1 /* 2 * Copyright (c) 1994, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.util; 27 28 import java.io.IOException; 29 import java.io.ObjectInputStream; 30 import java.io.StreamCorruptedException; 31 import java.util.function.Consumer; 32 import java.util.function.Predicate; 33 import java.util.function.UnaryOperator; 34 35 /** 36 * The {@code Vector} class implements a growable array of 37 * objects. Like an array, it contains components that can be 38 * accessed using an integer index. However, the size of a 39 * {@code Vector} can grow or shrink as needed to accommodate 40 * adding and removing items after the {@code Vector} has been created. 41 * 42 * <p>Each vector tries to optimize storage management by maintaining a 43 * {@code capacity} and a {@code capacityIncrement}. The 44 * {@code capacity} is always at least as large as the vector 45 * size; it is usually larger because as components are added to the 46 * vector, the vector's storage increases in chunks the size of 47 * {@code capacityIncrement}. An application can increase the 48 * capacity of a vector before inserting a large number of 49 * components; this reduces the amount of incremental reallocation. 50 * 51 * <p id="fail-fast"> 52 * The iterators returned by this class's {@link #iterator() iterator} and 53 * {@link #listIterator(int) listIterator} methods are <em>fail-fast</em>: 54 * if the vector is structurally modified at any time after the iterator is 55 * created, in any way except through the iterator's own 56 * {@link ListIterator#remove() remove} or 57 * {@link ListIterator#add(Object) add} methods, the iterator will throw a 58 * {@link ConcurrentModificationException}. Thus, in the face of 59 * concurrent modification, the iterator fails quickly and cleanly, rather 60 * than risking arbitrary, non-deterministic behavior at an undetermined 61 * time in the future. The {@link Enumeration Enumerations} returned by 62 * the {@link #elements() elements} method are <em>not</em> fail-fast; if the 63 * Vector is structurally modified at any time after the enumeration is 64 * created then the results of enumerating are undefined. 65 * 66 * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed 67 * as it is, generally speaking, impossible to make any hard guarantees in the 68 * presence of unsynchronized concurrent modification. Fail-fast iterators 69 * throw {@code ConcurrentModificationException} on a best-effort basis. 70 * Therefore, it would be wrong to write a program that depended on this 71 * exception for its correctness: <i>the fail-fast behavior of iterators 72 * should be used only to detect bugs.</i> 73 * 74 * <p>As of the Java 2 platform v1.2, this class was retrofitted to 75 * implement the {@link List} interface, making it a member of the 76 * <a href="{@docRoot}/java.base/java/util/package-summary.html#CollectionsFramework"> 77 * Java Collections Framework</a>. Unlike the new collection 78 * implementations, {@code Vector} is synchronized. If a thread-safe 79 * implementation is not needed, it is recommended to use {@link 80 * ArrayList} in place of {@code Vector}. 81 * 82 * @param <E> Type of component elements 83 * 84 * @author Lee Boynton 85 * @author Jonathan Payne 86 * @see Collection 87 * @see LinkedList 88 * @since 1.0 89 */ 90 public class Vector<E> 91 extends AbstractList<E> 92 implements List<E>, RandomAccess, Cloneable, java.io.Serializable 93 { 94 /** 95 * The array buffer into which the components of the vector are 96 * stored. The capacity of the vector is the length of this array buffer, 97 * and is at least large enough to contain all the vector's elements. 98 * 99 * <p>Any array elements following the last element in the Vector are null. 100 * 101 * @serial 102 */ 103 protected Object[] elementData; 104 105 /** 106 * The number of valid components in this {@code Vector} object. 107 * Components {@code elementData[0]} through 108 * {@code elementData[elementCount-1]} are the actual items. 109 * 110 * @serial 111 */ 112 protected int elementCount; 113 114 /** 115 * The amount by which the capacity of the vector is automatically 116 * incremented when its size becomes greater than its capacity. If 117 * the capacity increment is less than or equal to zero, the capacity 118 * of the vector is doubled each time it needs to grow. 119 * 120 * @serial 121 */ 122 protected int capacityIncrement; 123 124 /** use serialVersionUID from JDK 1.0.2 for interoperability */ 125 private static final long serialVersionUID = -2767605614048989439L; 126 127 /** 128 * Constructs an empty vector with the specified initial capacity and 129 * capacity increment. 130 * 131 * @param initialCapacity the initial capacity of the vector 132 * @param capacityIncrement the amount by which the capacity is 133 * increased when the vector overflows 134 * @throws IllegalArgumentException if the specified initial capacity 135 * is negative 136 */ 137 public Vector(int initialCapacity, int capacityIncrement) { 138 super(); 139 if (initialCapacity < 0) 140 throw new IllegalArgumentException("Illegal Capacity: "+ 141 initialCapacity); 142 this.elementData = new Object[initialCapacity]; 143 this.capacityIncrement = capacityIncrement; 144 } 145 146 /** 147 * Constructs an empty vector with the specified initial capacity and 148 * with its capacity increment equal to zero. 149 * 150 * @param initialCapacity the initial capacity of the vector 151 * @throws IllegalArgumentException if the specified initial capacity 152 * is negative 153 */ 154 public Vector(int initialCapacity) { 155 this(initialCapacity, 0); 156 } 157 158 /** 159 * Constructs an empty vector so that its internal data array 160 * has size {@code 10} and its standard capacity increment is 161 * zero. 162 */ 163 public Vector() { 164 this(10); 165 } 166 167 /** 168 * Constructs a vector containing the elements of the specified 169 * collection, in the order they are returned by the collection's 170 * iterator. 171 * 172 * @param c the collection whose elements are to be placed into this 173 * vector 174 * @throws NullPointerException if the specified collection is null 175 * @since 1.2 176 */ 177 public Vector(Collection<? extends E> c) { 178 elementData = c.toArray(); 179 elementCount = elementData.length; 180 // defend against c.toArray (incorrectly) not returning Object[] 181 // (see e.g. https://bugs.openjdk.java.net/browse/JDK-6260652) 182 if (elementData.getClass() != Object[].class) 183 elementData = Arrays.copyOf(elementData, elementCount, Object[].class); 184 } 185 186 /** 187 * Copies the components of this vector into the specified array. 