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| 1 | /* | ||
| 2 | * Copyright (c) 1997, 2010, 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 | /** | ||
| 29 | * This class provides a skeletal implementation of the {@link List} | ||
| 30 | * interface to minimize the effort required to implement this interface | ||
| 31 | * backed by a "random access" data store (such as an array). For sequential | ||
| 32 | * access data (such as a linked list), {@link AbstractSequentialList} should | ||
| 33 | * be used in preference to this class. | ||
| 34 | * | ||
| 35 | * <p>To implement an unmodifiable list, the programmer needs only to extend | ||
| 36 | * this class and provide implementations for the {@link #get(int)} and | ||
| 37 | * {@link List#size() size()} methods. | ||
| 38 | * | ||
| 39 | * <p>To implement a modifiable list, the programmer must additionally | ||
| 40 | * override the {@link #set(int, Object) set(int, E)} method (which otherwise | ||
| 41 | * throws an {@code UnsupportedOperationException}). If the list is | ||
| 42 | * variable-size the programmer must additionally override the | ||
| 43 | * {@link #add(int, Object) add(int, E)} and {@link #remove(int)} methods. | ||
| 44 | * | ||
| 45 | * <p>The programmer should generally provide a void (no argument) and collection | ||
| 46 | * constructor, as per the recommendation in the {@link Collection} interface | ||
| 47 | * specification. | ||
| 48 | * | ||
| 49 | * <p>Unlike the other abstract collection implementations, the programmer does | ||
| 50 | * <i>not</i> have to provide an iterator implementation; the iterator and | ||
| 51 | * list iterator are implemented by this class, on top of the "random access" | ||
| 52 | * methods: | ||
| 53 | * {@link #get(int)}, | ||
| 54 | * {@link #set(int, Object) set(int, E)}, | ||
| 55 | * {@link #add(int, Object) add(int, E)} and | ||
| 56 | * {@link #remove(int)}. | ||
| 57 | * | ||
| 58 | * <p>The documentation for each non-abstract method in this class describes its | ||
| 59 | * implementation in detail. Each of these methods may be overridden if the | ||
| 60 | * collection being implemented admits a more efficient implementation. | ||
| 61 | * | ||
| 62 | * <p>This class is a member of the | ||
| 63 | * <a href="{@docRoot}/../technotes/guides/collections/index.html"> | ||
| 64 | * Java Collections Framework</a>. | ||
| 65 | * | ||
| 66 | * @author Josh Bloch | ||
| 67 | * @author Neal Gafter | ||
| 68 | * @since 1.2 | ||
| 69 | */ | ||
| 70 | |||
| 71 | public abstract class AbstractList<E> extends AbstractCollection<E> implements List<E> { | ||
| 72 | /** | ||
| 73 | * Sole constructor. (For invocation by subclass constructors, typically | ||
| 74 | * implicit.) | ||
| 75 | */ | ||
| 76 | protected AbstractList() { | ||
| 77 | } | ||
| 78 | |||
| 79 | /** | ||
| 80 | * Appends the specified element to the end of this list (optional | ||
| 81 | * operation). | ||
| 82 | * | ||
| 83 | * <p>Lists that support this operation may place limitations on what | ||
| 84 | * elements may be added to this list. In particular, some | ||
| 85 | * lists will refuse to add null elements, and others will impose | ||
| 86 | * restrictions on the type of elements that may be added. List | ||
| 87 | * classes should clearly specify in their documentation any restrictions | ||
| 88 | * on what elements may be added. | ||
| 89 | * | ||
| 90 | * <p>This implementation calls {@code add(size(), e)}. | ||
| 91 | * | ||
| 92 | * <p>Note that this implementation throws an | ||
| 93 | * {@code UnsupportedOperationException} unless | ||
| 94 | * {@link #add(int, Object) add(int, E)} is overridden. | ||
| 95 | * | ||
| 96 | * @param e element to be appended to this list | ||
| 97 | * @return {@code true} (as specified by {@link Collection#add}) | ||
| 98 | * @throws UnsupportedOperationException if the {@code add} operation | ||
| 99 | * is not supported by this list | ||
