| Vector.java |
1 /*
2 * %W% %E%
3 *
4 * Copyright (c) 2006, Oracle and/or its affiliates. All rights reserved.
5 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6 */
7
8 package java.util;
9
10 /**
11 * The {@code Vector} class implements a growable array of
12 * objects. Like an array, it contains components that can be
13 * accessed using an integer index. However, the size of a
14 * {@code Vector} can grow or shrink as needed to accommodate
15 * adding and removing items after the {@code Vector} has been created.
16 *
17 * <p>Each vector tries to optimize storage management by maintaining a
18 * {@code capacity} and a {@code capacityIncrement}. The
19 * {@code capacity} is always at least as large as the vector
20 * size; it is usually larger because as components are added to the
21 * vector, the vector's storage increases in chunks the size of
22 * {@code capacityIncrement}. An application can increase the
23 * capacity of a vector before inserting a large number of
24 * components; this reduces the amount of incremental reallocation.
25 *
26 * <p>The Iterators returned by Vector's iterator and listIterator
27 * methods are <em>fail-fast</em>: if the Vector is structurally modified
28 * at any time after the Iterator is created, in any way except through the
29 * Iterator's own remove or add methods, the Iterator will throw a
30 * ConcurrentModificationException. Thus, in the face of concurrent
31 * modification, the Iterator fails quickly and cleanly, rather than risking
32 * arbitrary, non-deterministic behavior at an undetermined time in the future.
33 * The Enumerations returned by Vector's elements method are <em>not</em>
34 * fail-fast.
35 *
36 * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed
37 * as it is, generally speaking, impossible to make any hard guarantees in the
38 * presence of unsynchronized concurrent modification. Fail-fast iterators
39 * throw {@code ConcurrentModificationException} on a best-effort basis.
40 * Therefore, it would be wrong to write a program that depended on this
41 * exception for its correctness: <i>the fail-fast behavior of iterators
42 * should be used only to detect bugs.</i>
43 *
44 * <p>As of the Java 2 platform v1.2, this class was retrofitted to
45 * implement the {@link List} interface, making it a member of the
46 * <a href="{@docRoot}/../technotes/guides/collections/index.html"> Java
47 * Collections Framework</a>. Unlike the new collection
48 * implementations, {@code Vector} is synchronized.
49 *
50 * @author Lee Boynton
51 * @author Jonathan Payne
52 * @version %I%, %G%
53 * @see Collection
54 * @see List
55 * @see ArrayList
56 * @see LinkedList
57 * @since JDK1.0
58 */
59 public class Vector<E>
60 extends AbstractList<E>
61 implements List<E>, RandomAccess, Cloneable, java.io.Serializable
62 {
63 /**
64 * The array buffer into which the components of the vector are
65 * stored. The capacity of the vector is the length of this array buffer,
66 * and is at least large enough to contain all the vector's elements.
67 *
68 * <p>Any array elements following the last element in the Vector are null.
69 *
70 * @serial
71 */
72 protected Object[] elementData;
73
74 /**
75 * The number of valid components in this {@code Vector} object.
76 * Components {@code elementData[0]} through
77 * {@code elementData[elementCount-1]} are the actual items.
78 *
79 * @serial
80 */
81 protected int elementCount;
82
83 /**
84 * The amount by which the capacity of the vector is automatically
85 * incremented when its size becomes greater than its capacity. If
86 * the capacity increment is less than or equal to zero, the capacity
87 * of the vector is doubled each time it needs to grow.
88 *
89 * @serial
90 */
91 protected int capacityIncrement;
92
93 /** use serialVersionUID from JDK 1.0.2 for interoperability */
94 private static final long serialVersionUID = -2767605614048989439L;
95
96 /**
97 * Constructs an empty vector with the specified initial capacity and
98 * capacity increment.
