J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1994-2007 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package java.util; |
| 27 | |
| 28 | /** |
| 29 | * The {@code Vector} class implements a growable array of |
| 30 | * objects. Like an array, it contains components that can be |
| 31 | * accessed using an integer index. However, the size of a |
| 32 | * {@code Vector} can grow or shrink as needed to accommodate |
| 33 | * adding and removing items after the {@code Vector} has been created. |
| 34 | * |
| 35 | * <p>Each vector tries to optimize storage management by maintaining a |
| 36 | * {@code capacity} and a {@code capacityIncrement}. The |
| 37 | * {@code capacity} is always at least as large as the vector |
| 38 | * size; it is usually larger because as components are added to the |
| 39 | * vector, the vector's storage increases in chunks the size of |
| 40 | * {@code capacityIncrement}. An application can increase the |
| 41 | * capacity of a vector before inserting a large number of |
| 42 | * components; this reduces the amount of incremental reallocation. |
| 43 | * |
| 44 | * <p><a name="fail-fast"/> |
| 45 | * The iterators returned by this class's {@link #iterator() iterator} and |
| 46 | * {@link #listIterator(int) listIterator} methods are <em>fail-fast</em>: |
| 47 | * if the vector is structurally modified at any time after the iterator is |
| 48 | * created, in any way except through the iterator's own |
| 49 | * {@link ListIterator#remove() remove} or |
| 50 | * {@link ListIterator#add(Object) add} methods, the iterator will throw a |
| 51 | * {@link ConcurrentModificationException}. Thus, in the face of |
| 52 | * concurrent modification, the iterator fails quickly and cleanly, rather |
| 53 | * than risking arbitrary, non-deterministic behavior at an undetermined |
| 54 | * time in the future. The {@link Enumeration Enumerations} returned by |
| 55 | * the {@link #elements() elements} method are <em>not</em> fail-fast. |
| 56 | * |
| 57 | * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed |
| 58 | * as it is, generally speaking, impossible to make any hard guarantees in the |
| 59 | * presence of unsynchronized concurrent modification. Fail-fast iterators |
| 60 | * throw {@code ConcurrentModificationException} on a best-effort basis. |
| 61 | * Therefore, it would be wrong to write a program that depended on this |
| 62 | * exception for its correctness: <i>the fail-fast behavior of iterators |
| 63 | * should be used only to detect bugs.</i> |
| 64 | * |
| 65 | * <p>As of the Java 2 platform v1.2, this class was retrofitted to |
| 66 | * implement the {@link List} interface, making it a member of the |
| 67 | * <a href="{@docRoot}/../technotes/guides/collections/index.html"> Java |
| 68 | * Collections Framework</a>. Unlike the new collection |
| 69 | * implementations, {@code Vector} is synchronized. |
| 70 | * |
| 71 | * @author Lee Boynton |
| 72 | * @author Jonathan Payne |
| 73 | * @see Collection |
| 74 | * @see List |
| 75 | * @see ArrayList |
| 76 | * @see LinkedList |
| 77 | * @since JDK1.0 |
| 78 | */ |
| 79 | public class Vector<E> |
| 80 | extends AbstractList<E> |
| 81 | implements List<E>, RandomAccess, Cloneable, java.io.Serializable |
| 82 | { |
| 83 | /** |
| 84 | * The array buffer into which the components of the vector are |
| 85 | * stored. The capacity of the vector is the length of this array buffer, |
| 86 | * and is at least large enough to contain all the vector's elements. |
| 87 | * |
| 88 | * <p>Any array elements following the last element in the Vector are null. |
| 89 | * |
| 90 | * @serial |
| 91 | */ |
| 92 | protected Object[] elementData; |
| 93 | |
| 94 | /** |
| 95 | * The number of valid components in this {@code Vector} object. |
| 96 | * Components {@code elementData[0]} through |
| 97 | * {@code elementData[elementCount-1]} are the actual items. |
| 98 | * |
| 99 | * @serial |
| 100 | */ |
| 101 | protected int elementCount; |
| 102 | |
| 103 | /** |
| 104 | * The amount by which the capacity of the vector is automatically |
| 105 | * incremented when its size becomes greater than its capacity. If |
| 106 | * the capacity increment is less than or equal to zero, the capacity |
| 107 | * of the vector is doubled each time it needs to grow. |
| 108 | * |
| 109 | * @serial |
| 110 | */ |
| 111 | protected int capacityIncrement; |
| 112 | |
| 113 | /** use serialVersionUID from JDK 1.0.2 for interoperability */ |
| 114 | private static final long serialVersionUID = -2767605614048989439L; |
| 115 | |
| 116 | /** |
| 117 | * Constructs an empty vector with the specified initial capacity and |
| 118 | * capacity increment. |
| 119 | * |
| 120 | * @param initialCapacity the initial capacity of the vector |
| 121 | * @param capacityIncrement the amount by which the capacity is |
| 122 | * increased when the vector overflows |
| 123 | * @throws IllegalArgumentException if the specified initial capacity |
| 124 | * is negative |
| 125 | */ |
| 126 | public Vector(int initialCapacity, int capacityIncrement) { |
| 127 | super(); |
| 128 | if (initialCapacity < 0) |
| 129 | throw new IllegalArgumentException("Illegal Capacity: "+ |
| 130 | initialCapacity); |
| 131 | this.elementData = new Object[initialCapacity]; |
| 132 | this.capacityIncrement = capacityIncrement; |
| 133 | } |
| 134 | |
| 135 | /** |
| 136 | * Constructs an empty vector with the specified initial capacity and |
| 137 | * with its capacity increment equal to zero. |
| 138 | * |
| 139 | * @param initialCapacity the initial capacity of the vector |
| 140 | * @throws IllegalArgumentException if the specified initial capacity |
| 141 | * is negative |
| 142 | */ |
| 143 | public Vector(int initialCapacity) { |
| 144 | this(initialCapacity, 0); |
| 145 | } |
| 146 | |
| 147 | /** |
| 148 | * Constructs an empty vector so that its internal data array |
| 149 | * has size {@code 10} and its standard capacity increment is |
| 150 | * zero. |
| 151 | */ |
| 152 | public Vector() { |
| 153 | this(10); |