| 100 | * @throws ClassCastException if the class of the specified element | ||
| 101 | * prevents it from being added to this list | ||
| 102 | * @throws NullPointerException if the specified element is null and this | ||
| 103 | * list does not permit null elements | ||
| 104 | * @throws IllegalArgumentException if some property of this element | ||
| 105 | * prevents it from being added to this list | ||
| 106 | */ | ||
| 107 | public boolean add(E e) { | ||
| 108 | add(size(), e); | ||
| 109 | return true; | ||
| 110 | } | ||
| 111 | |||
| 112 | /** | ||
| 113 | * {@inheritDoc} | ||
| 114 | * | ||
| 115 | * @throws IndexOutOfBoundsException {@inheritDoc} | ||
| 116 | */ | ||
| 117 | abstract public E get(int index); | ||
| 118 | |||
| 119 | /** | ||
| 120 | * {@inheritDoc} | ||
| 121 | * | ||
| 122 | * <p>This implementation always throws an | ||
| 123 | * {@code UnsupportedOperationException}. | ||
| 124 | * | ||
| 125 | * @throws UnsupportedOperationException {@inheritDoc} | ||
| 126 | * @throws ClassCastException {@inheritDoc} | ||
| 127 | * @throws NullPointerException {@inheritDoc} | ||
| 128 | * @throws IllegalArgumentException {@inheritDoc} | ||
| 129 | * @throws IndexOutOfBoundsException {@inheritDoc} | ||
| 130 | */ | ||
| 131 | public E set(int index, E element) { | ||
| 132 | throw new UnsupportedOperationException(); | ||
| 133 | } | ||
| 134 | |||
| 135 | /** | ||
| 136 | * {@inheritDoc} | ||
| 137 | * | ||
| 138 | * <p>This implementation always throws an | ||
| 139 | * {@code UnsupportedOperationException}. | ||
| 140 | * | ||
| 141 | * @throws UnsupportedOperationException {@inheritDoc} | ||
| 142 | * @throws ClassCastException {@inheritDoc} | ||
| 143 | * @throws NullPointerException {@inheritDoc} | ||
| 144 | * @throws IllegalArgumentException {@inheritDoc} | ||
| 145 | * @throws IndexOutOfBoundsException {@inheritDoc} | ||
| 146 | */ | ||
| 147 | public void add(int index, E element) { | ||
| 148 | throw new UnsupportedOperationException(); | ||
| 149 | } | ||
| 150 | |||
| 151 | /** | ||
| 152 | * {@inheritDoc} | ||
| 153 | * | ||
| 154 | * <p>This implementation always throws an | ||
| 155 | * {@code UnsupportedOperationException}. | ||
| 156 | * | ||
| 157 | * @throws UnsupportedOperationException {@inheritDoc} | ||
| 158 | * @throws IndexOutOfBoundsException {@inheritDoc} | ||
| 159 | */ | ||
| 160 | public E remove(int index) { | ||
| 161 | throw new UnsupportedOperationException(); | ||
| 162 | } | ||
| 163 | |||
| 164 | |||
| 165 | // Search Operations | ||
| 166 | |||
| 167 | /** | ||
| 168 | * {@inheritDoc} | ||
| 169 | * | ||
| 170 | * <p>This implementation first gets a list iterator (with | ||
| 171 | * {@code listIterator()}). Then, it iterates over the list until the | ||
| 172 | * specified element is found or the end of the list is reached. | ||
| 173 | * | ||
| 174 | * @throws ClassCastException {@inheritDoc} | ||
| 175 | * @throws NullPointerException {@inheritDoc} | ||
| 176 | */ | ||
| 177 | public int indexOf(Object o) { | ||
| 178 | ListIterator<E> it = listIterator(); | ||
| 179 | if (o==null) { | ||
| 180 | while (it.hasNext()) | ||
| 181 | if (it.next()==null) | ||
| 182 | return it.previousIndex(); | ||
| 183 | } else { | ||
| 184 | while (it.hasNext()) | ||
| 185 | if (o.equals(it.next())) | ||
| 186 | return it.previousIndex(); | ||
| 187 | } | ||
| 188 | return -1; | ||
| 189 | } | ||
| 190 | |||
| 191 | /** | ||
| 192 | * {@inheritDoc} | ||
| 193 | * | ||
| 194 | * <p>This implementation first gets a list iterator that points to the end | ||
| 195 | * of the list (with {@code listIterator(size())}). Then, it iterates | ||
| 196 | * backwards over the list until the specified element is found, or the | ||
| 197 | * beginning of the list is reached. | ||
| 198 | * | ||
| 199 | * @throws ClassCastException {@inheritDoc} | ||
| 200 | * @throws NullPointerException {@inheritDoc} | ||
| 201 | */ | ||
| 202 | public int lastIndexOf(Object o) { | ||
