| 1 | /******************************************************************************* |
| 2 | * Copyright (c) 2000, 2007 IBM Corporation and others. |
| 3 | * All rights reserved. This program and the accompanying materials |
| 4 | * are made available under the terms of the Eclipse Public License v1.0 |
| 5 | * which accompanies this distribution, and is available at |
| 6 | * http://www.eclipse.org/legal/epl-v10.html |
| 7 | * |
| 8 | * Contributors: |
| 9 | * IBM Corporation - initial API and implementation |
| 10 | *******************************************************************************/ |
| 11 | |
| 12 | package org.eclipse.jface.util; |
| 13 | |
| 14 | import java.util.Collections; |
| 15 | import java.util.List; |
| 16 | import java.util.MissingResourceException; |
| 17 | import java.util.ResourceBundle; |
| 18 | import java.util.SortedSet; |
| 19 | import java.util.TreeSet; |
| 20 | |
| 21 | /** |
| 22 | * <p> |
| 23 | * A static class providing utility methods to all of JFace. |
| 24 | * </p> |
| 25 | * |
| 26 | * @since 3.1 |
| 27 | */ |
| 28 | public final class Util { |
| 29 | |
| 30 | /** |
| 31 | * An unmodifiable, empty, sorted set. This value is guaranteed to never |
| 32 | * change and never be <code>null</code>. |
| 33 | */ |
| 34 | public static final SortedSet EMPTY_SORTED_SET = Collections |
| 35 | .unmodifiableSortedSet(new TreeSet()); |
| 36 | |
| 37 | /** |
| 38 | * A common zero-length string. It avoids needing write <code>NON-NLS</code> |
| 39 | * next to code fragments. It's also a bit clearer to read. |
| 40 | */ |
| 41 | public static final String ZERO_LENGTH_STRING = ""; //$NON-NLS-1$ |
| 42 | |
| 43 | /** |
| 44 | * Verifies that the given object is an instance of the given class. |
| 45 | * |
| 46 | * @param object |
| 47 | * The object to check; may be <code>null</code>. |
| 48 | * @param c |
| 49 | * The class which the object should be; must not be |
| 50 | * <code>null</code>. |
| 51 | */ |
| 52 | public static final void assertInstance(final Object object, final Class c) { |
| 53 | assertInstance(object, c, false); |
| 54 | } |
| 55 | |
| 56 | /** |
| 57 | * Verifies the given object is an instance of the given class. It is |
| 58 | * possible to specify whether the object is permitted to be |
| 59 | * <code>null</code>. |
| 60 | * |
| 61 | * @param object |
| 62 | * The object to check; may be <code>null</code>. |
| 63 | * @param c |
| 64 | * The class which the object should be; must not be |
| 65 | * <code>null</code>. |
| 66 | * @param allowNull |
| 67 | * Whether the object is allowed to be <code>null</code>. |
| 68 | */ |
| 69 | private static final void assertInstance(final Object object, |
| 70 | final Class c, final boolean allowNull) { |
| 71 | if (object == null && allowNull) { |
| 72 | return; |
| 73 | } |
| 74 | |
| 75 | if (object == null || c == null) { |
| 76 | throw new NullPointerException(); |
| 77 | } else if (!c.isInstance(object)) { |
| 78 | throw new IllegalArgumentException(); |
| 79 | } |
| 80 | } |
| 81 | |
| 82 | /** |
| 83 | * Compares two boolean values. <code>false</code> is considered to be |
| 84 | * "less than" <code>true</code>. |
| 85 | * |
| 86 | * @param left |
| 87 | * The left value to compare |
| 88 | * @param right |
| 89 | * The right value to compare |
| 90 | * @return <code>-1</code> if the left is <code>false</code> and the |
| 91 | * right is <code>true</code>. <code>1</code> if the opposite |
| 92 | * is true. If they are equal, then it returns <code>0</code>. |
| 93 | */ |
| 94 | public static final int compare(final boolean left, final boolean right) { |
| 95 | return left == false ? (right == true ? -1 : 0) : 1; |
| 96 | } |
| 97 | |
| 98 | /** |
| 99 | * Compares two integer values. |
| 100 | * |
| 101 | * @param left |
| 102 | * The left value to compare |
| 103 | * @param right |
| 104 | * The right value to compare |
| 105 | * @return <code>left - right</code> |
| 106 | */ |
| 107 | public static final int compare(final int left, final int right) { |
| 108 | return left - right; |
| 109 | } |
| 110 | |
| 111 | /** |
| 112 | * Compares to comparable objects -- defending against <code>null</code>. |
| 113 | * |
| 114 | * @param left |
| 115 | * The left object to compare; may be <code>null</code>. |
| 116 | * @param right |