188 * The item at index {@code k} in this vector is copied into 189 * component {@code k} of {@code anArray}. 190 * 191 * @param anArray the array into which the components get copied 192 * @throws NullPointerException if the given array is null 193 * @throws IndexOutOfBoundsException if the specified array is not 194 * large enough to hold all the components of this vector 195 * @throws ArrayStoreException if a component of this vector is not of 196 * a runtime type that can be stored in the specified array 197 * @see #toArray(Object[]) 198 */ 199 public synchronized void copyInto(Object[] anArray) { 200 System.arraycopy(elementData, 0, anArray, 0, elementCount); 201 } 202 203 /** 204 * Trims the capacity of this vector to be the vector's current 205 * size. If the capacity of this vector is larger than its current 206 * size, then the capacity is changed to equal the size by replacing 207 * its internal data array, kept in the field {@code elementData}, 208 * with a smaller one. An application can use this operation to 209 * minimize the storage of a vector. 210 */ 211 public synchronized void trimToSize() { 212 modCount++; 213 int oldCapacity = elementData.length; 214 if (elementCount < oldCapacity) { 215 elementData = Arrays.copyOf(elementData, elementCount); 216 } 217 } 218 219 /** 220 * Increases the capacity of this vector, if necessary, to ensure 221 * that it can hold at least the number of components specified by 222 * the minimum capacity argument. 223 * 224 * <p>If the current capacity of this vector is less than 225 * {@code minCapacity}, then its capacity is increased by replacing its 226 * internal data array, kept in the field {@code elementData}, with a 227 * larger one. The size of the new data array will be the old size plus 228 * {@code capacityIncrement}, unless the value of 229 * {@code capacityIncrement} is less than or equal to zero, in which case 230 * the new capacity will be twice the old capacity; but if this new size 231 * is still smaller than {@code minCapacity}, then the new capacity will 232 * be {@code minCapacity}. 233 * 234 * @param minCapacity the desired minimum capacity 235 */ 236 public synchronized void ensureCapacity(int minCapacity) { 237 if (minCapacity > 0) { 238 modCount++; 239 if (minCapacity > elementData.length) 240 grow(minCapacity); 241 } 242 } 243 244 /** 245 * The maximum size of array to allocate (unless necessary). 246 * Some VMs reserve some header words in an array. 247 * Attempts to allocate larger arrays may result in 248 * OutOfMemoryError: Requested array size exceeds VM limit 249 */ 250 private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8; 251 252 /** 253 * Increases the capacity to ensure that it can hold at least the 254 * number of elements specified by the minimum capacity argument. 255 * 256 * @param minCapacity the desired minimum capacity 257 * @throws OutOfMemoryError if minCapacity is less than zero 258 */ 259 private Object[] grow(int minCapacity) { 260 return elementData = Arrays.copyOf(elementData, 261 newCapacity(minCapacity)); 262 } 263 264 private Object[] grow() { 265 return grow(elementCount + 1); 266 } 267 268 /** 269 * Returns a capacity at least as large as the given minimum capacity. 270 * Will not return a capacity greater than MAX_ARRAY_SIZE unless 271 * the given minimum capacity is greater than MAX_ARRAY_SIZE. 272 * 273 * @param minCapacity the desired minimum capacity 274 * @throws OutOfMemoryError if minCapacity is less than zero 275 */ 276 private int newCapacity(int minCapacity) { 277 // overflow-conscious code 278 int oldCapacity = elementData.length; 279 int newCapacity = oldCapacity + ((capacityIncrement > 0) ? 280 capacityIncrement : oldCapacity); 281 if (newCapacity - minCapacity <= 0) { 282 if (minCapacity < 0) // overflow 283 throw new OutOfMemoryError(); 284 return minCapacity; 285 } 286 return (newCapacity - MAX_ARRAY_SIZE <= 0) 287 ? newCapacity 288 : hugeCapacity(minCapacity); 289 } 290 291 private static int hugeCapacity(int minCapacity) { 292 if (minCapacity < 0) // overflow 293 throw new OutOfMemoryError(); 294 return (minCapacity > MAX_ARRAY_SIZE) ? 295 Integer.MAX_VALUE : 296 MAX_ARRAY_SIZE; 297 } 298 299 /** 300 * Sets the size of this vector. If the new size is greater than the 301 * current size, new {@code null} items are added to the end of 302 * the vector. If the new size is less than the current size, all 303 * components at index {@code newSize} and greater are discarded. 304 * 305 * @param newSize the new size of this vector 306 * @throws ArrayIndexOutOfBoundsException if the new size is negative 307 */ 308 public synchronized void setSize(int newSize) { 309 modCount++; 310 if (newSize > elementData.length) 311 grow(newSize); 312 final Object[] es = elementData; 313 for (int to = elementCount, i = newSize; i < to; i++) 314 es[i] = null; 315 elementCount = newSize; 316 } 317 318 /** 319 * Returns the current capacity of this vector. 320 * 321 * @return the current capacity (the length of its internal 322 * data array, kept in the field {@code elementData} 323 * of this vector) 324 */ 325 public synchronized int capacity() { 326 return elementData.length; 327 } 328 329 /** 330 * Returns the number of components in this vector. 331 * 332 * @return the number of components in this vector 333 */ 334 public synchronized int size() { 335 return elementCount; 336 } 337 338 /** 339 * Tests if this vector has no components. 340 * 341 * @return {@code true} if and only if this vector has 342 * no components, that is, its size is zero; 343 * {@code false} otherwise. 344 */ 345 public synchronized boolean isEmpty() { 346 return elementCount == 0; 347 } 348 349 /** 350 * Returns an enumeration of the components of this vector. The 351 * returned {@code Enumeration} object will generate all items in 352 * this vector. The first item generated is the item at index {@code 0}, 353 * then the item at index {@code 1}, and so on. If the vector is 354 * structurally modified while enumerating over the elements then the 355 * results of enumerating are undefined. 356 * 357 * @return an enumeration of the components of this vector 358 * @see Iterator 359 */ 360 public Enumeration<E> elements() { 361 return new Enumeration<E>() { 362 int count = 0; 363 364 public boolean hasMoreElements() { 365 return count < elementCount; 366 } 367 368 public E nextElement() { 369 synchronized (Vector.this) { 370 if (count < elementCount) { 371 return elementData(count++); 372 } 373 } 374 throw new NoSuchElementException("Vector Enumeration"); 375 } 376 }; 377 } 378 379 /** 380 * Returns {@code true} if this vector contains the specified element. 