| 203 | ListIterator<E> it = listIterator(size()); | ||
| 204 | if (o==null) { | ||
| 205 | while (it.hasPrevious()) | ||
| 206 | if (it.previous()==null) | ||
| 207 | return it.nextIndex(); | ||
| 208 | } else { | ||
| 209 | while (it.hasPrevious()) | ||
| 210 | if (o.equals(it.previous())) | ||
| 211 | return it.nextIndex(); | ||
| 212 | } | ||
| 213 | return -1; | ||
| 214 | } | ||
| 215 | |||
| 216 | |||
| 217 | // Bulk Operations | ||
| 218 | |||
| 219 | /** | ||
| 220 | * Removes all of the elements from this list (optional operation). | ||
| 221 | * The list will be empty after this call returns. | ||
| 222 | * | ||
| 223 | * <p>This implementation calls {@code removeRange(0, size())}. | ||
| 224 | * | ||
| 225 | * <p>Note that this implementation throws an | ||
| 226 | * {@code UnsupportedOperationException} unless {@code remove(int | ||
| 227 | * index)} or {@code removeRange(int fromIndex, int toIndex)} is | ||
| 228 | * overridden. | ||
| 229 | * | ||
| 230 | * @throws UnsupportedOperationException if the {@code clear} operation | ||
| 231 | * is not supported by this list | ||
| 232 | */ | ||
| 233 | public void clear() { | ||
| 234 | removeRange(0, size()); | ||
| 235 | } | ||
| 236 | |||
| 237 | /** | ||
| 238 | * {@inheritDoc} | ||
| 239 | * | ||
| 240 | * <p>This implementation gets an iterator over the specified collection | ||
| 241 | * and iterates over it, inserting the elements obtained from the | ||
| 242 | * iterator into this list at the appropriate position, one at a time, | ||
| 243 | * using {@code add(int, E)}. | ||
| 244 | * Many implementations will override this method for efficiency. | ||
| 245 | * | ||
| 246 | * <p>Note that this implementation throws an | ||
| 247 | * {@code UnsupportedOperationException} unless | ||
| 248 | * {@link #add(int, Object) add(int, E)} is overridden. | ||
| 249 | * | ||
| 250 | * @throws UnsupportedOperationException {@inheritDoc} | ||
| 251 | * @throws ClassCastException {@inheritDoc} | ||
| 252 | * @throws NullPointerException {@inheritDoc} | ||
| 253 | * @throws IllegalArgumentException {@inheritDoc} | ||
| 254 | * @throws IndexOutOfBoundsException {@inheritDoc} | ||
| 255 | */ | ||
| 256 | public boolean addAll(int index, Collection<? extends E> c) { | ||
| 257 | rangeCheckForAdd(index); | ||
| 258 | boolean modified = false; | ||
| 259 | for (E e : c) { | ||
| 260 | add(index++, e); | ||
| 261 | modified = true; | ||
| 262 | } | ||
| 263 | return modified; | ||
| 264 | } | ||
| 265 | |||
| 266 | |||
| 267 | // Iterators | ||
| 268 | |||
| 269 | /** | ||
| 270 | * Returns an iterator over the elements in this list in proper sequence. | ||
| 271 | * | ||
| 272 | * <p>This implementation returns a straightforward implementation of the | ||
| 273 | * iterator interface, relying on the backing list's {@code size()}, | ||
| 274 | * {@code get(int)}, and {@code remove(int)} methods. | ||
| 275 | * | ||
| 276 | * <p>Note that the iterator returned by this method will throw an | ||
| 277 | * {@link UnsupportedOperationException} in response to its | ||
| 278 | * {@code remove} method unless the list's {@code remove(int)} method is | ||
| 279 | * overridden. | ||
| 280 | * | ||
| 281 | * <p>This implementation can be made to throw runtime exceptions in the | ||
| 282 | * face of concurrent modification, as described in the specification | ||
| 283 | * for the (protected) {@link #modCount} field. | ||
| 284 | * | ||
| 285 | * @return an iterator over the elements in this list in proper sequence | ||
| 286 | */ | ||
| 287 | public Iterator<E> iterator() { | ||
| 288 | return new Itr(); | ||
| 289 | } | ||
| 290 | |||
| 291 | /** | ||
| 292 | * {@inheritDoc} | ||
| 293 | * | ||
| 294 | * <p>This implementation returns {@code listIterator(0)}. | ||
| 295 | * | ||
| 296 | * @see #listIterator(int) | ||
| 297 | */ | ||
| 298 | public ListIterator<E> listIterator() { | ||
| 299 | return listIterator(0); | ||