99 *
100 * @param initialCapacity the initial capacity of the vector
101 * @param capacityIncrement the amount by which the capacity is
102 * increased when the vector overflows
103 * @throws IllegalArgumentException if the specified initial capacity
104 * is negative
105 */
106 public Vector(int initialCapacity, int capacityIncrement) {
107 super();
108 if (initialCapacity < 0)
109 throw new IllegalArgumentException("Illegal Capacity: "+
110 initialCapacity);
111 this.elementData = new Object[initialCapacity];
112 this.capacityIncrement = capacityIncrement;
113 }
114
115 /**
116 * Constructs an empty vector with the specified initial capacity and
117 * with its capacity increment equal to zero.
118 *
119 * @param initialCapacity the initial capacity of the vector
120 * @throws IllegalArgumentException if the specified initial capacity
121 * is negative
122 */
123 public Vector(int initialCapacity) {
124 this(initialCapacity, 0);
125 }
126
127 /**
128 * Constructs an empty vector so that its internal data array
129 * has size {@code 10} and its standard capacity increment is
130 * zero.
131 */
132 public Vector() {
133 this(10);
134 }
135
136 /**
137 * Constructs a vector containing the elements of the specified
138 * collection, in the order they are returned by the collection's
139 * iterator.
140 *
141 * @param c the collection whose elements are to be placed into this
142 * vector
143 * @throws NullPointerException if the specified collection is null
144 * @since 1.2
145 */
146 public Vector(Collection<? extends E> c) {
147 elementData = c.toArray();
148 elementCount = elementData.length;
149 // c.toArray might (incorrectly) not return Object[] (see 6260652)
150 if (elementData.getClass() != Object[].class)
151 elementData = Arrays.copyOf(elementData, elementCount, Object[].class);
152 }
153
154 /**
155 * Copies the components of this vector into the specified array.
156 * The item at index {@code k} in this vector is copied into
157 * component {@code k} of {@code anArray}.
158 *
159 * @param anArray the array into which the components get copied
160 * @throws NullPointerException if the given array is null
161 * @throws IndexOutOfBoundsException if the specified array is not
162 * large enough to hold all the components of this vector
163 * @throws ArrayStoreException if a component of this vector is not of
164 * a runtime type that can be stored in the specified array
165 * @see #toArray(Object[])
166 */
167 public synchronized void copyInto(Object[] anArray) {
168 System.arraycopy(elementData, 0, anArray, 0, elementCount);
169 }
170
171 /**
172 * Trims the capacity of this vector to be the vector's current
173 * size. If the capacity of this vector is larger than its current
174 * size, then the capacity is changed to equal the size by replacing
175 * its internal data array, kept in the field {@code elementData},
176 * with a smaller one. An application can use this operation to
177 * minimize the storage of a vector.
178 */
179 public synchronized void trimToSize() {
180 modCount++;
181 int oldCapacity = elementData.length;
182 if (elementCount < oldCapacity) {
183 elementData = Arrays.copyOf(elementData, elementCount);
184 }
185 }
186
187 /**
188 * Increases the capacity of this vector, if necessary, to ensure
189 * that it can hold at least the number of components specified by
190 * the minimum capacity argument.
191 *
192 * <p>If the current capacity of this vector is less than
193 * {@code minCapacity}, then its capacity is increased by replacing its
194 * internal data array, kept in the field {@code elementData}, with a
195 * larger one. The size of the new data array will be the old size plus
196 * {@code capacityIncrement}, unless the value of
197 * {@code capacityIncrement} is less than or equal to zero, in which case
198 * the new capacity will be twice the old capacity; but if this new size
199 * is still smaller than {@code minCapacity}, then the new capacity will
200 * be {@code minCapacity}.
201 *
202 * @param minCapacity the desired minimum capacity
203 */
204 public synchronized void ensureCapacity(int minCapacity) {
205 modCount++;
206 ensureCapacityHelper(minCapacity);
207 }
208
209 /**
210 * This implements the unsynchronized semantics of ensureCapacity.
211 * Synchronized methods in this class can internally call this
212 * method for ensuring capacity without incurring the cost of an
213 * extra synchronization.
