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| 1 | /* | ||
| 2 | * Copyright (c) 2007, 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 sun.awt.util; | ||
| 27 | |||
| 28 | import java.util.AbstractList; | ||
| 29 | import java.util.Arrays; | ||
| 30 | import java.util.Collection; | ||
| 31 | import java.util.ConcurrentModificationException; | ||
| 32 | import java.util.List; | ||
| 33 | import java.util.RandomAccess; | ||
| 34 | |||
| 35 | /** | ||
| 36 | * Resizable-array implementation of the <tt>List</tt> interface. Implements | ||
| 37 | * all optional list operations, and permits all elements, including | ||
| 38 | * <tt>null</tt>. In addition to implementing the <tt>List</tt> interface, | ||
| 39 | * this class provides methods to manipulate the size of the array that is | ||
| 40 | * used internally to store the list. (This class is roughly equivalent to | ||
| 41 | * <tt>Vector</tt>, except that it is unsynchronized.)<p> | ||
| 42 | * | ||
| 43 | * The <tt>size</tt>, <tt>isEmpty</tt>, <tt>get</tt>, <tt>set</tt>, | ||
| 44 | * <tt>iterator</tt>, and <tt>listIterator</tt> operations run in constant | ||
| 45 | * time. The <tt>add</tt> operation runs in <i>amortized constant time</i>, | ||
| 46 | * that is, adding n elements requires O(n) time. All of the other operations | ||
| 47 | * run in linear time (roughly speaking). The constant factor is low compared | ||
| 48 | * to that for the <tt>LinkedList</tt> implementation.<p> | ||
| 49 | * | ||
| 50 | * Each <tt>IdentityArrayList</tt> instance has a <i>capacity</i>. The capacity is | ||
| 51 | * the size of the array used to store the elements in the list. It is always | ||
| 52 | * at least as large as the list size. As elements are added to an IdentityArrayList, | ||
| 53 | * its capacity grows automatically. The details of the growth policy are not | ||
| 54 | * specified beyond the fact that adding an element has constant amortized | ||
| 55 | * time cost.<p> | ||
| 56 | * | ||
| 57 | * An application can increase the capacity of an <tt>IdentityArrayList</tt> instance | ||
| 58 | * before adding a large number of elements using the <tt>ensureCapacity</tt> | ||
| 59 | * operation. This may reduce the amount of incremental reallocation. | ||
| 60 | * | ||
| 61 | * <p><strong>Note that this implementation is not synchronized.</strong> | ||
| 62 | * If multiple threads access an <tt>IdentityArrayList</tt> instance concurrently, | ||
| 63 | * and at least one of the threads modifies the list structurally, it | ||
| 64 | * <i>must</i> be synchronized externally. (A structural modification is | ||
| 65 | * any operation that adds or deletes one or more elements, or explicitly | ||
| 66 | * resizes the backing array; merely setting the value of an element is not | ||
| 67 | * a structural modification.) This is typically accomplished by | ||
| 68 | * synchronizing on some object that naturally encapsulates the list. | ||
| 69 | * | ||
| 70 | * If no such object exists, the list should be "wrapped" using the | ||
| 71 | * {@link Collections#synchronizedList Collections.synchronizedList} | ||
| 72 | * method. This is best done at creation time, to prevent accidental | ||
| 73 | * unsynchronized access to the list:<pre> | ||
| 74 | * List list = Collections.synchronizedList(new IdentityArrayList(...));</pre> | ||
| 75 | * | ||
| 76 | * <p>The iterators returned by this class's <tt>iterator</tt> and | ||
| 77 | * <tt>listIterator</tt> methods are <i>fail-fast</i>: if the list is | ||
| 78 | * structurally modified at any time after the iterator is created, in any way | ||
| 79 | * except through the iterator's own <tt>remove</tt> or <tt>add</tt> methods, | ||
| 80 | * the iterator will throw a {@link ConcurrentModificationException}. Thus, in | ||
| 81 | * the face of concurrent modification, the iterator fails quickly and cleanly, | ||
| 82 | * rather than risking arbitrary, non-deterministic behavior at an undetermined | ||