| 300 | } | ||
| 301 | |||
| 302 | /** | ||
| 303 | * {@inheritDoc} | ||
| 304 | * | ||
| 305 | * <p>This implementation returns a straightforward implementation of the | ||
| 306 | * {@code ListIterator} interface that extends the implementation of the | ||
| 307 | * {@code Iterator} interface returned by the {@code iterator()} method. | ||
| 308 | * The {@code ListIterator} implementation relies on the backing list's | ||
| 309 | * {@code get(int)}, {@code set(int, E)}, {@code add(int, E)} | ||
| 310 | * and {@code remove(int)} methods. | ||
| 311 | * | ||
| 312 | * <p>Note that the list iterator returned by this implementation will | ||
| 313 | * throw an {@link UnsupportedOperationException} in response to its | ||
| 314 | * {@code remove}, {@code set} and {@code add} methods unless the | ||
| 315 | * list's {@code remove(int)}, {@code set(int, E)}, and | ||
| 316 | * {@code add(int, E)} methods are overridden. | ||
| 317 | * | ||
| 318 | * <p>This implementation can be made to throw runtime exceptions in the | ||
| 319 | * face of concurrent modification, as described in the specification for | ||
| 320 | * the (protected) {@link #modCount} field. | ||
| 321 | * | ||
| 322 | * @throws IndexOutOfBoundsException {@inheritDoc} | ||
| 323 | */ | ||
| 324 | public ListIterator<E> listIterator(final int index) { | ||
| 325 | rangeCheckForAdd(index); | ||
| 326 | |||
| 327 | return new ListItr(index); | ||
| 328 | } | ||
| 329 | |||
| 330 | private class Itr implements Iterator<E> { | ||
| 331 | /** | ||
| 332 | * Index of element to be returned by subsequent call to next. | ||
| 333 | */ | ||
| 334 | int cursor = 0; | ||
| 335 | |||
| 336 | /** | ||
| 337 | * Index of element returned by most recent call to next or | ||
| 338 | * previous. Reset to -1 if this element is deleted by a call | ||
| 339 | * to remove. | ||
| 340 | */ | ||
| 341 | int lastRet = -1; | ||
| 342 | |||
| 343 | /** | ||
| 344 | * The modCount value that the iterator believes that the backing | ||
| 345 | * List should have. If this expectation is violated, the iterator | ||
| 346 | * has detected concurrent modification. | ||
| 347 | */ | ||
| 348 | int expectedModCount = modCount; | ||
| 349 | |||
| 350 | public boolean hasNext() { | ||
| 351 | return cursor != size(); | ||
| 352 | } | ||
| 353 | |||
| 354 | public E next() { | ||
| 355 | checkForComodification(); | ||
| 356 | try { | ||
| 357 | int i = cursor; | ||
| 358 | E next = get(i); | ||
| 359 | lastRet = i; | ||
| 360 | cursor = i + 1; | ||
| 361 | return next; | ||
| 362 | } catch (IndexOutOfBoundsException e) { | ||
| 363 | checkForComodification(); | ||
| 364 | throw new NoSuchElementException(); | ||
| 365 | } | ||
| 366 | } | ||
| 367 | |||
| 368 | public void remove() { | ||
| 369 | if (lastRet < 0) | ||
| 370 | throw new IllegalStateException(); | ||
| 371 | checkForComodification(); | ||
| 372 | |||
| 373 | try { | ||
| 374 | AbstractList.this.remove(lastRet); | ||
| 375 | if (lastRet < cursor) | ||
| 376 | cursor--; | ||
| 377 | lastRet = -1; | ||
| 378 | expectedModCount = modCount; | ||
| 379 | } catch (IndexOutOfBoundsException e) { | ||
| 380 | throw new ConcurrentModificationException(); | ||
| 381 | } | ||
| 382 | } | ||
| 383 | |||
| 384 | final void checkForComodification() { | ||
| 385 | if (modCount != expectedModCount) | ||
| 386 | throw new ConcurrentModificationException(); | ||
| 387 | } | ||
| 388 | } | ||
| 389 | |||
| 390 | private class ListItr extends Itr implements ListIterator<E> { | ||
| 391 | ListItr(int index) { | ||
| 392 | cursor = index; | ||
| 393 | } | ||
| 394 | |||
| 395 | public boolean hasPrevious() { | ||
| 396 | return cursor != 0; | ||
| 397 | } | ||
| 398 | |||
| 399 | public E previous() { | ||
| 400 | checkForComodification(); | ||
| 401 | try { | ||
| 402 | int i = cursor - 1; | ||
| 403 | E previous = get(i); | ||
| 404 | lastRet = cursor = i; | ||
| 405 | return previous; | ||
