1 /* 2 * Copyright (c) 1994, 2013, 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 java.io.ObjectStreamField; 29 import java.io.UnsupportedEncodingException; 30 import java.nio.charset.Charset; 31 import java.util.ArrayList; 32 import java.util.Arrays; 33 import java.util.Comparator; 34 import java.util.Formatter; 35 import java.util.Locale; 36 import java.util.Objects; 37 import java.util.StringJoiner; 38 import java.util.regex.Matcher; 39 import java.util.regex.Pattern; 40 import java.util.regex.PatternSyntaxException; 41 42 /** 43 * The {@code String} class represents character strings. All 44 * string literals in Java programs, such as {@code "abc"}, are 45 * implemented as instances of this class. 46 * <p> 47 * Strings are constant; their values cannot be changed after they 48 * are created. String buffers support mutable strings. 49 * Because String objects are immutable they can be shared. For example: 50 * <blockquote><pre> 51 * String str = "abc"; 52 * </pre></blockquote><p> 53 * is equivalent to: 54 * <blockquote><pre> 55 * char data[] = {'a', 'b', 'c'}; 56 * String str = new String(data); 57 * </pre></blockquote><p> 58 * Here are some more examples of how strings can be used: 59 * <blockquote><pre> 60 * System.out.println("abc"); 61 * String cde = "cde"; 62 * System.out.println("abc" + cde); 63 * String c = "abc".substring(2,3); 64 * String d = cde.substring(1, 2); 65 * </pre></blockquote> 66 * <p> 67 * The class {@code String} includes methods for examining 68 * individual characters of the sequence, for comparing strings, for 69 * searching strings, for extracting substrings, and for creating a 70 * copy of a string with all characters translated to uppercase or to 71 * lowercase. Case mapping is based on the Unicode Standard version 72 * specified by the {@link java.lang.Character Character} class. 73 * <p> 74 * The Java language provides special support for the string 75 * concatenation operator ( + ), and for conversion of 76 * other objects to strings. String concatenation is implemented 77 * through the {@code StringBuilder}(or {@code StringBuffer}) 78 * class and its {@code append} method. 79 * String conversions are implemented through the method 80 * {@code toString}, defined by {@code Object} and 81 * inherited by all classes in Java. For additional information on 82 * string concatenation and conversion, see Gosling, Joy, and Steele, 83 * <i>The Java Language Specification</i>. 84 * 85 * <p> Unless otherwise noted, passing a <tt>null</tt> argument to a constructor 86 * or method in this class will cause a {@link NullPointerException} to be 87 * thrown. 88 * 89 * <p>A {@code String} represents a string in the UTF-16 format 90 * in which <em>supplementary characters</em> are represented by <em>surrogate 91 * pairs</em> (see the section <a href="Character.html#unicode">Unicode 92 * Character Representations</a> in the {@code Character} class for 93 * more information). 94 * Index values refer to {@code char} code units, so a supplementary 95 * character uses two positions in a {@code String}. 96 * <p>The {@code String} class provides methods for dealing with 97 * Unicode code points (i.e., characters), in addition to those for 98 * dealing with Unicode code units (i.e., {@code char} values). 99 * 100 * @author Lee Boynton 101 * @author Arthur van Hoff 102 * @author Martin Buchholz 103 * @author Ulf Zibis 104 * @see java.lang.Object#toString() 105 * @see java.lang.StringBuffer 106 * @see java.lang.StringBuilder 107 * @see java.nio.charset.Charset 108 * @since JDK1.0 109 */ 110 111 public final class String 112 implements java.io.Serializable, Comparable<String>, CharSequence { 113 /** The value is used for character storage. */ 114 private final char value[]; 115 116 /** Cache the hash code for the string */ 117 private int hash; // Default to 0 118 119 /** use serialVersionUID from JDK 1.0.2 for interoperability */ 120 private static final long serialVersionUID = -6849794470754667710L; 121 122 /** 123 * Class String is special cased within the Serialization Stream Protocol. 124 * 125 * A String instance is written into an ObjectOutputStream according to 126 * <a href="{@docroot}../platform/serialization/spec/output.html"> 127 * Object Serialization Specification, Section 6.2, "Stream Elements"</a> 128 */ 129 private static final ObjectStreamField[] serialPersistentFields = 130 new ObjectStreamField[0]; 131 132 /** 133 * Initializes a newly created {@code String} object so that it represents 134 * an empty character sequence. Note that use of this constructor is 135 * unnecessary since Strings are immutable. 136 */ 137 public String() { 138 this.value = new char[0]; 139 } 140 141 /** 142 * Initializes a newly created {@code String} object so that it represents 143 * the same sequence of characters as the argument; in other words, the 144 * newly created string is a copy of the argument string. Unless an 145 * explicit copy of {@code original} is needed, use of this constructor is 146 * unnecessary since Strings are immutable. 147 * 148 * @param original 149 * A {@code String} 150 */ 151 public String(String original) { 152 this.value = original.value; 153 this.hash = original.hash; 154 } 155 156 /** 157 * Allocates a new {@code String} so that it represents the sequence of 158 * characters currently contained in the character array argument. The 159 * contents of the character array are copied; subsequent modification of 160 * the character array does not affect the newly created string. 161 * 162 * @param value 163 * The initial value of the string 164 */ 165 public String(char value[]) { 166 this.value = Arrays.copyOf(value, value.length); 167 } 168 169 /** 170 * Allocates a new {@code String} that contains characters from a subarray 171 * of the character array argument. The {@code offset} argument is the 172 * index of the first character of the subarray and the {@code count} 173 * argument specifies the length of the subarray. The contents of the 174 * subarray are copied; subsequent modification of the character array does 175 * not affect the newly created string. 176 * 177 * @param value 178 * Array that is the source of characters 179 * 180 * @param offset 181 * The initial offset 182 * 183 * @param count 184 * The length 185 * 186 * @throws IndexOutOfBoundsException 187 * If the {@code offset} and {@code count} arguments index 188 * characters outside the bounds of the {@code value} array 189 */ 190 public String(char value[], int offset, int count) { 191 if (offset < 0) { 192 throw new StringIndexOutOfBoundsException(offset); 193 } 194 if (count < 0) { 195 throw new StringIndexOutOfBoundsException(count); 196 } 197 // Note: offset or count might be near -1>>>1. 198 if (offset > value.length - count) { 199 throw new StringIndexOutOfBoundsException(offset + count); 200 } 201 this.value = Arrays.copyOfRange(value, offset, offset+count); 202 } 203 204 /** 205 * Allocates a new {@code String} that contains characters from a subarray 206 * of the <a href="Character.html#unicode">Unicode code point</a> array 207 * argument. The {@code offset} argument is the index of the first code 208 * point of the subarray and the {@code count} argument specifies the 209 * length of the subarray. The contents of the subarray are converted to 210 * {@code char}s; subsequent modification of the {@code int} array does not 211 * affect the newly created string. 212 * 213 * @param codePoints 214 * Array that is the source of Unicode code points 215 * 216 * @param offset 217 * The initial offset 218 * 219 * @param count 220 * The length 221 * 222 * @throws IllegalArgumentException 223 * If any invalid Unicode code point is found in {@code 224 * codePoints} 225 * 226 * @throws IndexOutOfBoundsException 227 * If the {@code offset} and {@code count} arguments index 228 * characters outside the bounds of the {@code codePoints} array 229 * 230 * @since 1.5 231 */ 232 public String(int[] codePoints, int offset, int count) { 233 if (offset < 0) { 234 throw new StringIndexOutOfBoundsException(offset); 235 } 236 if (count < 0) { 237 throw new StringIndexOutOfBoundsException(count); 238 } 239 // Note: offset or count might be near -1>>>1. 240 if (offset > codePoints.length - count) { 241 throw new StringIndexOutOfBoundsException(offset + count); 242 } 243 244 final int end = offset + count; 245 246 // Pass 1: Compute precise size of char[] 247 int n = count; 248 for (int i = offset; i < end; i++) { 249 int c = codePoints[i]; 250 if (Character.isBmpCodePoint(c)) 251 continue; 252 else if (Character.isValidCodePoint(c)) 253 n++; 254 else throw new IllegalArgumentException(Integer.toString(c)); 255 } 256 257 // Pass 2: Allocate and fill in char[] 258 final char[] v = new char[n]; 259 260 for (int i = offset, j = 0; i < end; i++, j++) { 261 int c = codePoints[i]; 262 if (Character.isBmpCodePoint(c)) 263 v[j] = (char)c; 264 else 265 Character.toSurrogates(c, v, j++); 266 } 267 268 this.value = v; 269 } 270 271 /** 272 * Allocates a new {@code String} constructed from a subarray of an array 273 * of 8-bit integer values. 274 * 275 * <p> The {@code offset} argument is the index of the first byte of the 276 * subarray, and the {@code count} argument specifies the length of the 277 * subarray. 278 * 279 * <p> Each {@code byte} in the subarray is converted to a {@code char} as 280 * specified in the method above. 281 * 282 * @deprecated This method does not properly convert bytes into characters. 283 * As of JDK 1.1, the preferred way to do this is via the 284 * {@code String} constructors that take a {@link 285 * java.nio.charset.Charset}, charset name, or that use the platform's 286 * default charset. 287 * 288 * @param ascii 289 * The bytes to be converted to characters 290 * 291 * @param hibyte 292 * The top 8 bits of each 16-bit Unicode code unit 293 * 294 * @param offset 295 * The initial offset 296 * @param count 297 * The length 298 * 299 * @throws IndexOutOfBoundsException 300 * If the {@code offset} or {@code count} argument is invalid 301 * 302 * @see #String(byte[], int) 303 * @see #String(byte[], int, int, java.lang.String) 304 * @see #String(byte[], int, int, java.nio.charset.Charset) 305 * @see #String(byte[], int, int) 306 * @see #String(byte[], java.lang.String) 307 * @see #String(byte[], java.nio.charset.Charset) 308 * @see #String(byte[]) 309 */ 310 @Deprecated 311 public String(byte ascii[], int hibyte, int offset, int count) { 312 checkBounds(ascii, offset, count); 313 char value[] = new char[count]; 314 315 if (hibyte == 0) { 316 for (int i = count; i-- > 0;) { 317 value[i] = (char)(ascii[i + offset] & 0xff); 318 } 319 } else { 320 hibyte <<= 8; 321 for (int i = count; i-- > 0;) { 322 value[i] = (char)(hibyte | (ascii[i + offset] & 0xff)); 323 } 324 } 325 this.value = value; 326 } 327 328 /** 329 * Allocates a new {@code String} containing characters constructed from 330 * an array of 8-bit integer values. Each character <i>c</i>in the 331 * resulting string is constructed from the corresponding component 332 * <i>b</i> in the byte array such that: 333 * 334 * <blockquote><pre> 335 * <b><i>c</i></b> == (char)(((hibyte & 0xff) << 8) 336 * | (<b><i>b</i></b> & 0xff)) 337 * </pre></blockquote> 338 * 339 * @deprecated This method does not properly convert bytes into 340 * characters. As of JDK 1.1, the preferred way to do this is via the 341 * {@code String} constructors that take a {@link 342 * java.nio.charset.Charset}, charset name, or that use the platform's 343 * default charset. 344 * 345 * @param ascii 346 * The bytes to be converted to characters 347 * 348 * @param hibyte 349 * The top 8 bits of each 16-bit Unicode code unit 350 * 351 * @see #String(byte[], int, int, java.lang.String) 352 * @see #String(byte[], int, int, java.nio.charset.Charset) 353 * @see #String(byte[], int, int) 354 * @see #String(byte[], java.lang.String) 355 * @see #String(byte[], java.nio.charset.Charset) 356 * @see #String(byte[]) 357 */ 358 @Deprecated 359 public String(byte ascii[], int hibyte) { 360 this(ascii, hibyte, 0, ascii.length); 361 } 362 363 /* Common private utility method used to bounds check the byte array 364 * and requested offset & length values used by the String(byte[],..) 365 * constructors. 366 */ 367 private static void checkBounds(byte[] bytes, int offset, int length) { 368 if (length < 0) 369 throw new StringIndexOutOfBoundsException(length); 370 if (offset < 0) 371 throw new StringIndexOutOfBoundsException(offset); 372 if (offset > bytes.length - length) 373 throw new StringIndexOutOfBoundsException(offset + length); 374 } 375 376 /** 377 * Constructs a new {@code String} by decoding the specified subarray of 378 * bytes using the specified charset. The length of the new {@code String} 379 * is a function of the charset, and hence may not be equal to the length 380 * of the subarray. 381 * 382 * <p> The behavior of this constructor when the given bytes are not valid 383 * in the given charset is unspecified. The {@link 384 * java.nio.charset.CharsetDecoder} class should be used when more control 385 * over the decoding process is required. 386 * 387 * @param bytes 388 * The bytes to be decoded into characters 389 * 390 * @param offset 391 * The index of the first byte to decode 392 * 393 * @param length 394 * The number of bytes to decode 395 396 * @param charsetName 397 * The name of a supported {@linkplain java.nio.charset.Charset 398 * charset} 399 * 400 * @throws UnsupportedEncodingException 401 * If the named charset is not supported 402 * 403 * @throws IndexOutOfBoundsException 404 * If the {@code offset} and {@code length} arguments index 405 * characters outside the bounds of the {@code bytes} array 406 * 407 * @since JDK1.1 408 */ 409 public String(byte bytes[], int offset, int length, String charsetName) 410 throws UnsupportedEncodingException { 411 if (charsetName == null) 412 throw new NullPointerException("charsetName"); 413 checkBounds(bytes, offset, length); 414 this.value = StringCoding.decode(charsetName, bytes, offset, length); 415 } 416 417 /** 418 * Constructs a new {@code String} by decoding the specified subarray of 419 * bytes using the specified {@linkplain java.nio.charset.Charset charset}. 420 * The length of the new {@code String} is a function of the charset, and 421 * hence may not be equal to the length of the subarray. 