| 154 | } |
| 155 | |
| 156 | /** |
| 157 | * Constructs a vector containing the elements of the specified |
| 158 | * collection, in the order they are returned by the collection's |
| 159 | * iterator. |
| 160 | * |
| 161 | * @param c the collection whose elements are to be placed into this |
| 162 | * vector |
| 163 | * @throws NullPointerException if the specified collection is null |
| 164 | * @since 1.2 |
| 165 | */ |
| 166 | public Vector(Collection<? extends E> c) { |
| 167 | elementData = c.toArray(); |
| 168 | elementCount = elementData.length; |
| 169 | // c.toArray might (incorrectly) not return Object[] (see 6260652) |
| 170 | if (elementData.getClass() != Object[].class) |
| 171 | elementData = Arrays.copyOf(elementData, elementCount, Object[].class); |
| 172 | } |
| 173 | |
| 174 | /** |
| 175 | * Copies the components of this vector into the specified array. |
| 176 | * The item at index {@code k} in this vector is copied into |
| 177 | * component {@code k} of {@code anArray}. |
| 178 | * |
| 179 | * @param anArray the array into which the components get copied |
| 180 | * @throws NullPointerException if the given array is null |
| 181 | * @throws IndexOutOfBoundsException if the specified array is not |
| 182 | * large enough to hold all the components of this vector |
| 183 | * @throws ArrayStoreException if a component of this vector is not of |
| 184 | * a runtime type that can be stored in the specified array |
| 185 | * @see #toArray(Object[]) |
| 186 | */ |
| 187 | public synchronized void copyInto(Object[] anArray) { |
| 188 | System.arraycopy(elementData, 0, anArray, 0, elementCount); |
| 189 | } |
| 190 | |
| 191 | /** |
| 192 | * Trims the capacity of this vector to be the vector's current |
| 193 | * size. If the capacity of this vector is larger than its current |
| 194 | * size, then the capacity is changed to equal the size by replacing |
| 195 | * its internal data array, kept in the field {@code elementData}, |
| 196 | * with a smaller one. An application can use this operation to |
| 197 | * minimize the storage of a vector. |
| 198 | */ |
| 199 | public synchronized void trimToSize() { |
| 200 | modCount++; |
| 201 | int oldCapacity = elementData.length; |
| 202 | if (elementCount < oldCapacity) { |
| 203 | elementData = Arrays.copyOf(elementData, elementCount); |
| 204 | } |
| 205 | } |
| 206 | |
| 207 | /** |
| 208 | * Increases the capacity of this vector, if necessary, to ensure |
| 209 | * that it can hold at least the number of components specified by |
| 210 | * the minimum capacity argument. |
| 211 | * |
| 212 | * <p>If the current capacity of this vector is less than |
| 213 | * {@code minCapacity}, then its capacity is increased by replacing its |
| 214 | * internal data array, kept in the field {@code elementData}, with a |
| 215 | * larger one. The size of the new data array will be the old size plus |
| 216 | * {@code capacityIncrement}, unless the value of |
| 217 | * {@code capacityIncrement} is less than or equal to zero, in which case |
| 218 | * the new capacity will be twice the old capacity; but if this new size |
| 219 | * is still smaller than {@code minCapacity}, then the new capacity will |
| 220 | * be {@code minCapacity}. |
| 221 | * |
| 222 | * @param minCapacity the desired minimum capacity |
| 223 | */ |
| 224 | public synchronized void ensureCapacity(int minCapacity) { |
| 225 | modCount++; |
| 226 | ensureCapacityHelper(minCapacity); |
| 227 | } |
| 228 | |
| 229 | /** |
| 230 | * This implements the unsynchronized semantics of ensureCapacity. |
| 231 | * Synchronized methods in this class can internally call this |
| 232 | * method for ensuring capacity without incurring the cost of an |
| 233 | * extra synchronization. |
| 234 | * |
| 235 | * @see #ensureCapacity(int) |
| 236 | */ |
| 237 | private void ensureCapacityHelper(int minCapacity) { |
| 238 | int oldCapacity = elementData.length; |
| 239 | if (minCapacity > oldCapacity) { |
| 240 | Object[] oldData = elementData; |
| 241 | int newCapacity = (capacityIncrement > 0) ? |
| 242 | (oldCapacity + capacityIncrement) : (oldCapacity * 2); |
| 243 | if (newCapacity < minCapacity) { |
| 244 | newCapacity = minCapacity; |
| 245 | } |
| 246 | elementData = Arrays.copyOf(elementData, newCapacity); |
| 247 | } |
| 248 | } |
| 249 | |
| 250 | /** |
| 251 | * Sets the size of this vector. If the new size is greater than the |
| 252 | * current size, new {@code null} items are added to the end of |
| 253 | * the vector. If the new size is less than the current size, all |
| 254 | * components at index {@code newSize} and greater are discarded. |
| 255 | * |
| 256 | * @param newSize the new size of this vector |
| 257 | * @throws ArrayIndexOutOfBoundsException if the new size is negative |
| 258 | */ |
| 259 | public synchronized void setSize(int newSize) { |
| 260 | modCount++; |
| 261 | if (newSize > elementCount) { |
| 262 | ensureCapacityHelper(newSize); |
| 263 | } else { |
| 264 | for (int i = newSize ; i < elementCount ; i++) { |
| 265 | elementData[i] = null; |
| 266 | } |
| 267 | } |
| 268 | elementCount = newSize; |
| 269 | } |
| 270 | |
| 271 | /** |
| 272 | * Returns the current capacity of this vector. |
| 273 | * |
| 274 | * @return the current capacity (the length of its internal |
| 275 | * data array, kept in the field {@code elementData} |
| 276 | * of this vector) |
| 277 | */ |
| 278 | public synchronized int capacity() { |
| 279 | return elementData.length; |
| 280 | } |
| 281 | |
| 282 | /** |
| 283 | * Returns the number of components in this vector. |
| 284 | * |
| 285 | * @return the number of components in this vector |
| 286 | */ |
| 287 | public synchronized int size() { |
| 288 | return elementCount; |
| 289 | } |
| 290 | |
| 291 | /** |
| 292 | * Tests if this vector has no components. |
| 293 | * |
| 294 | * @return {@code true} if and only if this vector has |
| 295 | * no components, that is, its size is zero; |
| 296 | * {@code false} otherwise. |
| 297 | */ |
| 298 | public synchronized boolean isEmpty() { |