381 * More formally, returns {@code true} if and only if this vector 382 * contains at least one element {@code e} such that 383 * {@code Objects.equals(o, e)}. 384 * 385 * @param o element whose presence in this vector is to be tested 386 * @return {@code true} if this vector contains the specified element 387 */ 388 public boolean contains(Object o) { 389 return indexOf(o, 0) >= 0; 390 } 391 392 /** 393 * Returns the index of the first occurrence of the specified element 394 * in this vector, or -1 if this vector does not contain the element. 395 * More formally, returns the lowest index {@code i} such that 396 * {@code Objects.equals(o, get(i))}, 397 * or -1 if there is no such index. 398 * 399 * @param o element to search for 400 * @return the index of the first occurrence of the specified element in 401 * this vector, or -1 if this vector does not contain the element 402 */ 403 public int indexOf(Object o) { 404 return indexOf(o, 0); 405 } 406 407 /** 408 * Returns the index of the first occurrence of the specified element in 409 * this vector, searching forwards from {@code index}, or returns -1 if 410 * the element is not found. 411 * More formally, returns the lowest index {@code i} such that 412 * {@code (i >= index && Objects.equals(o, get(i)))}, 413 * or -1 if there is no such index. 414 * 415 * @param o element to search for 416 * @param index index to start searching from 417 * @return the index of the first occurrence of the element in 418 * this vector at position {@code index} or later in the vector; 419 * {@code -1} if the element is not found. 420 * @throws IndexOutOfBoundsException if the specified index is negative 421 * @see Object#equals(Object) 422 */ 423 public synchronized int indexOf(Object o, int index) { 424 if (o == null) { 425 for (int i = index ; i < elementCount ; i++) 426 if (elementData[i]==null) 427 return i; 428 } else { 429 for (int i = index ; i < elementCount ; i++) 430 if (o.equals(elementData[i])) 431 return i; 432 } 433 return -1; 434 } 435 436 /** 437 * Returns the index of the last occurrence of the specified element 438 * in this vector, or -1 if this vector does not contain the element. 439 * More formally, returns the highest index {@code i} such that 440 * {@code Objects.equals(o, get(i))}, 441 * or -1 if there is no such index. 442 * 443 * @param o element to search for 444 * @return the index of the last occurrence of the specified element in 445 * this vector, or -1 if this vector does not contain the element 446 */ 447 public synchronized int lastIndexOf(Object o) { 448 return lastIndexOf(o, elementCount-1); 449 } 450 451 /** 452 * Returns the index of the last occurrence of the specified element in 453 * this vector, searching backwards from {@code index}, or returns -1 if 454 * the element is not found. 455 * More formally, returns the highest index {@code i} such that 456 * {@code (i <= index && Objects.equals(o, get(i)))}, 457 * or -1 if there is no such index. 458 * 459 * @param o element to search for 460 * @param index index to start searching backwards from 461 * @return the index of the last occurrence of the element at position 462 * less than or equal to {@code index} in this vector; 463 * -1 if the element is not found. 464 * @throws IndexOutOfBoundsException if the specified index is greater 465 * than or equal to the current size of this vector 466 */ 467 public synchronized int lastIndexOf(Object o, int index) { 468 if (index >= elementCount) 469 throw new IndexOutOfBoundsException(index + " >= "+ elementCount); 470 471 if (o == null) { 472 for (int i = index; i >= 0; i--) 473 if (elementData[i]==null) 474 return i; 475 } else { 476 for (int i = index; i >= 0; i--) 477 if (o.equals(elementData[i])) 478 return i; 479 } 480 return -1; 481 } 482 483 /** 484 * Returns the component at the specified index. 485 * 486 * <p>This method is identical in functionality to the {@link #get(int)} 487 * method (which is part of the {@link List} interface). 488 * 489 * @param index an index into this vector 490 * @return the component at the specified index 491 * @throws ArrayIndexOutOfBoundsException if the index is out of range 492 * ({@code index < 0 || index >= size()}) 493 */ 494 public synchronized E elementAt(int index) { 495 if (index >= elementCount) { 496 throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount); 497 } 498 499 return elementData(index); 500 } 501 502 /** 503 * Returns the first component (the item at index {@code 0}) of 504 * this vector. 505 * 506 * @return the first component of this vector 507 * @throws NoSuchElementException if this vector has no components 508 */ 509 public synchronized E firstElement() { 510 if (elementCount == 0) { 511 throw new NoSuchElementException(); 512 } 513 return elementData(0); 514 } 515 516 /** 517 * Returns the last component of the vector. 518 * 519 * @return the last component of the vector, i.e., the component at index 520 * {@code size() - 1} 521 * @throws NoSuchElementException if this vector is empty 522 */ 523 public synchronized E lastElement() { 524 if (elementCount == 0) { 525 throw new NoSuchElementException(); 526 } 527 return elementData(elementCount - 1); 528 } 529 530 /** 531 * Sets the component at the specified {@code index} of this 532 * vector to be the specified object. The previous component at that 533 * position is discarded. 534 * 535 * <p>The index must be a value greater than or equal to {@code 0} 536 * and less than the current size of the vector. 537 * 538 * <p>This method is identical in functionality to the 539 * {@link #set(int, Object) set(int, E)} 540 * method (which is part of the {@link List} interface). Note that the 541 * {@code set} method reverses the order of the parameters, to more closely 542 * match array usage. Note also that the {@code set} method returns the 543 * old value that was stored at the specified position. 544 * 545 * @param obj what the component is to be set to 546 * @param index the specified index 547 * @throws ArrayIndexOutOfBoundsException if the index is out of range 548 * ({@code index < 0 || index >= size()}) 549 */ 550 public synchronized void setElementAt(E obj, int index) { 551 if (index >= elementCount) { 552 throw new ArrayIndexOutOfBoundsException(index + " >= " + 553 elementCount); 554 } 555 elementData[index] = obj; 556 } 557 558 /** 559 * Deletes the component at the specified index. Each component in 560 * this vector with an index greater or equal to the specified 561 * {@code index} is shifted downward to have an index one 562 * smaller than the value it had previously. The size of this vector 563 * is decreased by {@code 1}. 