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