214 *
215 * @see #ensureCapacity(int)
216 */
217 private void ensureCapacityHelper(int minCapacity) {
218 int oldCapacity = elementData.length;
219 if (minCapacity > oldCapacity) {
220 Object[] oldData = elementData;
221 int newCapacity = (capacityIncrement > 0) ?
222 (oldCapacity + capacityIncrement) : (oldCapacity * 2);
223 if (newCapacity < minCapacity) {
224 newCapacity = minCapacity;
225 }
226 elementData = Arrays.copyOf(elementData, newCapacity);
227 }
228 }
229
230 /**
231 * Sets the size of this vector. If the new size is greater than the
232 * current size, new {@code null} items are added to the end of
233 * the vector. If the new size is less than the current size, all
234 * components at index {@code newSize} and greater are discarded.
235 *
236 * @param newSize the new size of this vector
237 * @throws ArrayIndexOutOfBoundsException if the new size is negative
238 */
239 public synchronized void setSize(int newSize) {
240 modCount++;
241 if (newSize > elementCount) {
242 ensureCapacityHelper(newSize);
243 } else {
244 for (int i = newSize ; i < elementCount ; i++) {
245 elementData[i] = null;
246 }
247 }
248 elementCount = newSize;
249 }
250
251 /**
252 * Returns the current capacity of this vector.
253 *
254 * @return the current capacity (the length of its internal
255 * data array, kept in the field {@code elementData}
256 * of this vector)
257 */
258 public synchronized int capacity() {
259 return elementData.length;
260 }
261
262 /**
263 * Returns the number of components in this vector.
264 *
265 * @return the number of components in this vector
266 */
267 public synchronized int size() {
268 return elementCount;
269 }
270
271 /**
272 * Tests if this vector has no components.
273 *
274 * @return {@code true} if and only if this vector has
275 * no components, that is, its size is zero;
276 * {@code false} otherwise.
277 */
278 public synchronized boolean isEmpty() {
279 return elementCount == 0;
280 }
281
282 /**
283 * Returns an enumeration of the components of this vector. The
284 * returned {@code Enumeration} object will generate all items in
285 * this vector. The first item generated is the item at index {@code 0},
286 * then the item at index {@code 1}, and so on.
287 *
288 * @return an enumeration of the components of this vector
289 * @see Iterator
290 */
291 public Enumeration<E> elements() {
292 return new Enumeration<E>() {
293 int count = 0;
294
295 public boolean hasMoreElements() {
296 return count < elementCount;
297 }
298
299 public E nextElement() {
300 synchronized (Vector.this) {
301 if (count < elementCount) {
302 return (E)elementData[count++];
303 }
304 }
305 throw new NoSuchElementException("Vector Enumeration");
306 }
307 };
308 }
309
310 /**
311 * Returns {@code true} if this vector contains the specified element.
312 * More formally, returns {@code true} if and only if this vector
313 * contains at least one element {@code e} such that
314 * <tt>(o==null ? e==null : o.equals(e))</tt>.
315 *
316 * @param o element whose presence in this vector is to be tested
317 * @return {@code true} if this vector contains the specified element
318 */
319 public boolean contains(Object o) {
320 return indexOf(o, 0) >= 0;
321 }
322
323 /**
324 * Returns the index of the first occurrence of the specified element
325 * in this vector, or -1 if this vector does not contain the element.
326 * More formally, returns the lowest index {@code i} such that
327 * <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>,
328 * or -1 if there is no such index.
329 *
330 * @param o element to search for
331 * @return the index of the first occurrence of the specified element in
332 * this vector, or -1 if this vector does not contain the element
333 */
334 public int indexOf(Object o) {
335 return indexOf(o, 0);
336 }
337
338 /**
339 * Returns the index of the first occurrence of the specified element in
340 * this vector, searching forwards from {@code index}, or returns -1 if
341 * the element is not found.
342 * More formally, returns the lowest index {@code i} such that
343 * <tt>(i >= index && (o==null ? get(i)==null : o.equals(get(i))))</tt>,
344 * or -1 if there is no such index.
345 *
346 * @param o element to search for
347 * @param index index to start searching from
348 * @return the index of the first occurrence of the element in
349 * this vector at position {@code index} or later in the vector;
350 * {@code -1} if the element is not found.