422 * 423 * <p> This method always replaces malformed-input and unmappable-character 424 * sequences with this charset's default replacement string. The {@link 425 * java.nio.charset.CharsetDecoder} class should be used when more control 426 * over the decoding process is required. 427 * 428 * @param bytes 429 * The bytes to be decoded into characters 430 * 431 * @param offset 432 * The index of the first byte to decode 433 * 434 * @param length 435 * The number of bytes to decode 436 * 437 * @param charset 438 * The {@linkplain java.nio.charset.Charset charset} to be used to 439 * decode the {@code bytes} 440 * 441 * @throws IndexOutOfBoundsException 442 * If the {@code offset} and {@code length} arguments index 443 * characters outside the bounds of the {@code bytes} array 444 * 445 * @since 1.6 446 */ 447 public String(byte bytes[], int offset, int length, Charset charset) { 448 if (charset == null) 449 throw new NullPointerException("charset"); 450 checkBounds(bytes, offset, length); 451 this.value = StringCoding.decode(charset, bytes, offset, length); 452 } 453 454 /** 455 * Constructs a new {@code String} by decoding the specified array of bytes 456 * using the specified {@linkplain java.nio.charset.Charset charset}. The 457 * length of the new {@code String} is a function of the charset, and hence 458 * may not be equal to the length of the byte array. 459 * 460 * <p> The behavior of this constructor when the given bytes are not valid 461 * in the given charset is unspecified. The {@link 462 * java.nio.charset.CharsetDecoder} class should be used when more control 463 * over the decoding process is required. 464 * 465 * @param bytes 466 * The bytes to be decoded into characters 467 * 468 * @param charsetName 469 * The name of a supported {@linkplain java.nio.charset.Charset 470 * charset} 471 * 472 * @throws UnsupportedEncodingException 473 * If the named charset is not supported 474 * 475 * @since JDK1.1 476 */ 477 public String(byte bytes[], String charsetName) 478 throws UnsupportedEncodingException { 479 this(bytes, 0, bytes.length, charsetName); 480 } 481 482 /** 483 * Constructs a new {@code String} by decoding the specified array of 484 * bytes using the specified {@linkplain java.nio.charset.Charset charset}. 485 * The length of the new {@code String} is a function of the charset, and 486 * hence may not be equal to the length of the byte array. 487 * 488 * <p> This method always replaces malformed-input and unmappable-character 489 * sequences with this charset's default replacement string. The {@link 490 * java.nio.charset.CharsetDecoder} class should be used when more control 491 * over the decoding process is required. 492 * 493 * @param bytes 494 * The bytes to be decoded into characters 495 * 496 * @param charset 497 * The {@linkplain java.nio.charset.Charset charset} to be used to 498 * decode the {@code bytes} 499 * 500 * @since 1.6 501 */ 502 public String(byte bytes[], Charset charset) { 503 this(bytes, 0, bytes.length, charset); 504 } 505 506 /** 507 * Constructs a new {@code String} by decoding the specified subarray of 508 * bytes using the platform's default charset. The length of the new 509 * {@code String} is a function of the charset, and hence may not be equal 510 * to the length of the subarray. 511 * 512 * <p> The behavior of this constructor when the given bytes are not valid 513 * in the default charset is unspecified. The {@link 514 * java.nio.charset.CharsetDecoder} class should be used when more control 515 * over the decoding process is required. 516 * 517 * @param bytes 518 * The bytes to be decoded into characters 519 * 520 * @param offset 521 * The index of the first byte to decode 522 * 523 * @param length 524 * The number of bytes to decode 525 * 526 * @throws IndexOutOfBoundsException 527 * If the {@code offset} and the {@code length} arguments index 528 * characters outside the bounds of the {@code bytes} array 529 * 530 * @since JDK1.1 531 */ 532 public String(byte bytes[], int offset, int length) { 533 checkBounds(bytes, offset, length); 534 this.value = StringCoding.decode(bytes, offset, length); 535 } 536 537 /** 538 * Constructs a new {@code String} by decoding the specified array of bytes 539 * using the platform's default charset. The length of the new {@code 540 * String} is a function of the charset, and hence may not be equal to the 541 * length of the byte array. 542 * 543 * <p> The behavior of this constructor when the given bytes are not valid 544 * in the default charset is unspecified. The {@link 545 * java.nio.charset.CharsetDecoder} class should be used when more control 546 * over the decoding process is required. 547 * 548 * @param bytes 549 * The bytes to be decoded into characters 550 * 551 * @since JDK1.1 552 */ 553 public String(byte bytes[]) { 554 this(bytes, 0, bytes.length); 555 } 556 557 /** 558 * Allocates a new string that contains the sequence of characters 559 * currently contained in the string buffer argument. The contents of the 560 * string buffer are copied; subsequent modification of the string buffer 561 * does not affect the newly created string. 562 * 563 * @param buffer 564 * A {@code StringBuffer} 565 */ 566 public String(StringBuffer buffer) { 567 synchronized(buffer) { 568 this.value = Arrays.copyOf(buffer.getValue(), buffer.length()); 569 } 570 } 571 572 /** 573 * Allocates a new string that contains the sequence of characters 574 * currently contained in the string builder argument. The contents of the 575 * string builder are copied; subsequent modification of the string builder 576 * does not affect the newly created string. 577 * 578 * <p> This constructor is provided to ease migration to {@code 579 * StringBuilder}. Obtaining a string from a string builder via the {@code 580 * toString} method is likely to run faster and is generally preferred. 581 * 582 * @param builder 583 * A {@code StringBuilder} 584 * 585 * @since 1.5 586 */ 587 public String(StringBuilder builder) { 588 this.value = Arrays.copyOf(builder.getValue(), builder.length()); 589 } 590 591 /* 592 * Package private constructor which shares value array for speed. 593 * this constructor is always expected to be called with share==true. 594 * a separate constructor is needed because we already have a public 595 * String(char[]) constructor that makes a copy of the given char[]. 596 */ 597 String(char[] value, boolean share) { 598 // assert share : "unshared not supported"; 599 this.value = value; 600 } 601 602 /** 603 * Returns the length of this string. 604 * The length is equal to the number of <a href="Character.html#unicode">Unicode 605 * code units</a> in the string. 606 * 607 * @return the length of the sequence of characters represented by this 608 * object. 609 */ 610 public int length() { 611 return value.length; 612 } 613 614 /** 615 * Returns {@code true} if, and only if, {@link #length()} is {@code 0}. 616 * 617 * @return {@code true} if {@link #length()} is {@code 0}, otherwise 618 * {@code false} 619 * 620 * @since 1.6 621 */ 622 public boolean isEmpty() { 623 return value.length == 0; 624 } 625 626 /** 627 * Returns the {@code char} value at the 628 * specified index. An index ranges from {@code 0} to 629 * {@code length() - 1}. The first {@code char} value of the sequence 630 * is at index {@code 0}, the next at index {@code 1}, 631 * and so on, as for array indexing. 632 * 633 * <p>If the {@code char} value specified by the index is a 634 * <a href="Character.html#unicode">surrogate</a>, the surrogate 635 * value is returned. 636 * 637 * @param index the index of the {@code char} value. 638 * @return the {@code char} value at the specified index of this string. 639 * The first {@code char} value is at index {@code 0}. 640 * @exception IndexOutOfBoundsException if the {@code index} 641 * argument is negative or not less than the length of this 642 * string. 643 */ 644 public char charAt(int index) { 645 if ((index < 0) || (index >= value.length)) { 646 throw new StringIndexOutOfBoundsException(index); 647 } 648 return value[index]; 649 } 650 651 /** 652 * Returns the character (Unicode code point) at the specified 653 * index. The index refers to {@code char} values 654 * (Unicode code units) and ranges from {@code 0} to 655 * {@link #length()}{@code - 1}. 656 * 657 * <p> If the {@code char} value specified at the given index 658 * is in the high-surrogate range, the following index is less 659 * than the length of this {@code String}, and the 660 * {@code char} value at the following index is in the 661 * low-surrogate range, then the supplementary code point 662 * corresponding to this surrogate pair is returned. Otherwise, 663 * the {@code char} value at the given index is returned. 664 * 665 * @param index the index to the {@code char} values 666 * @return the code point value of the character at the 667 * {@code index} 668 * @exception IndexOutOfBoundsException if the {@code index} 669 * argument is negative or not less than the length of this 670 * string. 671 * @since 1.5 672 */ 673 public int codePointAt(int index) { 674 if ((index < 0) || (index >= value.length)) { 675 throw new StringIndexOutOfBoundsException(index); 676 } 677 return Character.codePointAtImpl(value, index, value.length); 678 } 679 680 /** 681 * Returns the character (Unicode code point) before the specified 682 * index. The index refers to {@code char} values 683 * (Unicode code units) and ranges from {@code 1} to {@link 684 * CharSequence#length() length}. 685 * 686 * <p> If the {@code char} value at {@code (index - 1)} 687 * is in the low-surrogate range, {@code (index - 2)} is not 688 * negative, and the {@code char} value at {@code (index - 689 * 2)} is in the high-surrogate range, then the 690 * supplementary code point value of the surrogate pair is 691 * returned. If the {@code char} value at {@code index - 692 * 1} is an unpaired low-surrogate or a high-surrogate, the 693 * surrogate value is returned. 694 * 695 * @param index the index following the code point that should be returned 696 * @return the Unicode code point value before the given index. 697 * @exception IndexOutOfBoundsException if the {@code index} 698 * argument is less than 1 or greater than the length 699 * of this string. 700 * @since 1.5 701 */ 702 public int codePointBefore(int index) { 703 int i = index - 1; 704 if ((i < 0) || (i >= value.length)) { 705 throw new StringIndexOutOfBoundsException(index); 706 } 707 return Character.codePointBeforeImpl(value, index, 0); 708 } 709 710 /** 711 * Returns the number of Unicode code points in the specified text 712 * range of this {@code String}. The text range begins at the 713 * specified {@code beginIndex} and extends to the 714 * {@code char} at index {@code endIndex - 1}. Thus the 715 * length (in {@code char}s) of the text range is 716 * {@code endIndex-beginIndex}. Unpaired surrogates within 717 * the text range count as one code point each. 718 * 719 * @param beginIndex the index to the first {@code char} of 720 * the text range. 721 * @param endIndex the index after the last {@code char} of 722 * the text range. 723 * @return the number of Unicode code points in the specified text 724 * range 725 * @exception IndexOutOfBoundsException if the 726 * {@code beginIndex} is negative, or {@code endIndex} 727 * is larger than the length of this {@code String}, or 728 * {@code beginIndex} is larger than {@code endIndex}. 729 * @since 1.5 730 */ 731 public int codePointCount(int beginIndex, int endIndex) { 732 if (beginIndex < 0 || endIndex > value.length || beginIndex > endIndex) { 733 throw new IndexOutOfBoundsException(); 734 } 735 return Character.codePointCountImpl(value, beginIndex, endIndex - beginIndex); 736 } 737 738 /** 739 * Returns the index within this {@code String} that is 740 * offset from the given {@code index} by 741 * {@code codePointOffset} code points. Unpaired surrogates 742 * within the text range given by {@code index} and 743 * {@code codePointOffset} count as one code point each. 744 * 745 * @param index the index to be offset 746 * @param codePointOffset the offset in code points 747 * @return the index within this {@code String} 748 * @exception IndexOutOfBoundsException if {@code index} 749 * is negative or larger then the length of this 750 * {@code String}, or if {@code codePointOffset} is positive 751 * and the substring starting with {@code index} has fewer 752 * than {@code codePointOffset} code points, 753 * or if {@code codePointOffset} is negative and the substring 754 * before {@code index} has fewer than the absolute value 755 * of {@code codePointOffset} code points. 756 * @since 1.5 757 */ 758 public int offsetByCodePoints(int index, int codePointOffset) { 759 if (index < 0 || index > value.length) { 760 throw new IndexOutOfBoundsException(); 761 } 762 return Character.offsetByCodePointsImpl(value, 0, value.length, 763 index, codePointOffset); 764 } 765 766 /** 767 * Copy characters from this string into dst starting at dstBegin. 768 * This method doesn't perform any range checking. 769 */ 770 void getChars(char dst[], int dstBegin) { 771 System.arraycopy(value, 0, dst, dstBegin, value.length); 772 } 773 774 /** 775 * Copies characters from this string into the destination character 776 * array. 777 * <p> 778 * The first character to be copied is at index {@code srcBegin}; 779 * the last character to be copied is at index {@code srcEnd-1} 780 * (thus the total number of characters to be copied is 781 * {@code srcEnd-srcBegin}). The characters are copied into the 782 * subarray of {@code dst} starting at index {@code dstBegin} 783 * and ending at index: 784 * <blockquote><pre> 785 * dstbegin + (srcEnd-srcBegin) - 1 786 * </pre></blockquote> 787 * 788 * @param srcBegin index of the first character in the string 789 * to copy. 790 * @param srcEnd index after the last character in the string 791 * to copy. 792 * @param dst the destination array. 793 * @param dstBegin the start offset in the destination array. 794 * @exception IndexOutOfBoundsException If any of the following 795 * is true: 796 * <ul><li>{@code srcBegin} is negative. 