| 406 | } catch (IndexOutOfBoundsException e) { | ||
| 407 | checkForComodification(); | ||
| 408 | throw new NoSuchElementException(); | ||
| 409 | } | ||
| 410 | } | ||
| 411 | |||
| 412 | public int nextIndex() { | ||
| 413 | return cursor; | ||
| 414 | } | ||
| 415 | |||
| 416 | public int previousIndex() { | ||
| 417 | return cursor-1; | ||
| 418 | } | ||
| 419 | |||
| 420 | public void set(E e) { | ||
| 421 | if (lastRet < 0) | ||
| 422 | throw new IllegalStateException(); | ||
| 423 | checkForComodification(); | ||
| 424 | |||
| 425 | try { | ||
| 426 | AbstractList.this.set(lastRet, e); | ||
| 427 | expectedModCount = modCount; | ||
| 428 | } catch (IndexOutOfBoundsException ex) { | ||
| 429 | throw new ConcurrentModificationException(); | ||
| 430 | } | ||
| 431 | } | ||
| 432 | |||
| 433 | public void add(E e) { | ||
| 434 | checkForComodification(); | ||
| 435 | |||
| 436 | try { | ||
| 437 | int i = cursor; | ||
| 438 | AbstractList.this.add(i, e); | ||
| 439 | lastRet = -1; | ||
| 440 | cursor = i + 1; | ||
| 441 | expectedModCount = modCount; | ||
| 442 | } catch (IndexOutOfBoundsException ex) { | ||
| 443 | throw new ConcurrentModificationException(); | ||
| 444 | } | ||
| 445 | } | ||
| 446 | } | ||
| 447 | |||
| 448 | /** | ||
| 449 | * {@inheritDoc} | ||
| 450 | * | ||
| 451 | * <p>This implementation returns a list that subclasses | ||
| 452 | * {@code AbstractList}. The subclass stores, in private fields, the | ||
| 453 | * offset of the subList within the backing list, the size of the subList | ||
| 454 | * (which can change over its lifetime), and the expected | ||
| 455 | * {@code modCount} value of the backing list. There are two variants | ||
| 456 | * of the subclass, one of which implements {@code RandomAccess}. | ||
| 457 | * If this list implements {@code RandomAccess} the returned list will | ||
| 458 | * be an instance of the subclass that implements {@code RandomAccess}. | ||
| 459 | * | ||
| 460 | * <p>The subclass's {@code set(int, E)}, {@code get(int)}, | ||
| 461 | * {@code add(int, E)}, {@code remove(int)}, {@code addAll(int, | ||
| 462 | * Collection)} and {@code removeRange(int, int)} methods all | ||
| 463 | * delegate to the corresponding methods on the backing abstract list, | ||
| 464 | * after bounds-checking the index and adjusting for the offset. The | ||
| 465 | * {@code addAll(Collection c)} method merely returns {@code addAll(size, | ||
| 466 | * c)}. | ||
| 467 | * | ||
| 468 | * <p>The {@code listIterator(int)} method returns a "wrapper object" | ||
| 469 | * over a list iterator on the backing list, which is created with the | ||
| 470 | * corresponding method on the backing list. The {@code iterator} method | ||
| 471 | * merely returns {@code listIterator()}, and the {@code size} method | ||
| 472 | * merely returns the subclass's {@code size} field. | ||
| 473 | * | ||
| 474 | * <p>All methods first check to see if the actual {@code modCount} of | ||
| 475 | * the backing list is equal to its expected value, and throw a | ||
| 476 | * {@code ConcurrentModificationException} if it is not. | ||
| 477 | * | ||
| 478 | * @throws IndexOutOfBoundsException if an endpoint index value is out of range | ||
| 479 | * {@code (fromIndex < 0 || toIndex > size)} | ||
| 480 | * @throws IllegalArgumentException if the endpoint indices are out of order | ||
| 481 | * {@code (fromIndex > toIndex)} | ||
| 482 | */ | ||
| 483 | public List<E> subList(int fromIndex, int toIndex) { | ||
| 484 | return (this instanceof RandomAccess ? | ||
| 485 | new RandomAccessSubList<>(this, fromIndex, toIndex) : | ||
| 486 | new SubList<>(this, fromIndex, toIndex)); | ||
| 487 | } | ||
| 488 | |||
| 489 | // Comparison and hashing | ||
| 490 | |||
| 491 | /** | ||
| 492 | * Compares the specified object with this list for equality. Returns | ||
| 493 | * {@code true} if and only if the specified object is also a list, both | ||