351 * @throws IndexOutOfBoundsException if the specified index is negative
352 * @see Object#equals(Object)
353 */
354 public synchronized int indexOf(Object o, int index) {
355 if (o == null) {
356 for (int i = index ; i < elementCount ; i++)
357 if (elementData[i]==null)
358 return i;
359 } else {
360 for (int i = index ; i < elementCount ; i++)
361 if (o.equals(elementData[i]))
362 return i;
363 }
364 return -1;
365 }
366
367 /**
368 * Returns the index of the last occurrence of the specified element
369 * in this vector, or -1 if this vector does not contain the element.
370 * More formally, returns the highest index {@code i} such that
371 * <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>,
372 * or -1 if there is no such index.
373 *
374 * @param o element to search for
375 * @return the index of the last occurrence of the specified element in
376 * this vector, or -1 if this vector does not contain the element
377 */
378 public synchronized int lastIndexOf(Object o) {
379 return lastIndexOf(o, elementCount-1);
380 }
381
382 /**
383 * Returns the index of the last occurrence of the specified element in
384 * this vector, searching backwards from {@code index}, or returns -1 if
385 * the element is not found.
386 * More formally, returns the highest index {@code i} such that
387 * <tt>(i <= index && (o==null ? get(i)==null : o.equals(get(i))))</tt>,
388 * or -1 if there is no such index.
389 *
390 * @param o element to search for
391 * @param index index to start searching backwards from
392 * @return the index of the last occurrence of the element at position
393 * less than or equal to {@code index} in this vector;
394 * -1 if the element is not found.
395 * @throws IndexOutOfBoundsException if the specified index is greater
396 * than or equal to the current size of this vector
397 */
398 public synchronized int lastIndexOf(Object o, int index) {
399 if (index >= elementCount)
400 throw new IndexOutOfBoundsException(index + " >= "+ elementCount);
401
402 if (o == null) {
403 for (int i = index; i >= 0; i--)
404 if (elementData[i]==null)
405 return i;
406 } else {
407 for (int i = index; i >= 0; i--)
408 if (o.equals(elementData[i]))
409 return i;
410 }
411 return -1;
412 }
413
414 /**
415 * Returns the component at the specified index.
416 *
417 * <p>This method is identical in functionality to the {@link #get(int)}
418 * method (which is part of the {@link List} interface).
419 *
420 * @param index an index into this vector
421 * @return the component at the specified index
422 * @throws ArrayIndexOutOfBoundsException if the index is out of range
423 * ({@code index < 0 || index >= size()})
424 */
425 public synchronized E elementAt(int index) {
426 if (index >= elementCount) {
427 throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount);
428 }
429
430 return (E)elementData[index];
431 }
432
433 /**
434 * Returns the first component (the item at index {@code 0}) of
435 * this vector.
436 *
437 * @return the first component of this vector
438 * @throws NoSuchElementException if this vector has no components
439 */
440 public synchronized E firstElement() {
441 if (elementCount == 0) {
442 throw new NoSuchElementException();
443 }
444 return (E)elementData[0];
445 }
446
447 /**
448 * Returns the last component of the vector.
449 *
450 * @return the last component of the vector, i.e., the component at index
451 * <code>size() - 1</code>.
452 * @throws NoSuchElementException if this vector is empty
453 */
454 public synchronized E lastElement() {
455 if (elementCount == 0) {
456 throw new NoSuchElementException();
457 }
458 return (E)elementData[elementCount - 1];
459 }
460
461 /**
462 * Sets the component at the specified {@code index} of this
463 * vector to be the specified object. The previous component at that
464 * position is discarded.
465 *
466 * <p>The index must be a value greater than or equal to {@code 0}
467 * and less than the current size of the vector.
468 *
469 * <p>This method is identical in functionality to the
470 * {@link #set(int, Object) set(int, E)}
471 * method (which is part of the {@link List} interface). Note that the
472 * {@code set} method reverses the order of the parameters, to more closely
473 * match array usage. Note also that the {@code set} method returns the
474 * old value that was stored at the specified position.
