Showing the changes to java/pkg/java/util/StringTokenizer.java (1 of 18352 files). Show all
Unified · Split
| @@ -0,0 +1,431 @@ | |||
| 1 | /* | ||
| 2 | * Copyright (c) 1994, 2004, 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.util; | ||
| 27 | |||
| 28 | import java.lang.*; | ||
| 29 | |||
| 30 | /** | ||
| 31 | * The string tokenizer class allows an application to break a | ||
| 32 | * string into tokens. The tokenization method is much simpler than | ||
| 33 | * the one used by the <code>StreamTokenizer</code> class. The | ||
| 34 | * <code>StringTokenizer</code> methods do not distinguish among | ||
| 35 | * identifiers, numbers, and quoted strings, nor do they recognize | ||
| 36 | * and skip comments. | ||
| 37 | * <p> | ||
| 38 | * The set of delimiters (the characters that separate tokens) may | ||
| 39 | * be specified either at creation time or on a per-token basis. | ||
| 40 | * <p> | ||
| 41 | * An instance of <code>StringTokenizer</code> behaves in one of two | ||
| 42 | * ways, depending on whether it was created with the | ||
| 43 | * <code>returnDelims</code> flag having the value <code>true</code> | ||
| 44 | * or <code>false</code>: | ||
| 45 | * <ul> | ||
| 46 | * <li>If the flag is <code>false</code>, delimiter characters serve to | ||
| 47 | * separate tokens. A token is a maximal sequence of consecutive | ||
| 48 | * characters that are not delimiters. | ||
| 49 | * <li>If the flag is <code>true</code>, delimiter characters are themselves | ||
| 50 | * considered to be tokens. A token is thus either one delimiter | ||
| 51 | * character, or a maximal sequence of consecutive characters that are | ||
| 52 | * not delimiters. | ||
| 53 | * </ul><p> | ||
| 54 | * A <tt>StringTokenizer</tt> object internally maintains a current | ||
| 55 | * position within the string to be tokenized. Some operations advance this | ||
| 56 | * current position past the characters processed.<p> | ||
| 57 | * A token is returned by taking a substring of the string that was used to | ||
| 58 | * create the <tt>StringTokenizer</tt> object. | ||
| 59 | * <p> | ||
| 60 | * The following is one example of the use of the tokenizer. The code: | ||
| 61 | * <blockquote><pre> | ||
| 62 | * StringTokenizer st = new StringTokenizer("this is a test"); | ||
| 63 | * while (st.hasMoreTokens()) { | ||
| 64 | * System.out.println(st.nextToken()); | ||
| 65 | * } | ||
| 66 | * </pre></blockquote> | ||
| 67 | * <p> | ||
| 68 | * prints the following output: | ||
| 69 | * <blockquote><pre> | ||
| 70 | * this | ||
| 71 | * is | ||
| 72 | * a | ||
| 73 | * test | ||
| 74 | * </pre></blockquote> | ||
| 75 | * | ||
| 76 | * <p> | ||
| 77 | * <tt>StringTokenizer</tt> is a legacy class that is retained for | ||
| 78 | * compatibility reasons although its use is discouraged in new code. It is | ||
| 79 | * recommended that anyone seeking this functionality use the <tt>split</tt> | ||
| 80 | * method of <tt>String</tt> or the java.util.regex package instead. | ||
| 81 | * <p> | ||
| 82 | * The following example illustrates how the <tt>String.split</tt> | ||
| 83 | * method can be used to break up a string into its basic tokens: | ||
| 84 | * <blockquote><pre> | ||
| 85 | * String[] result = "this is a test".split("\\s"); | ||
| 86 | * for (int x=0; x<result.length; x++) | ||
| 87 | * System.out.println(result[x]); | ||
| 88 | * </pre></blockquote> | ||
| 89 | * <p> | ||
| 90 | * prints the following output: | ||
| 91 | * <blockquote><pre> | ||
| 92 | * this | ||
| 93 | * is | ||
