1 /*
2 * Copyright (c) 1994, 2013, 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 *
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20 *
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23 * questions.
24 */
25
26 package java.util;
27
28 import java.util.function.Consumer;
29 import java.util.function.Predicate;
30 import java.util.function.UnaryOperator;
31
32 import java.util.function.Consumer;
33
34 /**
35 * The {@code Vector} class implements a growable array of
36 * objects. Like an array, it contains components that can be
37 * accessed using an integer index. However, the size of a
38 * {@code Vector} can grow or shrink as needed to accommodate
39 * adding and removing items after the {@code Vector} has been created.
40 *
41 * <p>Each vector tries to optimize storage management by maintaining a
42 * {@code capacity} and a {@code capacityIncrement}. The
43 * {@code capacity} is always at least as large as the vector
44 * size; it is usually larger because as components are added to the
45 * vector, the vector's storage increases in chunks the size of
46 * {@code capacityIncrement}. An application can increase the
47 * capacity of a vector before inserting a large number of
48 * components; this reduces the amount of incremental reallocation.
49 *
50 * <p><a name="fail-fast"/>
51 * The iterators returned by this class's {@link #iterator() iterator} and
52 * {@link #listIterator(int) listIterator} methods are <em>fail-fast</em>:
53 * if the vector is structurally modified at any time after the iterator is
54 * created, in any way except through the iterator's own
55 * {@link ListIterator#remove() remove} or
56 * {@link ListIterator#add(Object) add} methods, the iterator will throw a
57 * {@link ConcurrentModificationException}. Thus, in the face of
58 * concurrent modification, the iterator fails quickly and cleanly, rather
59 * than risking arbitrary, non-deterministic behavior at an undetermined
60 * time in the future. The {@link Enumeration Enumerations} returned by
61 * the {@link #elements() elements} method are <em>not</em> fail-fast.
62 *
63 * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed
64 * as it is, generally speaking, impossible to make any hard guarantees in the
65 * presence of unsynchronized concurrent modification. Fail-fast iterators
66 * throw {@code ConcurrentModificationException} on a best-effort basis.
67 * Therefore, it would be wrong to write a program that depended on this
68 * exception for its correctness: <i>the fail-fast behavior of iterators
69 * should be used only to detect bugs.</i>
70 *
71 * <p>As of the Java 2 platform v1.2, this class was retrofitted to
72 * implement the {@link List} interface, making it a member of the
73 * <a href="{@docRoot}/../technotes/guides/collections/index.html">
74 * Java Collections Framework</a>. Unlike the new collection
75 * implementations, {@code Vector} is synchronized. If a thread-safe
76 * implementation is not needed, it is recommended to use {@link
77 * ArrayList} in place of {@code Vector}.
78 *
79 * @author Lee Boynton
80 * @author Jonathan Payne
81 * @see Collection
82 * @see LinkedList
83 * @since JDK1.0
84 */
85 public class Vector<E>
86 extends AbstractList<E>
87 implements List<E>, RandomAccess, Cloneable, java.io.Serializable
88 {
89 /**
90 * The array buffer into which the components of the vector are
91 * stored. The capacity of the vector is the length of this array buffer,
92 * and is at least large enough to contain all the vector's elements.
93 *
94 * <p>Any array elements following the last element in the Vector are null.
95 *
96 * @serial
97 */
98 protected Object[] elementData;
99
100 /**
101 * The number of valid components in this {@code Vector} object.
102 * Components {@code elementData[0]} through
103 * {@code elementData[elementCount-1]} are the actual items.
104 *
105 * @serial
106 */
107 protected int elementCount;
108
109 /**
110 * The amount by which the capacity of the vector is automatically
111 * incremented when its size becomes greater than its capacity. If
112 * the capacity increment is less than or equal to zero, the capacity
113 * of the vector is doubled each time it needs to grow.
114 *
115 * @serial
116 */
117 protected int capacityIncrement;
118
119 /** use serialVersionUID from JDK 1.0.2 for interoperability */
120 private static final long serialVersionUID = -2767605614048989439L;
121
122 /**
123 * Constructs an empty vector with the specified initial capacity and
124 * capacity increment.
125 *
126 * @param initialCapacity the initial capacity of the vector
127 * @param capacityIncrement the amount by which the capacity is
128 * increased when the vector overflows
129 * @throws IllegalArgumentException if the specified initial capacity
130 * is negative
131 */
132 public Vector(int initialCapacity, int capacityIncrement) {
133 super();
134 if (initialCapacity < 0)
135 throw new IllegalArgumentException("Illegal Capacity: "+
136 initialCapacity);
137 this.elementData = new Object[initialCapacity];
138 this.capacityIncrement = capacityIncrement;
139 }
140
141 /**
142 * Constructs an empty vector with the specified initial capacity and
143 * with its capacity increment equal to zero.
144 *
145 * @param initialCapacity the initial capacity of the vector
146 * @throws IllegalArgumentException if the specified initial capacity
147 * is negative
148 */
149 public Vector(int initialCapacity) {
150 this(initialCapacity, 0);
151 }
152
153 /**
154 * Constructs an empty vector so that its internal data array
155 * has size {@code 10} and its standard capacity increment is
156 * zero.
157 */
158 public Vector() {
159 this(10);
160 }
161
162 /**
163 * Constructs a vector containing the elements of the specified
164 * collection, in the order they are returned by the collection's
165 * iterator.
166 *
167 * @param c the collection whose elements are to be placed into this
168 * vector
169 * @throws NullPointerException if the specified collection is null
170 * @since 1.2
171 */
172 public Vector(Collection<? extends E> c) {
173 elementData = c.toArray();
174 elementCount = elementData.length;
175 // c.toArray might (incorrectly) not return Object[] (see 6260652)
176 if (elementData.getClass() != Object[].class)
177 elementData = Arrays.copyOf(elementData, elementCount, Object[].class);
178 }
179
180 /**
181 * Copies the components of this vector into the specified array.
182 * The item at index {@code k} in this vector is copied into
183 * component {@code k} of {@code anArray}.