475 *
476 * @param obj what the component is to be set to
477 * @param index the specified index
478 * @throws ArrayIndexOutOfBoundsException if the index is out of range
479 * ({@code index < 0 || index >= size()})
480 */
481 public synchronized void setElementAt(E obj, int index) {
482 if (index >= elementCount) {
483 throw new ArrayIndexOutOfBoundsException(index + " >= " +
484 elementCount);
485 }
486 elementData[index] = obj;
487 }
488
489 /**
490 * Deletes the component at the specified index. Each component in
491 * this vector with an index greater or equal to the specified
492 * {@code index} is shifted downward to have an index one
493 * smaller than the value it had previously. The size of this vector
494 * is decreased by {@code 1}.
495 *
496 * <p>The index must be a value greater than or equal to {@code 0}
497 * and less than the current size of the vector.
498 *
499 * <p>This method is identical in functionality to the {@link #remove(int)}
500 * method (which is part of the {@link List} interface). Note that the
501 * {@code remove} method returns the old value that was stored at the
502 * specified position.
503 *
504 * @param index the index of the object to remove
505 * @throws ArrayIndexOutOfBoundsException if the index is out of range
506 * ({@code index < 0 || index >= size()})
507 */
508 public synchronized void removeElementAt(int index) {
509 modCount++;
510 if (index >= elementCount) {
511 throw new ArrayIndexOutOfBoundsException(index + " >= " +
512 elementCount);
513 }
514 else if (index < 0) {
515 throw new ArrayIndexOutOfBoundsException(index);
516 }
517 int j = elementCount - index - 1;
518 if (j > 0) {
519 System.arraycopy(elementData, index + 1, elementData, index, j);
520 }
521 elementCount--;
522 elementData[elementCount] = null; /* to let gc do its work */
523 }
524
525 /**
526 * Inserts the specified object as a component in this vector at the
527 * specified {@code index}. Each component in this vector with
528 * an index greater or equal to the specified {@code index} is
529 * shifted upward to have an index one greater than the value it had
530 * previously.
531 *
532 * <p>The index must be a value greater than or equal to {@code 0}
533 * and less than or equal to the current size of the vector. (If the
534 * index is equal to the current size of the vector, the new element
535 * is appended to the Vector.)
536 *
537 * <p>This method is identical in functionality to the
538 * {@link #add(int, Object) add(int, E)}
539 * method (which is part of the {@link List} interface). Note that the
540 * {@code add} method reverses the order of the parameters, to more closely
541 * match array usage.
542 *
543 * @param obj the component to insert
544 * @param index where to insert the new component
545 * @throws ArrayIndexOutOfBoundsException if the index is out of range
546 * ({@code index < 0 || index > size()})
547 */
548 public synchronized void insertElementAt(E obj, int index) {
549 modCount++;
550 if (index > elementCount) {
551 throw new ArrayIndexOutOfBoundsException(index
552 + " > " + elementCount);
553 }
554 ensureCapacityHelper(elementCount + 1);
555 System.arraycopy(elementData, index, elementData, index + 1, elementCount - index);
556 elementData[index] = obj;
557 elementCount++;
558 }
559
560 /**
561 * Adds the specified component to the end of this vector,
562 * increasing its size by one. The capacity of this vector is
563 * increased if its size becomes greater than its capacity.
564 *
565 * <p>This method is identical in functionality to the
566 * {@link #add(Object) add(E)}
567 * method (which is part of the {@link List} interface).
568 *
569 * @param obj the component to be added
570 */
571 public synchronized void addElement(E obj) {
572 modCount++;
573 ensureCapacityHelper(elementCount + 1);
574 elementData[elementCount++] = obj;
575 }
576
577 /**
578 * Removes the first (lowest-indexed) occurrence of the argument
579 * from this vector. If the object is found in this vector, each
580 * component in the vector with an index greater or equal to the
581 * object's index is shifted downward to have an index one smaller
582 * than the value it had previously.