| 299 | return elementCount == 0; |
| 300 | } |
| 301 | |
| 302 | /** |
| 303 | * Returns an enumeration of the components of this vector. The |
| 304 | * returned {@code Enumeration} object will generate all items in |
| 305 | * this vector. The first item generated is the item at index {@code 0}, |
| 306 | * then the item at index {@code 1}, and so on. |
| 307 | * |
| 308 | * @return an enumeration of the components of this vector |
| 309 | * @see Iterator |
| 310 | */ |
| 311 | public Enumeration<E> elements() { |
| 312 | return new Enumeration<E>() { |
| 313 | int count = 0; |
| 314 | |
| 315 | public boolean hasMoreElements() { |
| 316 | return count < elementCount; |
| 317 | } |
| 318 | |
| 319 | public E nextElement() { |
| 320 | synchronized (Vector.this) { |
| 321 | if (count < elementCount) { |
| 322 | return elementData(count++); |
| 323 | } |
| 324 | } |
| 325 | throw new NoSuchElementException("Vector Enumeration"); |
| 326 | } |
| 327 | }; |
| 328 | } |
| 329 | |
| 330 | /** |
| 331 | * Returns {@code true} if this vector contains the specified element. |
| 332 | * More formally, returns {@code true} if and only if this vector |
| 333 | * contains at least one element {@code e} such that |
| 334 | * <tt>(o==null ? e==null : o.equals(e))</tt>. |
| 335 | * |
| 336 | * @param o element whose presence in this vector is to be tested |
| 337 | * @return {@code true} if this vector contains the specified element |
| 338 | */ |
| 339 | public boolean contains(Object o) { |
| 340 | return indexOf(o, 0) >= 0; |
| 341 | } |
| 342 | |
| 343 | /** |
| 344 | * Returns the index of the first occurrence of the specified element |
| 345 | * in this vector, or -1 if this vector does not contain the element. |
| 346 | * More formally, returns the lowest index {@code i} such that |
| 347 | * <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>, |
| 348 | * or -1 if there is no such index. |
| 349 | * |
| 350 | * @param o element to search for |
| 351 | * @return the index of the first occurrence of the specified element in |
| 352 | * this vector, or -1 if this vector does not contain the element |
| 353 | */ |
| 354 | public int indexOf(Object o) { |
| 355 | return indexOf(o, 0); |
| 356 | } |
| 357 | |
| 358 | /** |
| 359 | * Returns the index of the first occurrence of the specified element in |
| 360 | * this vector, searching forwards from {@code index}, or returns -1 if |
| 361 | * the element is not found. |
| 362 | * More formally, returns the lowest index {@code i} such that |
| 363 | * <tt>(i >= index && (o==null ? get(i)==null : o.equals(get(i))))</tt>, |
| 364 | * or -1 if there is no such index. |
| 365 | * |
| 366 | * @param o element to search for |
| 367 | * @param index index to start searching from |
| 368 | * @return the index of the first occurrence of the element in |
| 369 | * this vector at position {@code index} or later in the vector; |
| 370 | * {@code -1} if the element is not found. |
| 371 | * @throws IndexOutOfBoundsException if the specified index is negative |
| 372 | * @see Object#equals(Object) |
| 373 | */ |
| 374 | public synchronized int indexOf(Object o, int index) { |
| 375 | if (o == null) { |
| 376 | for (int i = index ; i < elementCount ; i++) |
| 377 | if (elementData[i]==null) |
| 378 | return i; |
| 379 | } else { |
| 380 | for (int i = index ; i < elementCount ; i++) |
| 381 | if (o.equals(elementData[i])) |
| 382 | return i; |
| 383 | } |
| 384 | return -1; |
| 385 | } |
| 386 | |
| 387 | /** |
| 388 | * Returns the index of the last occurrence of the specified element |
| 389 | * in this vector, or -1 if this vector does not contain the element. |
| 390 | * More formally, returns the highest index {@code i} such that |
| 391 | * <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>, |
| 392 | * or -1 if there is no such index. |
| 393 | * |
| 394 | * @param o element to search for |
| 395 | * @return the index of the last occurrence of the specified element in |
| 396 | * this vector, or -1 if this vector does not contain the element |
| 397 | */ |
| 398 | public synchronized int lastIndexOf(Object o) { |
| 399 | return lastIndexOf(o, elementCount-1); |
| 400 | } |
| 401 | |
| 402 | /** |
| 403 | * Returns the index of the last occurrence of the specified element in |
| 404 | * this vector, searching backwards from {@code index}, or returns -1 if |
| 405 | * the element is not found. |
| 406 | * More formally, returns the highest index {@code i} such that |
| 407 | * <tt>(i <= index && (o==null ? get(i)==null : o.equals(get(i))))</tt>, |
| 408 | * or -1 if there is no such index. |
| 409 | * |
| 410 | * @param o element to search for |
| 411 | * @param index index to start searching backwards from |
| 412 | * @return the index of the last occurrence of the element at position |
| 413 | * less than or equal to {@code index} in this vector; |
| 414 | * -1 if the element is not found. |
| 415 | * @throws IndexOutOfBoundsException if the specified index is greater |
| 416 | * than or equal to the current size of this vector |
| 417 | */ |
| 418 | public synchronized int lastIndexOf(Object o, int index) { |
| 419 | if (index >= elementCount) |
| 420 | throw new IndexOutOfBoundsException(index + " >= "+ elementCount); |
| 421 | |
| 422 | if (o == null) { |
| 423 | for (int i = index; i >= 0; i--) |
| 424 | if (elementData[i]==null) |
| 425 | return i; |
| 426 | } else { |
| 427 | for (int i = index; i >= 0; i--) |
| 428 | if (o.equals(elementData[i])) |
| 429 | return i; |
| 430 | } |
| 431 | return -1; |
| 432 | } |
| 433 | |
| 434 | /** |
| 435 | * Returns the component at the specified index. |
| 436 | * |
| 437 | * <p>This method is identical in functionality to the {@link #get(int)} |
| 438 | * method (which is part of the {@link List} interface). |
| 439 | * |
| 440 | * @param index an index into this vector |
| 441 | * @return the component at the specified index |
| 442 | * @throws ArrayIndexOutOfBoundsException if the index is out of range |
| 443 | * ({@code index < 0 || index >= size()}) |