184 *
185 * @param anArray the array into which the components get copied
186 * @throws NullPointerException if the given array is null
187 * @throws IndexOutOfBoundsException if the specified array is not
188 * large enough to hold all the components of this vector
189 * @throws ArrayStoreException if a component of this vector is not of
190 * a runtime type that can be stored in the specified array
191 * @see #toArray(Object[])
192 */
193 public synchronized void copyInto(Object[] anArray) {
194 System.arraycopy(elementData, 0, anArray, 0, elementCount);
195 }
196
197 /**
198 * Trims the capacity of this vector to be the vector's current
199 * size. If the capacity of this vector is larger than its current
200 * size, then the capacity is changed to equal the size by replacing
201 * its internal data array, kept in the field {@code elementData},
202 * with a smaller one. An application can use this operation to
203 * minimize the storage of a vector.
204 */
205 public synchronized void trimToSize() {
206 modCount++;
207 int oldCapacity = elementData.length;
208 if (elementCount < oldCapacity) {
209 elementData = Arrays.copyOf(elementData, elementCount);
210 }
211 }
212
213 /**
214 * Increases the capacity of this vector, if necessary, to ensure
215 * that it can hold at least the number of components specified by
216 * the minimum capacity argument.
217 *
218 * <p>If the current capacity of this vector is less than
219 * {@code minCapacity}, then its capacity is increased by replacing its
220 * internal data array, kept in the field {@code elementData}, with a
221 * larger one. The size of the new data array will be the old size plus
222 * {@code capacityIncrement}, unless the value of
223 * {@code capacityIncrement} is less than or equal to zero, in which case
224 * the new capacity will be twice the old capacity; but if this new size
225 * is still smaller than {@code minCapacity}, then the new capacity will
226 * be {@code minCapacity}.
227 *
228 * @param minCapacity the desired minimum capacity
229 */
230 public synchronized void ensureCapacity(int minCapacity) {
231 if (minCapacity > 0) {
232 modCount++;
233 ensureCapacityHelper(minCapacity);
234 }
235 }
236
237 /**
238 * This implements the unsynchronized semantics of ensureCapacity.
239 * Synchronized methods in this class can internally call this
240 * method for ensuring capacity without incurring the cost of an
241 * extra synchronization.
242 *
243 * @see #ensureCapacity(int)
244 */
245 private void ensureCapacityHelper(int minCapacity) {
246 // overflow-conscious code
247 if (minCapacity - elementData.length > 0)
248 grow(minCapacity);
249 }
250
251 /**
252 * The maximum size of array to allocate.
253 * Some VMs reserve some header words in an array.
254 * Attempts to allocate larger arrays may result in
255 * OutOfMemoryError: Requested array size exceeds VM limit
256 */
257 private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
258
259 private void grow(int minCapacity) {
260 // overflow-conscious code
261 int oldCapacity = elementData.length;
262 int newCapacity = oldCapacity + ((capacityIncrement > 0) ?
263 capacityIncrement : oldCapacity);
264 if (newCapacity - minCapacity < 0)
265 newCapacity = minCapacity;
266 if (newCapacity - MAX_ARRAY_SIZE > 0)
267 newCapacity = hugeCapacity(minCapacity);
268 elementData = Arrays.copyOf(elementData, newCapacity);
269 }
270
271 private static int hugeCapacity(int minCapacity) {
272 if (minCapacity < 0) // overflow
273 throw new OutOfMemoryError();
274 return (minCapacity > MAX_ARRAY_SIZE) ?
275 Integer.MAX_VALUE :
276 MAX_ARRAY_SIZE;
277 }
278
279 /**
280 * Sets the size of this vector. If the new size is greater than the
281 * current size, new {@code null} items are added to the end of
282 * the vector. If the new size is less than the current size, all
283 * components at index {@code newSize} and greater are discarded.
284 *
285 * @param newSize the new size of this vector
286 * @throws ArrayIndexOutOfBoundsException if the new size is negative
287 */
288 public synchronized void setSize(int newSize) {
289 modCount++;
290 if (newSize > elementCount) {
291 ensureCapacityHelper(newSize);
292 } else {
293 for (int i = newSize ; i < elementCount ; i++) {
294 elementData[i] = null;
295 }
296 }
297 elementCount = newSize;
298 }
299
300 /**
301 * Returns the current capacity of this vector.
302 *
303 * @return the current capacity (the length of its internal
304 * data array, kept in the field {@code elementData}
305 * of this vector)
306 */
307 public synchronized int capacity() {
308 return elementData.length;
309 }
310
311 /**
312 * Returns the number of components in this vector.
313 *
314 * @return the number of components in this vector
315 */
316 public synchronized int size() {
317 return elementCount;
318 }
319
320 /**
321 * Tests if this vector has no components.
322 *
323 * @return {@code true} if and only if this vector has
324 * no components, that is, its size is zero;
325 * {@code false} otherwise.
326 */
327 public synchronized boolean isEmpty() {
328 return elementCount == 0;
329 }
330
331 /**
332 * Returns an enumeration of the components of this vector. The
333 * returned {@code Enumeration} object will generate all items in
334 * this vector. The first item generated is the item at index {@code 0},
335 * then the item at index {@code 1}, and so on.
336 *
337 * @return an enumeration of the components of this vector
338 * @see Iterator
339 */
340 public Enumeration<E> elements() {
341 return new Enumeration<E>() {
342 int count = 0;
343
344 public boolean hasMoreElements() {
345 return count < elementCount;
346 }
347
348 public E nextElement() {
349 synchronized (Vector.this) {
350 if (count < elementCount) {
351 return elementData(count++);
352 }
353 }
354 throw new NoSuchElementException("Vector Enumeration");
355 }
356 };
357 }
358
359 /**
360 * Returns {@code true} if this vector contains the specified element.
361 * More formally, returns {@code true} if and only if this vector
362 * contains at least one element {@code e} such that
363 * <tt>(o==null ? e==null : o.equals(e))</tt>.