797 * <li>{@code srcBegin} is greater than {@code srcEnd} 798 * <li>{@code srcEnd} is greater than the length of this 799 * string 800 * <li>{@code dstBegin} is negative 801 * <li>{@code dstBegin+(srcEnd-srcBegin)} is larger than 802 * {@code dst.length}</ul> 803 */ 804 public void getChars(int srcBegin, int srcEnd, char dst[], int dstBegin) { 805 if (srcBegin < 0) { 806 throw new StringIndexOutOfBoundsException(srcBegin); 807 } 808 if (srcEnd > value.length) { 809 throw new StringIndexOutOfBoundsException(srcEnd); 810 } 811 if (srcBegin > srcEnd) { 812 throw new StringIndexOutOfBoundsException(srcEnd - srcBegin); 813 } 814 System.arraycopy(value, srcBegin, dst, dstBegin, srcEnd - srcBegin); 815 } 816 817 /** 818 * Copies characters from this string into the destination byte array. Each 819 * byte receives the 8 low-order bits of the corresponding character. The 820 * eight high-order bits of each character are not copied and do not 821 * participate in the transfer in any way. 822 * 823 * <p> The first character to be copied is at index {@code srcBegin}; the 824 * last character to be copied is at index {@code srcEnd-1}. The total 825 * number of characters to be copied is {@code srcEnd-srcBegin}. The 826 * characters, converted to bytes, are copied into the subarray of {@code 827 * dst} starting at index {@code dstBegin} and ending at index: 828 * 829 * <blockquote><pre> 830 * dstbegin + (srcEnd-srcBegin) - 1 831 * </pre></blockquote> 832 * 833 * @deprecated This method does not properly convert characters into 834 * bytes. As of JDK 1.1, the preferred way to do this is via the 835 * {@link #getBytes()} method, which uses the platform's default charset. 836 * 837 * @param srcBegin 838 * Index of the first character in the string to copy 839 * 840 * @param srcEnd 841 * Index after the last character in the string to copy 842 * 843 * @param dst 844 * The destination array 845 * 846 * @param dstBegin 847 * The start offset in the destination array 848 * 849 * @throws IndexOutOfBoundsException 850 * If any of the following is true: 851 * <ul> 852 * <li> {@code srcBegin} is negative 853 * <li> {@code srcBegin} is greater than {@code srcEnd} 854 * <li> {@code srcEnd} is greater than the length of this String 855 * <li> {@code dstBegin} is negative 856 * <li> {@code dstBegin+(srcEnd-srcBegin)} is larger than {@code 857 * dst.length} 858 * </ul> 859 */ 860 @Deprecated 861 public void getBytes(int srcBegin, int srcEnd, byte dst[], int dstBegin) { 862 if (srcBegin < 0) { 863 throw new StringIndexOutOfBoundsException(srcBegin); 864 } 865 if (srcEnd > value.length) { 866 throw new StringIndexOutOfBoundsException(srcEnd); 867 } 868 if (srcBegin > srcEnd) { 869 throw new StringIndexOutOfBoundsException(srcEnd - srcBegin); 870 } 871 Objects.requireNonNull(dst); 872 873 int j = dstBegin; 874 int n = srcEnd; 875 int i = srcBegin; 876 char[] val = value; /* avoid getfield opcode */ 877 878 while (i < n) { 879 dst[j++] = (byte)val[i++]; 880 } 881 } 882 883 /** 884 * Encodes this {@code String} into a sequence of bytes using the named 885 * charset, storing the result into a new byte array. 886 * 887 * <p> The behavior of this method when this string cannot be encoded in 888 * the given charset is unspecified. The {@link 889 * java.nio.charset.CharsetEncoder} class should be used when more control 890 * over the encoding process is required. 891 * 892 * @param charsetName 893 * The name of a supported {@linkplain java.nio.charset.Charset 894 * charset} 895 * 896 * @return The resultant byte array 897 * 898 * @throws UnsupportedEncodingException 899 * If the named charset is not supported 900 * 901 * @since JDK1.1 902 */ 903 public byte[] getBytes(String charsetName) 904 throws UnsupportedEncodingException { 905 if (charsetName == null) throw new NullPointerException(); 906 return StringCoding.encode(charsetName, value, 0, value.length); 907 } 908 909 /** 910 * Encodes this {@code String} into a sequence of bytes using the given 911 * {@linkplain java.nio.charset.Charset charset}, storing the result into a 912 * new byte array. 913 * 914 * <p> This method always replaces malformed-input and unmappable-character 915 * sequences with this charset's default replacement byte array. The 916 * {@link java.nio.charset.CharsetEncoder} class should be used when more 917 * control over the encoding process is required. 918 * 919 * @param charset 920 * The {@linkplain java.nio.charset.Charset} to be used to encode 921 * the {@code String} 922 * 923 * @return The resultant byte array 924 * 925 * @since 1.6 926 */ 927 public byte[] getBytes(Charset charset) { 928 if (charset == null) throw new NullPointerException(); 929 return StringCoding.encode(charset, value, 0, value.length); 930 } 931 932 /** 933 * Encodes this {@code String} into a sequence of bytes using the 934 * platform's default charset, storing the result into a new byte array. 935 * 936 * <p> The behavior of this method when this string cannot be encoded in 937 * the default charset is unspecified. The {@link 938 * java.nio.charset.CharsetEncoder} class should be used when more control 939 * over the encoding process is required. 940 * 941 * @return The resultant byte array 942 * 943 * @since JDK1.1 944 */ 945 public byte[] getBytes() { 946 return StringCoding.encode(value, 0, value.length); 947 } 948 949 /** 950 * Compares this string to the specified object. The result is {@code 951 * true} if and only if the argument is not {@code null} and is a {@code 952 * String} object that represents the same sequence of characters as this 953 * object. 954 * 955 * @param anObject 956 * The object to compare this {@code String} against 957 * 958 * @return {@code true} if the given object represents a {@code String} 959 * equivalent to this string, {@code false} otherwise 960 * 961 * @see #compareTo(String) 962 * @see #equalsIgnoreCase(String) 963 */ 964 public boolean equals(Object anObject) { 965 if (this == anObject) { 966 return true; 967 } 968 if (anObject instanceof String) { 969 String anotherString = (String)anObject; 970 int n = value.length; 971 if (n == anotherString.value.length) { 972 char v1[] = value; 973 char v2[] = anotherString.value; 974 int i = 0; 975 while (n-- != 0) { 976 if (v1[i] != v2[i]) 977 return false; 978 i++; 979 } 980 return true; 981 } 982 } 983 return false; 984 } 985 986 /** 987 * Compares this string to the specified {@code StringBuffer}. The result 988 * is {@code true} if and only if this {@code String} represents the same 989 * sequence of characters as the specified {@code StringBuffer}. This method 990 * synchronizes on the {@code StringBuffer}. 991 * 992 * @param sb 993 * The {@code StringBuffer} to compare this {@code String} against 994 * 995 * @return {@code true} if this {@code String} represents the same 996 * sequence of characters as the specified {@code StringBuffer}, 997 * {@code false} otherwise 998 * 999 * @since 1.4 1000 */ 1001 public boolean contentEquals(StringBuffer sb) { 1002 return contentEquals((CharSequence)sb); 1003 } 1004 1005 private boolean nonSyncContentEquals(AbstractStringBuilder sb) { 1006 char v1[] = value; 1007 char v2[] = sb.getValue(); 1008 int n = v1.length; 1009 if (n != sb.length()) { 1010 return false; 1011 } 1012 for (int i = 0; i < n; i++) { 1013 if (v1[i] != v2[i]) { 1014 return false; 1015 } 1016 } 1017 return true; 1018 } 1019 1020 /** 1021 * Compares this string to the specified {@code CharSequence}. The 1022 * result is {@code true} if and only if this {@code String} represents the 1023 * same sequence of char values as the specified sequence. Note that if the 1024 * {@code CharSequence} is a {@code StringBuffer} then the method 1025 * synchronizes on it. 1026 * 1027 * @param cs 1028 * The sequence to compare this {@code String} against 1029 * 1030 * @return {@code true} if this {@code String} represents the same 1031 * sequence of char values as the specified sequence, {@code 1032 * false} otherwise 1033 * 1034 * @since 1.5 1035 */ 1036 public boolean contentEquals(CharSequence cs) { 1037 // Argument is a StringBuffer, StringBuilder 1038 if (cs instanceof AbstractStringBuilder) { 1039 if (cs instanceof StringBuffer) { 1040 synchronized(cs) { 1041 return nonSyncContentEquals((AbstractStringBuilder)cs); 1042 } 1043 } else { 1044 return nonSyncContentEquals((AbstractStringBuilder)cs); 1045 } 1046 } 1047 // Argument is a String 1048 if (cs.equals(this)) 1049 return true; 1050 // Argument is a generic CharSequence 1051 char v1[] = value; 1052 int n = v1.length; 1053 if (n != cs.length()) { 1054 return false; 1055 } 1056 for (int i = 0; i < n; i++) { 1057 if (v1[i] != cs.charAt(i)) { 1058 return false; 1059 } 1060 } 1061 return true; 1062 } 1063 1064 /** 1065 * Compares this {@code String} to another {@code String}, ignoring case 1066 * considerations. Two strings are considered equal ignoring case if they 1067 * are of the same length and corresponding characters in the two strings 1068 * are equal ignoring case. 1069 * 1070 * <p> Two characters {@code c1} and {@code c2} are considered the same 1071 * ignoring case if at least one of the following is true: 1072 * <ul> 1073 * <li> The two characters are the same (as compared by the 1074 * {@code ==} operator) 1075 * <li> Applying the method {@link 1076 * java.lang.Character#toUpperCase(char)} to each character 1077 * produces the same result 1078 * <li> Applying the method {@link 1079 * java.lang.Character#toLowerCase(char)} to each character 1080 * produces the same result 1081 * </ul> 1082 * 1083 * @param anotherString 1084 * The {@code String} to compare this {@code String} against 1085 * 1086 * @return {@code true} if the argument is not {@code null} and it 1087 * represents an equivalent {@code String} ignoring case; {@code 1088 * false} otherwise 1089 * 1090 * @see #equals(Object) 1091 */ 1092 public boolean equalsIgnoreCase(String anotherString) { 1093 return (this == anotherString) ? true 1094 : (anotherString != null) 1095 && (anotherString.value.length == value.length) 1096 && regionMatches(true, 0, anotherString, 0, value.length); 1097 } 1098 1099 /** 1100 * Compares two strings lexicographically. 1101 * The comparison is based on the Unicode value of each character in 1102 * the strings. The character sequence represented by this 1103 * {@code String} object is compared lexicographically to the 1104 * character sequence represented by the argument string. The result is 1105 * a negative integer if this {@code String} object 1106 * lexicographically precedes the argument string. The result is a 1107 * positive integer if this {@code String} object lexicographically 1108 * follows the argument string. The result is zero if the strings 1109 * are equal; {@code compareTo} returns {@code 0} exactly when 1110 * the {@link #equals(Object)} method would return {@code true}. 1111 * <p> 1112 * This is the definition of lexicographic ordering. If two strings are 1113 * different, then either they have different characters at some index 1114 * that is a valid index for both strings, or their lengths are different, 1115 * or both. If they have different characters at one or more index 1116 * positions, let <i>k</i> be the smallest such index; then the string 1117 * whose character at position <i>k</i> has the smaller value, as 1118 * determined by using the < operator, lexicographically precedes the 1119 * other string. In this case, {@code compareTo} returns the 1120 * difference of the two character values at position {@code k} in 1121 * the two string -- that is, the value: 1122 * <blockquote><pre> 1123 * this.charAt(k)-anotherString.charAt(k) 1124 * </pre></blockquote> 1125 * If there is no index position at which they differ, then the shorter 1126 * string lexicographically precedes the longer string. In this case, 1127 * {@code compareTo} returns the difference of the lengths of the 1128 * strings -- that is, the value: 1129 * <blockquote><pre> 1130 * this.length()-anotherString.length() 1131 * </pre></blockquote> 1132 * 1133 * @param anotherString the {@code String} to be compared. 1134 * @return the value {@code 0} if the argument string is equal to 1135 * this string; a value less than {@code 0} if this string 1136 * is lexicographically less than the string argument; and a 1137 * value greater than {@code 0} if this string is 1138 * lexicographically greater than the string argument. 1139 */ 1140 public int compareTo(String anotherString) { 1141 int len1 = value.length; 1142 int len2 = anotherString.value.length; 1143 int lim = Math.min(len1, len2); 1144 char v1[] = value; 1145 char v2[] = anotherString.value; 1146 1147 int k = 0; 1148 while (k < lim) { 1149 char c1 = v1[k]; 1150 char c2 = v2[k]; 1151 if (c1 != c2) { 1152 return c1 - c2; 1153 } 1154 k++; 1155 } 1156 return len1 - len2; 1157 } 1158 1159 /** 1160 * A Comparator that orders {@code String} objects as by 1161 * {@code compareToIgnoreCase}. This comparator is serializable. 1162 * <p> 1163 * Note that this Comparator does <em>not</em> take locale into account, 1164 * and will result in an unsatisfactory ordering for certain locales. 1165 * The java.text package provides <em>Collators</em> to allow 1166 * locale-sensitive ordering. 1167 * 1168 * @see java.text.Collator#compare(String, String) 1169 * @since 1.2 1170 */ 1171 public static final Comparator<String> CASE_INSENSITIVE_ORDER 1172 = new CaseInsensitiveComparator(); 1173 private static class CaseInsensitiveComparator 1174 implements Comparator<String>, java.io.Serializable { 1175 // use serialVersionUID from JDK 1.2.2 for interoperability 1176 private static final long serialVersionUID = 8575799808933029326L; 1177 1178 public int compare(String s1, String s2) { 1179 int n1 = s1.length(); 1180 int n2 = s2.length(); 1181 int min = Math.min(n1, n2); 1182 for (int i = 0; i < min; i++) { 1183 char c1 = s1.charAt(i); 1184 char c2 = s2.charAt(i); 1185 if (c1 != c2) { 1186 c1 = Character.toUpperCase(c1); 1187 c2 = Character.toUpperCase(c2); 1188 if (c1 != c2) { 1189 c1 = Character.toLowerCase(c1); 1190 c2 = Character.toLowerCase(c2); 1191 if (c1 != c2) { 1192 // No overflow because of numeric promotion 1193 return c1 - c2; 1194 } 1195 } 1196 } 1197 } 1198 return n1 - n2; 1199 } 1200 1201 /** Replaces the de-serialized object. */ 1202 private Object readResolve() { return CASE_INSENSITIVE_ORDER; } 1203 } 1204 1205 /** 1206 * Compares two strings lexicographically, ignoring case 1207 * differences. This method returns an integer whose sign is that of 1208 * calling {@code compareTo} with normalized versions of the strings 1209 * where case differences have been eliminated by calling 1210 * {@code Character.toLowerCase(Character.toUpperCase(character))} on 1211 * each character. 