| 444 | */ |
| 445 | public synchronized E elementAt(int index) { |
| 446 | if (index >= elementCount) { |
| 447 | throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount); |
| 448 | } |
| 449 | |
| 450 | return elementData(index); |
| 451 | } |
| 452 | |
| 453 | /** |
| 454 | * Returns the first component (the item at index {@code 0}) of |
| 455 | * this vector. |
| 456 | * |
| 457 | * @return the first component of this vector |
| 458 | * @throws NoSuchElementException if this vector has no components |
| 459 | */ |
| 460 | public synchronized E firstElement() { |
| 461 | if (elementCount == 0) { |
| 462 | throw new NoSuchElementException(); |
| 463 | } |
| 464 | return elementData(0); |
| 465 | } |
| 466 | |
| 467 | /** |
| 468 | * Returns the last component of the vector. |
| 469 | * |
| 470 | * @return the last component of the vector, i.e., the component at index |
| 471 | * <code>size() - 1</code>. |
| 472 | * @throws NoSuchElementException if this vector is empty |
| 473 | */ |
| 474 | public synchronized E lastElement() { |
| 475 | if (elementCount == 0) { |
| 476 | throw new NoSuchElementException(); |
| 477 | } |
| 478 | return elementData(elementCount - 1); |
| 479 | } |
| 480 | |
| 481 | /** |
| 482 | * Sets the component at the specified {@code index} of this |
| 483 | * vector to be the specified object. The previous component at that |
| 484 | * position is discarded. |
| 485 | * |
| 486 | * <p>The index must be a value greater than or equal to {@code 0} |
| 487 | * and less than the current size of the vector. |
| 488 | * |
| 489 | * <p>This method is identical in functionality to the |
| 490 | * {@link #set(int, Object) set(int, E)} |
| 491 | * method (which is part of the {@link List} interface). Note that the |
| 492 | * {@code set} method reverses the order of the parameters, to more closely |
| 493 | * match array usage. Note also that the {@code set} method returns the |
| 494 | * old value that was stored at the specified position. |
| 495 | * |
| 496 | * @param obj what the component is to be set to |
| 497 | * @param index the specified index |
| 498 | * @throws ArrayIndexOutOfBoundsException if the index is out of range |
| 499 | * ({@code index < 0 || index >= size()}) |
| 500 | */ |
| 501 | public synchronized void setElementAt(E obj, int index) { |
| 502 | if (index >= elementCount) { |
| 503 | throw new ArrayIndexOutOfBoundsException(index + " >= " + |
| 504 | elementCount); |
| 505 | } |
| 506 | elementData[index] = obj; |
| 507 | } |
| 508 | |
| 509 | /** |
| 510 | * Deletes the component at the specified index. Each component in |
| 511 | * this vector with an index greater or equal to the specified |
| 512 | * {@code index} is shifted downward to have an index one |
| 513 | * smaller than the value it had previously. The size of this vector |
| 514 | * is decreased by {@code 1}. |
| 515 | * |
| 516 | * <p>The index must be a value greater than or equal to {@code 0} |
| 517 | * and less than the current size of the vector. |
| 518 | * |
| 519 | * <p>This method is identical in functionality to the {@link #remove(int)} |
| 520 | * method (which is part of the {@link List} interface). Note that the |
| 521 | * {@code remove} method returns the old value that was stored at the |
| 522 | * specified position. |
| 523 | * |
| 524 | * @param index the index of the object to remove |
| 525 | * @throws ArrayIndexOutOfBoundsException if the index is out of range |
| 526 | * ({@code index < 0 || index >= size()}) |
| 527 | */ |
| 528 | public synchronized void removeElementAt(int index) { |
| 529 | modCount++; |
| 530 | if (index >= elementCount) { |
| 531 | throw new ArrayIndexOutOfBoundsException(index + " >= " + |
| 532 | elementCount); |
| 533 | } |
| 534 | else if (index < 0) { |
| 535 | throw new ArrayIndexOutOfBoundsException(index); |
| 536 | } |
| 537 | int j = elementCount - index - 1; |
| 538 | if (j > 0) { |
| 539 | System.arraycopy(elementData, index + 1, elementData, index, j); |
| 540 | } |
| 541 | elementCount--; |
| 542 | elementData[elementCount] = null; /* to let gc do its work */ |
| 543 | } |
| 544 | |
| 545 | /** |
| 546 | * Inserts the specified object as a component in this vector at the |
| 547 | * specified {@code index}. Each component in this vector with |
| 548 | * an index greater or equal to the specified {@code index} is |
| 549 | * shifted upward to have an index one greater than the value it had |
| 550 | * previously. |
| 551 | * |
| 552 | * <p>The index must be a value greater than or equal to {@code 0} |
| 553 | * and less than or equal to the current size of the vector. (If the |
| 554 | * index is equal to the current size of the vector, the new element |
| 555 | * is appended to the Vector.) |
| 556 | * |
| 557 | * <p>This method is identical in functionality to the |
| 558 | * {@link #add(int, Object) add(int, E)} |
| 559 | * method (which is part of the {@link List} interface). Note that the |
| 560 | * {@code add} method reverses the order of the parameters, to more closely |
| 561 | * match array usage. |
| 562 | * |
| 563 | * @param obj the component to insert |
| 564 | * @param index where to insert the new component |
| 565 | * @throws ArrayIndexOutOfBoundsException if the index is out of range |
| 566 | * ({@code index < 0 || index > size()}) |
| 567 | */ |
| 568 | public synchronized void insertElementAt(E obj, int index) { |
| 569 | modCount++; |
| 570 | if (index > elementCount) { |
| 571 | throw new ArrayIndexOutOfBoundsException(index |
| 572 | + " > " + elementCount); |
| 573 | } |
| 574 | ensureCapacityHelper(elementCount + 1); |
| 575 | System.arraycopy(elementData, index, elementData, index + 1, elementCount - index); |
| 576 | elementData[index] = obj; |
| 577 | elementCount++; |
| 578 | } |
| 579 | |
| 580 | /** |
| 581 | * Adds the specified component to the end of this vector, |
| 582 | * increasing its size by one. The capacity of this vector is |
| 583 | * increased if its size becomes greater than its capacity. |
| 584 | * |