564 * 565 * <p>The index must be a value greater than or equal to {@code 0} 566 * and less than the current size of the vector. 567 * 568 * <p>This method is identical in functionality to the {@link #remove(int)} 569 * method (which is part of the {@link List} interface). Note that the 570 * {@code remove} method returns the old value that was stored at the 571 * specified position. 572 * 573 * @param index the index of the object to remove 574 * @throws ArrayIndexOutOfBoundsException if the index is out of range 575 * ({@code index < 0 || index >= size()}) 576 */ 577 public synchronized void removeElementAt(int index) { 578 if (index >= elementCount) { 579 throw new ArrayIndexOutOfBoundsException(index + " >= " + 580 elementCount); 581 } 582 else if (index < 0) { 583 throw new ArrayIndexOutOfBoundsException(index); 584 } 585 int j = elementCount - index - 1; 586 if (j > 0) { 587 System.arraycopy(elementData, index + 1, elementData, index, j); 588 } 589 modCount++; 590 elementCount--; 591 elementData[elementCount] = null; /* to let gc do its work */ 592 } 593 594 /** 595 * Inserts the specified object as a component in this vector at the 596 * specified {@code index}. Each component in this vector with 597 * an index greater or equal to the specified {@code index} is 598 * shifted upward to have an index one greater than the value it had 599 * previously. 600 * 601 * <p>The index must be a value greater than or equal to {@code 0} 602 * and less than or equal to the current size of the vector. (If the 603 * index is equal to the current size of the vector, the new element 604 * is appended to the Vector.) 605 * 606 * <p>This method is identical in functionality to the 607 * {@link #add(int, Object) add(int, E)} 608 * method (which is part of the {@link List} interface). Note that the 609 * {@code add} method reverses the order of the parameters, to more closely 610 * match array usage. 611 * 612 * @param obj the component to insert 613 * @param index where to insert the new component 614 * @throws ArrayIndexOutOfBoundsException if the index is out of range 615 * ({@code index < 0 || index > size()}) 616 */ 617 public synchronized void insertElementAt(E obj, int index) { 618 if (index > elementCount) { 619 throw new ArrayIndexOutOfBoundsException(index 620 + " > " + elementCount); 621 } 622 modCount++; 623 final int s = elementCount; 624 Object[] elementData = this.elementData; 625 if (s == elementData.length) 626 elementData = grow(); 627 System.arraycopy(elementData, index, 628 elementData, index + 1, 629 s - index); 630 elementData[index] = obj; 631 elementCount = s + 1; 632 } 633 634 /** 635 * Adds the specified component to the end of this vector, 636 * increasing its size by one. The capacity of this vector is 637 * increased if its size becomes greater than its capacity. 638 * 639 * <p>This method is identical in functionality to the 640 * {@link #add(Object) add(E)} 641 * method (which is part of the {@link List} interface). 642 * 643 * @param obj the component to be added 644 */ 645 public synchronized void addElement(E obj) { 646 modCount++; 647 add(obj, elementData, elementCount); 648 } 649 650 /** 651 * Removes the first (lowest-indexed) occurrence of the argument 652 * from this vector. If the object is found in this vector, each 653 * component in the vector with an index greater or equal to the 654 * object's index is shifted downward to have an index one smaller 655 * than the value it had previously. 656 * 657 * <p>This method is identical in functionality to the 658 * {@link #remove(Object)} method (which is part of the 659 * {@link List} interface). 660 * 661 * @param obj the component to be removed 662 * @return {@code true} if the argument was a component of this 663 * vector; {@code false} otherwise. 664 */ 665 public synchronized boolean removeElement(Object obj) { 666 modCount++; 667 int i = indexOf(obj); 668 if (i >= 0) { 669 removeElementAt(i); 670 return true; 671 } 672 return false; 673 } 674 675 /** 676 * Removes all components from this vector and sets its size to zero. 677 * 678 * <p>This method is identical in functionality to the {@link #clear} 679 * method (which is part of the {@link List} interface). 680 */ 681 public synchronized void removeAllElements() { 682 final Object[] es = elementData; 683 for (int to = elementCount, i = elementCount = 0; i < to; i++) 684 es[i] = null; 685 modCount++; 686 } 687 688 /** 689 * Returns a clone of this vector. The copy will contain a 690 * reference to a clone of the internal data array, not a reference 691 * to the original internal data array of this {@code Vector} object. 692 * 693 * @return a clone of this vector 694 */ 695 public synchronized Object clone() { 696 try { 697 @SuppressWarnings("unchecked") 698 Vector<E> v = (Vector<E>) super.clone(); 699 v.elementData = Arrays.copyOf(elementData, elementCount); 700 v.modCount = 0; 701 return v; 702 } catch (CloneNotSupportedException e) { 703 // this shouldn't happen, since we are Cloneable 704 throw new InternalError(e); 705 } 706 } 707 708 /** 709 * Returns an array containing all of the elements in this Vector 710 * in the correct order. 711 * 712 * @since 1.2 713 */ 714 public synchronized Object[] toArray() { 715 return Arrays.copyOf(elementData, elementCount); 716 } 717 718 /** 719 * Returns an array containing all of the elements in this Vector in the 720 * correct order; the runtime type of the returned array is that of the 721 * specified array. If the Vector fits in the specified array, it is 722 * returned therein. Otherwise, a new array is allocated with the runtime 723 * type of the specified array and the size of this Vector. 724 * 725 * <p>If the Vector fits in the specified array with room to spare 726 * (i.e., the array has more elements than the Vector), 727 * the element in the array immediately following the end of the 728 * Vector is set to null. (This is useful in determining the length 729 * of the Vector <em>only</em> if the caller knows that the Vector 730 * does not contain any null elements.) 731 * 732 * @param <T> type of array elements. The same type as {@code <E>} or a 733 * supertype of {@code <E>}. 734 * @param a the array into which the elements of the Vector are to 735 * be stored, if it is big enough; otherwise, a new array of the 736 * same runtime type is allocated for this purpose. 