| 83 | * time in the future.<p> | ||
| 84 | * | ||
| 85 | * Note that the fail-fast behavior of an iterator cannot be guaranteed | ||
| 86 | * as it is, generally speaking, impossible to make any hard guarantees in the | ||
| 87 | * presence of unsynchronized concurrent modification. Fail-fast iterators | ||
| 88 | * throw <tt>ConcurrentModificationException</tt> on a best-effort basis. | ||
| 89 | * Therefore, it would be wrong to write a program that depended on this | ||
| 90 | * exception for its correctness: <i>the fail-fast behavior of iterators | ||
| 91 | * should be used only to detect bugs.</i><p> | ||
| 92 | * | ||
| 93 | */ | ||
| 94 | |||
| 95 | public class IdentityArrayList<E> extends AbstractList<E> | ||
| 96 | implements List<E>, RandomAccess | ||
| 97 | { | ||
| 98 | |||
| 99 | /** | ||
| 100 | * The array buffer into which the elements of the IdentityArrayList are stored. | ||
| 101 | * The capacity of the IdentityArrayList is the length of this array buffer. | ||
| 102 | */ | ||
| 103 | private transient Object[] elementData; | ||
| 104 | |||
| 105 | /** | ||
| 106 | * The size of the IdentityArrayList (the number of elements it contains). | ||
| 107 | * | ||
| 108 | * @serial | ||
| 109 | */ | ||
| 110 | private int size; | ||
| 111 | |||
| 112 | /** | ||
| 113 | * Constructs an empty list with the specified initial capacity. | ||
| 114 | * | ||
| 115 | * @param initialCapacity the initial capacity of the list | ||
| 116 | * @exception IllegalArgumentException if the specified initial capacity | ||
| 117 | * is negative | ||
| 118 | */ | ||
| 119 | public IdentityArrayList(int initialCapacity) { | ||
| 120 | super(); | ||
| 121 | if (initialCapacity < 0) | ||
| 122 | throw new IllegalArgumentException("Illegal Capacity: "+ | ||
| 123 | initialCapacity); | ||
| 124 | this.elementData = new Object[initialCapacity]; | ||
| 125 | } | ||
| 126 | |||
| 127 | /** | ||
| 128 | * Constructs an empty list with an initial capacity of ten. | ||
| 129 | */ | ||
| 130 | public IdentityArrayList() { | ||
| 131 | this(10); | ||
| 132 | } | ||
| 133 | |||
| 134 | /** | ||
| 135 | * Constructs a list containing the elements of the specified | ||
| 136 | * collection, in the order they are returned by the collection's | ||
| 137 | * iterator. | ||
| 138 | * | ||
| 139 | * @param c the collection whose elements are to be placed into this list | ||
| 140 | * @throws NullPointerException if the specified collection is null | ||
| 141 | */ | ||
| 142 | public IdentityArrayList(Collection<? extends E> c) { | ||
| 143 | elementData = c.toArray(); | ||
| 144 | size = elementData.length; | ||
| 145 | // c.toArray might (incorrectly) not return Object[] (see 6260652) | ||
| 146 | if (elementData.getClass() != Object[].class) | ||
| 147 | elementData = Arrays.copyOf(elementData, size, Object[].class); | ||
| 148 | } | ||
| 149 | |||
| 150 | /** | ||
| 151 | * Trims the capacity of this <tt>IdentityArrayList</tt> instance to be the | ||
| 152 | * list's current size. An application can use this operation to minimize | ||
| 153 | * the storage of an <tt>IdentityArrayList</tt> instance. | ||
| 154 | */ | ||
| 155 | public void trimToSize() { | ||
| 156 | modCount++; | ||
| 157 | int oldCapacity = elementData.length; | ||
| 158 | if (size < oldCapacity) { | ||
| 159 | elementData = Arrays.copyOf(elementData, size); | ||
| 160 | } | ||
| 161 | } | ||
| 162 | |||
| 163 | /** | ||
| 164 | * Increases the capacity of this <tt>IdentityArrayList</tt> instance, if | ||
| 165 | * necessary, to ensure that it can hold at least the number of elements | ||
| 166 | * specified by the minimum capacity argument. | ||
| 167 | * | ||
| 168 | * @param minCapacity the desired minimum capacity | ||
| 169 | */ | ||
| 170 | public void ensureCapacity(int minCapacity) { | ||
| 171 | modCount++; | ||
| 172 | int oldCapacity = elementData.length; | ||
| 173 | if (minCapacity > oldCapacity) { | ||
| 174 | Object oldData[] = elementData; | ||