| 585 | * <p>This method is identical in functionality to the |
| 586 | * {@link #add(Object) add(E)} |
| 587 | * method (which is part of the {@link List} interface). |
| 588 | * |
| 589 | * @param obj the component to be added |
| 590 | */ |
| 591 | public synchronized void addElement(E obj) { |
| 592 | modCount++; |
| 593 | ensureCapacityHelper(elementCount + 1); |
| 594 | elementData[elementCount++] = obj; |
| 595 | } |
| 596 | |
| 597 | /** |
| 598 | * Removes the first (lowest-indexed) occurrence of the argument |
| 599 | * from this vector. If the object is found in this vector, each |
| 600 | * component in the vector with an index greater or equal to the |
| 601 | * object's index is shifted downward to have an index one smaller |
| 602 | * than the value it had previously. |
| 603 | * |
| 604 | * <p>This method is identical in functionality to the |
| 605 | * {@link #remove(Object)} method (which is part of the |
| 606 | * {@link List} interface). |
| 607 | * |
| 608 | * @param obj the component to be removed |
| 609 | * @return {@code true} if the argument was a component of this |
| 610 | * vector; {@code false} otherwise. |
| 611 | */ |
| 612 | public synchronized boolean removeElement(Object obj) { |
| 613 | modCount++; |
| 614 | int i = indexOf(obj); |
| 615 | if (i >= 0) { |
| 616 | removeElementAt(i); |
| 617 | return true; |
| 618 | } |
| 619 | return false; |
| 620 | } |
| 621 | |
| 622 | /** |
| 623 | * Removes all components from this vector and sets its size to zero. |
| 624 | * |
| 625 | * <p>This method is identical in functionality to the {@link #clear} |
| 626 | * method (which is part of the {@link List} interface). |
| 627 | */ |
| 628 | public synchronized void removeAllElements() { |
| 629 | modCount++; |
| 630 | // Let gc do its work |
| 631 | for (int i = 0; i < elementCount; i++) |
| 632 | elementData[i] = null; |
| 633 | |
| 634 | elementCount = 0; |
| 635 | } |
| 636 | |
| 637 | /** |
| 638 | * Returns a clone of this vector. The copy will contain a |
| 639 | * reference to a clone of the internal data array, not a reference |
| 640 | * to the original internal data array of this {@code Vector} object. |
| 641 | * |
| 642 | * @return a clone of this vector |
| 643 | */ |
| 644 | public synchronized Object clone() { |
| 645 | try { |
| 646 | @SuppressWarnings("unchecked") |
| 647 | Vector<E> v = (Vector<E>) super.clone(); |
| 648 | v.elementData = Arrays.copyOf(elementData, elementCount); |
| 649 | v.modCount = 0; |
| 650 | return v; |
| 651 | } catch (CloneNotSupportedException e) { |
| 652 | // this shouldn't happen, since we are Cloneable |
| 653 | throw new InternalError(); |
| 654 | } |
| 655 | } |
| 656 | |
| 657 | /** |
| 658 | * Returns an array containing all of the elements in this Vector |
| 659 | * in the correct order. |
| 660 | * |
| 661 | * @since 1.2 |
| 662 | */ |
| 663 | public synchronized Object[] toArray() { |
| 664 | return Arrays.copyOf(elementData, elementCount); |
| 665 | } |
| 666 | |
| 667 | /** |
| 668 | * Returns an array containing all of the elements in this Vector in the |
| 669 | * correct order; the runtime type of the returned array is that of the |
| 670 | * specified array. If the Vector fits in the specified array, it is |
| 671 | * returned therein. Otherwise, a new array is allocated with the runtime |
| 672 | * type of the specified array and the size of this Vector. |
| 673 | * |
| 674 | * <p>If the Vector fits in the specified array with room to spare |
| 675 | * (i.e., the array has more elements than the Vector), |
| 676 | * the element in the array immediately following the end of the |
| 677 | * Vector is set to null. (This is useful in determining the length |
| 678 | * of the Vector <em>only</em> if the caller knows that the Vector |
| 679 | * does not contain any null elements.) |
| 680 | * |
| 681 | * @param a the array into which the elements of the Vector are to |
| 682 | * be stored, if it is big enough; otherwise, a new array of the |
| 683 | * same runtime type is allocated for this purpose. |
| 684 | * @return an array containing the elements of the Vector |
| 685 | * @throws ArrayStoreException if the runtime type of a is not a supertype |
| 686 | * of the runtime type of every element in this Vector |
| 687 | * @throws NullPointerException if the given array is null |
| 688 | * @since 1.2 |
| 689 | */ |
| 690 | @SuppressWarnings("unchecked") |
| 691 | public synchronized <T> T[] toArray(T[] a) { |
| 692 | if (a.length < elementCount) |
| 693 | return (T[]) Arrays.copyOf(elementData, elementCount, a.getClass()); |
| 694 | |
| 695 | System.arraycopy(elementData, 0, a, 0, elementCount); |
| 696 | |
| 697 | if (a.length > elementCount) |
| 698 | a[elementCount] = null; |
| 699 | |
| 700 | return a; |
| 701 | } |
| 702 | |
| 703 | // Positional Access Operations |
| 704 | |
| 705 | @SuppressWarnings("unchecked") |
| 706 | E elementData(int index) { |
| 707 | return (E) elementData[index]; |
| 708 | } |
| 709 | |
| 710 | /** |
| 711 | * Returns the element at the specified position in this Vector. |
| 712 | * |
| 713 | * @param index index of the element to return |
| 714 | * @return object at the specified index |
| 715 | * @throws ArrayIndexOutOfBoundsException if the index is out of range |
| 716 | * ({@code index < 0 || index >= size()}) |
| 717 | * @since 1.2 |
| 718 | */ |
| 719 | public synchronized E get(int index) { |
| 720 | if (index >= elementCount) |
| 721 | throw new ArrayIndexOutOfBoundsException(index); |
| 722 | |
| 723 | return elementData(index); |
| 724 | } |
| 725 | |
| 726 | /** |
| 727 | * Replaces the element at the specified position in this Vector with the |
| 728 | * specified element. |
| 729 | * |
| 730 | * @param index index of the element to replace |
| 731 | * @param element element to be stored at the specified position |
| 732 | * @return the element previously at the specified position |
| 733 | * @throws ArrayIndexOutOfBoundsException if the index is out of range |
| 734 | * ({@code index < 0 || index >= size()}) |