583 *
584 * <p>This method is identical in functionality to the
585 * {@link #remove(Object)} method (which is part of the
586 * {@link List} interface).
587 *
588 * @param obj the component to be removed
589 * @return {@code true} if the argument was a component of this
590 * vector; {@code false} otherwise.
591 */
592 public synchronized boolean removeElement(Object obj) {
593 modCount++;
594 int i = indexOf(obj);
595 if (i >= 0) {
596 removeElementAt(i);
597 return true;
598 }
599 return false;
600 }
601
602 /**
603 * Removes all components from this vector and sets its size to zero.
604 *
605 * <p>This method is identical in functionality to the {@link #clear}
606 * method (which is part of the {@link List} interface).
607 */
608 public synchronized void removeAllElements() {
609 modCount++;
610 // Let gc do its work
611 for (int i = 0; i < elementCount; i++)
612 elementData[i] = null;
613
614 elementCount = 0;
615 }
616
617 /**
618 * Returns a clone of this vector. The copy will contain a
619 * reference to a clone of the internal data array, not a reference
620 * to the original internal data array of this {@code Vector} object.
621 *
622 * @return a clone of this vector
623 */
624 public synchronized Object clone() {
625 try {
626 Vector<E> v = (Vector<E>) super.clone();
627 v.elementData = Arrays.copyOf(elementData, elementCount);
628 v.modCount = 0;
629 return v;
630 } catch (CloneNotSupportedException e) {
631 // this shouldn't happen, since we are Cloneable
632 throw new InternalError();
633 }
634 }
635
636 /**
637 * Returns an array containing all of the elements in this Vector
638 * in the correct order.
639 *
640 * @since 1.2
641 */
642 public synchronized Object[] toArray() {
643 return Arrays.copyOf(elementData, elementCount);
644 }
645
646 /**
647 * Returns an array containing all of the elements in this Vector in the
648 * correct order; the runtime type of the returned array is that of the
649 * specified array. If the Vector fits in the specified array, it is
650 * returned therein. Otherwise, a new array is allocated with the runtime
651 * type of the specified array and the size of this Vector.
652 *
653 * <p>If the Vector fits in the specified array with room to spare
654 * (i.e., the array has more elements than the Vector),
655 * the element in the array immediately following the end of the
656 * Vector is set to null. (This is useful in determining the length
657 * of the Vector <em>only</em> if the caller knows that the Vector
658 * does not contain any null elements.)
659 *
660 * @param a the array into which the elements of the Vector are to
661 * be stored, if it is big enough; otherwise, a new array of the
662 * same runtime type is allocated for this purpose.
663 * @return an array containing the elements of the Vector
664 * @throws ArrayStoreException if the runtime type of a is not a supertype
665 * of the runtime type of every element in this Vector
666 * @throws NullPointerException if the given array is null
667 * @since 1.2
668 */
669 public synchronized <T> T[] toArray(T[] a) {
670 if (a.length < elementCount)
671 return (T[]) Arrays.copyOf(elementData, elementCount, a.getClass());
672
673 System.arraycopy(elementData, 0, a, 0, elementCount);
674
675 if (a.length > elementCount)
676 a[elementCount] = null;
677
678 return a;
679 }
680
681 // Positional Access Operations
682
683 /**
684 * Returns the element at the specified position in this Vector.
685 *
686 * @param index index of the element to return
687 * @return object at the specified index
688 * @throws ArrayIndexOutOfBoundsException if the index is out of range
689 * ({@code index < 0 || index >= size()})
690 * @since 1.2
691 */
692 public synchronized E get(int index) {
693 if (index >= elementCount)
694 throw new ArrayIndexOutOfBoundsException(index);
695
696 return (E)elementData[index];
697 }
698
699 /**
700 * Replaces the element at the specified position in this Vector with the
701 * specified element.