| 175 | int newCapacity = (oldCapacity * 3)/2 + 1; | ||
| 176 | if (newCapacity < minCapacity) | ||
| 177 | newCapacity = minCapacity; | ||
| 178 | // minCapacity is usually close to size, so this is a win: | ||
| 179 | elementData = Arrays.copyOf(elementData, newCapacity); | ||
| 180 | } | ||
| 181 | } | ||
| 182 | |||
| 183 | /** | ||
| 184 | * Returns the number of elements in this list. | ||
| 185 | * | ||
| 186 | * @return the number of elements in this list | ||
| 187 | */ | ||
| 188 | public int size() { | ||
| 189 | return size; | ||
| 190 | } | ||
| 191 | |||
| 192 | /** | ||
| 193 | * Returns <tt>true</tt> if this list contains no elements. | ||
| 194 | * | ||
| 195 | * @return <tt>true</tt> if this list contains no elements | ||
| 196 | */ | ||
| 197 | public boolean isEmpty() { | ||
| 198 | return size == 0; | ||
| 199 | } | ||
| 200 | |||
| 201 | /** | ||
| 202 | * Returns <tt>true</tt> if this list contains the specified element. | ||
| 203 | * More formally, returns <tt>true</tt> if and only if this list contains | ||
| 204 | * at least one element <tt>e</tt> such that | ||
| 205 | * <tt>(o==null ? e==null : o == e)</tt>. | ||
| 206 | * | ||
| 207 | * @param o element whose presence in this list is to be tested | ||
| 208 | * @return <tt>true</tt> if this list contains the specified element | ||
| 209 | */ | ||
| 210 | public boolean contains(Object o) { | ||
| 211 | return indexOf(o) >= 0; | ||
| 212 | } | ||
| 213 | |||
| 214 | /** | ||
| 215 | * Returns the index of the first occurrence of the specified element | ||
| 216 | * in this list, or -1 if this list does not contain the element. | ||
| 217 | * More formally, returns the lowest index <tt>i</tt> such that | ||
| 218 | * <tt>(o==null ? get(i)==null : o == get(i))</tt>, | ||
| 219 | * or -1 if there is no such index. | ||
| 220 | */ | ||
| 221 | public int indexOf(Object o) { | ||
| 222 | for (int i = 0; i < size; i++) { | ||
| 223 | if (o == elementData[i]) { | ||
| 224 | return i; | ||
| 225 | } | ||
| 226 | } | ||
| 227 | return -1; | ||
| 228 | } | ||
| 229 | |||
| 230 | /** | ||
| 231 | * Returns the index of the last occurrence of the specified element | ||
| 232 | * in this list, or -1 if this list does not contain the element. | ||
| 233 | * More formally, returns the highest index <tt>i</tt> such that | ||
| 234 | * <tt>(o==null ? get(i)==null : o == get(i))</tt>, | ||
| 235 | * or -1 if there is no such index. | ||
| 236 | */ | ||
| 237 | public int lastIndexOf(Object o) { | ||
| 238 | for (int i = size-1; i >= 0; i--) { | ||
| 239 | if (o == elementData[i]) { | ||
| 240 | return i; | ||
| 241 | } | ||
| 242 | } | ||
| 243 | return -1; | ||
| 244 | } | ||
| 245 | |||
| 246 | /** | ||
| 247 | * Returns an array containing all of the elements in this list | ||
| 248 | * in proper sequence (from first to last element). | ||
| 249 | * | ||
| 250 | * <p>The returned array will be "safe" in that no references to it are | ||
| 251 | * maintained by this list. (In other words, this method must allocate | ||
| 252 | * a new array). The caller is thus free to modify the returned array. | ||
| 253 | * | ||
| 254 | * <p>This method acts as bridge between array-based and collection-based | ||
| 255 | * APIs. | ||
| 256 | * | ||
| 257 | * @return an array containing all of the elements in this list in | ||
| 258 | * proper sequence | ||
| 259 | */ | ||
| 260 | public Object[] toArray() { | ||
| 261 | return Arrays.copyOf(elementData, size); | ||
| 262 | } | ||
| 263 | |||
| 264 | /** | ||
| 265 | * Returns an array containing all of the elements in this list in proper | ||
| 266 | * sequence (from first to last element); the runtime type of the returned | ||
| 267 | * array is that of the specified array. If the list fits in the | ||
| 268 | * specified array, it is returned therein. Otherwise, a new array is | ||
| 269 | * allocated with the runtime type of the specified array and the size of | ||
| 270 | * this list. | ||
| 271 | * | ||