| 735 | * @since 1.2 |
| 736 | */ |
| 737 | public synchronized E set(int index, E element) { |
| 738 | if (index >= elementCount) |
| 739 | throw new ArrayIndexOutOfBoundsException(index); |
| 740 | |
| 741 | E oldValue = elementData(index); |
| 742 | elementData[index] = element; |
| 743 | return oldValue; |
| 744 | } |
| 745 | |
| 746 | /** |
| 747 | * Appends the specified element to the end of this Vector. |
| 748 | * |
| 749 | * @param e element to be appended to this Vector |
| 750 | * @return {@code true} (as specified by {@link Collection#add}) |
| 751 | * @since 1.2 |
| 752 | */ |
| 753 | public synchronized boolean add(E e) { |
| 754 | modCount++; |
| 755 | ensureCapacityHelper(elementCount + 1); |
| 756 | elementData[elementCount++] = e; |
| 757 | return true; |
| 758 | } |
| 759 | |
| 760 | /** |
| 761 | * Removes the first occurrence of the specified element in this Vector |
| 762 | * If the Vector does not contain the element, it is unchanged. More |
| 763 | * formally, removes the element with the lowest index i such that |
| 764 | * {@code (o==null ? get(i)==null : o.equals(get(i)))} (if such |
| 765 | * an element exists). |
| 766 | * |
| 767 | * @param o element to be removed from this Vector, if present |
| 768 | * @return true if the Vector contained the specified element |
| 769 | * @since 1.2 |
| 770 | */ |
| 771 | public boolean remove(Object o) { |
| 772 | return removeElement(o); |
| 773 | } |
| 774 | |
| 775 | /** |
| 776 | * Inserts the specified element at the specified position in this Vector. |
| 777 | * Shifts the element currently at that position (if any) and any |
| 778 | * subsequent elements to the right (adds one to their indices). |
| 779 | * |
| 780 | * @param index index at which the specified element is to be inserted |
| 781 | * @param element element to be inserted |
| 782 | * @throws ArrayIndexOutOfBoundsException if the index is out of range |
| 783 | * ({@code index < 0 || index > size()}) |
| 784 | * @since 1.2 |
| 785 | */ |
| 786 | public void add(int index, E element) { |
| 787 | insertElementAt(element, index); |
| 788 | } |
| 789 | |
| 790 | /** |
| 791 | * Removes the element at the specified position in this Vector. |
| 792 | * Shifts any subsequent elements to the left (subtracts one from their |
| 793 | * indices). Returns the element that was removed from the Vector. |
| 794 | * |
| 795 | * @throws ArrayIndexOutOfBoundsException if the index is out of range |
| 796 | * ({@code index < 0 || index >= size()}) |
| 797 | * @param index the index of the element to be removed |
| 798 | * @return element that was removed |
| 799 | * @since 1.2 |
| 800 | */ |
| 801 | public synchronized E remove(int index) { |
| 802 | modCount++; |
| 803 | if (index >= elementCount) |
| 804 | throw new ArrayIndexOutOfBoundsException(index); |
| 805 | E oldValue = elementData(index); |
| 806 | |
| 807 | int numMoved = elementCount - index - 1; |
| 808 | if (numMoved > 0) |
| 809 | System.arraycopy(elementData, index+1, elementData, index, |
| 810 | numMoved); |
| 811 | elementData[--elementCount] = null; // Let gc do its work |
| 812 | |
| 813 | return oldValue; |
| 814 | } |
| 815 | |
| 816 | /** |
| 817 | * Removes all of the elements from this Vector. The Vector will |
| 818 | * be empty after this call returns (unless it throws an exception). |
| 819 | * |
| 820 | * @since 1.2 |
| 821 | */ |
| 822 | public void clear() { |
| 823 | removeAllElements(); |
| 824 | } |
| 825 | |
| 826 | // Bulk Operations |
| 827 | |
| 828 | /** |
| 829 | * Returns true if this Vector contains all of the elements in the |
| 830 | * specified Collection. |
| 831 | * |
| 832 | * @param c a collection whose elements will be tested for containment |
| 833 | * in this Vector |
| 834 | * @return true if this Vector contains all of the elements in the |
| 835 | * specified collection |
| 836 | * @throws NullPointerException if the specified collection is null |
| 837 | */ |
| 838 | public synchronized boolean containsAll(Collection<?> c) { |
| 839 | return super.containsAll(c); |
| 840 | } |
| 841 | |
| 842 | /** |
| 843 | * Appends all of the elements in the specified Collection to the end of |
| 844 | * this Vector, in the order that they are returned by the specified |
| 845 | * Collection's Iterator. The behavior of this operation is undefined if |
| 846 | * the specified Collection is modified while the operation is in progress. |
| 847 | * (This implies that the behavior of this call is undefined if the |
| 848 | * specified Collection is this Vector, and this Vector is nonempty.) |
| 849 | * |
| 850 | * @param c elements to be inserted into this Vector |
| 851 | * @return {@code true} if this Vector changed as a result of the call |
| 852 | * @throws NullPointerException if the specified collection is null |
| 853 | * @since 1.2 |
| 854 | */ |
| 855 | public synchronized boolean addAll(Collection<? extends E> c) { |
| 856 | modCount++; |
| 857 | Object[] a = c.toArray(); |
| 858 | int numNew = a.length; |
| 859 | ensureCapacityHelper(elementCount + numNew); |
| 860 | System.arraycopy(a, 0, elementData, elementCount, numNew); |
| 861 | elementCount += numNew; |
| 862 | return numNew != 0; |
| 863 | } |
| 864 | |
| 865 | /** |
| 866 | * Removes from this Vector all of its elements that are contained in the |
| 867 | * specified Collection. |
| 868 | * |
| 869 | * @param c a collection of elements to be removed from the Vector |
| 870 | * @return true if this Vector changed as a result of the call |
| 871 | * @throws ClassCastException if the types of one or more elements |
| 872 | * in this vector are incompatible with the specified |
| 873 | * collection (optional) |
| 874 | * @throws NullPointerException if this vector contains one or more null |
| 875 | * elements and the specified collection does not support null |
| 876 | * elements (optional), or if the specified collection is null |
| 877 | * @since 1.2 |
| 878 | */ |
| 879 | public synchronized boolean removeAll(Collection<?> c) { |
| 880 | return super.removeAll(c); |