364 *
365 * @param o element whose presence in this vector is to be tested
366 * @return {@code true} if this vector contains the specified element
367 */
368 public boolean contains(Object o) {
369 return indexOf(o, 0) >= 0;
370 }
371
372 /**
373 * Returns the index of the first occurrence of the specified element
374 * in this vector, or -1 if this vector does not contain the element.
375 * More formally, returns the lowest index {@code i} such that
376 * <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>,
377 * or -1 if there is no such index.
378 *
379 * @param o element to search for
380 * @return the index of the first occurrence of the specified element in
381 * this vector, or -1 if this vector does not contain the element
382 */
383 public int indexOf(Object o) {
384 return indexOf(o, 0);
385 }
386
387 /**
388 * Returns the index of the first occurrence of the specified element in
389 * this vector, searching forwards from {@code index}, or returns -1 if
390 * the element is not found.
391 * More formally, returns the lowest index {@code i} such that
392 * <tt>(i >= index && (o==null ? get(i)==null : o.equals(get(i))))</tt>,
393 * or -1 if there is no such index.
394 *
395 * @param o element to search for
396 * @param index index to start searching from
397 * @return the index of the first occurrence of the element in
398 * this vector at position {@code index} or later in the vector;
399 * {@code -1} if the element is not found.
400 * @throws IndexOutOfBoundsException if the specified index is negative
401 * @see Object#equals(Object)
402 */
403 public synchronized int indexOf(Object o, int index) {
404 if (o == null) {
405 for (int i = index ; i < elementCount ; i++)
406 if (elementData[i]==null)
407 return i;
408 } else {
409 for (int i = index ; i < elementCount ; i++)
410 if (o.equals(elementData[i]))
411 return i;
412 }
413 return -1;
414 }
415
416 /**
417 * Returns the index of the last occurrence of the specified element
418 * in this vector, or -1 if this vector does not contain the element.
419 * More formally, returns the highest index {@code i} such that
420 * <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>,
421 * or -1 if there is no such index.
422 *
423 * @param o element to search for
424 * @return the index of the last occurrence of the specified element in
425 * this vector, or -1 if this vector does not contain the element
426 */
427 public synchronized int lastIndexOf(Object o) {
428 return lastIndexOf(o, elementCount-1);
429 }
430
431 /**
432 * Returns the index of the last occurrence of the specified element in
433 * this vector, searching backwards from {@code index}, or returns -1 if
434 * the element is not found.
435 * More formally, returns the highest index {@code i} such that
436 * <tt>(i <= index && (o==null ? get(i)==null : o.equals(get(i))))</tt>,
437 * or -1 if there is no such index.
438 *
439 * @param o element to search for
440 * @param index index to start searching backwards from
441 * @return the index of the last occurrence of the element at position
442 * less than or equal to {@code index} in this vector;
443 * -1 if the element is not found.
444 * @throws IndexOutOfBoundsException if the specified index is greater
445 * than or equal to the current size of this vector
446 */
447 public synchronized int lastIndexOf(Object o, int index) {
448 if (index >= elementCount)
449 throw new IndexOutOfBoundsException(index + " >= "+ elementCount);
450
451 if (o == null) {
452 for (int i = index; i >= 0; i--)
453 if (elementData[i]==null)
454 return i;
455 } else {
456 for (int i = index; i >= 0; i--)
457 if (o.equals(elementData[i]))
458 return i;
459 }
460 return -1;
461 }
462
463 /**
464 * Returns the component at the specified index.
465 *
466 * <p>This method is identical in functionality to the {@link #get(int)}
467 * method (which is part of the {@link List} interface).
468 *
469 * @param index an index into this vector
470 * @return the component at the specified index
471 * @throws ArrayIndexOutOfBoundsException if the index is out of range
472 * ({@code index < 0 || index >= size()})
473 */
474 public synchronized E elementAt(int index) {
475 if (index >= elementCount) {
476 throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount);
477 }
478
479 return elementData(index);
480 }
481
482 /**
483 * Returns the first component (the item at index {@code 0}) of
484 * this vector.
485 *
486 * @return the first component of this vector
487 * @throws NoSuchElementException if this vector has no components
488 */
489 public synchronized E firstElement() {
490 if (elementCount == 0) {
491 throw new NoSuchElementException();
492 }
493 return elementData(0);
494 }
495
496 /**
497 * Returns the last component of the vector.
498 *
499 * @return the last component of the vector, i.e., the component at index
500 * <code>size() - 1</code>.
501 * @throws NoSuchElementException if this vector is empty
502 */
503 public synchronized E lastElement() {
504 if (elementCount == 0) {
505 throw new NoSuchElementException();
506 }
507 return elementData(elementCount - 1);
508 }
509
510 /**
511 * Sets the component at the specified {@code index} of this
512 * vector to be the specified object. The previous component at that
513 * position is discarded.
514 *
515 * <p>The index must be a value greater than or equal to {@code 0}
516 * and less than the current size of the vector.
517 *
518 * <p>This method is identical in functionality to the
519 * {@link #set(int, Object) set(int, E)}
520 * method (which is part of the {@link List} interface). Note that the
521 * {@code set} method reverses the order of the parameters, to more closely
522 * match array usage. Note also that the {@code set} method returns the
523 * old value that was stored at the specified position.
524 *
525 * @param obj what the component is to be set to
526 * @param index the specified index
527 * @throws ArrayIndexOutOfBoundsException if the index is out of range
528 * ({@code index < 0 || index >= size()})
529 */
530 public synchronized void setElementAt(E obj, int index) {
531 if (index >= elementCount) {
532 throw new ArrayIndexOutOfBoundsException(index + " >= " +
533 elementCount);
534 }
535 elementData[index] = obj;
536 }
537
538 /**
539 * Deletes the component at the specified index. Each component in
540 * this vector with an index greater or equal to the specified
541 * {@code index} is shifted downward to have an index one
542 * smaller than the value it had previously. The size of this vector
543 * is decreased by {@code 1}.