1212 * <p> 1213 * Note that this method does <em>not</em> take locale into account, 1214 * and will result in an unsatisfactory ordering for certain locales. 1215 * The java.text package provides <em>collators</em> to allow 1216 * locale-sensitive ordering. 1217 * 1218 * @param str the {@code String} to be compared. 1219 * @return a negative integer, zero, or a positive integer as the 1220 * specified String is greater than, equal to, or less 1221 * than this String, ignoring case considerations. 1222 * @see java.text.Collator#compare(String, String) 1223 * @since 1.2 1224 */ 1225 public int compareToIgnoreCase(String str) { 1226 return CASE_INSENSITIVE_ORDER.compare(this, str); 1227 } 1228 1229 /** 1230 * Tests if two string regions are equal. 1231 * <p> 1232 * A substring of this {@code String} object is compared to a substring 1233 * of the argument other. The result is true if these substrings 1234 * represent identical character sequences. The substring of this 1235 * {@code String} object to be compared begins at index {@code toffset} 1236 * and has length {@code len}. The substring of other to be compared 1237 * begins at index {@code ooffset} and has length {@code len}. The 1238 * result is {@code false} if and only if at least one of the following 1239 * is true: 1240 * <ul><li>{@code toffset} is negative. 1241 * <li>{@code ooffset} is negative. 1242 * <li>{@code toffset+len} is greater than the length of this 1243 * {@code String} object. 1244 * <li>{@code ooffset+len} is greater than the length of the other 1245 * argument. 1246 * <li>There is some nonnegative integer <i>k</i> less than {@code len} 1247 * such that: 1248 * {@code this.charAt(toffset + }<i>k</i>{@code ) != other.charAt(ooffset + } 1249 * <i>k</i>{@code )} 1250 * </ul> 1251 * 1252 * @param toffset the starting offset of the subregion in this string. 1253 * @param other the string argument. 1254 * @param ooffset the starting offset of the subregion in the string 1255 * argument. 1256 * @param len the number of characters to compare. 1257 * @return {@code true} if the specified subregion of this string 1258 * exactly matches the specified subregion of the string argument; 1259 * {@code false} otherwise. 1260 */ 1261 public boolean regionMatches(int toffset, String other, int ooffset, 1262 int len) { 1263 char ta[] = value; 1264 int to = toffset; 1265 char pa[] = other.value; 1266 int po = ooffset; 1267 // Note: toffset, ooffset, or len might be near -1>>>1. 1268 if ((ooffset < 0) || (toffset < 0) 1269 || (toffset > (long)value.length - len) 1270 || (ooffset > (long)other.value.length - len)) { 1271 return false; 1272 } 1273 while (len-- > 0) { 1274 if (ta[to++] != pa[po++]) { 1275 return false; 1276 } 1277 } 1278 return true; 1279 } 1280 1281 /** 1282 * Tests if two string regions are equal. 1283 * <p> 1284 * A substring of this {@code String} object is compared to a substring 1285 * of the argument {@code other}. The result is {@code true} if these 1286 * substrings represent character sequences that are the same, ignoring 1287 * case if and only if {@code ignoreCase} is true. The substring of 1288 * this {@code String} object to be compared begins at index 1289 * {@code toffset} and has length {@code len}. The substring of 1290 * {@code other} to be compared begins at index {@code ooffset} and 1291 * has length {@code len}. The result is {@code false} if and only if 1292 * at least one of the following is true: 1293 * <ul><li>{@code toffset} is negative. 1294 * <li>{@code ooffset} is negative. 1295 * <li>{@code toffset+len} is greater than the length of this 1296 * {@code String} object. 1297 * <li>{@code ooffset+len} is greater than the length of the other 1298 * argument. 1299 * <li>{@code ignoreCase} is {@code false} and there is some nonnegative 1300 * integer <i>k</i> less than {@code len} such that: 1301 * <blockquote><pre> 1302 * this.charAt(toffset+k) != other.charAt(ooffset+k) 1303 * </pre></blockquote> 1304 * <li>{@code ignoreCase} is {@code true} and there is some nonnegative 1305 * integer <i>k</i> less than {@code len} such that: 1306 * <blockquote><pre> 1307 * Character.toLowerCase(this.charAt(toffset+k)) != 1308 Character.toLowerCase(other.charAt(ooffset+k)) 1309 * </pre></blockquote> 1310 * and: 1311 * <blockquote><pre> 1312 * Character.toUpperCase(this.charAt(toffset+k)) != 1313 * Character.toUpperCase(other.charAt(ooffset+k)) 1314 * </pre></blockquote> 1315 * </ul> 1316 * 1317 * @param ignoreCase if {@code true}, ignore case when comparing 1318 * characters. 1319 * @param toffset the starting offset of the subregion in this 1320 * string. 1321 * @param other the string argument. 1322 * @param ooffset the starting offset of the subregion in the string 1323 * argument. 1324 * @param len the number of characters to compare. 1325 * @return {@code true} if the specified subregion of this string 1326 * matches the specified subregion of the string argument; 1327 * {@code false} otherwise. Whether the matching is exact 1328 * or case insensitive depends on the {@code ignoreCase} 1329 * argument. 1330 */ 1331 public boolean regionMatches(boolean ignoreCase, int toffset, 1332 String other, int ooffset, int len) { 1333 char ta[] = value; 1334 int to = toffset; 1335 char pa[] = other.value; 1336 int po = ooffset; 1337 // Note: toffset, ooffset, or len might be near -1>>>1. 1338 if ((ooffset < 0) || (toffset < 0) 1339 || (toffset > (long)value.length - len) 1340 || (ooffset > (long)other.value.length - len)) { 1341 return false; 1342 } 1343 while (len-- > 0) { 1344 char c1 = ta[to++]; 1345 char c2 = pa[po++]; 1346 if (c1 == c2) { 1347 continue; 1348 } 1349 if (ignoreCase) { 1350 // If characters don't match but case may be ignored, 1351 // try converting both characters to uppercase. 1352 // If the results match, then the comparison scan should 1353 // continue. 1354 char u1 = Character.toUpperCase(c1); 1355 char u2 = Character.toUpperCase(c2); 1356 if (u1 == u2) { 1357 continue; 1358 } 1359 // Unfortunately, conversion to uppercase does not work properly 1360 // for the Georgian alphabet, which has strange rules about case 1361 // conversion. So we need to make one last check before 1362 // exiting. 1363 if (Character.toLowerCase(u1) == Character.toLowerCase(u2)) { 1364 continue; 1365 } 1366 } 1367 return false; 1368 } 1369 return true; 1370 } 1371 1372 /** 1373 * Tests if the substring of this string beginning at the 1374 * specified index starts with the specified prefix. 1375 * 1376 * @param prefix the prefix. 1377 * @param toffset where to begin looking in this string. 1378 * @return {@code true} if the character sequence represented by the 1379 * argument is a prefix of the substring of this object starting 1380 * at index {@code toffset}; {@code false} otherwise. 1381 * The result is {@code false} if {@code toffset} is 1382 * negative or greater than the length of this 1383 * {@code String} object; otherwise the result is the same 1384 * as the result of the expression 1385 * <pre> 1386 * this.substring(toffset).startsWith(prefix) 1387 * </pre> 1388 */ 1389 public boolean startsWith(String prefix, int toffset) { 1390 char ta[] = value; 1391 int to = toffset; 1392 char pa[] = prefix.value; 1393 int po = 0; 1394 int pc = prefix.value.length; 1395 // Note: toffset might be near -1>>>1. 1396 if ((toffset < 0) || (toffset > value.length - pc)) { 1397 return false; 1398 } 1399 while (--pc >= 0) { 1400 if (ta[to++] != pa[po++]) { 1401 return false; 1402 } 1403 } 1404 return true; 1405 } 1406 1407 /** 1408 * Tests if this string starts with the specified prefix. 1409 * 1410 * @param prefix the prefix. 1411 * @return {@code true} if the character sequence represented by the 1412 * argument is a prefix of the character sequence represented by 1413 * this string; {@code false} otherwise. 1414 * Note also that {@code true} will be returned if the 1415 * argument is an empty string or is equal to this 1416 * {@code String} object as determined by the 1417 * {@link #equals(Object)} method. 1418 * @since 1. 0 1419 */ 1420 public boolean startsWith(String prefix) { 1421 return startsWith(prefix, 0); 1422 } 1423 1424 /** 1425 * Tests if this string ends with the specified suffix. 1426 * 1427 * @param suffix the suffix. 1428 * @return {@code true} if the character sequence represented by the 1429 * argument is a suffix of the character sequence represented by 1430 * this object; {@code false} otherwise. Note that the 1431 * result will be {@code true} if the argument is the 1432 * empty string or is equal to this {@code String} object 1433 * as determined by the {@link #equals(Object)} method. 1434 */ 1435 public boolean endsWith(String suffix) { 1436 return startsWith(suffix, value.length - suffix.value.length); 1437 } 1438 1439 /** 1440 * Returns a hash code for this string. The hash code for a 1441 * {@code String} object is computed as 1442 * <blockquote><pre> 1443 * s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1] 1444 * </pre></blockquote> 1445 * using {@code int} arithmetic, where {@code s[i]} is the 1446 * <i>i</i>th character of the string, {@code n} is the length of 1447 * the string, and {@code ^} indicates exponentiation. 1448 * (The hash value of the empty string is zero.) 1449 * 1450 * @return a hash code value for this object. 1451 */ 1452 public int hashCode() { 1453 int h = hash; 1454 if (h == 0 && value.length > 0) { 1455 char val[] = value; 1456 1457 for (int i = 0; i < value.length; i++) { 1458 h = 31 * h + val[i]; 1459 } 1460 hash = h; 1461 } 1462 return h; 1463 } 1464 1465 /** 1466 * Returns the index within this string of the first occurrence of 1467 * the specified character. If a character with value 1468 * {@code ch} occurs in the character sequence represented by 1469 * this {@code String} object, then the index (in Unicode 1470 * code units) of the first such occurrence is returned. For 1471 * values of {@code ch} in the range from 0 to 0xFFFF 1472 * (inclusive), this is the smallest value <i>k</i> such that: 1473 * <blockquote><pre> 1474 * this.charAt(<i>k</i>) == ch 1475 * </pre></blockquote> 1476 * is true. For other values of {@code ch}, it is the 1477 * smallest value <i>k</i> such that: 1478 * <blockquote><pre> 1479 * this.codePointAt(<i>k</i>) == ch 1480 * </pre></blockquote> 1481 * is true. In either case, if no such character occurs in this 1482 * string, then {@code -1} is returned. 1483 * 1484 * @param ch a character (Unicode code point). 1485 * @return the index of the first occurrence of the character in the 1486 * character sequence represented by this object, or 1487 * {@code -1} if the character does not occur. 1488 */ 1489 public int indexOf(int ch) { 1490 return indexOf(ch, 0); 1491 } 1492 1493 /** 1494 * Returns the index within this string of the first occurrence of the 1495 * specified character, starting the search at the specified index. 1496 * <p> 1497 * If a character with value {@code ch} occurs in the 1498 * character sequence represented by this {@code String} 1499 * object at an index no smaller than {@code fromIndex}, then 1500 * the index of the first such occurrence is returned. For values 1501 * of {@code ch} in the range from 0 to 0xFFFF (inclusive), 1502 * this is the smallest value <i>k</i> such that: 1503 * <blockquote><pre> 1504 * (this.charAt(<i>k</i>) == ch) {@code &&} (<i>k</i> >= fromIndex) 1505 * </pre></blockquote> 1506 * is true. For other values of {@code ch}, it is the 1507 * smallest value <i>k</i> such that: 1508 * <blockquote><pre> 1509 * (this.codePointAt(<i>k</i>) == ch) {@code &&} (<i>k</i> >= fromIndex) 1510 * </pre></blockquote> 1511 * is true. In either case, if no such character occurs in this 1512 * string at or after position {@code fromIndex}, then 1513 * {@code -1} is returned. 1514 * 1515 * <p> 1516 * There is no restriction on the value of {@code fromIndex}. If it 1517 * is negative, it has the same effect as if it were zero: this entire 1518 * string may be searched. If it is greater than the length of this 1519 * string, it has the same effect as if it were equal to the length of 1520 * this string: {@code -1} is returned. 1521 * 1522 * <p>All indices are specified in {@code char} values 1523 * (Unicode code units). 1524 * 1525 * @param ch a character (Unicode code point). 1526 * @param fromIndex the index to start the search from. 1527 * @return the index of the first occurrence of the character in the 1528 * character sequence represented by this object that is greater 1529 * than or equal to {@code fromIndex}, or {@code -1} 1530 * if the character does not occur. 1531 */ 1532 public int indexOf(int ch, int fromIndex) { 1533 final int max = value.length; 1534 if (fromIndex < 0) { 1535 fromIndex = 0; 1536 } else if (fromIndex >= max) { 1537 // Note: fromIndex might be near -1>>>1. 1538 return -1; 1539 } 1540 1541 if (ch < Character.MIN_SUPPLEMENTARY_CODE_POINT) { 1542 // handle most cases here (ch is a BMP code point or a 1543 // negative value (invalid code point)) 1544 final char[] value = this.value; 1545 for (int i = fromIndex; i < max; i++) { 1546 if (value[i] == ch) { 1547 return i; 1548 } 1549 } 1550 return -1; 1551 } else { 1552 return indexOfSupplementary(ch, fromIndex); 1553 } 1554 } 1555 1556 /** 1557 * Handles (rare) calls of indexOf with a supplementary character. 1558 */ 1559 private int indexOfSupplementary(int ch, int fromIndex) { 1560 if (Character.isValidCodePoint(ch)) { 1561 final char[] value = this.value; 1562 final char hi = Character.highSurrogate(ch); 1563 final char lo = Character.lowSurrogate(ch); 1564 final int max = value.length - 1; 1565 for (int i = fromIndex; i < max; i++) { 1566 if (value[i] == hi && value[i + 1] == lo) { 1567 return i; 1568 } 1569 } 1570 } 1571 return -1; 1572 } 1573 1574 /** 1575 * Returns the index within this string of the last occurrence of 1576 * the specified character. For values of {@code ch} in the 1577 * range from 0 to 0xFFFF (inclusive), the index (in Unicode code 1578 * units) returned is the largest value <i>k</i> such that: 1579 * <blockquote><pre> 1580 * this.charAt(<i>k</i>) == ch 1581 * </pre></blockquote> 1582 * is true. For other values of {@code ch}, it is the 1583 * largest value <i>k</i> such that: 1584 * <blockquote><pre> 1585 * this.codePointAt(<i>k</i>) == ch 1586 * </pre></blockquote> 1587 * is true. In either case, if no such character occurs in this 1588 * string, then {@code -1} is returned. The 1589 * {@code String} is searched backwards starting at the last 1590 * character. 