| 881 | } |
| 882 | |
| 883 | /** |
| 884 | * Retains only the elements in this Vector that are contained in the |
| 885 | * specified Collection. In other words, removes from this Vector all |
| 886 | * of its elements that are not contained in the specified Collection. |
| 887 | * |
| 888 | * @param c a collection of elements to be retained in this Vector |
| 889 | * (all other elements are removed) |
| 890 | * @return true if this Vector changed as a result of the call |
| 891 | * @throws ClassCastException if the types of one or more elements |
| 892 | * in this vector are incompatible with the specified |
| 893 | * collection (optional) |
| 894 | * @throws NullPointerException if this vector contains one or more null |
| 895 | * elements and the specified collection does not support null |
| 896 | * elements (optional), or if the specified collection is null |
| 897 | * @since 1.2 |
| 898 | */ |
| 899 | public synchronized boolean retainAll(Collection<?> c) { |
| 900 | return super.retainAll(c); |
| 901 | } |
| 902 | |
| 903 | /** |
| 904 | * Inserts all of the elements in the specified Collection into this |
| 905 | * Vector at the specified position. Shifts the element currently at |
| 906 | * that position (if any) and any subsequent elements to the right |
| 907 | * (increases their indices). The new elements will appear in the Vector |
| 908 | * in the order that they are returned by the specified Collection's |
| 909 | * iterator. |
| 910 | * |
| 911 | * @param index index at which to insert the first element from the |
| 912 | * specified collection |
| 913 | * @param c elements to be inserted into this Vector |
| 914 | * @return {@code true} if this Vector changed as a result of the call |
| 915 | * @throws ArrayIndexOutOfBoundsException if the index is out of range |
| 916 | * ({@code index < 0 || index > size()}) |
| 917 | * @throws NullPointerException if the specified collection is null |
| 918 | * @since 1.2 |
| 919 | */ |
| 920 | public synchronized boolean addAll(int index, Collection<? extends E> c) { |
| 921 | modCount++; |
| 922 | if (index < 0 || index > elementCount) |
| 923 | throw new ArrayIndexOutOfBoundsException(index); |
| 924 | |
| 925 | Object[] a = c.toArray(); |
| 926 | int numNew = a.length; |
| 927 | ensureCapacityHelper(elementCount + numNew); |
| 928 | |
| 929 | int numMoved = elementCount - index; |
| 930 | if (numMoved > 0) |
| 931 | System.arraycopy(elementData, index, elementData, index + numNew, |
| 932 | numMoved); |
| 933 | |
| 934 | System.arraycopy(a, 0, elementData, index, numNew); |
| 935 | elementCount += numNew; |
| 936 | return numNew != 0; |
| 937 | } |
| 938 | |
| 939 | /** |
| 940 | * Compares the specified Object with this Vector for equality. Returns |
| 941 | * true if and only if the specified Object is also a List, both Lists |
| 942 | * have the same size, and all corresponding pairs of elements in the two |
| 943 | * Lists are <em>equal</em>. (Two elements {@code e1} and |
| 944 | * {@code e2} are <em>equal</em> if {@code (e1==null ? e2==null : |
| 945 | * e1.equals(e2))}.) In other words, two Lists are defined to be |
| 946 | * equal if they contain the same elements in the same order. |
| 947 | * |
| 948 | * @param o the Object to be compared for equality with this Vector |
| 949 | * @return true if the specified Object is equal to this Vector |
| 950 | */ |
| 951 | public synchronized boolean equals(Object o) { |
| 952 | return super.equals(o); |
| 953 | } |
| 954 | |
| 955 | /** |
| 956 | * Returns the hash code value for this Vector. |
| 957 | */ |
| 958 | public synchronized int hashCode() { |
| 959 | return super.hashCode(); |
| 960 | } |
| 961 | |
| 962 | /** |
| 963 | * Returns a string representation of this Vector, containing |
| 964 | * the String representation of each element. |
| 965 | */ |
| 966 | public synchronized String toString() { |
| 967 | return super.toString(); |
| 968 | } |
| 969 | |
| 970 | /** |
| 971 | * Returns a view of the portion of this List between fromIndex, |
| 972 | * inclusive, and toIndex, exclusive. (If fromIndex and toIndex are |
| 973 | * equal, the returned List is empty.) The returned List is backed by this |
| 974 | * List, so changes in the returned List are reflected in this List, and |
| 975 | * vice-versa. The returned List supports all of the optional List |
| 976 | * operations supported by this List. |
| 977 | * |
| 978 | * <p>This method eliminates the need for explicit range operations (of |
| 979 | * the sort that commonly exist for arrays). Any operation that expects |
| 980 | * a List can be used as a range operation by operating on a subList view |
| 981 | * instead of a whole List. For example, the following idiom |
| 982 | * removes a range of elements from a List: |
| 983 | * <pre> |
| 984 | * list.subList(from, to).clear(); |
| 985 | * </pre> |
| 986 | * Similar idioms may be constructed for indexOf and lastIndexOf, |
| 987 | * and all of the algorithms in the Collections class can be applied to |
| 988 | * a subList. |
| 989 | * |
| 990 | * <p>The semantics of the List returned by this method become undefined if |
| 991 | * the backing list (i.e., this List) is <i>structurally modified</i> in |
| 992 | * any way other than via the returned List. (Structural modifications are |
| 993 | * those that change the size of the List, or otherwise perturb it in such |
| 994 | * a fashion that iterations in progress may yield incorrect results.) |
| 995 | * |
| 996 | * @param fromIndex low endpoint (inclusive) of the subList |
| 997 | * @param toIndex high endpoint (exclusive) of the subList |
| 998 | * @return a view of the specified range within this List |
| 999 | * @throws IndexOutOfBoundsException if an endpoint index value is out of range |
| 1000 | * {@code (fromIndex < 0 || toIndex > size)} |
| 1001 | * @throws IllegalArgumentException if the endpoint indices are out of order |
| 1002 | * {@code (fromIndex > toIndex)} |
| 1003 | */ |
| 1004 | public synchronized List<E> subList(int fromIndex, int toIndex) { |