544 *
545 * <p>The index must be a value greater than or equal to {@code 0}
546 * and less than the current size of the vector.
547 *
548 * <p>This method is identical in functionality to the {@link #remove(int)}
549 * method (which is part of the {@link List} interface). Note that the
550 * {@code remove} method returns the old value that was stored at the
551 * specified position.
552 *
553 * @param index the index of the object to remove
554 * @throws ArrayIndexOutOfBoundsException if the index is out of range
555 * ({@code index < 0 || index >= size()})
556 */
557 public synchronized void removeElementAt(int index) {
558 modCount++;
559 if (index >= elementCount) {
560 throw new ArrayIndexOutOfBoundsException(index + " >= " +
561 elementCount);
562 }
563 else if (index < 0) {
564 throw new ArrayIndexOutOfBoundsException(index);
565 }
566 int j = elementCount - index - 1;
567 if (j > 0) {
568 System.arraycopy(elementData, index + 1, elementData, index, j);
569 }
570 elementCount--;
571 elementData[elementCount] = null; /* to let gc do its work */
572 }
573
574 /**
575 * Inserts the specified object as a component in this vector at the
576 * specified {@code index}. Each component in this vector with
577 * an index greater or equal to the specified {@code index} is
578 * shifted upward to have an index one greater than the value it had
579 * previously.
580 *
581 * <p>The index must be a value greater than or equal to {@code 0}
582 * and less than or equal to the current size of the vector. (If the
583 * index is equal to the current size of the vector, the new element
584 * is appended to the Vector.)
585 *
586 * <p>This method is identical in functionality to the
587 * {@link #add(int, Object) add(int, E)}
588 * method (which is part of the {@link List} interface). Note that the
589 * {@code add} method reverses the order of the parameters, to more closely
590 * match array usage.
591 *
592 * @param obj the component to insert
593 * @param index where to insert the new component
594 * @throws ArrayIndexOutOfBoundsException if the index is out of range
595 * ({@code index < 0 || index > size()})
596 */
597 public synchronized void insertElementAt(E obj, int index) {
598 modCount++;
599 if (index > elementCount) {
600 throw new ArrayIndexOutOfBoundsException(index
601 + " > " + elementCount);
602 }
603 ensureCapacityHelper(elementCount + 1);
604 System.arraycopy(elementData, index, elementData, index + 1, elementCount - index);
605 elementData[index] = obj;
606 elementCount++;
607 }
608
609 /**
610 * Adds the specified component to the end of this vector,
611 * increasing its size by one. The capacity of this vector is
612 * increased if its size becomes greater than its capacity.
613 *
614 * <p>This method is identical in functionality to the
615 * {@link #add(Object) add(E)}
616 * method (which is part of the {@link List} interface).
617 *
618 * @param obj the component to be added
619 */
620 public synchronized void addElement(E obj) {
621 modCount++;
622 ensureCapacityHelper(elementCount + 1);
623 elementData[elementCount++] = obj;
624 }
625
626 /**
627 * Removes the first (lowest-indexed) occurrence of the argument
628 * from this vector. If the object is found in this vector, each
629 * component in the vector with an index greater or equal to the
630 * object's index is shifted downward to have an index one smaller
631 * than the value it had previously.
632 *
633 * <p>This method is identical in functionality to the
634 * {@link #remove(Object)} method (which is part of the
635 * {@link List} interface).
636 *
637 * @param obj the component to be removed
638 * @return {@code true} if the argument was a component of this
639 * vector; {@code false} otherwise.
640 */
641 public synchronized boolean removeElement(Object obj) {
642 modCount++;
643 int i = indexOf(obj);
644 if (i >= 0) {
645 removeElementAt(i);
646 return true;
647 }
648 return false;
649 }
650
651 /**
652 * Removes all components from this vector and sets its size to zero.
653 *
654 * <p>This method is identical in functionality to the {@link #clear}
655 * method (which is part of the {@link List} interface).
656 */
657 public synchronized void removeAllElements() {
658 modCount++;
659 // Let gc do its work
660 for (int i = 0; i < elementCount; i++)
661 elementData[i] = null;
662
663 elementCount = 0;
664 }
665
666 /**
667 * Returns a clone of this vector. The copy will contain a
668 * reference to a clone of the internal data array, not a reference
669 * to the original internal data array of this {@code Vector} object.
670 *
671 * @return a clone of this vector
672 */
673 public synchronized Object clone() {
674 try {
675 @SuppressWarnings("unchecked")
676 Vector<E> v = (Vector<E>) super.clone();
677 v.elementData = Arrays.copyOf(elementData, elementCount);
678 v.modCount = 0;
679 return v;
680 } catch (CloneNotSupportedException e) {
681 // this shouldn't happen, since we are Cloneable
682 throw new InternalError(e);
683 }
684 }
685
686 /**
687 * Returns an array containing all of the elements in this Vector
688 * in the correct order.
689 *
690 * @since 1.2
691 */
692 public synchronized Object[] toArray() {
693 return Arrays.copyOf(elementData, elementCount);
694 }
695
696 /**
697 * Returns an array containing all of the elements in this Vector in the
698 * correct order; the runtime type of the returned array is that of the
699 * specified array. If the Vector fits in the specified array, it is
700 * returned therein. Otherwise, a new array is allocated with the runtime
701 * type of the specified array and the size of this Vector.
702 *
703 * <p>If the Vector fits in the specified array with room to spare
704 * (i.e., the array has more elements than the Vector),
705 * the element in the array immediately following the end of the
706 * Vector is set to null. (This is useful in determining the length
707 * of the Vector <em>only</em> if the caller knows that the Vector
708 * does not contain any null elements.)
709 *
710 * @param a the array into which the elements of the Vector are to
711 * be stored, if it is big enough; otherwise, a new array of the
712 * same runtime type is allocated for this purpose.
