the string representation of the {@code char} 1197 * argument into this sequence. 1198 * <p> 1199 * The overall effect is exactly as if the second argument were 1200 * converted to a string by the method {@link String#valueOf(char)}, 1201 * and the character in that string were then 1202 * {@link #insert(int,String) inserted} into this character 1203 * sequence at the indicated offset. 1204 * <p> 1205 * The {@code offset} argument must be greater than or equal to 1206 * {@code 0}, and less than or equal to the {@linkplain #length() length} 1207 * of this sequence. 1208 * 1209 * @param offset the offset. 1210 * @param c a {@code char}. 1211 * @return a reference to this object. 1212 * @throws IndexOutOfBoundsException if the offset is invalid. 1213 */ insert(int offset, char c)1214 public AbstractStringBuilder insert(int offset, char c) { 1215 ensureCapacityInternal(count + 1); 1216 System.arraycopy(value, offset, value, offset + 1, count - offset); 1217 value[offset] = c; 1218 count += 1; 1219 return this; 1220 } 1221 1222 /** 1223 * Inserts the string representation of the second {@code int} 1224 * argument into this sequence. 1225 * <p> 1226 * The overall effect is exactly as if the second argument were 1227 * converted to a string by the method {@link String#valueOf(int)}, 1228 * and the characters of that string were then 1229 * {@link #insert(int,String) inserted} into this character 1230 * sequence at the indicated offset. 1231 * <p> 1232 * The {@code offset} argument must be greater than or equal to 1233 * {@code 0}, and less than or equal to the {@linkplain #length() length} 1234 * of this sequence. 1235 * 1236 * @param offset the offset. 1237 * @param i an {@code int}. 1238 * @return a reference to this object. 1239 * @throws StringIndexOutOfBoundsException if the offset is invalid. 1240 */ insert(int offset, int i)1241 public AbstractStringBuilder insert(int offset, int i) { 1242 return insert(offset, String.valueOf(i)); 1243 } 1244 1245 /** 1246 * Inserts the string representation of the {@code long} 1247 * argument into this sequence. 1248 * <p> 1249 * The overall effect is exactly as if the second argument were 1250 * converted to a string by the method {@link String#valueOf(long)}, 1251 * and the characters of that string were then 1252 * {@link #insert(int,String) inserted} into this character 1253 * sequence at the indicated offset. 1254 * <p> 1255 * The {@code offset} argument must be greater than or equal to 1256 * {@code 0}, and less than or equal to the {@linkplain #length() length} 1257 * of this sequence. 1258 * 1259 * @param offset the offset. 1260 * @param l a {@code long}. 1261 * @return a reference to this object. 1262 * @throws StringIndexOutOfBoundsException if the offset is invalid. 1263 */ insert(int offset, long l)1264 public AbstractStringBuilder insert(int offset, long l) { 1265 return insert(offset, String.valueOf(l)); 1266 } 1267 1268 /** 1269 * Inserts the string representation of the {@code float} 1270 * argument into this sequence. 1271 * <p> 1272 * The overall effect is exactly as if the second argument were 1273 * converted to a string by the method {@link String#valueOf(float)}, 1274 * and the characters of that string were then 1275 * {@link #insert(int,String) inserted} into this character 1276 * sequence at the indicated offset. 1277 * <p> 1278 * The {@code offset} argument must be greater than or equal to 1279 * {@code 0}, and less than or equal to the {@linkplain #length() length} 1280 * of this sequence. 1281 * 1282 * @param offset the offset. 1283 * @param f a {@code float}. 1284 * @return a reference to this object. 1285 * @throws StringIndexOutOfBoundsException if the offset is invalid. 1286 */ insert(int offset, float f)1287 public AbstractStringBuilder insert(int offset, float f) { 1288 return insert(offset, String.valueOf(f)); 1289 } 1290 1291 /** 1292 * Inserts the string representation of the {@code double} 1293 * argument into this sequence. 1294 * <p> 1295 * The overall effect is exactly as if the second argument were 1296 * converted to a string by the method {@link String#valueOf(double)}, 1297 * and the characters of that string were then 1298 * {@link #insert(int,String) inserted} into this character 1299 * sequence at the indicated offset. 1300 * <p> 1301 * The {@code offset} argument must be greater than or equal to 1302 * {@code 0}, and less than or equal to the {@linkplain #length() length} 1303 * of this sequence. 1304 * 1305 * @param offset the offset. 1306 * @param d a {@code double}. 1307 * @return a reference to this object. 1308 * @throws StringIndexOutOfBoundsException if the offset is invalid. 1309 */ insert(int offset, double d)1310 public AbstractStringBuilder insert(int offset, double d) { 1311 return insert(offset, String.valueOf(d)); 1312 } 1313 1314 /** 1315 * Returns the index within this string of the first occurrence of the 1316 * specified substring. The integer returned is the smallest value 1317 * <i>k</i> such that: 1318 * <pre>{@code 1319 * this.toString().startsWith(str, <i>k</i>) 1320 * }</pre> 1321 * is {@code true}. 1322 * 1323 * @param str any string. 