| 94 | * a | ||
| 95 | * test | ||
| 96 | * </pre></blockquote> | ||
| 97 | * | ||
| 98 | * @author unascribed | ||
| 99 | * @see java.io.StreamTokenizer | ||
| 100 | * @since JDK1.0 | ||
| 101 | */ | ||
| 102 | public | ||
| 103 | class StringTokenizer implements Enumeration<Object> { | ||
| 104 | private int currentPosition; | ||
| 105 | private int newPosition; | ||
| 106 | private int maxPosition; | ||
| 107 | private String str; | ||
| 108 | private String delimiters; | ||
| 109 | private boolean retDelims; | ||
| 110 | private boolean delimsChanged; | ||
| 111 | |||
| 112 | /** | ||
| 113 | * maxDelimCodePoint stores the value of the delimiter character with the | ||
| 114 | * highest value. It is used to optimize the detection of delimiter | ||
| 115 | * characters. | ||
| 116 | * | ||
| 117 | * It is unlikely to provide any optimization benefit in the | ||
| 118 | * hasSurrogates case because most string characters will be | ||
| 119 | * smaller than the limit, but we keep it so that the two code | ||
| 120 | * paths remain similar. | ||
| 121 | */ | ||
| 122 | private int maxDelimCodePoint; | ||
| 123 | |||
| 124 | /** | ||
| 125 | * If delimiters include any surrogates (including surrogate | ||
| 126 | * pairs), hasSurrogates is true and the tokenizer uses the | ||
| 127 | * different code path. This is because String.indexOf(int) | ||
| 128 | * doesn't handle unpaired surrogates as a single character. | ||
| 129 | */ | ||
| 130 | private boolean hasSurrogates = false; | ||
| 131 | |||
| 132 | /** | ||
| 133 | * When hasSurrogates is true, delimiters are converted to code | ||
| 134 | * points and isDelimiter(int) is used to determine if the given | ||
| 135 | * codepoint is a delimiter. | ||
| 136 | */ | ||
| 137 | private int[] delimiterCodePoints; | ||
| 138 | |||
| 139 | /** | ||
| 140 | * Set maxDelimCodePoint to the highest char in the delimiter set. | ||
| 141 | */ | ||
| 142 | private void setMaxDelimCodePoint() { | ||
| 143 | if (delimiters == null) { | ||
| 144 | maxDelimCodePoint = 0; | ||
| 145 | return; | ||
| 146 | } | ||
| 147 | |||
| 148 | int m = 0; | ||
| 149 | int c; | ||
| 150 | int count = 0; | ||
| 151 | for (int i = 0; i < delimiters.length(); i += Character.charCount(c)) { | ||
| 152 | c = delimiters.charAt(i); | ||
| 153 | if (c >= Character.MIN_HIGH_SURROGATE && c <= Character.MAX_LOW_SURROGATE) { | ||
| 154 | c = delimiters.codePointAt(i); | ||
| 155 | hasSurrogates = true; | ||
| 156 | } | ||
| 157 | if (m < c) | ||
| 158 | m = c; | ||
| 159 | count++; | ||
| 160 | } | ||
| 161 | maxDelimCodePoint = m; | ||
| 162 | |||
| 163 | if (hasSurrogates) { | ||
| 164 | delimiterCodePoints = new int[count]; | ||
| 165 | for (int i = 0, j = 0; i < count; i++, j += Character.charCount(c)) { | ||
| 166 | c = delimiters.codePointAt(j); | ||
| 167 | delimiterCodePoints[i] = c; | ||
| 168 | } | ||
| 169 | } | ||
| 170 | } | ||
| 171 | |||
| 172 | /** | ||
| 173 | * Constructs a string tokenizer for the specified string. All | ||
| 174 | * characters in the <code>delim</code> argument are the delimiters | ||
| 175 | * for separating tokens. | ||
| 176 | * <p> | ||
| 177 | * If the <code>returnDelims</code> flag is <code>true</code>, then | ||
| 178 | * the delimiter characters are also returned as tokens. Each | ||
| 179 | * delimiter is returned as a string of length one. If the flag is | ||
| 180 | * <code>false</code>, the delimiter characters are skipped and only | ||
| 181 | * serve as separators between tokens. | ||
| 182 | * <p> | ||