713 * @return an array containing the elements of the Vector
714 * @throws ArrayStoreException if the runtime type of a is not a supertype
715 * of the runtime type of every element in this Vector
716 * @throws NullPointerException if the given array is null
717 * @since 1.2
718 */
719 @SuppressWarnings("unchecked")
720 public synchronized <T> T[] toArray(T[] a) {
721 if (a.length < elementCount)
722 return (T[]) Arrays.copyOf(elementData, elementCount, a.getClass());
723
724 System.arraycopy(elementData, 0, a, 0, elementCount);
725
726 if (a.length > elementCount)
727 a[elementCount] = null;
728
729 return a;
730 }
731
732 // Positional Access Operations
733
734 @SuppressWarnings("unchecked")
735 E elementData(int index) {
736 return (E) elementData[index];
737 }
738
739 /**
740 * Returns the element at the specified position in this Vector.
741 *
742 * @param index index of the element to return
743 * @return object at the specified index
744 * @throws ArrayIndexOutOfBoundsException if the index is out of range
745 * ({@code index < 0 || index >= size()})
746 * @since 1.2
747 */
748 public synchronized E get(int index) {
749 if (index >= elementCount)
750 throw new ArrayIndexOutOfBoundsException(index);
751
752 return elementData(index);
753 }
754
755 /**
756 * Replaces the element at the specified position in this Vector with the
757 * specified element.
758 *
759 * @param index index of the element to replace
760 * @param element element to be stored at the specified position
761 * @return the element previously at the specified position
762 * @throws ArrayIndexOutOfBoundsException if the index is out of range
763 * ({@code index < 0 || index >= size()})
764 * @since 1.2
765 */
766 public synchronized E set(int index, E element) {
767 if (index >= elementCount)
768 throw new ArrayIndexOutOfBoundsException(index);
769
770 E oldValue = elementData(index);
771 elementData[index] = element;
772 return oldValue;
773 }
774
775 /**
776 * Appends the specified element to the end of this Vector.
777 *
778 * @param e element to be appended to this Vector
779 * @return {@code true} (as specified by {@link Collection#add})
780 * @since 1.2
781 */
782 public synchronized boolean add(E e) {
783 modCount++;
784 ensureCapacityHelper(elementCount + 1);
785 elementData[elementCount++] = e;
786 return true;
787 }
788
789 /**
790 * Removes the first occurrence of the specified element in this Vector
791 * If the Vector does not contain the element, it is unchanged. More
792 * formally, removes the element with the lowest index i such that
793 * {@code (o==null ? get(i)==null : o.equals(get(i)))} (if such
794 * an element exists).
795 *
796 * @param o element to be removed from this Vector, if present
797 * @return true if the Vector contained the specified element
798 * @since 1.2
799 */
800 public boolean remove(Object o) {
801 return removeElement(o);
802 }
803
804 /**
805 * Inserts the specified element at the specified position in this Vector.
806 * Shifts the element currently at that position (if any) and any
807 * subsequent elements to the right (adds one to their indices).
808 *
809 * @param index index at which the specified element is to be inserted
810 * @param element element to be inserted
811 * @throws ArrayIndexOutOfBoundsException if the index is out of range
812 * ({@code index < 0 || index > size()})
813 * @since 1.2
814 */
815 public void add(int index, E element) {
816 insertElementAt(element, index);
817 }
818
819 /**
820 * Removes the element at the specified position in this Vector.
821 * Shifts any subsequent elements to the left (subtracts one from their
822 * indices). Returns the element that was removed from the Vector.
823 *
824 * @throws ArrayIndexOutOfBoundsException if the index is out of range
825 * ({@code index < 0 || index >= size()})
826 * @param index the index of the element to be removed
827 * @return element that was removed
828 * @since 1.2
829 */
830 public synchronized E remove(int index) {
831 modCount++;
832 if (index >= elementCount)
833 throw new ArrayIndexOutOfBoundsException(index);
834 E oldValue = elementData(index);
835
836 int numMoved = elementCount - index - 1;
837 if (numMoved > 0)
838 System.arraycopy(elementData, index+1, elementData, index,
839 numMoved);
840 elementData[--elementCount] = null; // Let gc do its work
841
842 return oldValue;
843 }
844
845 /**
846 * Removes all of the elements from this Vector. The Vector will
847 * be empty after this call returns (unless it throws an exception).
848 *
849 * @since 1.2
850 */
851 public void clear() {
852 removeAllElements();
853 }
854
855 // Bulk Operations
856
857 /**
858 * Returns true if this Vector contains all of the elements in the
859 * specified Collection.
860 *
861 * @param c a collection whose elements will be tested for containment
862 * in this Vector
863 * @return true if this Vector contains all of the elements in the
864 * specified collection
865 * @throws NullPointerException if the specified collection is null
866 */
867 public synchronized boolean containsAll(Collection<?> c) {
868 return super.containsAll(c);
869 }
870
871 /**
872 * Appends all of the elements in the specified Collection to the end of
873 * this Vector, in the order that they are returned by the specified
874 * Collection's Iterator. The behavior of this operation is undefined if
875 * the specified Collection is modified while the operation is in progress.
876 * (This implies that the behavior of this call is undefined if the
877 * specified Collection is this Vector, and this Vector is nonempty.)
878 *
879 * @param c elements to be inserted into this Vector
880 * @return {@code true} if this Vector changed as a result of the call
881 * @throws NullPointerException if the specified collection is null
882 * @since 1.2
883 */
884 public synchronized boolean addAll(Collection<? extends E> c) {
885 modCount++;
886 Object[] a = c.toArray();
887 int numNew = a.length;
888 ensureCapacityHelper(elementCount + numNew);
889 System.arraycopy(a, 0, elementData, elementCount, numNew);
890 elementCount += numNew;
891 return numNew != 0;
892 }
893
894 /**
895 * Removes from this Vector all of its elements that are contained in the
896 * specified Collection.