| 272 | * <p>If the list fits in the specified array with room to spare | ||
| 273 | * (i.e., the array has more elements than the list), the element in | ||
| 274 | * the array immediately following the end of the collection is set to | ||
| 275 | * <tt>null</tt>. (This is useful in determining the length of the | ||
| 276 | * list <i>only</i> if the caller knows that the list does not contain | ||
| 277 | * any null elements.) | ||
| 278 | * | ||
| 279 | * @param a the array into which the elements of the list are to | ||
| 280 | * be stored, if it is big enough; otherwise, a new array of the | ||
| 281 | * same runtime type is allocated for this purpose. | ||
| 282 | * @return an array containing the elements of the list | ||
| 283 | * @throws ArrayStoreException if the runtime type of the specified array | ||
| 284 | * is not a supertype of the runtime type of every element in | ||
| 285 | * this list | ||
| 286 | * @throws NullPointerException if the specified array is null | ||
| 287 | */ | ||
| 288 | public <T> T[] toArray(T[] a) { | ||
| 289 | if (a.length < size) | ||
| 290 | // Make a new array of a's runtime type, but my contents: | ||
| 291 | return (T[]) Arrays.copyOf(elementData, size, a.getClass()); | ||
| 292 | System.arraycopy(elementData, 0, a, 0, size); | ||
| 293 | if (a.length > size) | ||
| 294 | a[size] = null; | ||
| 295 | return a; | ||
| 296 | } | ||
| 297 | |||
| 298 | // Positional Access Operations | ||
| 299 | |||
| 300 | /** | ||
| 301 | * Returns the element at the specified position in this list. | ||
| 302 | * | ||
| 303 | * @param index index of the element to return | ||
| 304 | * @return the element at the specified position in this list | ||
| 305 | * @throws IndexOutOfBoundsException {@inheritDoc} | ||
| 306 | */ | ||
| 307 | public E get(int index) { | ||
| 308 | rangeCheck(index); | ||
| 309 | |||
| 310 | return (E) elementData[index]; | ||
| 311 | } | ||
| 312 | |||
| 313 | /** | ||
| 314 | * Replaces the element at the specified position in this list with | ||
| 315 | * the specified element. | ||
| 316 | * | ||
| 317 | * @param index index of the element to replace | ||
| 318 | * @param element element to be stored at the specified position | ||
| 319 | * @return the element previously at the specified position | ||
| 320 | * @throws IndexOutOfBoundsException {@inheritDoc} | ||
| 321 | */ | ||
| 322 | public E set(int index, E element) { | ||
| 323 | rangeCheck(index); | ||
| 324 | |||
| 325 | E oldValue = (E) elementData[index]; | ||
| 326 | elementData[index] = element; | ||
| 327 | return oldValue; | ||
| 328 | } | ||
| 329 | |||
| 330 | /** | ||
| 331 | * Appends the specified element to the end of this list. | ||
| 332 | * | ||
| 333 | * @param e element to be appended to this list | ||
| 334 | * @return <tt>true</tt> (as specified by {@link Collection#add}) | ||
| 335 | */ | ||
| 336 | public boolean add(E e) { | ||
| 337 | ensureCapacity(size + 1); // Increments modCount!! | ||
| 338 | elementData[size++] = e; | ||
| 339 | return true; | ||
| 340 | } | ||
| 341 | |||
| 342 | /** | ||
| 343 | * Inserts the specified element at the specified position in this | ||
| 344 | * list. Shifts the element currently at that position (if any) and | ||
| 345 | * any subsequent elements to the right (adds one to their indices). | ||
| 346 | * | ||
| 347 | * @param index index at which the specified element is to be inserted | ||
| 348 | * @param element element to be inserted | ||
| 349 | * @throws IndexOutOfBoundsException {@inheritDoc} | ||
| 350 | */ | ||
| 351 | public void add(int index, E element) { | ||
| 352 | rangeCheckForAdd(index); | ||
| 353 | |||
| 354 | ensureCapacity(size+1); // Increments modCount!! | ||
| 355 | System.arraycopy(elementData, index, elementData, index + 1, | ||
| 356 | size - index); | ||
| 357 | elementData[index] = element; | ||
| 358 | size++; | ||
| 359 | } | ||
| 360 | |||
| 361 | /** | ||
| 362 | * Removes the element at the specified position in this list. | ||