| 117 | * The right object to compare; may be <code>null</code>. |
| 118 | * @return The result of the comparison. <code>null</code> is considered |
| 119 | * to be the least possible value. |
| 120 | */ |
| 121 | public static final int compare(final Comparable left, |
| 122 | final Comparable right) { |
| 123 | if (left == null && right == null) { |
| 124 | return 0; |
| 125 | } else if (left == null) { |
| 126 | return -1; |
| 127 | } else if (right == null) { |
| 128 | return 1; |
| 129 | } else { |
| 130 | return left.compareTo(right); |
| 131 | } |
| 132 | } |
| 133 | |
| 134 | /** |
| 135 | * Compares two arrays of comparable objects -- accounting for |
| 136 | * <code>null</code>. |
| 137 | * |
| 138 | * @param left |
| 139 | * The left array to be compared; may be <code>null</code>. |
| 140 | * @param right |
| 141 | * The right array to be compared; may be <code>null</code>. |
| 142 | * @return The result of the comparison. <code>null</code> is considered |
| 143 | * to be the least possible value. A shorter array is considered |
| 144 | * less than a longer array. |
| 145 | */ |
| 146 | public static final int compare(final Comparable[] left, |
| 147 | final Comparable[] right) { |
| 148 | if (left == null && right == null) { |
| 149 | return 0; |
| 150 | } else if (left == null) { |
| 151 | return -1; |
| 152 | } else if (right == null) { |
| 153 | return 1; |
| 154 | } else { |
| 155 | int l = left.length; |
| 156 | int r = right.length; |
| 157 | |
| 158 | if (l != r) { |
| 159 | return l - r; |
| 160 | } |
| 161 | |
| 162 | for (int i = 0; i < l; i++) { |
| 163 | int compareTo = compare(left[i], right[i]); |
| 164 | |
| 165 | if (compareTo != 0) { |
| 166 | return compareTo; |
| 167 | } |
| 168 | } |
| 169 | |
| 170 | return 0; |
| 171 | } |
| 172 | } |
| 173 | |
| 174 | /** |
| 175 | * Compares two lists -- account for <code>null</code>. The lists must |
| 176 | * contain comparable objects. |
| 177 | * |
| 178 | * @param left |
| 179 | * The left list to compare; may be <code>null</code>. This |
| 180 | * list must only contain instances of <code>Comparable</code>. |
| 181 | * @param right |
| 182 | * The right list to compare; may be <code>null</code>. This |
| 183 | * list must only contain instances of <code>Comparable</code>. |
| 184 | * @return The result of the comparison. <code>null</code> is considered |
| 185 | * to be the least possible value. A shorter list is considered less |
| 186 | * than a longer list. |
| 187 | */ |
| 188 | public static final int compare(final List left, final List right) { |
| 189 | if (left == null && right == null) { |
| 190 | return 0; |
| 191 | } else if (left == null) { |
| 192 | return -1; |
| 193 | } else if (right == null) { |
| 194 | return 1; |
| 195 | } else { |
| 196 | int l = left.size(); |
| 197 | int r = right.size(); |
| 198 | |
| 199 | if (l != r) { |
| 200 | return l - r; |
| 201 | } |
| 202 | |
| 203 | for (int i = 0; i < l; i++) { |
| 204 | int compareTo = compare((Comparable) left.get(i), |
| 205 | (Comparable) right.get(i)); |
| 206 | |
| 207 | if (compareTo != 0) { |
| 208 | return compareTo; |
| 209 | } |
| 210 | } |
| 211 | |
| 212 | return 0; |
| 213 | } |
| 214 | } |
| 215 | |
| 216 | /** |
| 217 | * Tests whether the first array ends with the second array. |
| 218 | * |
| 219 | * @param left |
| 220 | * The array to check (larger); may be <code>null</code>. |
| 221 | * @param right |
| 222 | * The array that should be a subsequence (smaller); may be |
| 223 | * <code>null</code>. |
| 224 | * @param equals |
| 225 | * Whether the two array are allowed to be equal. |
| 226 | * @return <code>true</code> if the second array is a subsequence of the |
| 227 | * array list, and they share end elements. |
| 228 | */ |
| 229 | public static final boolean endsWith(final Object[] left, |
| 230 | final Object[] right, final boolean equals) { |
| 231 | if (left == null || right == null) { |
| 232 | return false; |
| 233 | } |
| 234 | |
| 235 | int l = left.length; |
| 236 | int r = right.length; |
| 237 | |
| 238 | if (r > l || !equals && r == l) { |
| 239 | return false; |
| 240 | } |
| 241 | |
| 242 | for (int i = 0; i < r; i++) { |
| 243 | if (!equals(left[l - i - 1], right[r - i - 1])) { |
| 244 | return false; |
| 245 | } |
| 246 | } |
| 247 | |
| 248 | return true; |
| 249 | } |