897 *
898 * @param c a collection of elements to be removed from the Vector
899 * @return true if this Vector changed as a result of the call
900 * @throws ClassCastException if the types of one or more elements
901 * in this vector are incompatible with the specified
902 * collection
903 * (<a href="Collection.html#optional-restrictions">optional</a>)
904 * @throws NullPointerException if this vector contains one or more null
905 * elements and the specified collection does not support null
906 * elements
907 * (<a href="Collection.html#optional-restrictions">optional</a>),
908 * or if the specified collection is null
909 * @since 1.2
910 */
911 public synchronized boolean removeAll(Collection<?> c) {
912 return super.removeAll(c);
913 }
914
915 /**
916 * Retains only the elements in this Vector that are contained in the
917 * specified Collection. In other words, removes from this Vector all
918 * of its elements that are not contained in the specified Collection.
919 *
920 * @param c a collection of elements to be retained in this Vector
921 * (all other elements are removed)
922 * @return true if this Vector changed as a result of the call
923 * @throws ClassCastException if the types of one or more elements
924 * in this vector are incompatible with the specified
925 * collection
926 * (<a href="Collection.html#optional-restrictions">optional</a>)
927 * @throws NullPointerException if this vector contains one or more null
928 * elements and the specified collection does not support null
929 * elements
930 * (<a href="Collection.html#optional-restrictions">optional</a>),
931 * or if the specified collection is null
932 * @since 1.2
933 */
934 public synchronized boolean retainAll(Collection<?> c) {
935 return super.retainAll(c);
936 }
937
938 /**
939 * Inserts all of the elements in the specified Collection into this
940 * Vector at the specified position. Shifts the element currently at
941 * that position (if any) and any subsequent elements to the right
942 * (increases their indices). The new elements will appear in the Vector
943 * in the order that they are returned by the specified Collection's
944 * iterator.
945 *
946 * @param index index at which to insert the first element from the
947 * specified collection
948 * @param c elements to be inserted into this Vector
949 * @return {@code true} if this Vector changed as a result of the call
950 * @throws ArrayIndexOutOfBoundsException if the index is out of range
951 * ({@code index < 0 || index > size()})
952 * @throws NullPointerException if the specified collection is null
953 * @since 1.2
954 */
955 public synchronized boolean addAll(int index, Collection<? extends E> c) {
956 modCount++;
957 if (index < 0 || index > elementCount)
958 throw new ArrayIndexOutOfBoundsException(index);
959
960 Object[] a = c.toArray();
961 int numNew = a.length;
962 ensureCapacityHelper(elementCount + numNew);
963
964 int numMoved = elementCount - index;
965 if (numMoved > 0)
966 System.arraycopy(elementData, index, elementData, index + numNew,
967 numMoved);
968
969 System.arraycopy(a, 0, elementData, index, numNew);
970 elementCount += numNew;
971 return numNew != 0;
972 }
973
974 /**
975 * Compares the specified Object with this Vector for equality. Returns
976 * true if and only if the specified Object is also a List, both Lists
977 * have the same size, and all corresponding pairs of elements in the two
978 * Lists are <em>equal</em>. (Two elements {@code e1} and
979 * {@code e2} are <em>equal</em> if {@code (e1==null ? e2==null :
980 * e1.equals(e2))}.) In other words, two Lists are defined to be
981 * equal if they contain the same elements in the same order.
982 *
983 * @param o the Object to be compared for equality with this Vector
984 * @return true if the specified Object is equal to this Vector
985 */
986 public synchronized boolean equals(Object o) {
987 return super.equals(o);
988 }
989
990 /**
991 * Returns the hash code value for this Vector.
992 */
993 public synchronized int hashCode() {
994 return super.hashCode();
995 }
996
997 /**
998 * Returns a string representation of this Vector, containing
999 * the String representation of each element.
1000 */
1001 public synchronized String toString() {
1002 return super.toString();
1003 }
1004
1005 /**
1006 * Returns a view of the portion of this List between fromIndex,
1007 * inclusive, and toIndex, exclusive. (If fromIndex and toIndex are
1008 * equal, the returned List is empty.) The returned List is backed by this
1009 * List, so changes in the returned List are reflected in this List, and
1010 * vice-versa. The returned List supports all of the optional List
1011 * operations supported by this List.
1012 *
1013 * <p>This method eliminates the need for explicit range operations (of
1014 * the sort that commonly exist for arrays). Any operation that expects
1015 * a List can be used as a range operation by operating on a subList view
1016 * instead of a whole List. For example, the following idiom
1017 * removes a range of elements from a List:
1018 * <pre>
1019 * list.subList(from, to).clear();
1020 * </pre>
1021 * Similar idioms may be constructed for indexOf and lastIndexOf,
1022 * and all of the algorithms in the Collections class can be applied to
1023 * a subList.
1024 *
1025 * <p>The semantics of the List returned by this method become undefined if
1026 * the backing list (i.e., this List) is <i>structurally modified</i> in
1027 * any way other than via the returned List. (Structural modifications are
1028 * those that change the size of the List, or otherwise perturb it in such
1029 * a fashion that iterations in progress may yield incorrect results.)
1030 *
1031 * @param fromIndex low endpoint (inclusive) of the subList
1032 * @param toIndex high endpoint (exclusive) of the subList
1033 * @return a view of the specified range within this List
1034 * @throws IndexOutOfBoundsException if an endpoint index value is out of range
1035 * {@code (fromIndex < 0 || toIndex > size)}
1036 * @throws IllegalArgumentException if the endpoint indices are out of order
1037 * {@code (fromIndex > toIndex)}
1038 */
1039 public synchronized List<E> subList(int fromIndex, int toIndex) {
1040 return Collections.synchronizedList(super.subList(fromIndex, toIndex),
1041 this);
1042 }
1043
1044 /**
1045 * Removes from this list all of the elements whose index is between
1046 * {@code fromIndex}, inclusive, and {@code toIndex}, exclusive.
1047 * Shifts any succeeding elements to the left (reduces their index).
1048 * This call shortens the list by {@code (toIndex - fromIndex)} elements.
1049 * (If {@code toIndex==fromIndex}, this operation has no effect.)