| 363 | * Shifts any subsequent elements to the left (subtracts one from their | ||
| 364 | * indices). | ||
| 365 | * | ||
| 366 | * @param index the index of the element to be removed | ||
| 367 | * @return the element that was removed from the list | ||
| 368 | * @throws IndexOutOfBoundsException {@inheritDoc} | ||
| 369 | */ | ||
| 370 | public E remove(int index) { | ||
| 371 | rangeCheck(index); | ||
| 372 | |||
| 373 | modCount++; | ||
| 374 | E oldValue = (E) elementData[index]; | ||
| 375 | |||
| 376 | int numMoved = size - index - 1; | ||
| 377 | if (numMoved > 0) | ||
| 378 | System.arraycopy(elementData, index+1, elementData, index, | ||
| 379 | numMoved); | ||
| 380 | elementData[--size] = null; // Let gc do its work | ||
| 381 | |||
| 382 | return oldValue; | ||
| 383 | } | ||
| 384 | |||
| 385 | /** | ||
| 386 | * Removes the first occurrence of the specified element from this list, | ||
| 387 | * if it is present. If the list does not contain the element, it is | ||
| 388 | * unchanged. More formally, removes the element with the lowest index | ||
| 389 | * <tt>i</tt> such that | ||
| 390 | * <tt>(o==null ? get(i)==null : o == get(i))</tt> | ||
| 391 | * (if such an element exists). Returns <tt>true</tt> if this list | ||
| 392 | * contained the specified element (or equivalently, if this list | ||
| 393 | * changed as a result of the call). | ||
| 394 | * | ||
| 395 | * @param o element to be removed from this list, if present | ||
| 396 | * @return <tt>true</tt> if this list contained the specified element | ||
| 397 | */ | ||
| 398 | public boolean remove(Object o) { | ||
| 399 | for (int index = 0; index < size; index++) { | ||
| 400 | if (o == elementData[index]) { | ||
| 401 | fastRemove(index); | ||
| 402 | return true; | ||
| 403 | } | ||
| 404 | } | ||
| 405 | return false; | ||
| 406 | } | ||
| 407 | |||
| 408 | /* | ||
| 409 | * Private remove method that skips bounds checking and does not | ||
| 410 | * return the value removed. | ||
| 411 | */ | ||
| 412 | private void fastRemove(int index) { | ||
| 413 | modCount++; | ||
| 414 | int numMoved = size - index - 1; | ||
| 415 | if (numMoved > 0) | ||
| 416 | System.arraycopy(elementData, index+1, elementData, index, | ||
| 417 | numMoved); | ||
| 418 | elementData[--size] = null; // Let gc do its work | ||
| 419 | } | ||
| 420 | |||
| 421 | /** | ||
| 422 | * Removes all of the elements from this list. The list will | ||
| 423 | * be empty after this call returns. | ||
| 424 | */ | ||
| 425 | public void clear() { | ||
| 426 | modCount++; | ||
| 427 | |||
| 428 | // Let gc do its work | ||
| 429 | for (int i = 0; i < size; i++) | ||
| 430 | elementData[i] = null; | ||
| 431 | |||
| 432 | size = 0; | ||
| 433 | } | ||
| 434 | |||
| 435 | /** | ||
| 436 | * Appends all of the elements in the specified collection to the end of | ||
| 437 | * this list, in the order that they are returned by the | ||
| 438 | * specified collection's Iterator. The behavior of this operation is | ||
| 439 | * undefined if the specified collection is modified while the operation | ||
| 440 | * is in progress. (This implies that the behavior of this call is | ||
| 441 | * undefined if the specified collection is this list, and this | ||
| 442 | * list is nonempty.) | ||
| 443 | * | ||
| 444 | * @param c collection containing elements to be added to this list | ||
| 445 | * @return <tt>true</tt> if this list changed as a result of the call | ||
| 446 | * @throws NullPointerException if the specified collection is null | ||
| 447 | */ | ||
| 448 | public boolean addAll(Collection<? extends E> c) { | ||
| 449 | Object[] a = c.toArray(); | ||
| 450 | int numNew = a.length; | ||
| 451 | ensureCapacity(size + numNew); // Increments modCount | ||
| 452 | System.arraycopy(a, 0, elementData, size, numNew); | ||
| 453 | size += numNew; | ||
| 454 | return numNew != 0; | ||
| 455 | } | ||
| 456 | |||
| 457 | /** | ||