1591 * 1592 * @param ch a character (Unicode code point). 1593 * @return the index of the last occurrence of the character in the 1594 * character sequence represented by this object, or 1595 * {@code -1} if the character does not occur. 1596 */ 1597 public int lastIndexOf(int ch) { 1598 return lastIndexOf(ch, value.length - 1); 1599 } 1600 1601 /** 1602 * Returns the index within this string of the last occurrence of 1603 * the specified character, searching backward starting at the 1604 * specified index. For values of {@code ch} in the range 1605 * from 0 to 0xFFFF (inclusive), the index returned is the largest 1606 * value <i>k</i> such that: 1607 * <blockquote><pre> 1608 * (this.charAt(<i>k</i>) == ch) {@code &&} (<i>k</i> <= fromIndex) 1609 * </pre></blockquote> 1610 * is true. For other values of {@code ch}, it is the 1611 * largest value <i>k</i> such that: 1612 * <blockquote><pre> 1613 * (this.codePointAt(<i>k</i>) == ch) {@code &&} (<i>k</i> <= fromIndex) 1614 * </pre></blockquote> 1615 * is true. In either case, if no such character occurs in this 1616 * string at or before position {@code fromIndex}, then 1617 * {@code -1} is returned. 1618 * 1619 * <p>All indices are specified in {@code char} values 1620 * (Unicode code units). 1621 * 1622 * @param ch a character (Unicode code point). 1623 * @param fromIndex the index to start the search from. There is no 1624 * restriction on the value of {@code fromIndex}. If it is 1625 * greater than or equal to the length of this string, it has 1626 * the same effect as if it were equal to one less than the 1627 * length of this string: this entire string may be searched. 1628 * If it is negative, it has the same effect as if it were -1: 1629 * -1 is returned. 1630 * @return the index of the last occurrence of the character in the 1631 * character sequence represented by this object that is less 1632 * than or equal to {@code fromIndex}, or {@code -1} 1633 * if the character does not occur before that point. 1634 */ 1635 public int lastIndexOf(int ch, int fromIndex) { 1636 if (ch < Character.MIN_SUPPLEMENTARY_CODE_POINT) { 1637 // handle most cases here (ch is a BMP code point or a 1638 // negative value (invalid code point)) 1639 final char[] value = this.value; 1640 int i = Math.min(fromIndex, value.length - 1); 1641 for (; i >= 0; i--) { 1642 if (value[i] == ch) { 1643 return i; 1644 } 1645 } 1646 return -1; 1647 } else { 1648 return lastIndexOfSupplementary(ch, fromIndex); 1649 } 1650 } 1651 1652 /** 1653 * Handles (rare) calls of lastIndexOf with a supplementary character. 1654 */ 1655 private int lastIndexOfSupplementary(int ch, int fromIndex) { 1656 if (Character.isValidCodePoint(ch)) { 1657 final char[] value = this.value; 1658 char hi = Character.highSurrogate(ch); 1659 char lo = Character.lowSurrogate(ch); 1660 int i = Math.min(fromIndex, value.length - 2); 1661 for (; i >= 0; i--) { 1662 if (value[i] == hi && value[i + 1] == lo) { 1663 return i; 1664 } 1665 } 1666 } 1667 return -1; 1668 } 1669 1670 /** 1671 * Returns the index within this string of the first occurrence of the 1672 * specified substring. 1673 * 1674 * <p>The returned index is the smallest value <i>k</i> for which: 1675 * <blockquote><pre> 1676 * this.startsWith(str, <i>k</i>) 1677 * </pre></blockquote> 1678 * If no such value of <i>k</i> exists, then {@code -1} is returned. 1679 * 1680 * @param str the substring to search for. 1681 * @return the index of the first occurrence of the specified substring, 1682 * or {@code -1} if there is no such occurrence. 1683 */ 1684 public int indexOf(String str) { 1685 return indexOf(str, 0); 1686 } 1687 1688 /** 1689 * Returns the index within this string of the first occurrence of the 1690 * specified substring, starting at the specified index. 1691 * 1692 * <p>The returned index is the smallest value <i>k</i> for which: 1693 * <blockquote><pre> 1694 * <i>k</i> >= fromIndex {@code &&} this.startsWith(str, <i>k</i>) 1695 * </pre></blockquote> 1696 * If no such value of <i>k</i> exists, then {@code -1} is returned. 1697 * 1698 * @param str the substring to search for. 1699 * @param fromIndex the index from which to start the search. 1700 * @return the index of the first occurrence of the specified substring, 1701 * starting at the specified index, 1702 * or {@code -1} if there is no such occurrence. 1703 */ 1704 public int indexOf(String str, int fromIndex) { 1705 return indexOf(value, 0, value.length, 1706 str.value, 0, str.value.length, fromIndex); 1707 } 1708 1709 /** 1710 * Code shared by String and AbstractStringBuilder to do searches. The 1711 * source is the character array being searched, and the target 1712 * is the string being searched for. 1713 * 1714 * @param source the characters being searched. 1715 * @param sourceOffset offset of the source string. 1716 * @param sourceCount count of the source string. 1717 * @param target the characters being searched for. 1718 * @param fromIndex the index to begin searching from. 1719 */ 1720 static int indexOf(char[] source, int sourceOffset, int sourceCount, 1721 String target, int fromIndex) { 1722 return indexOf(source, sourceOffset, sourceCount, 1723 target.value, 0, target.value.length, 1724 fromIndex); 1725 } 1726 1727 /** 1728 * Code shared by String and StringBuffer to do searches. The 1729 * source is the character array being searched, and the target 1730 * is the string being searched for. 1731 * 1732 * @param source the characters being searched. 1733 * @param sourceOffset offset of the source string. 1734 * @param sourceCount count of the source string. 1735 * @param target the characters being searched for. 1736 * @param targetOffset offset of the target string. 1737 * @param targetCount count of the target string. 1738 * @param fromIndex the index to begin searching from. 1739 */ 1740 static int indexOf(char[] source, int sourceOffset, int sourceCount, 1741 char[] target, int targetOffset, int targetCount, 1742 int fromIndex) { 1743 if (fromIndex >= sourceCount) { 1744 return (targetCount == 0 ? sourceCount : -1); 1745 } 1746 if (fromIndex < 0) { 1747 fromIndex = 0; 1748 } 1749 if (targetCount == 0) { 1750 return fromIndex; 1751 } 1752 1753 char first = target[targetOffset]; 1754 int max = sourceOffset + (sourceCount - targetCount); 1755 1756 for (int i = sourceOffset + fromIndex; i <= max; i++) { 1757 /* Look for first character. */ 1758 if (source[i] != first) { 1759 while (++i <= max && source[i] != first); 1760 } 1761 1762 /* Found first character, now look at the rest of v2 */ 1763 if (i <= max) { 1764 int j = i + 1; 1765 int end = j + targetCount - 1; 1766 for (int k = targetOffset + 1; j < end && source[j] 1767 == target[k]; j++, k++); 1768 1769 if (j == end) { 1770 /* Found whole string. */ 1771 return i - sourceOffset; 1772 } 1773 } 1774 } 1775 return -1; 1776 } 1777 1778 /** 1779 * Returns the index within this string of the last occurrence of the 1780 * specified substring. The last occurrence of the empty string "" 1781 * is considered to occur at the index value {@code this.length()}. 1782 * 1783 * <p>The returned index is the largest value <i>k</i> for which: 1784 * <blockquote><pre> 1785 * this.startsWith(str, <i>k</i>) 1786 * </pre></blockquote> 1787 * If no such value of <i>k</i> exists, then {@code -1} is returned. 1788 * 1789 * @param str the substring to search for. 1790 * @return the index of the last occurrence of the specified substring, 1791 * or {@code -1} if there is no such occurrence. 1792 */ 1793 public int lastIndexOf(String str) { 1794 return lastIndexOf(str, value.length); 1795 } 1796 1797 /** 1798 * Returns the index within this string of the last occurrence of the 1799 * specified substring, searching backward starting at the specified index. 1800 * 1801 * <p>The returned index is the largest value <i>k</i> for which: 1802 * <blockquote><pre> 1803 * <i>k</i> {@code <=} fromIndex {@code &&} this.startsWith(str, <i>k</i>) 1804 * </pre></blockquote> 1805 * If no such value of <i>k</i> exists, then {@code -1} is returned. 1806 * 1807 * @param str the substring to search for. 1808 * @param fromIndex the index to start the search from. 1809 * @return the index of the last occurrence of the specified substring, 1810 * searching backward from the specified index, 1811 * or {@code -1} if there is no such occurrence. 1812 */ 1813 public int lastIndexOf(String str, int fromIndex) { 1814 return lastIndexOf(value, 0, value.length, 1815 str.value, 0, str.value.length, fromIndex); 1816 } 1817 1818 /** 1819 * Code shared by String and AbstractStringBuilder to do searches. The 1820 * source is the character array being searched, and the target 1821 * is the string being searched for. 1822 * 1823 * @param source the characters being searched. 1824 * @param sourceOffset offset of the source string. 1825 * @param sourceCount count of the source string. 1826 * @param target the characters being searched for. 1827 * @param fromIndex the index to begin searching from. 1828 */ 1829 static int lastIndexOf(char[] source, int sourceOffset, int sourceCount, 1830 String target, int fromIndex) { 1831 return lastIndexOf(source, sourceOffset, sourceCount, 1832 target.value, 0, target.value.length, 1833 fromIndex); 1834 } 1835 1836 /** 1837 * Code shared by String and StringBuffer to do searches. The 1838 * source is the character array being searched, and the target 1839 * is the string being searched for. 1840 * 1841 * @param source the characters being searched. 1842 * @param sourceOffset offset of the source string. 1843 * @param sourceCount count of the source string. 1844 * @param target the characters being searched for. 1845 * @param targetOffset offset of the target string. 1846 * @param targetCount count of the target string. 1847 * @param fromIndex the index to begin searching from. 1848 */ 1849 static int lastIndexOf(char[] source, int sourceOffset, int sourceCount, 1850 char[] target, int targetOffset, int targetCount, 1851 int fromIndex) { 1852 /* 1853 * Check arguments; return immediately where possible. For 1854 * consistency, don't check for null str. 1855 */ 1856 int rightIndex = sourceCount - targetCount; 1857 if (fromIndex < 0) { 1858 return -1; 1859 } 1860 if (fromIndex > rightIndex) { 1861 fromIndex = rightIndex; 1862 } 1863 /* Empty string always matches. */ 1864 if (targetCount == 0) { 1865 return fromIndex; 1866 } 1867 1868 int strLastIndex = targetOffset + targetCount - 1; 1869 char strLastChar = target[strLastIndex]; 1870 int min = sourceOffset + targetCount - 1; 1871 int i = min + fromIndex; 1872 1873 startSearchForLastChar: 1874 while (true) { 1875 while (i >= min && source[i] != strLastChar) { 1876 i--; 1877 } 1878 if (i < min) { 1879 return -1; 1880 } 1881 int j = i - 1; 1882 int start = j - (targetCount - 1); 1883 int k = strLastIndex - 1; 1884 1885 while (j > start) { 1886 if (source[j--] != target[k--]) { 1887 i--; 1888 continue startSearchForLastChar; 1889 } 1890 } 1891 return start - sourceOffset + 1; 1892 } 1893 } 1894 1895 /** 1896 * Returns a new string that is a substring of this string. The 1897 * substring begins with the character at the specified index and 1898 * extends to the end of this string. <p> 1899 * Examples: 1900 * <blockquote><pre> 1901 * "unhappy".substring(2) returns "happy" 1902 * "Harbison".substring(3) returns "bison" 1903 * "emptiness".substring(9) returns "" (an empty string) 1904 * </pre></blockquote> 1905 * 1906 * @param beginIndex the beginning index, inclusive. 1907 * @return the specified substring. 1908 * @exception IndexOutOfBoundsException if 1909 * {@code beginIndex} is negative or larger than the 1910 * length of this {@code String} object. 1911 */ 1912 public String substring(int beginIndex) { 1913 if (beginIndex < 0) { 1914 throw new StringIndexOutOfBoundsException(beginIndex); 1915 } 1916 int subLen = value.length - beginIndex; 1917 if (subLen < 0) { 1918 throw new StringIndexOutOfBoundsException(subLen); 1919 } 1920 return (beginIndex == 0) ? this : new String(value, beginIndex, subLen); 1921 } 1922 1923 /** 1924 * Returns a new string that is a substring of this string. The 1925 * substring begins at the specified {@code beginIndex} and 1926 * extends to the character at index {@code endIndex - 1}. 1927 * Thus the length of the substring is {@code endIndex-beginIndex}. 1928 * <p> 1929 * Examples: 1930 * <blockquote><pre> 1931 * "hamburger".substring(4, 8) returns "urge" 1932 * "smiles".substring(1, 5) returns "mile" 1933 * </pre></blockquote> 1934 * 1935 * @param beginIndex the beginning index, inclusive. 1936 * @param endIndex the ending index, exclusive. 1937 * @return the specified substring. 1938 * @exception IndexOutOfBoundsException if the 1939 * {@code beginIndex} is negative, or 1940 * {@code endIndex} is larger than the length of 1941 * this {@code String} object, or 1942 * {@code beginIndex} is larger than 1943 * {@code endIndex}. 1944 */ 1945 public String substring(int beginIndex, int endIndex) { 1946 if (beginIndex < 0) { 1947 throw new StringIndexOutOfBoundsException(beginIndex); 1948 } 1949 if (endIndex > value.length) { 1950 throw new StringIndexOutOfBoundsException(endIndex); 1951 } 1952 int subLen = endIndex - beginIndex; 1953 if (subLen < 0) { 1954 throw new StringIndexOutOfBoundsException(subLen); 1955 } 1956 return ((beginIndex == 0) && (endIndex == value.length)) ? this 1957 : new String(value, beginIndex, subLen); 1958 } 1959 1960 /** 1961 * Returns a new character sequence that is a subsequence of this sequence. 1962 * 1963 * <p> An invocation of this method of the form 1964 * 1965 * <blockquote><pre> 1966 * str.subSequence(begin, end)</pre></blockquote> 1967 * 1968 * behaves in exactly the same way as the invocation 1969 * 1970 * <blockquote><pre> 1971 * str.substring(begin, end)</pre></blockquote> 1972 * 1973 * This method is defined so that the {@code String} class can implement 1974 * the {@link CharSequence} interface. 