1050 */
1051 protected synchronized void removeRange(int fromIndex, int toIndex) {
1052 modCount++;
1053 int numMoved = elementCount - toIndex;
1054 System.arraycopy(elementData, toIndex, elementData, fromIndex,
1055 numMoved);
1056
1057 // Let gc do its work
1058 int newElementCount = elementCount - (toIndex-fromIndex);
1059 while (elementCount != newElementCount)
1060 elementData[--elementCount] = null;
1061 }
1062
1063 /**
1064 * Save the state of the {@code Vector} instance to a stream (that
1065 * is, serialize it).
1066 * This method performs synchronization to ensure the consistency
1067 * of the serialized data.
1068 */
1069 private void writeObject(java.io.ObjectOutputStream s)
1070 throws java.io.IOException {
1071 final java.io.ObjectOutputStream.PutField fields = s.putFields();
1072 final Object[] data;
1073 synchronized (this) {
1074 fields.put("capacityIncrement", capacityIncrement);
1075 fields.put("elementCount", elementCount);
1076 data = elementData.clone();
1077 }
1078 fields.put("elementData", data);
1079 s.writeFields();
1080 }
1081
1082 /**
1083 * Returns a list iterator over the elements in this list (in proper
1084 * sequence), starting at the specified position in the list.
1085 * The specified index indicates the first element that would be
1086 * returned by an initial call to {@link ListIterator#next next}.
1087 * An initial call to {@link ListIterator#previous previous} would
1088 * return the element with the specified index minus one.
1089 *
1090 * <p>The returned list iterator is <a href="#fail-fast"><i>fail-fast</i></a>.
1091 *
1092 * @throws IndexOutOfBoundsException {@inheritDoc}
1093 */
1094 public synchronized ListIterator<E> listIterator(int index) {
1095 if (index < 0 || index > elementCount)
1096 throw new IndexOutOfBoundsException("Index: "+index);
1097 return new ListItr(index);
1098 }
1099
1100 /**
1101 * Returns a list iterator over the elements in this list (in proper
1102 * sequence).
1103 *
1104 * <p>The returned list iterator is <a href="#fail-fast"><i>fail-fast</i></a>.
1105 *
1106 * @see #listIterator(int)
1107 */
1108 public synchronized ListIterator<E> listIterator() {
1109 return new ListItr(0);
1110 }
1111
1112 /**
1113 * Returns an iterator over the elements in this list in proper sequence.
1114 *
1115 * <p>The returned iterator is <a href="#fail-fast"><i>fail-fast</i></a>.
1116 *
1117 * @return an iterator over the elements in this list in proper sequence
1118 */
1119 public synchronized Iterator<E> iterator() {
1120 return new Itr();
1121 }
1122
1123 /**
1124 * An optimized version of AbstractList.Itr
1125 */
1126 private class Itr implements Iterator<E> {
1127 int cursor; // index of next element to return
1128 int lastRet = -1; // index of last element returned; -1 if no such
1129 int expectedModCount = modCount;
1130
1131 public boolean hasNext() {
1132 // Racy but within spec, since modifications are checked
1133 // within or after synchronization in next/previous
1134 return cursor != elementCount;
1135 }
1136
1137 public E next() {
1138 synchronized (Vector.this) {
1139 checkForComodification();
1140 int i = cursor;
1141 if (i >= elementCount)
1142 throw new NoSuchElementException();
1143 cursor = i + 1;
1144 return elementData(lastRet = i);
1145 }
1146 }
1147
1148 public void remove() {
1149 if (lastRet == -1)
1150 throw new IllegalStateException();
1151 synchronized (Vector.this) {
1152 checkForComodification();
1153 Vector.this.remove(lastRet);
1154 expectedModCount = modCount;
1155 }
1156 cursor = lastRet;
1157 lastRet = -1;
1158 }
1159
1160 @Override
1161 public void forEachRemaining(Consumer<? super E> action) {
1162 Objects.requireNonNull(action);
1163 synchronized (Vector.this) {
1164 final int size = Vector.this.elementCount;
1165 int i = cursor;
1166 if (i >= size) {
1167 return;
1168 }
1169 final Object[] elementData = Vector.this.elementData;
1170 if (i >= elementData.length) {
1171 throw new ConcurrentModificationException();
1172 }
1173 while (i != size && modCount == expectedModCount) {
1174 action.accept((E) elementData[i++]);
1175 }
1176 // update once at end of iteration to reduce heap write traffic
1177 lastRet = cursor = i;
1178 checkForComodification();
1179 }
1180 }
1181
1182 final void checkForComodification() {
1183 if (modCount != expectedModCount)
1184 throw new ConcurrentModificationException();
1185 }
1186 }
1187
1188 /**
1189 * An optimized version of AbstractList.ListItr
1190 */
1191 final class ListItr extends Itr implements ListIterator<E> {
1192 ListItr(int index) {
1193 super();
1194 cursor = index;
1195 }
1196
1197 public boolean hasPrevious() {
1198 return cursor != 0;
1199 }
1200
1201 public int nextIndex() {
1202 return cursor;
1203 }
1204
1205 public int previousIndex() {
1206 return cursor - 1;
1207 }
1208
1209 public E previous() {
1210 synchronized (Vector.this) {
1211 checkForComodification();
1212 int i = cursor - 1;
1213 if (i < 0)
1214 throw new NoSuchElementException();
1215 cursor = i;
1216 return elementData(lastRet = i);
1217 }
1218 }
1219
1220 public void set(E e) {
1221 if (lastRet == -1)
1222 throw new IllegalStateException();
1223 synchronized (Vector.this) {
1224 checkForComodification();
1225 Vector.this.set(lastRet, e);
1226 }
1227 }
1228
1229 public void add(E e) {
1230 int i = cursor;
1231 synchronized (Vector.this) {
1232 checkForComodification();
1233 Vector.this.add(i, e);
1234 expectedModCount = modCount;
1235 }
1236 cursor = i + 1;
1237 lastRet = -1;
1238 }
1239 }
1240
1241 @Override