| 458 | * Inserts all of the elements in the specified collection into this | ||
| 459 | * list, starting at the specified position. Shifts the element | ||
| 460 | * currently at that position (if any) and any subsequent elements to | ||
| 461 | * the right (increases their indices). The new elements will appear | ||
| 462 | * in the list in the order that they are returned by the | ||
| 463 | * specified collection's iterator. | ||
| 464 | * | ||
| 465 | * @param index index at which to insert the first element from the | ||
| 466 | * specified collection | ||
| 467 | * @param c collection containing elements to be added to this list | ||
| 468 | * @return <tt>true</tt> if this list changed as a result of the call | ||
| 469 | * @throws IndexOutOfBoundsException {@inheritDoc} | ||
| 470 | * @throws NullPointerException if the specified collection is null | ||
| 471 | */ | ||
| 472 | public boolean addAll(int index, Collection<? extends E> c) { | ||
| 473 | rangeCheckForAdd(index); | ||
| 474 | |||
| 475 | Object[] a = c.toArray(); | ||
| 476 | int numNew = a.length; | ||
| 477 | ensureCapacity(size + numNew); // Increments modCount | ||
| 478 | |||
| 479 | int numMoved = size - index; | ||
| 480 | if (numMoved > 0) { | ||
| 481 | System.arraycopy(elementData, index, elementData, index + numNew, numMoved); | ||
| 482 | } | ||
| 483 | |||
| 484 | System.arraycopy(a, 0, elementData, index, numNew); | ||
| 485 | size += numNew; | ||
| 486 | return numNew != 0; | ||
| 487 | } | ||
| 488 | |||
| 489 | /** | ||
| 490 | * Removes from this list all of the elements whose index is between | ||
| 491 | * <tt>fromIndex</tt>, inclusive, and <tt>toIndex</tt>, exclusive. | ||
| 492 | * Shifts any succeeding elements to the left (reduces their index). | ||
| 493 | * This call shortens the list by <tt>(toIndex - fromIndex)</tt> elements. | ||
| 494 | * (If <tt>toIndex==fromIndex</tt>, this operation has no effect.) | ||
| 495 | * | ||
| 496 | * @param fromIndex index of first element to be removed | ||
| 497 | * @param toIndex index after last element to be removed | ||
| 498 | * @throws IndexOutOfBoundsException if fromIndex or toIndex out of | ||
| 499 | * range (fromIndex < 0 || fromIndex >= size() || toIndex | ||
| 500 | * > size() || toIndex < fromIndex) | ||
| 501 | */ | ||
| 502 | protected void removeRange(int fromIndex, int toIndex) { | ||
| 503 | modCount++; | ||
| 504 | int numMoved = size - toIndex; | ||
| 505 | System.arraycopy(elementData, toIndex, elementData, fromIndex, | ||
| 506 | numMoved); | ||
| 507 | |||
| 508 | // Let gc do its work | ||
| 509 | int newSize = size - (toIndex-fromIndex); | ||
| 510 | while (size != newSize) | ||
| 511 | elementData[--size] = null; | ||
| 512 | } | ||
| 513 | |||
| 514 | /** | ||
| 515 | * Checks if the given index is in range. If not, throws an appropriate | ||
| 516 | * runtime exception. This method does *not* check if the index is | ||
| 517 | * negative: It is always used immediately prior to an array access, | ||
| 518 | * which throws an ArrayIndexOutOfBoundsException if index is negative. | ||
| 519 | */ | ||
| 520 | private void rangeCheck(int index) { | ||
| 521 | if (index >= size) | ||
| 522 | throw new IndexOutOfBoundsException(outOfBoundsMsg(index)); | ||
| 523 | } | ||
| 524 | |||
| 525 | /** | ||
| 526 | * A version of rangeCheck used by add and addAll. | ||
| 527 | */ | ||
| 528 | private void rangeCheckForAdd(int index) { | ||
| 529 | if (index > size || index < 0) | ||
| 530 | throw new IndexOutOfBoundsException(outOfBoundsMsg(index)); | ||
| 531 | } | ||
| 532 | |||
| 533 | /** | ||
| 534 | * Constructs an IndexOutOfBoundsException detail message. | ||
| 535 | * Of the many possible refactorings of the error handling code, | ||
| 536 | * this "outlining" performs best with both server and client VMs. | ||
| 537 | */ | ||
| 538 | private String outOfBoundsMsg(int index) { | ||
| 539 | return "Index: "+index+", Size: "+size; | ||
| 540 | } | ||
| 541 | } | ||