737 * @return an array containing the elements of the Vector 738 * @throws ArrayStoreException if the runtime type of a, {@code <T>}, is not 739 * a supertype of the runtime type, {@code <E>}, of every element in this 740 * Vector 741 * @throws NullPointerException if the given array is null 742 * @since 1.2 743 */ 744 @SuppressWarnings("unchecked") 745 public synchronized <T> T[] toArray(T[] a) { 746 if (a.length < elementCount) 747 return (T[]) Arrays.copyOf(elementData, elementCount, a.getClass()); 748 749 System.arraycopy(elementData, 0, a, 0, elementCount); 750 751 if (a.length > elementCount) 752 a[elementCount] = null; 753 754 return a; 755 } 756 757 // Positional Access Operations 758 759 @SuppressWarnings("unchecked") 760 E elementData(int index) { 761 return (E) elementData[index]; 762 } 763 764 @SuppressWarnings("unchecked") 765 static <E> E elementAt(Object[] es, int index) { 766 return (E) es[index]; 767 } 768 769 /** 770 * Returns the element at the specified position in this Vector. 771 * 772 * @param index index of the element to return 773 * @return object at the specified index 774 * @throws ArrayIndexOutOfBoundsException if the index is out of range 775 * ({@code index < 0 || index >= size()}) 776 * @since 1.2 777 */ 778 public synchronized E get(int index) { 779 if (index >= elementCount) 780 throw new ArrayIndexOutOfBoundsException(index); 781 782 return elementData(index); 783 } 784 785 /** 786 * Replaces the element at the specified position in this Vector with the 787 * specified element. 788 * 789 * @param index index of the element to replace 790 * @param element element to be stored at the specified position 791 * @return the element previously at the specified position 792 * @throws ArrayIndexOutOfBoundsException if the index is out of range 793 * ({@code index < 0 || index >= size()}) 794 * @since 1.2 795 */ 796 public synchronized E set(int index, E element) { 797 if (index >= elementCount) 798 throw new ArrayIndexOutOfBoundsException(index); 799 800 E oldValue = elementData(index); 801 elementData[index] = element; 802 return oldValue; 803 } 804 805 /** 806 * This helper method split out from add(E) to keep method 807 * bytecode size under 35 (the -XX:MaxInlineSize default value), 808 * which helps when add(E) is called in a C1-compiled loop. 809 */ 810 private void add(E e, Object[] elementData, int s) { 811 if (s == elementData.length) 812 elementData = grow(); 813 elementData[s] = e; 814 elementCount = s + 1; 815 } 816 817 /** 818 * Appends the specified element to the end of this Vector. 819 * 820 * @param e element to be appended to this Vector 821 * @return {@code true} (as specified by {@link Collection#add}) 822 * @since 1.2 823 */ 824 public synchronized boolean add(E e) { 825 modCount++; 826 add(e, elementData, elementCount); 827 return true; 828 } 829 830 /** 831 * Removes the first occurrence of the specified element in this Vector 832 * If the Vector does not contain the element, it is unchanged. More 833 * formally, removes the element with the lowest index i such that 834 * {@code Objects.equals(o, get(i))} (if such 835 * an element exists). 836 * 837 * @param o element to be removed from this Vector, if present 838 * @return true if the Vector contained the specified element 839 * @since 1.2 840 */ 841 public boolean remove(Object o) { 842 return removeElement(o); 843 } 844 845 /** 846 * Inserts the specified element at the specified position in this Vector. 847 * Shifts the element currently at that position (if any) and any 848 * subsequent elements to the right (adds one to their indices). 849 * 850 * @param index index at which the specified element is to be inserted 851 * @param element element to be inserted 852 * @throws ArrayIndexOutOfBoundsException if the index is out of range 853 * ({@code index < 0 || index > size()}) 854 * @since 1.2 855 */ 856 public void add(int index, E element) { 857 insertElementAt(element, index); 858 } 859 860 /** 861 * Removes the element at the specified position in this Vector. 862 * Shifts any subsequent elements to the left (subtracts one from their 863 * indices). Returns the element that was removed from the Vector. 864 * 865 * @param index the index of the element to be removed 866 * @return element that was removed 867 * @throws ArrayIndexOutOfBoundsException if the index is out of range 868 * ({@code index < 0 || index >= size()}) 869 * @since 1.2 870 */ 871 public synchronized E remove(int index) { 872 modCount++; 873 if (index >= elementCount) 874 throw new ArrayIndexOutOfBoundsException(index); 875 E oldValue = elementData(index); 876 877 int numMoved = elementCount - index - 1; 878 if (numMoved > 0) 879 System.arraycopy(elementData, index+1, elementData, index, 880 numMoved); 881 elementData[--elementCount] = null; // Let gc do its work 882 883 return oldValue; 884 } 885 886 /** 887 * Removes all of the elements from this Vector. The Vector will 888 * be empty after this call returns (unless it throws an exception). 889 * 890 * @since 1.2 891 */ 892 public void clear() { 893 removeAllElements(); 894 } 895 896 // Bulk Operations 897 898 /** 899 * Returns true if this Vector contains all of the elements in the 900 * specified Collection. 901 * 902 * @param c a collection whose elements will be tested for containment 903 * in this Vector 904 * @return true if this Vector contains all of the elements in the 905 * specified collection 906 * @throws NullPointerException if the specified collection is null 907 */ 908 public synchronized boolean containsAll(Collection<?> c) { 909 return super.containsAll(c); 910 } 911 912 /** 913 * Appends all of the elements in the specified Collection to the end of 914 * this Vector, in the order that they are returned by the specified 915 * Collection's Iterator. The behavior of this operation is undefined if 916 * the specified Collection is modified while the operation is in progress. 917 * (This implies that the behavior of this call is undefined if the 918 * specified Collection is this Vector, and this Vector is nonempty.) 919 * 920 * @param c elements to be inserted into this Vector 921 * @return {@code true} if this Vector changed as a result of the call 922 * @throws NullPointerException if the specified collection is null 923 * @since 1.2 924 */ 925 public boolean addAll(Collection<? extends E> c) { 926 Object[] a = c.toArray(); 927 modCount++; 928 int numNew = a.length; 929 if (numNew == 0) 930 return false; 931 synchronized (this) { 932 Object[] elementData = this.elementData; 933 final int s = elementCount; 934 if (numNew > elementData.length - s) 935 elementData = grow(s + numNew); 936 System.arraycopy(a, 0, elementData, s, numNew); 937 elementCount = s + numNew; 938 return true; 939 } 940 } 941 942 /** 943 * Removes from this Vector all of its elements that are contained in the 944 * specified Collection. 