| 494 | * lists have the same size, and all corresponding pairs of elements in | ||
| 495 | * the two lists are <i>equal</i>. (Two elements {@code e1} and | ||
| 496 | * {@code e2} are <i>equal</i> if {@code (e1==null ? e2==null : | ||
| 497 | * e1.equals(e2))}.) In other words, two lists are defined to be | ||
| 498 | * equal if they contain the same elements in the same order.<p> | ||
| 499 | * | ||
| 500 | * This implementation first checks if the specified object is this | ||
| 501 | * list. If so, it returns {@code true}; if not, it checks if the | ||
| 502 | * specified object is a list. If not, it returns {@code false}; if so, | ||
| 503 | * it iterates over both lists, comparing corresponding pairs of elements. | ||
| 504 | * If any comparison returns {@code false}, this method returns | ||
| 505 | * {@code false}. If either iterator runs out of elements before the | ||
| 506 | * other it returns {@code false} (as the lists are of unequal length); | ||
| 507 | * otherwise it returns {@code true} when the iterations complete. | ||
| 508 | * | ||
| 509 | * @param o the object to be compared for equality with this list | ||
| 510 | * @return {@code true} if the specified object is equal to this list | ||
| 511 | */ | ||
| 512 | public boolean equals(Object o) { | ||
| 513 | if (o == this) | ||
| 514 | return true; | ||
| 515 | if (!(o instanceof List)) | ||
| 516 | return false; | ||
| 517 | |||
| 518 | ListIterator<E> e1 = listIterator(); | ||
| 519 | ListIterator e2 = ((List) o).listIterator(); | ||
| 520 | while (e1.hasNext() && e2.hasNext()) { | ||
| 521 | E o1 = e1.next(); | ||
| 522 | Object o2 = e2.next(); | ||
| 523 | if (!(o1==null ? o2==null : o1.equals(o2))) | ||
| 524 | return false; | ||
| 525 | } | ||
| 526 | return !(e1.hasNext() || e2.hasNext()); | ||
| 527 | } | ||
| 528 | |||
| 529 | /** | ||
| 530 | * Returns the hash code value for this list. | ||
| 531 | * | ||
| 532 | * <p>This implementation uses exactly the code that is used to define the | ||
| 533 | * list hash function in the documentation for the {@link List#hashCode} | ||
| 534 | * method. | ||
| 535 | * | ||
| 536 | * @return the hash code value for this list | ||
| 537 | */ | ||
| 538 | public int hashCode() { | ||
| 539 | int hashCode = 1; | ||
| 540 | for (E e : this) | ||
| 541 | hashCode = 31*hashCode + (e==null ? 0 : e.hashCode()); | ||
| 542 | return hashCode; | ||
| 543 | } | ||
| 544 | |||
| 545 | /** | ||
| 546 | * Removes from this list all of the elements whose index is between | ||
| 547 | * {@code fromIndex}, inclusive, and {@code toIndex}, exclusive. | ||
| 548 | * Shifts any succeeding elements to the left (reduces their index). | ||
| 549 | * This call shortens the list by {@code (toIndex - fromIndex)} elements. | ||
| 550 | * (If {@code toIndex==fromIndex}, this operation has no effect.) | ||
| 551 | * | ||
| 552 | * <p>This method is called by the {@code clear} operation on this list | ||
| 553 | * and its subLists. Overriding this method to take advantage of | ||
| 554 | * the internals of the list implementation can <i>substantially</i> | ||
| 555 | * improve the performance of the {@code clear} operation on this list | ||
| 556 | * and its subLists. | ||
| 557 | * | ||
| 558 | * <p>This implementation gets a list iterator positioned before | ||
| 559 | * {@code fromIndex}, and repeatedly calls {@code ListIterator.next} | ||
| 560 | * followed by {@code ListIterator.remove} until the entire range has | ||
| 561 | * been removed. <b>Note: if {@code ListIterator.remove} requires linear | ||
| 562 | * time, this implementation requires quadratic time.</b> | ||
| 563 | * | ||
| 564 | * @param fromIndex index of first element to be removed | ||
| 565 | * @param toIndex index after last element to be removed | ||
| 566 | */ | ||
| 567 | protected void removeRange(int fromIndex, int toIndex) { | ||
| 568 | ListIterator<E> it = listIterator(fromIndex); | ||
| 569 | for (int i=0, n=toIndex-fromIndex; i<n; i++) { | ||