702 *
703 * @param index index of the element to replace
704 * @param element element to be stored at the specified position
705 * @return the element previously at the specified position
706 * @throws ArrayIndexOutOfBoundsException if the index is out of range
707 * ({@code index < 0 || index >= size()})
708 * @since 1.2
709 */
710 public synchronized E set(int index, E element) {
711 if (index >= elementCount)
712 throw new ArrayIndexOutOfBoundsException(index);
713
714 Object oldValue = elementData[index];
715 elementData[index] = element;
716 return (E)oldValue;
717 }
718
719 /**
720 * Appends the specified element to the end of this Vector.
721 *
722 * @param e element to be appended to this Vector
723 * @return {@code true} (as specified by {@link Collection#add})
724 * @since 1.2
725 */
726 public synchronized boolean add(E e) {
727 modCount++;
728 ensureCapacityHelper(elementCount + 1);
729 elementData[elementCount++] = e;
730 return true;
731 }
732
733 /**
734 * Removes the first occurrence of the specified element in this Vector
735 * If the Vector does not contain the element, it is unchanged. More
736 * formally, removes the element with the lowest index i such that
737 * {@code (o==null ? get(i)==null : o.equals(get(i)))} (if such
738 * an element exists).
739 *
740 * @param o element to be removed from this Vector, if present
741 * @return true if the Vector contained the specified element
742 * @since 1.2
743 */
744 public boolean remove(Object o) {
745 return removeElement(o);
746 }
747
748 /**
749 * Inserts the specified element at the specified position in this Vector.
750 * Shifts the element currently at that position (if any) and any
751 * subsequent elements to the right (adds one to their indices).
752 *
753 * @param index index at which the specified element is to be inserted
754 * @param element element to be inserted
755 * @throws ArrayIndexOutOfBoundsException if the index is out of range
756 * ({@code index < 0 || index > size()})
757 * @since 1.2
758 */
759 public void add(int index, E element) {
760 insertElementAt(element, index);
761 }
762
763 /**
764 * Removes the element at the specified position in this Vector.
765 * Shifts any subsequent elements to the left (subtracts one from their
766 * indices). Returns the element that was removed from the Vector.
767 *
768 * @throws ArrayIndexOutOfBoundsException if the index is out of range
769 * ({@code index < 0 || index >= size()})
770 * @param index the index of the element to be removed
771 * @return element that was removed
772 * @since 1.2
773 */
774 public synchronized E remove(int index) {
775 modCount++;
776 if (index >= elementCount)
777 throw new ArrayIndexOutOfBoundsException(index);
778 Object oldValue = elementData[index];
779
780 int numMoved = elementCount - index - 1;
781 if (numMoved > 0)
782 System.arraycopy(elementData, index+1, elementData, index,
783 numMoved);
784 elementData[--elementCount] = null; // Let gc do its work
785
786 return (E)oldValue;
787 }
788
789 /**
790 * Removes all of the elements from this Vector. The Vector will
791 * be empty after this call returns (unless it throws an exception).
792 *
793 * @since 1.2
794 */
795 public void clear() {
796 removeAllElements();
797 }
798
799 // Bulk Operations
800
801 /**
802 * Returns true if this Vector contains all of the elements in the
803 * specified Collection.
804 *
805 * @param c a collection whose elements will be tested for containment
806 * in this Vector
807 * @return true if this Vector contains all of the elements in the
808 * specified collection
809 * @throws NullPointerException if the specified collection is null
810 */
811 public synchronized boolean containsAll(Collection<?> c) {
812 return super.containsAll(c);
813 }
814
815 /**
816 * Appends all of the elements in the specified Collection to the end of
817 * this Vector, in the order that they are returned by the specified
818 * Collection's Iterator. The behavior of this operation is undefined if
819 * the specified Collection is modified while the operation is in progress.
820 * (This implies that the behavior of this call is undefined if the
821 * specified Collection is this Vector, and this Vector is nonempty.)