| 183 | * Note that if <tt>delim</tt> is <tt>null</tt>, this constructor does | ||
| 184 | * not throw an exception. However, trying to invoke other methods on the | ||
| 185 | * resulting <tt>StringTokenizer</tt> may result in a | ||
| 186 | * <tt>NullPointerException</tt>. | ||
| 187 | * | ||
| 188 | * @param str a string to be parsed. | ||
| 189 | * @param delim the delimiters. | ||
| 190 | * @param returnDelims flag indicating whether to return the delimiters | ||
| 191 | * as tokens. | ||
| 192 | * @exception NullPointerException if str is <CODE>null</CODE> | ||
| 193 | */ | ||
| 194 | public StringTokenizer(String str, String delim, boolean returnDelims) { | ||
| 195 | currentPosition = 0; | ||
| 196 | newPosition = -1; | ||
| 197 | delimsChanged = false; | ||
| 198 | this.str = str; | ||
| 199 | maxPosition = str.length(); | ||
| 200 | delimiters = delim; | ||
| 201 | retDelims = returnDelims; | ||
| 202 | setMaxDelimCodePoint(); | ||
| 203 | } | ||
| 204 | |||
| 205 | /** | ||
| 206 | * Constructs a string tokenizer for the specified string. The | ||
| 207 | * characters in the <code>delim</code> argument are the delimiters | ||
| 208 | * for separating tokens. Delimiter characters themselves will not | ||
| 209 | * be treated as tokens. | ||
| 210 | * <p> | ||
| 211 | * Note that if <tt>delim</tt> is <tt>null</tt>, this constructor does | ||
| 212 | * not throw an exception. However, trying to invoke other methods on the | ||
| 213 | * resulting <tt>StringTokenizer</tt> may result in a | ||
| 214 | * <tt>NullPointerException</tt>. | ||
| 215 | * | ||
| 216 | * @param str a string to be parsed. | ||
| 217 | * @param delim the delimiters. | ||
| 218 | * @exception NullPointerException if str is <CODE>null</CODE> | ||
| 219 | */ | ||
| 220 | public StringTokenizer(String str, String delim) { | ||
| 221 | this(str, delim, false); | ||
| 222 | } | ||
| 223 | |||
| 224 | /** | ||
| 225 | * Constructs a string tokenizer for the specified string. The | ||
| 226 | * tokenizer uses the default delimiter set, which is | ||
| 227 | * <code>" \t\n\r\f"</code>: the space character, | ||
| 228 | * the tab character, the newline character, the carriage-return character, | ||
| 229 | * and the form-feed character. Delimiter characters themselves will | ||
| 230 | * not be treated as tokens. | ||
| 231 | * | ||
| 232 | * @param str a string to be parsed. | ||
| 233 | * @exception NullPointerException if str is <CODE>null</CODE> | ||
| 234 | */ | ||
| 235 | public StringTokenizer(String str) { | ||
| 236 | this(str, " \t\n\r\f", false); | ||
| 237 | } | ||
| 238 | |||
| 239 | /** | ||
| 240 | * Skips delimiters starting from the specified position. If retDelims | ||
| 241 | * is false, returns the index of the first non-delimiter character at or | ||
| 242 | * after startPos. If retDelims is true, startPos is returned. | ||
| 243 | */ | ||
| 244 | private int skipDelimiters(int startPos) { | ||
| 245 | if (delimiters == null) | ||
| 246 | throw new NullPointerException(); | ||
| 247 | |||
| 248 | int position = startPos; | ||
| 249 | while (!retDelims && position < maxPosition) { | ||
| 250 | if (!hasSurrogates) { | ||
| 251 | char c = str.charAt(position); | ||
| 252 | if ((c > maxDelimCodePoint) || (delimiters.indexOf(c) < 0)) | ||
| 253 | break; | ||
| 254 | position++; | ||
| 255 | } else { | ||
| 256 | int c = str.codePointAt(position); | ||
| 257 | if ((c > maxDelimCodePoint) || !isDelimiter(c)) { | ||
| 258 | break; | ||
| 259 | } | ||