| 570 | it.next(); | ||
| 571 | it.remove(); | ||
| 572 | } | ||
| 573 | } | ||
| 574 | |||
| 575 | /** | ||
| 576 | * The number of times this list has been <i>structurally modified</i>. | ||
| 577 | * Structural modifications are those that change the size of the | ||
| 578 | * list, or otherwise perturb it in such a fashion that iterations in | ||
| 579 | * progress may yield incorrect results. | ||
| 580 | * | ||
| 581 | * <p>This field is used by the iterator and list iterator implementation | ||
| 582 | * returned by the {@code iterator} and {@code listIterator} methods. | ||
| 583 | * If the value of this field changes unexpectedly, the iterator (or list | ||
| 584 | * iterator) will throw a {@code ConcurrentModificationException} in | ||
| 585 | * response to the {@code next}, {@code remove}, {@code previous}, | ||
| 586 | * {@code set} or {@code add} operations. This provides | ||
| 587 | * <i>fail-fast</i> behavior, rather than non-deterministic behavior in | ||
| 588 | * the face of concurrent modification during iteration. | ||
| 589 | * | ||
| 590 | * <p><b>Use of this field by subclasses is optional.</b> If a subclass | ||
| 591 | * wishes to provide fail-fast iterators (and list iterators), then it | ||
| 592 | * merely has to increment this field in its {@code add(int, E)} and | ||
| 593 | * {@code remove(int)} methods (and any other methods that it overrides | ||
| 594 | * that result in structural modifications to the list). A single call to | ||
| 595 | * {@code add(int, E)} or {@code remove(int)} must add no more than | ||
| 596 | * one to this field, or the iterators (and list iterators) will throw | ||
| 597 | * bogus {@code ConcurrentModificationExceptions}. If an implementation | ||
| 598 | * does not wish to provide fail-fast iterators, this field may be | ||
| 599 | * ignored. | ||
| 600 | */ | ||
| 601 | protected transient int modCount = 0; | ||
| 602 | |||
| 603 | private void rangeCheckForAdd(int index) { | ||
| 604 | if (index < 0 || index > size()) | ||
| 605 | throw new IndexOutOfBoundsException(outOfBoundsMsg(index)); | ||
| 606 | } | ||
| 607 | |||
| 608 | private String outOfBoundsMsg(int index) { | ||
| 609 | return "Index: "+index+", Size: "+size(); | ||
| 610 | } | ||
| 611 | } | ||
| 612 | |||
| 613 | class SubList<E> extends AbstractList<E> { | ||
| 614 | private final AbstractList<E> l; | ||
| 615 | private final int offset; | ||
| 616 | private int size; | ||
| 617 | |||
| 618 | SubList(AbstractList<E> list, int fromIndex, int toIndex) { | ||
| 619 | if (fromIndex < 0) | ||
| 620 | throw new IndexOutOfBoundsException("fromIndex = " + fromIndex); | ||
| 621 | if (toIndex > list.size()) | ||
| 622 | throw new IndexOutOfBoundsException("toIndex = " + toIndex); | ||
| 623 | if (fromIndex > toIndex) | ||
| 624 | throw new IllegalArgumentException("fromIndex(" + fromIndex + | ||
| 625 | ") > toIndex(" + toIndex + ")"); | ||
| 626 | l = list; | ||
| 627 | offset = fromIndex; | ||
| 628 | size = toIndex - fromIndex; | ||
| 629 | this.modCount = l.modCount; | ||
| 630 | } | ||
| 631 | |||
| 632 | public E set(int index, E element) { | ||
| 633 | rangeCheck(index); | ||
| 634 | checkForComodification(); | ||
| 635 | return l.set(index+offset, element); | ||
| 636 | } | ||
| 637 | |||
| 638 | public E get(int index) { | ||
| 639 | rangeCheck(index); | ||
| 640 | checkForComodification(); | ||
| 641 | return l.get(index+offset); | ||
| 642 | } | ||
| 643 | |||
| 644 | public int size() { | ||
| 645 | checkForComodification(); | ||
| 646 | return size; | ||
| 647 | } | ||
| 648 | |||
| 649 | public void add(int index, E element) { | ||
| 650 | rangeCheckForAdd(index); | ||
| 651 | checkForComodification(); | ||
| 652 | l.add(index+offset, element); | ||
| 653 | this.modCount = l.modCount; | ||
| 654 | size++; | ||
| 655 | } | ||
| 656 | |||
| 657 | public E remove(int index) { | ||
| 658 | rangeCheck(index); | ||
| 659 | checkForComodification(); | ||