1975 * 1976 * @param beginIndex the begin index, inclusive. 1977 * @param endIndex the end index, exclusive. 1978 * @return the specified subsequence. 1979 * 1980 * @throws IndexOutOfBoundsException 1981 * if {@code beginIndex} or {@code endIndex} is negative, 1982 * if {@code endIndex} is greater than {@code length()}, 1983 * or if {@code beginIndex} is greater than {@code endIndex} 1984 * 1985 * @since 1.4 1986 * @spec JSR-51 1987 */ 1988 public CharSequence subSequence(int beginIndex, int endIndex) { 1989 return this.substring(beginIndex, endIndex); 1990 } 1991 1992 /** 1993 * Concatenates the specified string to the end of this string. 1994 * <p> 1995 * If the length of the argument string is {@code 0}, then this 1996 * {@code String} object is returned. Otherwise, a new 1997 * {@code String} object is created, representing a character 1998 * sequence that is the concatenation of the character sequence 1999 * represented by this {@code String} object and the character 2000 * sequence represented by the argument string.<p> 2001 * Examples: 2002 * <blockquote><pre> 2003 * "cares".concat("s") returns "caress" 2004 * "to".concat("get").concat("her") returns "together" 2005 * </pre></blockquote> 2006 * 2007 * @param str the {@code String} that is concatenated to the end 2008 * of this {@code String}. 2009 * @return a string that represents the concatenation of this object's 2010 * characters followed by the string argument's characters. 2011 */ 2012 public String concat(String str) { 2013 int otherLen = str.length(); 2014 if (otherLen == 0) { 2015 return this; 2016 } 2017 int len = value.length; 2018 char buf[] = Arrays.copyOf(value, len + otherLen); 2019 str.getChars(buf, len); 2020 return new String(buf, true); 2021 } 2022 2023 /** 2024 * Returns a new string resulting from replacing all occurrences of 2025 * {@code oldChar} in this string with {@code newChar}. 2026 * <p> 2027 * If the character {@code oldChar} does not occur in the 2028 * character sequence represented by this {@code String} object, 2029 * then a reference to this {@code String} object is returned. 2030 * Otherwise, a new {@code String} object is created that 2031 * represents a character sequence identical to the character sequence 2032 * represented by this {@code String} object, except that every 2033 * occurrence of {@code oldChar} is replaced by an occurrence 2034 * of {@code newChar}. 2035 * <p> 2036 * Examples: 2037 * <blockquote><pre> 2038 * "mesquite in your cellar".replace('e', 'o') 2039 * returns "mosquito in your collar" 2040 * "the war of baronets".replace('r', 'y') 2041 * returns "the way of bayonets" 2042 * "sparring with a purple porpoise".replace('p', 't') 2043 * returns "starring with a turtle tortoise" 2044 * "JonL".replace('q', 'x') returns "JonL" (no change) 2045 * </pre></blockquote> 2046 * 2047 * @param oldChar the old character. 2048 * @param newChar the new character. 2049 * @return a string derived from this string by replacing every 2050 * occurrence of {@code oldChar} with {@code newChar}. 2051 */ 2052 public String replace(char oldChar, char newChar) { 2053 if (oldChar != newChar) { 2054 int len = value.length; 2055 int i = -1; 2056 char[] val = value; /* avoid getfield opcode */ 2057 2058 while (++i < len) { 2059 if (val[i] == oldChar) { 2060 break; 2061 } 2062 } 2063 if (i < len) { 2064 char buf[] = new char[len]; 2065 for (int j = 0; j < i; j++) { 2066 buf[j] = val[j]; 2067 } 2068 while (i < len) { 2069 char c = val[i]; 2070 buf[i] = (c == oldChar) ? newChar : c; 2071 i++; 2072 } 2073 return new String(buf, true); 2074 } 2075 } 2076 return this; 2077 } 2078 2079 /** 2080 * Tells whether or not this string matches the given <a 2081 * href="../util/regex/Pattern.html#sum">regular expression</a>. 2082 * 2083 * <p> An invocation of this method of the form 2084 * <i>str</i>{@code .matches(}<i>regex</i>{@code )} yields exactly the 2085 * same result as the expression 2086 * 2087 * <blockquote> 2088 * {@link java.util.regex.Pattern}.{@link java.util.regex.Pattern#matches(String,CharSequence) 2089 * matches(<i>regex</i>, <i>str</i>)} 2090 * </blockquote> 2091 * 2092 * @param regex 2093 * the regular expression to which this string is to be matched 2094 * 2095 * @return {@code true} if, and only if, this string matches the 2096 * given regular expression 2097 * 2098 * @throws PatternSyntaxException 2099 * if the regular expression's syntax is invalid 2100 * 2101 * @see java.util.regex.Pattern 2102 * 2103 * @since 1.4 2104 * @spec JSR-51 2105 */ 2106 public boolean matches(String regex) { 2107 return Pattern.matches(regex, this); 2108 } 2109 2110 /** 2111 * Returns true if and only if this string contains the specified 2112 * sequence of char values. 2113 * 2114 * @param s the sequence to search for 2115 * @return true if this string contains {@code s}, false otherwise 2116 * @since 1.5 2117 */ 2118 public boolean contains(CharSequence s) { 2119 return indexOf(s.toString()) > -1; 2120 } 2121 2122 /** 2123 * Replaces the first substring of this string that matches the given <a 2124 * href="../util/regex/Pattern.html#sum">regular expression</a> with the 2125 * given replacement. 2126 * 2127 * <p> An invocation of this method of the form 2128 * <i>str</i>{@code .replaceFirst(}<i>regex</i>{@code ,} <i>repl</i>{@code )} 2129 * yields exactly the same result as the expression 2130 * 2131 * <blockquote> 2132 * <code> 2133 * {@link java.util.regex.Pattern}.{@link 2134 * java.util.regex.Pattern#compile compile}(<i>regex</i>).{@link 2135 * java.util.regex.Pattern#matcher(java.lang.CharSequence) matcher}(<i>str</i>).{@link 2136 * java.util.regex.Matcher#replaceFirst replaceFirst}(<i>repl</i>) 2137 * </code> 2138 * </blockquote> 2139 * 2140 *<p> 2141 * Note that backslashes ({@code \}) and dollar signs ({@code $}) in the 2142 * replacement string may cause the results to be different than if it were 2143 * being treated as a literal replacement string; see 2144 * {@link java.util.regex.Matcher#replaceFirst}. 2145 * Use {@link java.util.regex.Matcher#quoteReplacement} to suppress the special 2146 * meaning of these characters, if desired. 2147 * 2148 * @param regex 2149 * the regular expression to which this string is to be matched 2150 * @param replacement 2151 * the string to be substituted for the first match 2152 * 2153 * @return The resulting {@code String} 2154 * 2155 * @throws PatternSyntaxException 2156 * if the regular expression's syntax is invalid 2157 * 2158 * @see java.util.regex.Pattern 2159 * 2160 * @since 1.4 2161 * @spec JSR-51 2162 */ 2163 public String replaceFirst(String regex, String replacement) { 2164 return Pattern.compile(regex).matcher(this).replaceFirst(replacement); 2165 } 2166 2167 /** 2168 * Replaces each substring of this string that matches the given <a 2169 * href="../util/regex/Pattern.html#sum">regular expression</a> with the 2170 * given replacement. 2171 * 2172 * <p> An invocation of this method of the form 2173 * <i>str</i>{@code .replaceAll(}<i>regex</i>{@code ,} <i>repl</i>{@code )} 2174 * yields exactly the same result as the expression 2175 * 2176 * <blockquote> 2177 * <code> 2178 * {@link java.util.regex.Pattern}.{@link 2179 * java.util.regex.Pattern#compile compile}(<i>regex</i>).{@link 2180 * java.util.regex.Pattern#matcher(java.lang.CharSequence) matcher}(<i>str</i>).{@link 2181 * java.util.regex.Matcher#replaceAll replaceAll}(<i>repl</i>) 2182 * </code> 2183 * </blockquote> 2184 * 2185 *<p> 2186 * Note that backslashes ({@code \}) and dollar signs ({@code $}) in the 2187 * replacement string may cause the results to be different than if it were 2188 * being treated as a literal replacement string; see 2189 * {@link java.util.regex.Matcher#replaceAll Matcher.replaceAll}. 2190 * Use {@link java.util.regex.Matcher#quoteReplacement} to suppress the special 2191 * meaning of these characters, if desired. 2192 * 2193 * @param regex 2194 * the regular expression to which this string is to be matched 2195 * @param replacement 2196 * the string to be substituted for each match 2197 * 2198 * @return The resulting {@code String} 2199 * 2200 * @throws PatternSyntaxException 2201 * if the regular expression's syntax is invalid 2202 * 2203 * @see java.util.regex.Pattern 2204 * 2205 * @since 1.4 2206 * @spec JSR-51 2207 */ 2208 public String replaceAll(String regex, String replacement) { 2209 return Pattern.compile(regex).matcher(this).replaceAll(replacement); 2210 } 2211 2212 /** 2213 * Replaces each substring of this string that matches the literal target 2214 * sequence with the specified literal replacement sequence. The 2215 * replacement proceeds from the beginning of the string to the end, for 2216 * example, replacing "aa" with "b" in the string "aaa" will result in 2217 * "ba" rather than "ab". 2218 * 2219 * @param target The sequence of char values to be replaced 2220 * @param replacement The replacement sequence of char values 2221 * @return The resulting string 2222 * @since 1.5 2223 */ 2224 public String replace(CharSequence target, CharSequence replacement) { 2225 return Pattern.compile(target.toString(), Pattern.LITERAL).matcher( 2226 this).replaceAll(Matcher.quoteReplacement(replacement.toString())); 2227 } 2228 2229 /** 2230 * Splits this string around matches of the given 2231 * <a href="../util/regex/Pattern.html#sum">regular expression</a>. 2232 * 2233 * <p> The array returned by this method contains each substring of this 2234 * string that is terminated by another substring that matches the given 2235 * expression or is terminated by the end of the string. The substrings in 2236 * the array are in the order in which they occur in this string. If the 2237 * expression does not match any part of the input then the resulting array 2238 * has just one element, namely this string. 2239 * 2240 * <p> The {@code limit} parameter controls the number of times the 2241 * pattern is applied and therefore affects the length of the resulting 2242 * array. If the limit <i>n</i> is greater than zero then the pattern 2243 * will be applied at most <i>n</i> - 1 times, the array's 2244 * length will be no greater than <i>n</i>, and the array's last entry 2245 * will contain all input beyond the last matched delimiter. If <i>n</i> 2246 * is non-positive then the pattern will be applied as many times as 2247 * possible and the array can have any length. If <i>n</i> is zero then 2248 * the pattern will be applied as many times as possible, the array can 2249 * have any length, and trailing empty strings will be discarded. 2250 * 2251 * <p> The string {@code "boo:and:foo"}, for example, yields the 2252 * following results with these parameters: 2253 * 2254 * <blockquote><table cellpadding=1 cellspacing=0 summary="Split example showing regex, limit, and result"> 2255 * <tr> 2256 * <th>Regex</th> 2257 * <th>Limit</th> 2258 * <th>Result</th> 2259 * </tr> 2260 * <tr><td align=center>:</td> 2261 * <td align=center>2</td> 2262 * <td>{@code { "boo", "and:foo" }}</td></tr> 2263 * <tr><td align=center>:</td> 2264 * <td align=center>5</td> 2265 * <td>{@code { "boo", "and", "foo" }}</td></tr> 2266 * <tr><td align=center>:</td> 2267 * <td align=center>-2</td> 2268 * <td>{@code { "boo", "and", "foo" }}</td></tr> 2269 * <tr><td align=center>o</td> 2270 * <td align=center>5</td> 2271 * <td>{@code { "b", "", ":and:f", "", "" }}</td></tr> 2272 * <tr><td align=center>o</td> 2273 * <td align=center>-2</td> 2274 * <td>{@code { "b", "", ":and:f", "", "" }}</td></tr> 2275 * <tr><td align=center>o</td> 2276 * <td align=center>0</td> 2277 * <td>{@code { "b", "", ":and:f" }}</td></tr> 2278 * </table></blockquote> 2279 * 2280 * <p> An invocation of this method of the form 2281 * <i>str.</i>{@code split(}<i>regex</i>{@code ,} <i>n</i>{@code )} 2282 * yields the same result as the expression 2283 * 2284 * <blockquote> 2285 * <code> 2286 * {@link java.util.regex.Pattern}.{@link 2287 * java.util.regex.Pattern#compile compile}(<i>regex</i>).{@link 2288 * java.util.regex.Pattern#split(java.lang.CharSequence,int) split}(<i>str</i>, <i>n</i>) 2289 * </code> 2290 * </blockquote> 2291 * 2292 * 2293 * @param regex 2294 * the delimiting regular expression 2295 * 2296 * @param limit 2297 * the result threshold, as described above 2298 * 2299 * @return the array of strings computed by splitting this string 2300 * around matches of the given regular expression 2301 * 2302 * @throws PatternSyntaxException 2303 * if the regular expression's syntax is invalid 2304 * 2305 * @see java.util.regex.Pattern 2306 * 2307 * @since 1.4 2308 * @spec JSR-51 2309 */ 2310 public String[] split(String regex, int limit) { 2311 /* fastpath if the regex is a 2312 (1)one-char String and this character is not one of the 2313 RegEx's meta characters ".$|()[{^?*+\\", or 2314 (2)two-char String and the first char is the backslash and 2315 the second is not the ascii digit or ascii letter. 2316 */ 2317 char ch = 0; 2318 if (((regex.value.length == 1 && 2319 ".$|()[{^?*+\\".indexOf(ch = regex.charAt(0)) == -1) || 2320 (regex.length() == 2 && 2321 regex.charAt(0) == '\\' && 2322 (((ch = regex.charAt(1))-'0')|('9'-ch)) < 0 && 2323 ((ch-'a')|('z'-ch)) < 0 && 2324 ((ch-'A')|('Z'-ch)) < 0)) && 2325 (ch < Character.MIN_HIGH_SURROGATE || 2326 ch > Character.MAX_LOW_SURROGATE)) 2327 { 2328 int off = 0; 2329 int next = 0; 2330 boolean limited = limit > 0; 2331 ArrayList<String> list = new ArrayList<>(); 2332 while ((next = indexOf(ch, off)) != -1) { 2333 if (!limited || list.size() < limit - 1) { 2334 list.add(substring(off, next)); 2335 off = next + 1; 2336 } else { // last one 2337 //assert (list.size() == limit - 1); 2338 list.add(substring(off, value.length)); 2339 off = value.length; 2340 break; 2341 } 2342 } 2343 // If no match was found, return this 2344 if (off == 0) 2345 return new String[]{this}; 2346 2347 // Add remaining segment 2348 if (!limited || list.size() < limit) 2349 list.add(substring(off, value.length)); 2350 2351 // Construct result 2352 int resultSize = list.size(); 2353 if (limit == 0) { 2354 while (resultSize > 0 && list.get(resultSize - 1).length() == 0) { 2355 resultSize--; 2356 } 2357 } 2358 String[] result = new String[resultSize]; 2359 return list.subList(0, resultSize).toArray(result); 2360 } 2361 return Pattern.compile(regex).split(this, limit); 2362 } 2363 2364 /** 2365 * Splits this string around matches of the given <a 2366 * href="../util/regex/Pattern.html#sum">regular expression</a>. 