945 * 946 * @param c a collection of elements to be removed from the Vector 947 * @return true if this Vector changed as a result of the call 948 * @throws ClassCastException if the types of one or more elements 949 * in this vector are incompatible with the specified 950 * collection 951 * (<a href="Collection.html#optional-restrictions">optional</a>) 952 * @throws NullPointerException if this vector contains one or more null 953 * elements and the specified collection does not support null 954 * elements 955 * (<a href="Collection.html#optional-restrictions">optional</a>), 956 * or if the specified collection is null 957 * @since 1.2 958 */ 959 public boolean removeAll(Collection<?> c) { 960 Objects.requireNonNull(c); 961 return bulkRemove(e -> c.contains(e)); 962 } 963 964 /** 965 * Retains only the elements in this Vector that are contained in the 966 * specified Collection. In other words, removes from this Vector all 967 * of its elements that are not contained in the specified Collection. 968 * 969 * @param c a collection of elements to be retained in this Vector 970 * (all other elements are removed) 971 * @return true if this Vector changed as a result of the call 972 * @throws ClassCastException if the types of one or more elements 973 * in this vector are incompatible with the specified 974 * collection 975 * (<a href="Collection.html#optional-restrictions">optional</a>) 976 * @throws NullPointerException if this vector contains one or more null 977 * elements and the specified collection does not support null 978 * elements 979 * (<a href="Collection.html#optional-restrictions">optional</a>), 980 * or if the specified collection is null 981 * @since 1.2 982 */ 983 public boolean retainAll(Collection<?> c) { 984 Objects.requireNonNull(c); 985 return bulkRemove(e -> !c.contains(e)); 986 } 987 988 /** 989 * @throws NullPointerException {@inheritDoc} 990 */ 991 @Override 992 public boolean removeIf(Predicate<? super E> filter) { 993 Objects.requireNonNull(filter); 994 return bulkRemove(filter); 995 } 996 997 // A tiny bit set implementation 998 999 private static long[] nBits(int n) { 1000 return new long[((n - 1) >> 6) + 1]; 1001 } 1002 private static void setBit(long[] bits, int i) { 1003 bits[i >> 6] |= 1L << i; 1004 } 1005 private static boolean isClear(long[] bits, int i) { 1006 return (bits[i >> 6] & (1L << i)) == 0; 1007 } 1008 1009 private synchronized boolean bulkRemove(Predicate<? super E> filter) { 1010 int expectedModCount = modCount; 1011 final Object[] es = elementData; 1012 final int end = elementCount; 1013 int i; 1014 // Optimize for initial run of survivors 1015 for (i = 0; i < end && !filter.test(elementAt(es, i)); i++) 1016 ; 1017 // Tolerate predicates that reentrantly access the collection for 1018 // read (but writers still get CME), so traverse once to find 1019 // elements to delete, a second pass to physically expunge. 1020 if (i < end) { 1021 final int beg = i; 1022 final long[] deathRow = nBits(end - beg); 1023 deathRow[0] = 1L; // set bit 0 1024 for (i = beg + 1; i < end; i++) 1025 if (filter.test(elementAt(es, i))) 1026 setBit(deathRow, i - beg); 1027 if (modCount != expectedModCount) 1028 throw new ConcurrentModificationException(); 1029 modCount++; 1030 int w = beg; 1031 for (i = beg; i < end; i++) 1032 if (isClear(deathRow, i - beg)) 1033 es[w++] = es[i]; 1034 for (i = elementCount = w; i < end; i++) 1035 es[i] = null; 1036 return true; 1037 } else { 1038 if (modCount != expectedModCount) 1039 throw new ConcurrentModificationException(); 1040 return false; 1041 } 1042 } 1043 1044 /** 1045 * Inserts all of the elements in the specified Collection into this 1046 * Vector at the specified position. Shifts the element currently at 1047 * that position (if any) and any subsequent elements to the right 1048 * (increases their indices). The new elements will appear in the Vector 1049 * in the order that they are returned by the specified Collection's 1050 * iterator. 1051 * 1052 * @param index index at which to insert the first element from the 1053 * specified collection 1054 * @param c elements to be inserted into this Vector 1055 * @return {@code true} if this Vector changed as a result of the call 1056 * @throws ArrayIndexOutOfBoundsException if the index is out of range 1057 * ({@code index < 0 || index > size()}) 1058 * @throws NullPointerException if the specified collection is null 1059 * @since 1.2 1060 */ 1061 public synchronized boolean addAll(int index, Collection<? extends E> c) { 1062 if (index < 0 || index > elementCount) 1063 throw new ArrayIndexOutOfBoundsException(index); 1064 1065 Object[] a = c.toArray(); 1066 modCount++; 1067 int numNew = a.length; 1068 if (numNew == 0) 1069 return false; 1070 Object[] elementData = this.elementData; 1071 final int s = elementCount; 1072 if (numNew > elementData.length - s) 1073 elementData = grow(s + numNew); 1074 1075 int numMoved = s - index; 1076 if (numMoved > 0) 1077 System.arraycopy(elementData, index, 1078 elementData, index + numNew, 1079 numMoved); 1080 System.arraycopy(a, 0, elementData, index, numNew); 1081 elementCount = s + numNew; 1082 return true; 1083 } 1084 1085 /** 1086 * Compares the specified Object with this Vector for equality. Returns 1087 * true if and only if the specified Object is also a List, both Lists 1088 * have the same size, and all corresponding pairs of elements in the two 1089 * Lists are <em>equal</em>. (Two elements {@code e1} and 1090 * {@code e2} are <em>equal</em> if {@code Objects.equals(e1, e2)}.) 1091 * In other words, two Lists are defined to be 1092 * equal if they contain the same elements in the same order. 1093 * 1094 * @param o the Object to be compared for equality with this Vector 1095 * @return true if the specified Object is equal to this Vector 1096 */ 1097 public synchronized boolean equals(Object o) { 1098 return super.equals(o); 1099 } 1100 1101 /** 1102 * Returns the hash code value for this Vector. 1103 */ 1104 public synchronized int hashCode() { 1105 return super.hashCode(); 1106 } 1107 1108 /** 1109 * Returns a string representation of this Vector, containing 1110 * the String representation of each element. 