| 250 | |
| 251 | /** |
| 252 | * Checks whether the two objects are <code>null</code> -- allowing for |
| 253 | * <code>null</code>. |
| 254 | * |
| 255 | * @param left |
| 256 | * The left object to compare; may be <code>null</code>. |
| 257 | * @param right |
| 258 | * The right object to compare; may be <code>null</code>. |
| 259 | * @return <code>true</code> if the two objects are equivalent; |
| 260 | * <code>false</code> otherwise. |
| 261 | */ |
| 262 | public static final boolean equals(final Object left, final Object right) { |
| 263 | return left == null ? right == null : ((right != null) && left |
| 264 | .equals(right)); |
| 265 | } |
| 266 | |
| 267 | /** |
| 268 | * Tests whether two arrays of objects are equal to each other. The arrays |
| 269 | * must not be <code>null</code>, but their elements may be |
| 270 | * <code>null</code>. |
| 271 | * |
| 272 | * @param leftArray |
| 273 | * The left array to compare; may be <code>null</code>, and |
| 274 | * may be empty and may contain <code>null</code> elements. |
| 275 | * @param rightArray |
| 276 | * The right array to compare; may be <code>null</code>, and |
| 277 | * may be empty and may contain <code>null</code> elements. |
| 278 | * @return <code>true</code> if the arrays are equal length and the |
| 279 | * elements at the same position are equal; <code>false</code> |
| 280 | * otherwise. |
| 281 | */ |
| 282 | public static final boolean equals(final Object[] leftArray, |
| 283 | final Object[] rightArray) { |
| 284 | if (leftArray == rightArray) { |
| 285 | return true; |
| 286 | } |
| 287 | |
| 288 | if (leftArray == null) { |
| 289 | return (rightArray == null); |
| 290 | } else if (rightArray == null) { |
| 291 | return false; |
| 292 | } |
| 293 | |
| 294 | if (leftArray.length != rightArray.length) { |
| 295 | return false; |
| 296 | } |
| 297 | |
| 298 | for (int i = 0; i < leftArray.length; i++) { |
| 299 | final Object left = leftArray[i]; |
| 300 | final Object right = rightArray[i]; |
| 301 | final boolean equal = (left == null) ? (right == null) : (left |
| 302 | .equals(right)); |
| 303 | if (!equal) { |
| 304 | return false; |
| 305 | } |
| 306 | } |
| 307 | |
| 308 | return true; |
| 309 | } |
| 310 | |
| 311 | /** |
| 312 | * Provides a hash code based on the given integer value. |
| 313 | * |
| 314 | * @param i |
| 315 | * The integer value |
| 316 | * @return <code>i</code> |
| 317 | */ |
| 318 | public static final int hashCode(final int i) { |
| 319 | return i; |
| 320 | } |
| 321 | |
| 322 | /** |
| 323 | * Provides a hash code for the object -- defending against |
| 324 | * <code>null</code>. |
| 325 | * |
| 326 | * @param object |
| 327 | * The object for which a hash code is required. |
| 328 | * @return <code>object.hashCode</code> or <code>0</code> if |
| 329 | * <code>object</code> if <code>null</code>. |
| 330 | */ |
| 331 | public static final int hashCode(final Object object) { |
| 332 | return object != null ? object.hashCode() : 0; |
| 333 | } |
| 334 | |
| 335 | /** |
| 336 | * Computes the hash code for an array of objects, but with defense against |
| 337 | * <code>null</code>. |
| 338 | * |
| 339 | * @param objects |
| 340 | * The array of objects for which a hash code is needed; may be |
| 341 | * <code>null</code>. |
| 342 | * @return The hash code for <code>objects</code>; or <code>0</code> if |
| 343 | * <code>objects</code> is <code>null</code>. |
| 344 | */ |
| 345 | public static final int hashCode(final Object[] objects) { |
| 346 | if (objects == null) { |
| 347 | return 0; |
| 348 | } |
| 349 | |
| 350 | int hashCode = 89; |
| 351 | for (int i = 0; i < objects.length; i++) { |
| 352 | final Object object = objects[i]; |
| 353 | if (object != null) { |
| 354 | hashCode = hashCode * 31 + object.hashCode(); |
| 355 | } |
| 356 | } |
| 357 | |
| 358 | return hashCode; |
| 359 | } |
| 360 | |
| 361 | /** |
| 362 | * Checks whether the second array is a subsequence of the first array, and |
| 363 | * that they share common starting elements. |
| 364 | * |
| 365 | * @param left |
| 366 | * The first array to compare (large); may be <code>null</code>. |
| 367 | * @param right |
| 368 | * The second array to compare (small); may be <code>null</code>. |
| 369 | * @param equals |
| 370 | * Whether it is allowed for the two arrays to be equivalent. |