| 1005 | return Collections.synchronizedList(super.subList(fromIndex, toIndex), |
| 1006 | this); |
| 1007 | } |
| 1008 | |
| 1009 | /** |
| 1010 | * Removes from this list all of the elements whose index is between |
| 1011 | * {@code fromIndex}, inclusive, and {@code toIndex}, exclusive. |
| 1012 | * Shifts any succeeding elements to the left (reduces their index). |
| 1013 | * This call shortens the list by {@code (toIndex - fromIndex)} elements. |
| 1014 | * (If {@code toIndex==fromIndex}, this operation has no effect.) |
| 1015 | */ |
| 1016 | protected synchronized void removeRange(int fromIndex, int toIndex) { |
| 1017 | modCount++; |
| 1018 | int numMoved = elementCount - toIndex; |
| 1019 | System.arraycopy(elementData, toIndex, elementData, fromIndex, |
| 1020 | numMoved); |
| 1021 | |
| 1022 | // Let gc do its work |
| 1023 | int newElementCount = elementCount - (toIndex-fromIndex); |
| 1024 | while (elementCount != newElementCount) |
| 1025 | elementData[--elementCount] = null; |
| 1026 | } |
| 1027 | |
| 1028 | /** |
| 1029 | * Save the state of the {@code Vector} instance to a stream (that |
| 1030 | * is, serialize it). This method is present merely for synchronization. |
| 1031 | * It just calls the default writeObject method. |
| 1032 | */ |
| 1033 | private synchronized void writeObject(java.io.ObjectOutputStream s) |
| 1034 | throws java.io.IOException |
| 1035 | { |
| 1036 | s.defaultWriteObject(); |
| 1037 | } |
| 1038 | |
| 1039 | /** |
| 1040 | * Returns a list iterator over the elements in this list (in proper |
| 1041 | * sequence), starting at the specified position in the list. |
| 1042 | * The specified index indicates the first element that would be |
| 1043 | * returned by an initial call to {@link ListIterator#next next}. |
| 1044 | * An initial call to {@link ListIterator#previous previous} would |
| 1045 | * return the element with the specified index minus one. |
| 1046 | * |
| 1047 | * <p>The returned list iterator is <a href="#fail-fast"><i>fail-fast</i></a>. |
| 1048 | * |
| 1049 | * @throws IndexOutOfBoundsException {@inheritDoc} |
| 1050 | */ |
| 1051 | public synchronized ListIterator<E> listIterator(int index) { |
| 1052 | if (index < 0 || index > elementCount) |
| 1053 | throw new IndexOutOfBoundsException("Index: "+index); |
| 1054 | return new ListItr(index); |
| 1055 | } |
| 1056 | |
| 1057 | /** |
| 1058 | * Returns a list iterator over the elements in this list (in proper |
| 1059 | * sequence). |
| 1060 | * |
| 1061 | * <p>The returned list iterator is <a href="#fail-fast"><i>fail-fast</i></a>. |
| 1062 | * |
| 1063 | * @see #listIterator(int) |
| 1064 | */ |
| 1065 | public synchronized ListIterator<E> listIterator() { |
| 1066 | return new ListItr(0); |
| 1067 | } |
| 1068 | |
| 1069 | /** |
| 1070 | * Returns an iterator over the elements in this list in proper sequence. |
| 1071 | * |
| 1072 | * <p>The returned iterator is <a href="#fail-fast"><i>fail-fast</i></a>. |
| 1073 | * |
| 1074 | * @return an iterator over the elements in this list in proper sequence |
| 1075 | */ |
| 1076 | public synchronized Iterator<E> iterator() { |
| 1077 | return new Itr(); |
| 1078 | } |
| 1079 | |
| 1080 | /** |
| 1081 | * An optimized version of AbstractList.Itr |
| 1082 | */ |
| 1083 | private class Itr implements Iterator<E> { |
| 1084 | int cursor; // index of next element to return |
| 1085 | int lastRet = -1; // index of last element returned; -1 if no such |
| 1086 | int expectedModCount = modCount; |
| 1087 | |
| 1088 | public boolean hasNext() { |
| 1089 | // Racy but within spec, since modifications are checked |
| 1090 | // within or after synchronization in next/previous |
| 1091 | return cursor != elementCount; |
| 1092 | } |
| 1093 | |
| 1094 | public E next() { |
| 1095 | synchronized (Vector.this) { |
| 1096 | checkForComodification(); |
| 1097 | int i = cursor; |
| 1098 | if (i >= elementCount) |
| 1099 | throw new NoSuchElementException(); |
| 1100 | cursor = i + 1; |
| 1101 | return elementData(lastRet = i); |
| 1102 | } |
| 1103 | } |
| 1104 | |
| 1105 | public void remove() { |
| 1106 | if (lastRet == -1) |
| 1107 | throw new IllegalStateException(); |
| 1108 | synchronized (Vector.this) { |
| 1109 | checkForComodification(); |
| 1110 | Vector.this.remove(lastRet); |
| 1111 | expectedModCount = modCount; |
| 1112 | } |
| 1113 | cursor = lastRet; |
| 1114 | lastRet = -1; |
| 1115 | } |
| 1116 | |
| 1117 | final void checkForComodification() { |
| 1118 | if (modCount != expectedModCount) |
| 1119 | throw new ConcurrentModificationException(); |
| 1120 | } |
| 1121 | } |
| 1122 | |
| 1123 | /** |
| 1124 | * An optimized version of AbstractList.ListItr |
| 1125 | */ |
| 1126 | final class ListItr extends Itr implements ListIterator<E> { |
| 1127 | ListItr(int index) { |
| 1128 | super(); |
| 1129 | cursor = index; |
| 1130 | } |
| 1131 | |
| 1132 | public boolean hasPrevious() { |
| 1133 | return cursor != 0; |
| 1134 | } |
| 1135 | |
| 1136 | public int nextIndex() { |
| 1137 | return cursor; |
| 1138 | } |
| 1139 | |
| 1140 | public int previousIndex() { |
| 1141 | return cursor - 1; |
| 1142 | } |
| 1143 | |
| 1144 | public E previous() { |
| 1145 | synchronized (Vector.this) { |
| 1146 | checkForComodification(); |
| 1147 | int i = cursor - 1; |
| 1148 | if (i < 0) |
| 1149 | throw new NoSuchElementException(); |
| 1150 | cursor = i; |
| 1151 | return elementData(lastRet = i); |
| 1152 | } |
| 1153 | } |
| 1154 | |
| 1155 | public void set(E e) { |
| 1156 | if (lastRet == -1) |
| 1157 | throw new IllegalStateException(); |
| 1158 | synchronized (Vector.this) { |
| 1159 | checkForComodification(); |
| 1160 | Vector.this.set(lastRet, e); |
| 1161 | } |
| 1162 | } |
| 1163 | |
| 1164 | public void add(E e) { |
| 1165 | int i = cursor; |
| 1166 | synchronized (Vector.this) { |
| 1167 | checkForComodification(); |
| 1168 | Vector.this.add(i, e); |
| 1169 | expectedModCount = modCount; |
| 1170 | } |
| 1171 | cursor = i + 1; |
| 1172 | lastRet = -1; |
| 1173 | } |
| 1174 | } |
| 1175 | } |