2367 * 2368 * <p> This method works as if by invoking the two-argument {@link 2369 * #split(String, int) split} method with the given expression and a limit 2370 * argument of zero. Trailing empty strings are therefore not included in 2371 * the resulting array. 2372 * 2373 * <p> The string {@code "boo:and:foo"}, for example, yields the following 2374 * results with these expressions: 2375 * 2376 * <blockquote><table cellpadding=1 cellspacing=0 summary="Split examples showing regex and result"> 2377 * <tr> 2378 * <th>Regex</th> 2379 * <th>Result</th> 2380 * </tr> 2381 * <tr><td align=center>:</td> 2382 * <td>{@code { "boo", "and", "foo" }}</td></tr> 2383 * <tr><td align=center>o</td> 2384 * <td>{@code { "b", "", ":and:f" }}</td></tr> 2385 * </table></blockquote> 2386 * 2387 * 2388 * @param regex 2389 * the delimiting regular expression 2390 * 2391 * @return the array of strings computed by splitting this string 2392 * around matches of the given regular expression 2393 * 2394 * @throws PatternSyntaxException 2395 * if the regular expression's syntax is invalid 2396 * 2397 * @see java.util.regex.Pattern 2398 * 2399 * @since 1.4 2400 * @spec JSR-51 2401 */ 2402 public String[] split(String regex) { 2403 return split(regex, 0); 2404 } 2405 2406 /** 2407 * Returns a new String composed of copies of the 2408 * {@code CharSequence elements} joined together with a copy of 2409 * the specified {@code delimiter}. 2410 * 2411 * <blockquote>For example, 2412 * <pre>{@code 2413 * String message = String.join("-", "Java", "is", "cool"); 2414 * // message returned is: "Java-is-cool" 2415 * }</pre></blockquote> 2416 * 2417 * Note that if an element is null, then {@code "null"} is added. 2418 * 2419 * @param delimiter the delimiter that separates each element 2420 * @param elements the elements to join together. 2421 * 2422 * @return a new {@code String} that is composed of the {@code elements} 2423 * separated by the {@code delimiter} 2424 * 2425 * @throws NullPointerException If {@code delimiter} or {@code elements} 2426 * is {@code null} 2427 * 2428 * @see java.util.StringJoiner 2429 * @since 1.8 2430 */ 2431 public static String join(CharSequence delimiter, CharSequence... elements) { 2432 Objects.requireNonNull(delimiter); 2433 Objects.requireNonNull(elements); 2434 // Number of elements not likely worth Arrays.stream overhead. 2435 StringJoiner joiner = new StringJoiner(delimiter); 2436 for (CharSequence cs: elements) { 2437 joiner.add(cs); 2438 } 2439 return joiner.toString(); 2440 } 2441 2442 /** 2443 * Returns a new {@code String} composed of copies of the 2444 * {@code CharSequence elements} joined together with a copy of the 2445 * specified {@code delimiter}. 2446 * 2447 * <blockquote>For example, 2448 * <pre>{@code 2449 * List<String> strings = new LinkedList<>(); 2450 * strings.add("Java");strings.add("is"); 2451 * strings.add("cool"); 2452 * String message = String.join(" ", strings); 2453 * //message returned is: "Java is cool" 2454 * 2455 * Set<String> strings = new LinkedHashSet<>(); 2456 * strings.add("Java"); strings.add("is"); 2457 * strings.add("very"); strings.add("cool"); 2458 * String message = String.join("-", strings); 2459 * //message returned is: "Java-is-very-cool" 2460 * }</pre></blockquote> 2461 * 2462 * Note that if an individual element is {@code null}, then {@code "null"} is added. 2463 * 2464 * @param delimiter a sequence of characters that is used to separate each 2465 * of the {@code elements} in the resulting {@code String} 2466 * @param elements an {@code Iterable} that will have its {@code elements} 2467 * joined together. 2468 * 2469 * @return a new {@code String} that is composed from the {@code elements} 2470 * argument 2471 * 2472 * @throws NullPointerException If {@code delimiter} or {@code elements} 2473 * is {@code null} 2474 * 2475 * @see #join(CharSequence,CharSequence...) 2476 * @see java.util.StringJoiner 2477 * @since 1.8 2478 */ 2479 public static String join(CharSequence delimiter, 2480 Iterable<? extends CharSequence> elements) { 2481 Objects.requireNonNull(delimiter); 2482 Objects.requireNonNull(elements); 2483 StringJoiner joiner = new StringJoiner(delimiter); 2484 for (CharSequence cs: elements) { 2485 joiner.add(cs); 2486 } 2487 return joiner.toString(); 2488 } 2489 2490 /** 2491 * Converts all of the characters in this {@code String} to lower 2492 * case using the rules of the given {@code Locale}. Case mapping is based 2493 * on the Unicode Standard version specified by the {@link java.lang.Character Character} 2494 * class. Since case mappings are not always 1:1 char mappings, the resulting 2495 * {@code String} may be a different length than the original {@code String}. 2496 * <p> 2497 * Examples of lowercase mappings are in the following table: 2498 * <table border="1" summary="Lowercase mapping examples showing language code of locale, upper case, lower case, and description"> 2499 * <tr> 2500 * <th>Language Code of Locale</th> 2501 * <th>Upper Case</th> 2502 * <th>Lower Case</th> 2503 * <th>Description</th> 2504 * </tr> 2505 * <tr> 2506 * <td>tr (Turkish)</td> 2507 * <td>\u0130</td> 2508 * <td>\u0069</td> 2509 * <td>capital letter I with dot above -> small letter i</td> 2510 * </tr> 2511 * <tr> 2512 * <td>tr (Turkish)</td> 2513 * <td>\u0049</td> 2514 * <td>\u0131</td> 2515 * <td>capital letter I -> small letter dotless i </td> 2516 * </tr> 2517 * <tr> 2518 * <td>(all)</td> 2519 * <td>French Fries</td> 2520 * <td>french fries</td> 2521 * <td>lowercased all chars in String</td> 2522 * </tr> 2523 * <tr> 2524 * <td>(all)</td> 2525 * <td><img src="doc-files/capiota.gif" alt="capiota"><img src="doc-files/capchi.gif" alt="capchi"> 2526 * <img src="doc-files/captheta.gif" alt="captheta"><img src="doc-files/capupsil.gif" alt="capupsil"> 2527 * <img src="doc-files/capsigma.gif" alt="capsigma"></td> 2528 * <td><img src="doc-files/iota.gif" alt="iota"><img src="doc-files/chi.gif" alt="chi"> 2529 * <img src="doc-files/theta.gif" alt="theta"><img src="doc-files/upsilon.gif" alt="upsilon"> 2530 * <img src="doc-files/sigma1.gif" alt="sigma"></td> 2531 * <td>lowercased all chars in String</td> 2532 * </tr> 2533 * </table> 2534 * 2535 * @param locale use the case transformation rules for this locale 2536 * @return the {@code String}, converted to lowercase. 2537 * @see java.lang.String#toLowerCase() 2538 * @see java.lang.String#toUpperCase() 2539 * @see java.lang.String#toUpperCase(Locale) 2540 * @since 1.1 2541 */ 2542 public String toLowerCase(Locale locale) { 2543 if (locale == null) { 2544 throw new NullPointerException(); 2545 } 2546 2547 int firstUpper; 2548 final int len = value.length; 2549 2550 /* Now check if there are any characters that need to be changed. */ 2551 scan: { 2552 for (firstUpper = 0 ; firstUpper < len; ) { 2553 char c = value[firstUpper]; 2554 if ((c >= Character.MIN_HIGH_SURROGATE) 2555 && (c <= Character.MAX_HIGH_SURROGATE)) { 2556 int supplChar = codePointAt(firstUpper); 2557 if (supplChar != Character.toLowerCase(supplChar)) { 2558 break scan; 2559 } 2560 firstUpper += Character.charCount(supplChar); 2561 } else { 2562 if (c != Character.toLowerCase(c)) { 2563 break scan; 2564 } 2565 firstUpper++; 2566 } 2567 } 2568 return this; 2569 } 2570 2571 char[] result = new char[len]; 2572 int resultOffset = 0; /* result may grow, so i+resultOffset 2573 * is the write location in result */ 2574 2575 /* Just copy the first few lowerCase characters. */ 2576 System.arraycopy(value, 0, result, 0, firstUpper); 2577 2578 String lang = locale.getLanguage(); 2579 boolean localeDependent = 2580 (lang == "tr" || lang == "az" || lang == "lt"); 2581 char[] lowerCharArray; 2582 int lowerChar; 2583 int srcChar; 2584 int srcCount; 2585 for (int i = firstUpper; i < len; i += srcCount) { 2586 srcChar = (int)value[i]; 2587 if ((char)srcChar >= Character.MIN_HIGH_SURROGATE 2588 && (char)srcChar <= Character.MAX_HIGH_SURROGATE) { 2589 srcChar = codePointAt(i); 2590 srcCount = Character.charCount(srcChar); 2591 } else { 2592 srcCount = 1; 2593 } 2594 if (localeDependent || srcChar == '\u03A3') { // GREEK CAPITAL LETTER SIGMA 2595 lowerChar = ConditionalSpecialCasing.toLowerCaseEx(this, i, locale); 2596 } else { 2597 lowerChar = Character.toLowerCase(srcChar); 2598 } 2599 if ((lowerChar == Character.ERROR) 2600 || (lowerChar >= Character.MIN_SUPPLEMENTARY_CODE_POINT)) { 2601 if (lowerChar == Character.ERROR) { 2602 lowerCharArray = 2603 ConditionalSpecialCasing.toLowerCaseCharArray(this, i, locale); 2604 } else if (srcCount == 2) { 2605 resultOffset += Character.toChars(lowerChar, result, i + resultOffset) - srcCount; 2606 continue; 2607 } else { 2608 lowerCharArray = Character.toChars(lowerChar); 2609 } 2610 2611 /* Grow result if needed */ 2612 int mapLen = lowerCharArray.length; 2613 if (mapLen > srcCount) { 2614 char[] result2 = new char[result.length + mapLen - srcCount]; 2615 System.arraycopy(result, 0, result2, 0, i + resultOffset); 2616 result = result2; 2617 } 2618 for (int x = 0; x < mapLen; ++x) { 2619 result[i + resultOffset + x] = lowerCharArray[x]; 2620 } 2621 resultOffset += (mapLen - srcCount); 2622 } else { 2623 result[i + resultOffset] = (char)lowerChar; 2624 } 2625 } 2626 return new String(result, 0, len + resultOffset); 2627 } 2628 2629 /** 2630 * Converts all of the characters in this {@code String} to lower 2631 * case using the rules of the default locale. This is equivalent to calling 2632 * {@code toLowerCase(Locale.getDefault())}. 2633 * <p> 2634 * <b>Note:</b> This method is locale sensitive, and may produce unexpected 2635 * results if used for strings that are intended to be interpreted locale 2636 * independently. 2637 * Examples are programming language identifiers, protocol keys, and HTML 2638 * tags. 2639 * For instance, {@code "TITLE".toLowerCase()} in a Turkish locale 2640 * returns {@code "t\u005Cu0131tle"}, where '\u005Cu0131' is the 2641 * LATIN SMALL LETTER DOTLESS I character. 2642 * To obtain correct results for locale insensitive strings, use 2643 * {@code toLowerCase(Locale.ROOT)}. 2644 * <p> 2645 * @return the {@code String}, converted to lowercase. 2646 * @see java.lang.String#toLowerCase(Locale) 2647 */ 2648 public String toLowerCase() { 2649 return toLowerCase(Locale.getDefault()); 2650 } 2651 2652 /** 2653 * Converts all of the characters in this {@code String} to upper 2654 * case using the rules of the given {@code Locale}. Case mapping is based 2655 * on the Unicode Standard version specified by the {@link java.lang.Character Character} 2656 * class. Since case mappings are not always 1:1 char mappings, the resulting 2657 * {@code String} may be a different length than the original {@code String}. 2658 * <p> 2659 * Examples of locale-sensitive and 1:M case mappings are in the following table. 2660 * 2661 * <table border="1" summary="Examples of locale-sensitive and 1:M case mappings. Shows Language code of locale, lower case, upper case, and description."> 2662 * <tr> 2663 * <th>Language Code of Locale</th> 2664 * <th>Lower Case</th> 2665 * <th>Upper Case</th> 2666 * <th>Description</th> 2667 * </tr> 2668 * <tr> 2669 * <td>tr (Turkish)</td> 2670 * <td>\u0069</td> 2671 * <td>\u0130</td> 2672 * <td>small letter i -> capital letter I with dot above</td> 2673 * </tr> 2674 * <tr> 2675 * <td>tr (Turkish)</td> 2676 * <td>\u0131</td> 2677 * <td>\u0049</td> 2678 * <td>small letter dotless i -> capital letter I</td> 2679 * </tr> 2680 * <tr> 2681 * <td>(all)</td> 2682 * <td>\u00df</td> 2683 * <td>\u0053 \u0053</td> 2684 * <td>small letter sharp s -> two letters: SS</td> 2685 * </tr> 2686 * <tr> 2687 * <td>(all)</td> 2688 * <td>Fahrvergnügen</td> 2689 * <td>FAHRVERGNÜGEN</td> 2690 * <td></td> 2691 * </tr> 2692 * </table> 2693 * @param locale use the case transformation rules for this locale 2694 * @return the {@code String}, converted to uppercase. 2695 * @see java.lang.String#toUpperCase() 2696 * @see java.lang.String#toLowerCase() 2697 * @see java.lang.String#toLowerCase(Locale) 2698 * @since 1.1 2699 */ 2700 public String toUpperCase(Locale locale) { 2701 if (locale == null) { 2702 throw new NullPointerException(); 2703 } 2704 2705 int firstLower; 2706 final int len = value.length; 2707 2708 /* Now check if there are any characters that need to be changed. */ 2709 scan: { 2710 for (firstLower = 0 ; firstLower < len; ) { 2711 int c = (int)value[firstLower]; 2712 int srcCount; 2713 if ((c >= Character.MIN_HIGH_SURROGATE) 2714 && (c <= Character.MAX_HIGH_SURROGATE)) { 2715 c = codePointAt(firstLower); 2716 srcCount = Character.charCount(c); 2717 } else { 2718 srcCount = 1; 2719 } 2720 int upperCaseChar = Character.toUpperCaseEx(c); 2721 if ((upperCaseChar == Character.ERROR) 2722 || (c != upperCaseChar)) { 2723 break scan; 2724 } 2725 firstLower += srcCount; 2726 } 2727 return this; 2728 } 2729 2730 /* result may grow, so i+resultOffset is the write location in result */ 2731 int resultOffset = 0; 2732 char[] result = new char[len]; /* may grow */ 2733 2734 /* Just copy the first few upperCase characters. */ 2735 System.arraycopy(value, 0, result, 0, firstLower); 2736 2737 String lang = locale.getLanguage(); 2738 boolean localeDependent = 2739 (lang == "tr" || lang == "az" || lang == "lt"); 2740 char[] upperCharArray; 2741 int upperChar; 2742 int srcChar; 2743 int srcCount; 2744 for (int i = firstLower; i < len; i += srcCount) { 2745 srcChar = (int)value[i]; 2746 if ((char)srcChar >= Character.MIN_HIGH_SURROGATE && 2747 (char)srcChar <= Character.MAX_HIGH_SURROGATE) { 2748 srcChar = codePointAt(i); 2749 srcCount = Character.charCount(srcChar); 2750 } else { 2751 srcCount = 1; 2752 } 2753 if (localeDependent) { 2754 upperChar = ConditionalSpecialCasing.toUpperCaseEx(this, i, locale); 2755 } else { 2756 upperChar = Character.toUpperCaseEx(srcChar); 2757 } 2758 if ((upperChar == Character.ERROR) 2759 || (upperChar >= Character.MIN_SUPPLEMENTARY_CODE_POINT)) { 2760 if (upperChar == Character.ERROR) { 2761 if (localeDependent) { 2762 upperCharArray = 2763 ConditionalSpecialCasing.toUpperCaseCharArray(this, i, locale); 2764 } else { 2765 upperCharArray = Character.toUpperCaseCharArray(srcChar); 2766 } 2767 } else if (srcCount == 2) { 2768 resultOffset += Character.toChars(upperChar, result, i + resultOffset) - srcCount; 2769 continue; 2770 } else { 2771 upperCharArray = Character.toChars(upperChar); 2772 } 2773 2774 /* Grow result if needed */ 2775 int mapLen = upperCharArray.length; 2776 if (mapLen > srcCount) { 2777 char[] result2 = new char[result.length + mapLen - srcCount]; 2778 System.arraycopy(result, 0, result2, 0, i + resultOffset); 2779 result = result2; 2780 } 2781 for (int x = 0; x < mapLen; ++x) { 2782 result[i + resultOffset + x] = upperCharArray[x]; 2783 } 2784 resultOffset += (mapLen - srcCount); 2785 } else { 2786 result[i + resultOffset] = (char)upperChar; 2787 } 2788 } 2789 return new String(result, 0, len + resultOffset); 2790 } 2791 2792 /** 2793 * Converts all of the characters in this {@code String} to upper 2794 * case using the rules of the default locale. This method is equivalent to 2795 * {@code toUpperCase(Locale.getDefault())}. 