1324 * @return if the string argument occurs as a substring within this 1325 * object, then the index of the first character of the first 1326 * such substring is returned; if it does not occur as a 1327 * substring, {@code -1} is returned. 1328 */ indexOf(String str)1329 public int indexOf(String str) { 1330 return indexOf(str, 0); 1331 } 1332 1333 /** 1334 * Returns the index within this string of the first occurrence of the 1335 * specified substring, starting at the specified index. The integer 1336 * returned is the smallest value {@code k} for which: 1337 * <pre>{@code 1338 * k >= Math.min(fromIndex, this.length()) && 1339 * this.toString().startsWith(str, k) 1340 * }</pre> 1341 * If no such value of <i>k</i> exists, then -1 is returned. 1342 * 1343 * @param str the substring for which to search. 1344 * @param fromIndex the index from which to start the search. 1345 * @return the index within this string of the first occurrence of the 1346 * specified substring, starting at the specified index. 1347 */ indexOf(String str, int fromIndex)1348 public int indexOf(String str, int fromIndex) { 1349 return String.indexOf(value, 0, count, str, fromIndex); 1350 } 1351 1352 /** 1353 * Returns the index within this string of the rightmost occurrence 1354 * of the specified substring. The rightmost empty string "" is 1355 * considered to occur at the index value {@code this.length()}. 1356 * The returned index is the largest value <i>k</i> such that 1357 * <pre>{@code 1358 * this.toString().startsWith(str, k) 1359 * }</pre> 1360 * is true. 1361 * 1362 * @param str the substring to search for. 1363 * @return if the string argument occurs one or more times as a substring 1364 * within this object, then the index of the first character of 1365 * the last such substring is returned. If it does not occur as 1366 * a substring, {@code -1} is returned. 1367 */ lastIndexOf(String str)1368 public int lastIndexOf(String str) { 1369 return lastIndexOf(str, count); 1370 } 1371 1372 /** 1373 * Returns the index within this string of the last occurrence of the 1374 * specified substring. The integer returned is the largest value <i>k</i> 1375 * such that: 1376 * <pre>{@code 1377 * k <= Math.min(fromIndex, this.length()) && 1378 * this.toString().startsWith(str, k) 1379 * }</pre> 1380 * If no such value of <i>k</i> exists, then -1 is returned. 1381 * 1382 * @param str the substring to search for. 1383 * @param fromIndex the index to start the search from. 1384 * @return the index within this sequence of the last occurrence of the 1385 * specified substring. 1386 */ lastIndexOf(String str, int fromIndex)1387 public int lastIndexOf(String str, int fromIndex) { 1388 return String.lastIndexOf(value, 0, count, str, fromIndex); 1389 } 1390 1391 /** 1392 * Causes this character sequence to be replaced by the reverse of 1393 * the sequence. If there are any surrogate pairs included in the 1394 * sequence, these are treated as single characters for the 1395 * reverse operation. Thus, the order of the high-low surrogates 1396 * is never reversed. 1397 * 1398 * Let <i>n</i> be the character length of this character sequence 1399 * (not the length in {@code char} values) just prior to 1400 * execution of the {@code reverse} method. Then the 1401 * character at index <i>k</i> in the new character sequence is 1402 * equal to the character at index <i>n-k-1</i> in the old 1403 * character sequence. 1404 * 1405 * <p>Note that the reverse operation may result in producing 1406 * surrogate pairs that were unpaired low-surrogates and 1407 * high-surrogates before the operation. For example, reversing 1408 * "\u005CuDC00\u005CuD800" produces "\u005CuD800\u005CuDC00" which is 1409 * a valid surrogate pair. 1410 * 1411 * @return a reference to this object. 1412 */ reverse()1413 public AbstractStringBuilder reverse() { 1414 boolean hasSurrogates = false; 1415 int n = count - 1; 1416 for (int j = (n-1) >> 1; j >= 0; j--) { 1417 int k = n - j; 1418 char cj = value[j]; 1419 char ck = value[k]; 1420 value[j] = ck; 1421 value[k] = cj; 1422 if (Character.isSurrogate(cj) || 1423 Character.isSurrogate(ck)) { 1424 hasSurrogates = true; 1425 } 1426 } 1427 if (hasSurrogates) { 1428 reverseAllValidSurrogatePairs(); 1429 } 1430 return this; 1431 } 1432 1433 /** Outlined helper method for reverse() */ reverseAllValidSurrogatePairs()1434 private void reverseAllValidSurrogatePairs() { 1435 for (int i = 0; i < count - 1; i++) { 1436 char c2 = value[i]; 1437 if (Character.isLowSurrogate(c2)) { 1438 char c1 = value[i + 1]; 1439 if (Character.isHighSurrogate(c1)) { 1440 value[i++] = c1; 1441 value[i] = c2; 1442 } 1443 } 1444 } 1445 } 1446 1447 /** 1448 * Returns a string representing the data in this sequence. 1449 * A new {@code String} object is allocated and initialized to 1450 * contain the character sequence currently represented by this 1451 * object. This {@code String} is then returned. Subsequent 1452 * changes to this sequence do not affect the contents of the 1453 * {@code String}. 1454 * 1455 * @return a string representation of this sequence of characters. 1456 */ 1457 @Override toString()1458 public abstract String toString(); 1459 1460 /** 1461 * Needed by {@code String} for the contentEquals method. 1462 */ getValue()1463 final char[] getValue() { 1464 return value; 1465 } 1466 1467 } 1468