| 260 | position += Character.charCount(c); | ||
| 261 | } | ||
| 262 | } | ||
| 263 | return position; | ||
| 264 | } | ||
| 265 | |||
| 266 | /** | ||
| 267 | * Skips ahead from startPos and returns the index of the next delimiter | ||
| 268 | * character encountered, or maxPosition if no such delimiter is found. | ||
| 269 | */ | ||
| 270 | private int scanToken(int startPos) { | ||
| 271 | int position = startPos; | ||
| 272 | while (position < maxPosition) { | ||
| 273 | if (!hasSurrogates) { | ||
| 274 | char c = str.charAt(position); | ||
| 275 | if ((c <= maxDelimCodePoint) && (delimiters.indexOf(c) >= 0)) | ||
| 276 | break; | ||
| 277 | position++; | ||
| 278 | } else { | ||
| 279 | int c = str.codePointAt(position); | ||
| 280 | if ((c <= maxDelimCodePoint) && isDelimiter(c)) | ||
| 281 | break; | ||
| 282 | position += Character.charCount(c); | ||
| 283 | } | ||
| 284 | } | ||
| 285 | if (retDelims && (startPos == position)) { | ||
| 286 | if (!hasSurrogates) { | ||
| 287 | char c = str.charAt(position); | ||
| 288 | if ((c <= maxDelimCodePoint) && (delimiters.indexOf(c) >= 0)) | ||
| 289 | position++; | ||
| 290 | } else { | ||
| 291 | int c = str.codePointAt(position); | ||
| 292 | if ((c <= maxDelimCodePoint) && isDelimiter(c)) | ||
| 293 | position += Character.charCount(c); | ||
| 294 | } | ||
| 295 | } | ||
| 296 | return position; | ||
| 297 | } | ||
| 298 | |||
| 299 | private boolean isDelimiter(int codePoint) { | ||
| 300 | for (int i = 0; i < delimiterCodePoints.length; i++) { | ||
| 301 | if (delimiterCodePoints[i] == codePoint) { | ||
| 302 | return true; | ||
| 303 | } | ||
| 304 | } | ||
| 305 | return false; | ||
| 306 | } | ||
| 307 | |||
| 308 | /** | ||
| 309 | * Tests if there are more tokens available from this tokenizer's string. | ||
| 310 | * If this method returns <tt>true</tt>, then a subsequent call to | ||
| 311 | * <tt>nextToken</tt> with no argument will successfully return a token. | ||
| 312 | * | ||
| 313 | * @return <code>true</code> if and only if there is at least one token | ||
| 314 | * in the string after the current position; <code>false</code> | ||
| 315 | * otherwise. | ||
| 316 | */ | ||
| 317 | public boolean hasMoreTokens() { | ||
| 318 | /* | ||
| 319 | * Temporarily store this position and use it in the following | ||
| 320 | * nextToken() method only if the delimiters haven't been changed in | ||
| 321 | * that nextToken() invocation. | ||
| 322 | */ | ||
| 323 | newPosition = skipDelimiters(currentPosition); | ||
| 324 | return (newPosition < maxPosition); | ||
| 325 | } | ||
| 326 | |||
| 327 | /** | ||
| 328 | * Returns the next token from this string tokenizer. | ||
| 329 | * | ||
| 330 | * @return the next token from this string tokenizer. | ||
| 331 | * @exception NoSuchElementException if there are no more tokens in this | ||
| 332 | * tokenizer's string. | ||
| 333 | */ | ||
| 334 | public String nextToken() { | ||
| 335 | /* | ||
| 336 | * If next position already computed in hasMoreElements() and | ||
| 337 | * delimiters have changed between the computation and this invocation, | ||
| 338 | * then use the computed value. | ||
| 339 | */ | ||
| 340 | |||
| 341 | currentPosition = (newPosition >= 0 && !delimsChanged) ? | ||
| 342 | newPosition : skipDelimiters(currentPosition); | ||
| 343 | |||
| 344 | /* Reset these anyway */ | ||
| 345 | delimsChanged = false; | ||
| 346 | newPosition = -1; | ||
| 347 | |||
| 348 | if (currentPosition >= maxPosition) | ||
| 349 | throw new NoSuchElementException(); | ||