1111 */ 1112 public synchronized String toString() { 1113 return super.toString(); 1114 } 1115 1116 /** 1117 * Returns a view of the portion of this List between fromIndex, 1118 * inclusive, and toIndex, exclusive. (If fromIndex and toIndex are 1119 * equal, the returned List is empty.) The returned List is backed by this 1120 * List, so changes in the returned List are reflected in this List, and 1121 * vice-versa. The returned List supports all of the optional List 1122 * operations supported by this List. 1123 * 1124 * <p>This method eliminates the need for explicit range operations (of 1125 * the sort that commonly exist for arrays). Any operation that expects 1126 * a List can be used as a range operation by operating on a subList view 1127 * instead of a whole List. For example, the following idiom 1128 * removes a range of elements from a List: 1129 * <pre> 1130 * list.subList(from, to).clear(); 1131 * </pre> 1132 * Similar idioms may be constructed for indexOf and lastIndexOf, 1133 * and all of the algorithms in the Collections class can be applied to 1134 * a subList. 1135 * 1136 * <p>The semantics of the List returned by this method become undefined if 1137 * the backing list (i.e., this List) is <i>structurally modified</i> in 1138 * any way other than via the returned List. (Structural modifications are 1139 * those that change the size of the List, or otherwise perturb it in such 1140 * a fashion that iterations in progress may yield incorrect results.) 1141 * 1142 * @param fromIndex low endpoint (inclusive) of the subList 1143 * @param toIndex high endpoint (exclusive) of the subList 1144 * @return a view of the specified range within this List 1145 * @throws IndexOutOfBoundsException if an endpoint index value is out of range 1146 * {@code (fromIndex < 0 || toIndex > size)} 1147 * @throws IllegalArgumentException if the endpoint indices are out of order 1148 * {@code (fromIndex > toIndex)} 1149 */ 1150 public synchronized List<E> subList(int fromIndex, int toIndex) { 1151 return Collections.synchronizedList(super.subList(fromIndex, toIndex), 1152 this); 1153 } 1154 1155 /** 1156 * Removes from this list all of the elements whose index is between 1157 * {@code fromIndex}, inclusive, and {@code toIndex}, exclusive. 1158 * Shifts any succeeding elements to the left (reduces their index). 1159 * This call shortens the list by {@code (toIndex - fromIndex)} elements. 1160 * (If {@code toIndex==fromIndex}, this operation has no effect.) 1161 */ 1162 protected synchronized void removeRange(int fromIndex, int toIndex) { 1163 modCount++; 1164 shiftTailOverGap(elementData, fromIndex, toIndex); 1165 } 1166 1167 /** Erases the gap from lo to hi, by sliding down following elements. */ 1168 private void shiftTailOverGap(Object[] es, int lo, int hi) { 1169 System.arraycopy(es, hi, es, lo, elementCount - hi); 1170 for (int to = elementCount, i = (elementCount -= hi - lo); i < to; i++) 1171 es[i] = null; 1172 } 1173 1174 /** 1175 * Loads a {@code Vector} instance from a stream 1176 * (that is, deserializes it). 1177 * This method performs checks to ensure the consistency 1178 * of the fields. 1179 * 1180 * @param in the stream 1181 * @throws java.io.IOException if an I/O error occurs 1182 * @throws ClassNotFoundException if the stream contains data 1183 * of a non-existing class 1184 */ 1185 private void readObject(ObjectInputStream in) 1186 throws IOException, ClassNotFoundException { 1187 ObjectInputStream.GetField gfields = in.readFields(); 1188 int count = gfields.get("elementCount", 0); 1189 Object[] data = (Object[])gfields.get("elementData", null); 1190 if (count < 0 || data == null || count > data.length) { 1191 throw new StreamCorruptedException("Inconsistent vector internals"); 1192 } 1193 elementCount = count; 1194 elementData = data.clone(); 1195 } 1196 1197 /** 1198 * Saves the state of the {@code Vector} instance to a stream 1199 * (that is, serializes it). 1200 * This method performs synchronization to ensure the consistency 1201 * of the serialized data. 1202 * 1203 * @param s the stream 1204 * @throws java.io.IOException if an I/O error occurs 1205 */ 1206 private void writeObject(java.io.ObjectOutputStream s) 1207 throws java.io.IOException { 1208 final java.io.ObjectOutputStream.PutField fields = s.putFields(); 1209 final Object[] data; 1210 synchronized (this) { 1211 fields.put("capacityIncrement", capacityIncrement); 1212 fields.put("elementCount", elementCount); 1213 data = elementData.clone(); 1214 } 1215 fields.put("elementData", data); 1216 s.writeFields(); 1217 } 1218 1219 /** 1220 * Returns a list iterator over the elements in this list (in proper 1221 * sequence), starting at the specified position in the list. 1222 * The specified index indicates the first element that would be 1223 * returned by an initial call to {@link ListIterator#next next}. 1224 * An initial call to {@link ListIterator#previous previous} would 1225 * return the element with the specified index minus one. 1226 * 1227 * <p>The returned list iterator is <a href="#fail-fast"><i>fail-fast</i></a>. 1228 * 1229 * @throws IndexOutOfBoundsException {@inheritDoc} 1230 */ 1231 public synchronized ListIterator<E> listIterator(int index) { 1232 if (index < 0 || index > elementCount) 1233 throw new IndexOutOfBoundsException("Index: "+index); 1234 return new ListItr(index); 1235 } 1236 1237 /** 1238 * Returns a list iterator over the elements in this list (in proper 1239 * sequence). 1240 * 1241 * <p>The returned list iterator is <a href="#fail-fast"><i>fail-fast</i></a>. 1242 * 1243 * @see #listIterator(int) 1244 */ 1245 public synchronized ListIterator<E> listIterator() { 1246 return new ListItr(0); 1247 } 1248 1249 /** 1250 * Returns an iterator over the elements in this list in proper sequence. 1251 * 1252 * <p>The returned iterator is <a href="#fail-fast"><i>fail-fast</i></a>. 