2796 * <p> 2797 * <b>Note:</b> This method is locale sensitive, and may produce unexpected 2798 * results if used for strings that are intended to be interpreted locale 2799 * independently. 2800 * Examples are programming language identifiers, protocol keys, and HTML 2801 * tags. 2802 * For instance, {@code "title".toUpperCase()} in a Turkish locale 2803 * returns {@code "T\u005Cu0130TLE"}, where '\u005Cu0130' is the 2804 * LATIN CAPITAL LETTER I WITH DOT ABOVE character. 2805 * To obtain correct results for locale insensitive strings, use 2806 * {@code toUpperCase(Locale.ROOT)}. 2807 * <p> 2808 * @return the {@code String}, converted to uppercase. 2809 * @see java.lang.String#toUpperCase(Locale) 2810 */ 2811 public String toUpperCase() { 2812 return toUpperCase(Locale.getDefault()); 2813 } 2814 2815 /** 2816 * Returns a copy of the string, with leading and trailing whitespace 2817 * omitted. 2818 * <p> 2819 * If this {@code String} object represents an empty character 2820 * sequence, or the first and last characters of character sequence 2821 * represented by this {@code String} object both have codes 2822 * greater than {@code '\u005Cu0020'} (the space character), then a 2823 * reference to this {@code String} object is returned. 2824 * <p> 2825 * Otherwise, if there is no character with a code greater than 2826 * {@code '\u005Cu0020'} in the string, then a new 2827 * {@code String} object representing an empty string is created 2828 * and returned. 2829 * <p> 2830 * Otherwise, let <i>k</i> be the index of the first character in the 2831 * string whose code is greater than {@code '\u005Cu0020'}, and let 2832 * <i>m</i> be the index of the last character in the string whose code 2833 * is greater than {@code '\u005Cu0020'}. A new {@code String} 2834 * object is created, representing the substring of this string that 2835 * begins with the character at index <i>k</i> and ends with the 2836 * character at index <i>m</i>-that is, the result of 2837 * {@code this.substring(k, m + 1)}. 2838 * <p> 2839 * This method may be used to trim whitespace (as defined above) from 2840 * the beginning and end of a string. 2841 * 2842 * @return A copy of this string with leading and trailing white 2843 * space removed, or this string if it has no leading or 2844 * trailing white space. 2845 */ 2846 public String trim() { 2847 int len = value.length; 2848 int st = 0; 2849 char[] val = value; /* avoid getfield opcode */ 2850 2851 while ((st < len) && (val[st] <= ' ')) { 2852 st++; 2853 } 2854 while ((st < len) && (val[len - 1] <= ' ')) { 2855 len--; 2856 } 2857 return ((st > 0) || (len < value.length)) ? substring(st, len) : this; 2858 } 2859 2860 /** 2861 * This object (which is already a string!) is itself returned. 2862 * 2863 * @return the string itself. 2864 */ 2865 public String toString() { 2866 return this; 2867 } 2868 2869 /** 2870 * Converts this string to a new character array. 2871 * 2872 * @return a newly allocated character array whose length is the length 2873 * of this string and whose contents are initialized to contain 2874 * the character sequence represented by this string. 2875 */ 2876 public char[] toCharArray() { 2877 // Cannot use Arrays.copyOf because of class initialization order issues 2878 char result[] = new char[value.length]; 2879 System.arraycopy(value, 0, result, 0, value.length); 2880 return result; 2881 } 2882 2883 /** 2884 * Returns a formatted string using the specified format string and 2885 * arguments. 2886 * 2887 * <p> The locale always used is the one returned by {@link 2888 * java.util.Locale#getDefault() Locale.getDefault()}. 2889 * 2890 * @param format 2891 * A <a href="../util/Formatter.html#syntax">format string</a> 2892 * 2893 * @param args 2894 * Arguments referenced by the format specifiers in the format 2895 * string. If there are more arguments than format specifiers, the 2896 * extra arguments are ignored. The number of arguments is 2897 * variable and may be zero. The maximum number of arguments is 2898 * limited by the maximum dimension of a Java array as defined by 2899 * <cite>The Java™ Virtual Machine Specification</cite>. 2900 * The behaviour on a 2901 * {@code null} argument depends on the <a 2902 * href="../util/Formatter.html#syntax">conversion</a>. 2903 * 2904 * @throws java.util.IllegalFormatException 2905 * If a format string contains an illegal syntax, a format 2906 * specifier that is incompatible with the given arguments, 2907 * insufficient arguments given the format string, or other 2908 * illegal conditions. For specification of all possible 2909 * formatting errors, see the <a 2910 * href="../util/Formatter.html#detail">Details</a> section of the 2911 * formatter class specification. 2912 * 2913 * @return A formatted string 2914 * 2915 * @see java.util.Formatter 2916 * @since 1.5 2917 */ 2918 public static String format(String format, Object... args) { 2919 return new Formatter().format(format, args).toString(); 2920 } 2921 2922 /** 2923 * Returns a formatted string using the specified locale, format string, 2924 * and arguments. 2925 * 2926 * @param l 2927 * The {@linkplain java.util.Locale locale} to apply during 2928 * formatting. If {@code l} is {@code null} then no localization 2929 * is applied. 2930 * 2931 * @param format 2932 * A <a href="../util/Formatter.html#syntax">format string</a> 2933 * 2934 * @param args 2935 * Arguments referenced by the format specifiers in the format 2936 * string. If there are more arguments than format specifiers, the 2937 * extra arguments are ignored. The number of arguments is 2938 * variable and may be zero. The maximum number of arguments is 2939 * limited by the maximum dimension of a Java array as defined by 2940 * <cite>The Java™ Virtual Machine Specification</cite>. 2941 * The behaviour on a 2942 * {@code null} argument depends on the 2943 * <a href="../util/Formatter.html#syntax">conversion</a>. 2944 * 2945 * @throws java.util.IllegalFormatException 2946 * If a format string contains an illegal syntax, a format 2947 * specifier that is incompatible with the given arguments, 2948 * insufficient arguments given the format string, or other 2949 * illegal conditions. For specification of all possible 2950 * formatting errors, see the <a 2951 * href="../util/Formatter.html#detail">Details</a> section of the 2952 * formatter class specification 2953 * 2954 * @return A formatted string 2955 * 2956 * @see java.util.Formatter 2957 * @since 1.5 2958 */ 2959 public static String format(Locale l, String format, Object... args) { 2960 return new Formatter(l).format(format, args).toString(); 2961 } 2962 2963 /** 2964 * Returns the string representation of the {@code Object} argument. 2965 * 2966 * @param obj an {@code Object}. 2967 * @return if the argument is {@code null}, then a string equal to 2968 * {@code "null"}; otherwise, the value of 2969 * {@code obj.toString()} is returned. 2970 * @see java.lang.Object#toString() 2971 */ 2972 public static String valueOf(Object obj) { 2973 return (obj == null) ? "null" : obj.toString(); 2974 } 2975 2976 /** 2977 * Returns the string representation of the {@code char} array 2978 * argument. The contents of the character array are copied; subsequent 2979 * modification of the character array does not affect the newly 2980 * created string. 2981 * 2982 * @param data a {@code char} array. 2983 * @return a newly allocated string representing the same sequence of 2984 * characters contained in the character array argument. 2985 */ 2986 public static String valueOf(char data[]) { 2987 return new String(data); 2988 } 2989 2990 /** 2991 * Returns the string representation of a specific subarray of the 2992 * {@code char} array argument. 2993 * <p> 2994 * The {@code offset} argument is the index of the first 2995 * character of the subarray. The {@code count} argument 2996 * specifies the length of the subarray. The contents of the subarray 2997 * are copied; subsequent modification of the character array does not 2998 * affect the newly created string. 2999 * 3000 * @param data the character array. 3001 * @param offset the initial offset into the value of the 3002 * {@code String}. 3003 * @param count the length of the value of the {@code String}. 3004 * @return a string representing the sequence of characters contained 3005 * in the subarray of the character array argument. 3006 * @exception IndexOutOfBoundsException if {@code offset} is 3007 * negative, or {@code count} is negative, or 3008 * {@code offset+count} is larger than 3009 * {@code data.length}. 3010 */ 3011 public static String valueOf(char data[], int offset, int count) { 3012 return new String(data, offset, count); 3013 } 3014 3015 /** 3016 * Returns a String that represents the character sequence in the 3017 * array specified. 3018 * 3019 * @param data the character array. 3020 * @param offset initial offset of the subarray. 3021 * @param count length of the subarray. 3022 * @return a {@code String} that contains the characters of the 3023 * specified subarray of the character array. 3024 */ 3025 public static String copyValueOf(char data[], int offset, int count) { 3026 // All public String constructors now copy the data. 3027 return new String(data, offset, count); 3028 } 3029 3030 /** 3031 * Returns a String that represents the character sequence in the 3032 * array specified. 3033 * 3034 * @param data the character array. 3035 * @return a {@code String} that contains the characters of the 3036 * character array. 3037 */ 3038 public static String copyValueOf(char data[]) { 3039 return new String(data); 3040 } 3041 3042 /** 3043 * Returns the string representation of the {@code boolean} argument. 3044 * 3045 * @param b a {@code boolean}. 3046 * @return if the argument is {@code true}, a string equal to 3047 * {@code "true"} is returned; otherwise, a string equal to 3048 * {@code "false"} is returned. 3049 */ 3050 public static String valueOf(boolean b) { 3051 return b ? "true" : "false"; 3052 } 3053 3054 /** 3055 * Returns the string representation of the {@code char} 3056 * argument. 3057 * 3058 * @param c a {@code char}. 3059 * @return a string of length {@code 1} containing 3060 * as its single character the argument {@code c}. 3061 */ 3062 public static String valueOf(char c) { 3063 char data[] = {c}; 3064 return new String(data, true); 3065 } 3066 3067 /** 3068 * Returns the string representation of the {@code int} argument. 3069 * <p> 3070 * The representation is exactly the one returned by the 3071 * {@code Integer.toString} method of one argument. 3072 * 3073 * @param i an {@code int}. 3074 * @return a string representation of the {@code int} argument. 3075 * @see java.lang.Integer#toString(int, int) 3076 */ 3077 public static String valueOf(int i) { 3078 return Integer.toString(i); 3079 } 3080 3081 /** 3082 * Returns the string representation of the {@code long} argument. 3083 * <p> 3084 * The representation is exactly the one returned by the 3085 * {@code Long.toString} method of one argument. 3086 * 3087 * @param l a {@code long}. 3088 * @return a string representation of the {@code long} argument. 3089 * @see java.lang.Long#toString(long) 3090 */ 3091 public static String valueOf(long l) { 3092 return Long.toString(l); 3093 } 3094 3095 /** 3096 * Returns the string representation of the {@code float} argument. 3097 * <p> 3098 * The representation is exactly the one returned by the 3099 * {@code Float.toString} method of one argument. 3100 * 3101 * @param f a {@code float}. 3102 * @return a string representation of the {@code float} argument. 3103 * @see java.lang.Float#toString(float) 3104 */ 3105 public static String valueOf(float f) { 3106 return Float.toString(f); 3107 } 3108 3109 /** 3110 * Returns the string representation of the {@code double} argument. 3111 * <p> 3112 * The representation is exactly the one returned by the 3113 * {@code Double.toString} method of one argument. 3114 * 3115 * @param d a {@code double}. 3116 * @return a string representation of the {@code double} argument. 3117 * @see java.lang.Double#toString(double) 3118 */ 3119 public static String valueOf(double d) { 3120 return Double.toString(d); 3121 } 3122 3123 /** 3124 * Returns a canonical representation for the string object. 3125 * <p> 3126 * A pool of strings, initially empty, is maintained privately by the 3127 * class {@code String}. 3128 * <p> 3129 * When the intern method is invoked, if the pool already contains a 3130 * string equal to this {@code String} object as determined by 3131 * the {@link #equals(Object)} method, then the string from the pool is 3132 * returned. Otherwise, this {@code String} object is added to the 3133 * pool and a reference to this {@code String} object is returned. 3134 * <p> 3135 * It follows that for any two strings {@code s} and {@code t}, 3136 * {@code s.intern() == t.intern()} is {@code true} 3137 * if and only if {@code s.equals(t)} is {@code true}. 3138 * <p> 3139 * All literal strings and string-valued constant expressions are 3140 * interned. String literals are defined in section 3.10.5 of the 3141 * <cite>The Java™ Language Specification</cite>. 3142 * 3143 * @return a string that has the same contents as this string, but is 3144 * guaranteed to be from a pool of unique strings. 3145 */ 3146 public native String intern(); 3147 }