| 350 | int start = currentPosition; | ||
| 351 | currentPosition = scanToken(currentPosition); | ||
| 352 | return str.substring(start, currentPosition); | ||
| 353 | } | ||
| 354 | |||
| 355 | /** | ||
| 356 | * Returns the next token in this string tokenizer's string. First, | ||
| 357 | * the set of characters considered to be delimiters by this | ||
| 358 | * <tt>StringTokenizer</tt> object is changed to be the characters in | ||
| 359 | * the string <tt>delim</tt>. Then the next token in the string | ||
| 360 | * after the current position is returned. The current position is | ||
| 361 | * advanced beyond the recognized token. The new delimiter set | ||
| 362 | * remains the default after this call. | ||
| 363 | * | ||
| 364 | * @param delim the new delimiters. | ||
| 365 | * @return the next token, after switching to the new delimiter set. | ||
| 366 | * @exception NoSuchElementException if there are no more tokens in this | ||
| 367 | * tokenizer's string. | ||
| 368 | * @exception NullPointerException if delim is <CODE>null</CODE> | ||
| 369 | */ | ||
| 370 | public String nextToken(String delim) { | ||
| 371 | delimiters = delim; | ||
| 372 | |||
| 373 | /* delimiter string specified, so set the appropriate flag. */ | ||
| 374 | delimsChanged = true; | ||
| 375 | |||
| 376 | setMaxDelimCodePoint(); | ||
| 377 | return nextToken(); | ||
| 378 | } | ||
| 379 | |||
| 380 | /** | ||
| 381 | * Returns the same value as the <code>hasMoreTokens</code> | ||
| 382 | * method. It exists so that this class can implement the | ||
| 383 | * <code>Enumeration</code> interface. | ||
| 384 | * | ||
| 385 | * @return <code>true</code> if there are more tokens; | ||
| 386 | * <code>false</code> otherwise. | ||
| 387 | * @see java.util.Enumeration | ||
| 388 | * @see java.util.StringTokenizer#hasMoreTokens() | ||
| 389 | */ | ||
| 390 | public boolean hasMoreElements() { | ||
| 391 | return hasMoreTokens(); | ||
| 392 | } | ||
| 393 | |||
| 394 | /** | ||
| 395 | * Returns the same value as the <code>nextToken</code> method, | ||
| 396 | * except that its declared return value is <code>Object</code> rather than | ||
| 397 | * <code>String</code>. It exists so that this class can implement the | ||
| 398 | * <code>Enumeration</code> interface. | ||
| 399 | * | ||
| 400 | * @return the next token in the string. | ||
| 401 | * @exception NoSuchElementException if there are no more tokens in this | ||
| 402 | * tokenizer's string. | ||
| 403 | * @see java.util.Enumeration | ||
| 404 | * @see java.util.StringTokenizer#nextToken() | ||
| 405 | */ | ||
| 406 | public Object nextElement() { | ||
| 407 | return nextToken(); | ||
| 408 | } | ||
| 409 | |||
| 410 | /** | ||
| 411 | * Calculates the number of times that this tokenizer's | ||
| 412 | * <code>nextToken</code> method can be called before it generates an | ||
| 413 | * exception. The current position is not advanced. | ||
| 414 | * | ||
| 415 | * @return the number of tokens remaining in the string using the current | ||
| 416 | * delimiter set. | ||
| 417 | * @see java.util.StringTokenizer#nextToken() | ||
| 418 | */ | ||
| 419 | public int countTokens() { | ||
| 420 | int count = 0; | ||
| 421 | int currpos = currentPosition; | ||
| 422 | while (currpos < maxPosition) { | ||
| 423 | currpos = skipDelimiters(currpos); | ||
| 424 | if (currpos >= maxPosition) | ||
| 425 | break; | ||
| 426 | currpos = scanToken(currpos); | ||
| 427 | count++; | ||
| 428 | } | ||
| 429 | return count; | ||
| 430 | } | ||
| 431 | } | ||