1253 * 1254 * @return an iterator over the elements in this list in proper sequence 1255 */ 1256 public synchronized Iterator<E> iterator() { 1257 return new Itr(); 1258 } 1259 1260 /** 1261 * An optimized version of AbstractList.Itr 1262 */ 1263 private class Itr implements Iterator<E> { 1264 int cursor; // index of next element to return 1265 int lastRet = -1; // index of last element returned; -1 if no such 1266 int expectedModCount = modCount; 1267 1268 public boolean hasNext() { 1269 // Racy but within spec, since modifications are checked 1270 // within or after synchronization in next/previous 1271 return cursor != elementCount; 1272 } 1273 1274 public E next() { 1275 synchronized (Vector.this) { 1276 checkForComodification(); 1277 int i = cursor; 1278 if (i >= elementCount) 1279 throw new NoSuchElementException(); 1280 cursor = i + 1; 1281 return elementData(lastRet = i); 1282 } 1283 } 1284 1285 public void remove() { 1286 if (lastRet == -1) 1287 throw new IllegalStateException(); 1288 synchronized (Vector.this) { 1289 checkForComodification(); 1290 Vector.this.remove(lastRet); 1291 expectedModCount = modCount; 1292 } 1293 cursor = lastRet; 1294 lastRet = -1; 1295 } 1296 1297 @Override 1298 public void forEachRemaining(Consumer<? super E> action) { 1299 Objects.requireNonNull(action); 1300 synchronized (Vector.this) { 1301 final int size = elementCount; 1302 int i = cursor; 1303 if (i >= size) { 1304 return; 1305 } 1306 final Object[] es = elementData; 1307 if (i >= es.length) 1308 throw new ConcurrentModificationException(); 1309 while (i < size && modCount == expectedModCount) 1310 action.accept(elementAt(es, i++)); 1311 // update once at end of iteration to reduce heap write traffic 1312 cursor = i; 1313 lastRet = i - 1; 1314 checkForComodification(); 1315 } 1316 } 1317 1318 final void checkForComodification() { 1319 if (modCount != expectedModCount) 1320 throw new ConcurrentModificationException(); 1321 } 1322 } 1323 1324 /** 1325 * An optimized version of AbstractList.ListItr 1326 */ 1327 final class ListItr extends Itr implements ListIterator<E> { 1328 ListItr(int index) { 1329 super(); 1330 cursor = index; 1331 } 1332 1333 public boolean hasPrevious() { 1334 return cursor != 0; 1335 } 1336 1337 public int nextIndex() { 1338 return cursor; 1339 } 1340 1341 public int previousIndex() { 1342 return cursor - 1; 1343 } 1344 1345 public E previous() { 1346 synchronized (Vector.this) { 1347 checkForComodification(); 1348 int i = cursor - 1; 1349 if (i < 0) 1350 throw new NoSuchElementException(); 1351 cursor = i; 1352 return elementData(lastRet = i); 1353 } 1354 } 1355 1356 public void set(E e) { 1357 if (lastRet == -1) 1358 throw new IllegalStateException(); 1359 synchronized (Vector.this) { 1360 checkForComodification(); 1361 Vector.this.set(lastRet, e); 1362 } 1363 } 1364 1365 public void add(E e) { 1366 int i = cursor; 1367 synchronized (Vector.this) { 1368 checkForComodification(); 1369 Vector.this.add(i, e); 1370 expectedModCount = modCount; 1371 } 1372 cursor = i + 1; 1373 lastRet = -1; 1374 } 1375 } 1376 1377 /** 1378 * @throws NullPointerException {@inheritDoc} 1379 */ 1380 @Override 1381 public synchronized void forEach(Consumer<? super E> action) { 1382 Objects.requireNonNull(action); 1383 final int expectedModCount = modCount; 1384 final Object[] es = elementData; 1385 final int size = elementCount; 1386 for (int i = 0; modCount == expectedModCount && i < size; i++) 1387 action.accept(elementAt(es, i)); 1388 if (modCount != expectedModCount) 1389 throw new ConcurrentModificationException(); 1390 } 1391 1392 /** 1393 * @throws NullPointerException {@inheritDoc} 1394 */ 1395 @Override 1396 public synchronized void replaceAll(UnaryOperator<E> operator) { 1397 Objects.requireNonNull(operator); 1398 final int expectedModCount = modCount; 1399 final Object[] es = elementData; 1400 final int size = elementCount; 1401 for (int i = 0; modCount == expectedModCount && i < size; i++) 1402 es[i] = operator.apply(elementAt(es, i)); 1403 if (modCount != expectedModCount) 1404 throw new ConcurrentModificationException(); 1405 modCount++; 1406 } 1407 1408 @SuppressWarnings("unchecked") 1409 @Override 1410 public synchronized void sort(Comparator<? super E> c) { 1411 final int expectedModCount = modCount; 1412 Arrays.sort((E[]) elementData, 0, elementCount, c); 1413 if (modCount != expectedModCount) 1414 throw new ConcurrentModificationException(); 1415 modCount++; 1416 } 1417 1418 /** 1419 * Creates a <em><a href="Spliterator.html#binding">late-binding</a></em> 1420 * and <em>fail-fast</em> {@link Spliterator} over the elements in this 1421 * list. 1422 * 1423 * <p>The {@code Spliterator} reports {@link Spliterator#SIZED}, 1424 * {@link Spliterator#SUBSIZED}, and {@link Spliterator#ORDERED}. 1425 * Overriding implementations should document the reporting of additional 1426 * characteristic values. 1427 * 1428 * @return a {@code Spliterator} over the elements in this list 1429 * @since 1.8 1430 */ 1431 @Override 1432 public Spliterator<E> spliterator() { 1433 return new VectorSpliterator(null, 0, -1, 0); 1434 } 1435 1436 /** Similar to ArrayList Spliterator */ 1437 final class VectorSpliterator implements Spliterator<E> { 1438 private Object[] array; 1439 private int index; // current index, modified on advance/split 1440 private int fence; // -1 until used; then one past last index 1441 private int expectedModCount; // initialized when fence set 1442 1443 /** Creates new spliterator covering the given range. */ 1444 VectorSpliterator(Object[] array, int origin, int fence, 1445 int expectedModCount) { 1446 this.array = array; 1447 this.index = origin; 1448 this.fence = fence; 1449 this.expectedModCount = expectedModCount; 1450 } 1451 1452 private int getFence() { // initialize on first use 1453 int hi; 1454 if ((hi = fence) < 0) { 1455 synchronized (Vector.this) { 1456 array = elementData; 1457 expectedModCount = modCount; 1458 hi = fence = elementCount; 1459 } 1460 } 1461 return hi; 1462 } 1463 1464 public Spliterator<E> trySplit() { 1465 int hi = getFence(), lo = index, mid = (lo + hi) >>> 1; 1466 return (lo >= mid) ? null : 1467 new VectorSpliterator(array, lo, index = mid, expectedModCount); 1468 } 1469 1470 @SuppressWarnings("unchecked") 1471 public boolean tryAdvance(Consumer<? super E> action) { 1472 Objects.requireNonNull(action); 1473 int i; 1474 if (getFence() > (i = index)) { 1475 index = i + 1; 1476 action.accept((E)array[i]); 1477 if (modCount != expectedModCount) 1478 throw new ConcurrentModificationException(); 1479 return true; 1480 } 1481 return false; 1482 } 1483 1484 @SuppressWarnings("unchecked") 1485 public void forEachRemaining(Consumer<? super E> action) { 1486 Objects.requireNonNull(action); 1487 final int hi = getFence(); 1488 final Object[] a = array; 1489 int i; 1490 for (i = index, index = hi; i < hi; i++) 1491 action.accept((E) a[i]); 1492 if (modCount != expectedModCount) 1493 throw new ConcurrentModificationException(); 1494 } 1495 1496 public long estimateSize() { 1497 return getFence() - index; 1498 } 1499 1500 public int characteristics() { 1501 return Spliterator.ORDERED | Spliterator.SIZED | Spliterator.SUBSIZED; 1502 } 1503 } 1504 1505 void checkInvariants() { 1506 // assert elementCount >= 0; 1507 // assert elementCount == elementData.length || elementData[elementCount] == null; 1508 } 1509 }