| 660 | E result = l.remove(index+offset); | ||
| 661 | this.modCount = l.modCount; | ||
| 662 | size--; | ||
| 663 | return result; | ||
| 664 | } | ||
| 665 | |||
| 666 | protected void removeRange(int fromIndex, int toIndex) { | ||
| 667 | checkForComodification(); | ||
| 668 | l.removeRange(fromIndex+offset, toIndex+offset); | ||
| 669 | this.modCount = l.modCount; | ||
| 670 | size -= (toIndex-fromIndex); | ||
| 671 | } | ||
| 672 | |||
| 673 | public boolean addAll(Collection<? extends E> c) { | ||
| 674 | return addAll(size, c); | ||
| 675 | } | ||
| 676 | |||
| 677 | public boolean addAll(int index, Collection<? extends E> c) { | ||
| 678 | rangeCheckForAdd(index); | ||
| 679 | int cSize = c.size(); | ||
| 680 | if (cSize==0) | ||
| 681 | return false; | ||
| 682 | |||
| 683 | checkForComodification(); | ||
| 684 | l.addAll(offset+index, c); | ||
| 685 | this.modCount = l.modCount; | ||
| 686 | size += cSize; | ||
| 687 | return true; | ||
| 688 | } | ||
| 689 | |||
| 690 | public Iterator<E> iterator() { | ||
| 691 | return listIterator(); | ||
| 692 | } | ||
| 693 | |||
| 694 | public ListIterator<E> listIterator(final int index) { | ||
| 695 | checkForComodification(); | ||
| 696 | rangeCheckForAdd(index); | ||
| 697 | |||
| 698 | return new ListIterator<E>() { | ||
| 699 | private final ListIterator<E> i = l.listIterator(index+offset); | ||
| 700 | |||
| 701 | public boolean hasNext() { | ||
| 702 | return nextIndex() < size; | ||
| 703 | } | ||
| 704 | |||
| 705 | public E next() { | ||
| 706 | if (hasNext()) | ||
| 707 | return i.next(); | ||
| 708 | else | ||
| 709 | throw new NoSuchElementException(); | ||
| 710 | } | ||
| 711 | |||
| 712 | public boolean hasPrevious() { | ||
| 713 | return previousIndex() >= 0; | ||
| 714 | } | ||
| 715 | |||
| 716 | public E previous() { | ||
| 717 | if (hasPrevious()) | ||
| 718 | return i.previous(); | ||
| 719 | else | ||
| 720 | throw new NoSuchElementException(); | ||
| 721 | } | ||
| 722 | |||
| 723 | public int nextIndex() { | ||
| 724 | return i.nextIndex() - offset; | ||
| 725 | } | ||
| 726 | |||
| 727 | public int previousIndex() { | ||
| 728 | return i.previousIndex() - offset; | ||
| 729 | } | ||
| 730 | |||
| 731 | public void remove() { | ||
| 732 | i.remove(); | ||
| 733 | SubList.this.modCount = l.modCount; | ||
| 734 | size--; | ||
| 735 | } | ||
| 736 | |||
| 737 | public void set(E e) { | ||
| 738 | i.set(e); | ||
| 739 | } | ||
| 740 | |||
| 741 | public void add(E e) { | ||
| 742 | i.add(e); | ||
| 743 | SubList.this.modCount = l.modCount; | ||
| 744 | size++; | ||
| 745 | } | ||
| 746 | }; | ||
| 747 | } | ||
| 748 | |||
| 749 | public List<E> subList(int fromIndex, int toIndex) { | ||
| 750 | return new SubList<>(this, fromIndex, toIndex); | ||
| 751 | } | ||
| 752 | |||
| 753 | private void rangeCheck(int index) { | ||
| 754 | if (index < 0 || index >= size) | ||
| 755 | throw new IndexOutOfBoundsException(outOfBoundsMsg(index)); | ||
| 756 | } | ||
| 757 | |||
| 758 | private void rangeCheckForAdd(int index) { | ||
| 759 | if (index < 0 || index > size) | ||
| 760 | throw new IndexOutOfBoundsException(outOfBoundsMsg(index)); | ||
| 761 | } | ||
| 762 | |||
| 763 | private String outOfBoundsMsg(int index) { | ||
| 764 | return "Index: "+index+", Size: "+size; | ||
| 765 | } | ||
| 766 | |||
| 767 | private void checkForComodification() { | ||
| 768 | if (this.modCount != l.modCount) | ||
| 769 | throw new ConcurrentModificationException(); | ||
| 770 | } | ||
| 771 | } | ||
| 772 | |||
| 773 | class RandomAccessSubList<E> extends SubList<E> implements RandomAccess { | ||
| 774 | RandomAccessSubList(AbstractList<E> list, int fromIndex, int toIndex) { | ||
| 775 | super(list, fromIndex, toIndex); | ||
| 776 | } | ||
| 777 | |||
| 778 | public List<E> subList(int fromIndex, int toIndex) { | ||
| 779 | return new RandomAccessSubList<>(this, fromIndex, toIndex); | ||
| 780 | } | ||
| 781 | } | ||