1242 public synchronized void forEach(Consumer<? super E> action) {
1243 Objects.requireNonNull(action);
1244 final int expectedModCount = modCount;
1245 @SuppressWarnings("unchecked")
1246 final E[] elementData = (E[]) this.elementData;
1247 final int elementCount = this.elementCount;
1248 for (int i=0; modCount == expectedModCount && i < elementCount; i++) {
1249 action.accept(elementData[i]);
1250 }
1251 if (modCount != expectedModCount) {
1252 throw new ConcurrentModificationException();
1253 }
1254 }
1255
1256 @Override
1257 @SuppressWarnings("unchecked")
1258 public synchronized boolean removeIf(Predicate<? super E> filter) {
1259 Objects.requireNonNull(filter);
1260 // figure out which elements are to be removed
1261 // any exception thrown from the filter predicate at this stage
1262 // will leave the collection unmodified
1263 int removeCount = 0;
1264 final int size = elementCount;
1265 final BitSet removeSet = new BitSet(size);
1266 final int expectedModCount = modCount;
1267 for (int i=0; modCount == expectedModCount && i < size; i++) {
1268 @SuppressWarnings("unchecked")
1269 final E element = (E) elementData[i];
1270 if (filter.test(element)) {
1271 removeSet.set(i);
1272 removeCount++;
1273 }
1274 }
1275 if (modCount != expectedModCount) {
1276 throw new ConcurrentModificationException();
1277 }
1278
1279 // shift surviving elements left over the spaces left by removed elements
1280 final boolean anyToRemove = removeCount > 0;
1281 if (anyToRemove) {
1282 final int newSize = size - removeCount;
1283 for (int i=0, j=0; (i < size) && (j < newSize); i++, j++) {
1284 i = removeSet.nextClearBit(i);
1285 elementData[j] = elementData[i];
1286 }
1287 for (int k=newSize; k < size; k++) {
1288 elementData[k] = null; // Let gc do its work
1289 }
1290 elementCount = newSize;
1291 if (modCount != expectedModCount) {
1292 throw new ConcurrentModificationException();
1293 }
1294 modCount++;
1295 }
1296
1297 return anyToRemove;
1298 }
1299
1300 @Override
1301 @SuppressWarnings("unchecked")
1302 public synchronized void replaceAll(UnaryOperator<E> operator) {
1303 Objects.requireNonNull(operator);
1304 final int expectedModCount = modCount;
1305 final int size = elementCount;
1306 for (int i=0; modCount == expectedModCount && i < size; i++) {
1307 elementData[i] = operator.apply((E) elementData[i]);
1308 }
1309 if (modCount != expectedModCount) {
1310 throw new ConcurrentModificationException();
1311 }
1312 modCount++;
1313 }
1314
1315 @Override
1316 @SuppressWarnings("unchecked")
1317 public synchronized void sort(Comparator<? super E> c) {
1318 final int expectedModCount = modCount;
1319 Arrays.sort((E[]) elementData, 0, elementCount, c);
1320 if (modCount != expectedModCount) {
1321 throw new ConcurrentModificationException();
1322 }
1323 modCount++;
1324 }
1325
1326 @Override
1327 public Spliterator<E> spliterator() {
1328 return new VectorSpliterator<>(this, null, 0, -1, 0);
1329 }
1330
1331 /** Similar to ArrayList Spliterator */
1332 static final class VectorSpliterator<E> implements Spliterator<E> {
1333 private final Vector<E> list;
1334 private Object[] array;
1335 private int index; // current index, modified on advance/split
1336 private int fence; // -1 until used; then one past last index
1337 private int expectedModCount; // initialized when fence set
1338
1339 /** Create new spliterator covering the given range */
1340 VectorSpliterator(Vector<E> list, Object[] array, int origin, int fence,
1341 int expectedModCount) {
1342 this.list = list;
1343 this.array = array;
1344 this.index = origin;
1345 this.fence = fence;
1346 this.expectedModCount = expectedModCount;
1347 }
1348
1349 private int getFence() { // initialize on first use
1350 int hi;
1351 if ((hi = fence) < 0) {
1352 synchronized(list) {
1353 array = list.elementData;
1354 expectedModCount = list.modCount;
1355 hi = fence = list.elementCount;
1356 }
1357 }
1358 return hi;
1359 }
1360
1361 public Spliterator<E> trySplit() {
1362 int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
1363 return (lo >= mid) ? null :
1364 new VectorSpliterator<E>(list, array, lo, index = mid,
1365 expectedModCount);
1366 }
1367
1368 @SuppressWarnings("unchecked")
1369 public boolean tryAdvance(Consumer<? super E> action) {
1370 int i;
1371 if (action == null)
1372 throw new NullPointerException();
1373 if (getFence() > (i = index)) {
1374 index = i + 1;
1375 action.accept((E)array[i]);
1376 if (list.modCount != expectedModCount)
1377 throw new ConcurrentModificationException();
1378 return true;
1379 }
1380 return false;
1381 }
1382
1383 @SuppressWarnings("unchecked")
1384 public void forEachRemaining(Consumer<? super E> action) {
1385 int i, hi; // hoist accesses and checks from loop
1386 Vector<E> lst; Object[] a;
1387 if (action == null)
1388 throw new NullPointerException();
1389 if ((lst = list) != null) {
1390 if ((hi = fence) < 0) {
1391 synchronized(lst) {
1392 expectedModCount = lst.modCount;
1393 a = array = lst.elementData;
1394 hi = fence = lst.elementCount;
1395 }
1396 }
1397 else
1398 a = array;
1399 if (a != null && (i = index) >= 0 && (index = hi) <= a.length) {
1400 while (i < hi)
1401 action.accept((E) a[i++]);
1402 if (lst.modCount == expectedModCount)
1403 return;
1404 }
1405 }
1406 throw new ConcurrentModificationException();
1407 }
1408
1409 public long estimateSize() {
1410 return (long) (getFence() - index);
1411 }
1412
1413 public int characteristics() {
1414 return Spliterator.ORDERED | Spliterator.SIZED | Spliterator.SUBSIZED;
1415 }
1416 }
1417 }