| 371 | * @return <code>true</code> if the first arrays starts with the second |
| 372 | * list; <code>false</code> otherwise. |
| 373 | */ |
| 374 | public static final boolean startsWith(final Object[] left, |
| 375 | final Object[] right, final boolean equals) { |
| 376 | if (left == null || right == null) { |
| 377 | return false; |
| 378 | } |
| 379 | |
| 380 | int l = left.length; |
| 381 | int r = right.length; |
| 382 | |
| 383 | if (r > l || !equals && r == l) { |
| 384 | return false; |
| 385 | } |
| 386 | |
| 387 | for (int i = 0; i < r; i++) { |
| 388 | if (!equals(left[i], right[i])) { |
| 389 | return false; |
| 390 | } |
| 391 | } |
| 392 | |
| 393 | return true; |
| 394 | } |
| 395 | |
| 396 | /** |
| 397 | * Converts an array into a string representation that is suitable for |
| 398 | * debugging. |
| 399 | * |
| 400 | * @param array |
| 401 | * The array to convert; may be <code>null</code>. |
| 402 | * @return The string representation of the array; never <code>null</code>. |
| 403 | */ |
| 404 | public static final String toString(final Object[] array) { |
| 405 | if (array == null) { |
| 406 | return "null"; //$NON-NLS-1$ |
| 407 | } |
| 408 | |
| 409 | final StringBuffer buffer = new StringBuffer(); |
| 410 | buffer.append('['); |
| 411 | |
| 412 | final int length = array.length; |
| 413 | for (int i = 0; i < length; i++) { |
| 414 | if (i != 0) { |
| 415 | buffer.append(','); |
| 416 | } |
| 417 | final Object object = array[i]; |
| 418 | final String element = String.valueOf(object); |
| 419 | buffer.append(element); |
| 420 | } |
| 421 | buffer.append(']'); |
| 422 | |
| 423 | return buffer.toString(); |
| 424 | } |
| 425 | |
| 426 | /** |
| 427 | * Provides a translation of a particular key from the resource bundle. |
| 428 | * |
| 429 | * @param resourceBundle |
| 430 | * The key to look up in the resource bundle; should not be |
| 431 | * <code>null</code>. |
| 432 | * @param key |
| 433 | * The key to look up in the resource bundle; should not be |
| 434 | * <code>null</code>. |
| 435 | * @param defaultString |
| 436 | * The value to return if the resource cannot be found; may be |
| 437 | * <code>null</code>. |
| 438 | * @return The value of the translated resource at <code>key</code>. If |
| 439 | * the key cannot be found, then it is simply the |
| 440 | * <code>defaultString</code>. |
| 441 | */ |
| 442 | public static final String translateString( |
| 443 | final ResourceBundle resourceBundle, final String key, |
| 444 | final String defaultString) { |
| 445 | if (resourceBundle != null && key != null) { |
| 446 | try { |
| 447 | final String translatedString = resourceBundle.getString(key); |
| 448 | |
| 449 | if (translatedString != null) { |
| 450 | return translatedString; |
| 451 | } |
| 452 | } catch (MissingResourceException eMissingResource) { |
| 453 | // Such is life. We'll return the key |
| 454 | } |
| 455 | } |
| 456 | |
| 457 | return defaultString; |
| 458 | } |
| 459 | |
| 460 | /** |
| 461 | * Foundation replacement for String.replaceAll(*). |
| 462 | * |
| 463 | * @param src the starting string. |
| 464 | * @param find the string to find. |
| 465 | * @param replacement the string to replace. |
| 466 | * @return The new string. |
| 467 | * @since 3.4 |
| 468 | */ |
| 469 | public static final String replaceAll(String src, String find, String replacement) { |
| 470 | final int len = src.length(); |
| 471 | final int findLen = find.length(); |
| 472 | |
| 473 | int idx = src.indexOf(find); |
| 474 | if (idx < 0) { |
| 475 | return src; |
| 476 | } |
| 477 | |
| 478 | StringBuffer buf = new StringBuffer(); |
| 479 | int beginIndex = 0; |
| 480 | while (idx != -1 && idx < len) { |
| 481 | buf.append(src.substring(beginIndex, idx)); |
| 482 | buf.append(replacement); |
| 483 | |
| 484 | beginIndex = idx + findLen; |
| 485 | if (beginIndex < len) { |
| 486 | idx = src.indexOf(find, beginIndex); |
| 487 | } else { |
| 488 | idx = -1; |
| 489 | } |
| 490 | } |
| 491 | if (beginIndex<len) { |
| 492 | buf.append(src.substring(beginIndex, (idx==-1?len:idx))); |
| 493 | } |
| 494 | return buf.toString(); |
| 495 | } |
| 496 | |
| 497 | /** |
| 498 | * This class should never be constructed. |
| 499 | */ |
| 500 | private Util() { |
| 501 | // Not allowed. |
| 502 | } |
| 503 | } |