822 *
823 * @param c elements to be inserted into this Vector
824 * @return {@code true} if this Vector changed as a result of the call
825 * @throws NullPointerException if the specified collection is null
826 * @since 1.2
827 */
828 public synchronized boolean addAll(Collection<? extends E> c) {
829 modCount++;
830 Object[] a = c.toArray();
831 int numNew = a.length;
832 ensureCapacityHelper(elementCount + numNew);
833 System.arraycopy(a, 0, elementData, elementCount, numNew);
834 elementCount += numNew;
835 return numNew != 0;
836 }
837
838 /**
839 * Removes from this Vector all of its elements that are contained in the
840 * specified Collection.
841 *
842 * @param c a collection of elements to be removed from the Vector
843 * @return true if this Vector changed as a result of the call
844 * @throws ClassCastException if the types of one or more elements
845 * in this vector are incompatible with the specified
846 * collection (optional)
847 * @throws NullPointerException if this vector contains one or more null
848 * elements and the specified collection does not support null
849 * elements (optional), or if the specified collection is null
850 * @since 1.2
851 */
852 public synchronized boolean removeAll(Collection<?> c) {
853 return super.removeAll(c);
854 }
855
856 /**
857 * Retains only the elements in this Vector that are contained in the
858 * specified Collection. In other words, removes from this Vector all
859 * of its elements that are not contained in the specified Collection.
860 *
861 * @param c a collection of elements to be retained in this Vector
862 * (all other elements are removed)
863 * @return true if this Vector changed as a result of the call
864 * @throws ClassCastException if the types of one or more elements
865 * in this vector are incompatible with the specified
866 * collection (optional)
867 * @throws NullPointerException if this vector contains one or more null
868 * elements and the specified collection does not support null
869 * elements (optional), or if the specified collection is null
870 * @since 1.2
871 */
872 public synchronized boolean retainAll(Collection<?> c) {
873 return super.retainAll(c);
874 }
875
876 /**
877 * Inserts all of the elements in the specified Collection into this
878 * Vector at the specified position. Shifts the element currently at
879 * that position (if any) and any subsequent elements to the right
880 * (increases their indices). The new elements will appear in the Vector
881 * in the order that they are returned by the specified Collection's
882 * iterator.
883 *
884 * @param index index at which to insert the first element from the
885 * specified collection
886 * @param c elements to be inserted into this Vector
887 * @return {@code true} if this Vector changed as a result of the call
888 * @throws ArrayIndexOutOfBoundsException if the index is out of range
889 * ({@code index < 0 || index > size()})
890 * @throws NullPointerException if the specified collection is null
891 * @since 1.2
892 */
893 public synchronized boolean addAll(int index, Collection<? extends E> c) {
894 modCount++;
895 if (index < 0 || index > elementCount)
896 throw new ArrayIndexOutOfBoundsException(index);
897
898 Object[] a = c.toArray();
899 int numNew = a.length;
900 ensureCapacityHelper(elementCount + numNew);
901
902 int numMoved = elementCount - index;
903 if (numMoved > 0)
904 System.arraycopy(elementData, index, elementData, index + numNew,
905 numMoved);
906
907 System.arraycopy(a, 0, elementData, index, numNew);
908 elementCount += numNew;
909 return numNew != 0;
910 }
911
912 /**
913 * Compares the specified Object with this Vector for equality. Returns
914 * true if and only if the specified Object is also a List, both Lists
915 * have the same size, and all corresponding pairs of elements in the two
916 * Lists are <em>equal</em>. (Two elements {@code e1} and
917 * {@code e2} are <em>equal</em> if {@code (e1==null ? e2==null :
918 * e1.equals(e2))}.) In other words, two Lists are defined to be
919 * equal if they contain the same elements in the same order.
920 *
921 * @param o the Object to be compared for equality with this Vector
922 * @return true if the specified Object is equal to this Vector
923 */
924 public synchronized boolean equals(Object o) {
925 return super.equals(o);
926 }
927
928 /**
929 * Returns the hash code value for this Vector.
930 */
931 public synchronized int hashCode() {
932 return super.hashCode();
933 }
934
935 /**
936 * Returns a string representation of this Vector, containing
937 * the String representation of each element.
938 */
939 public synchronized String toString() {
940 return super.toString();
941 }
942
943 /**
944 * Returns a view of the portion of this List between fromIndex,
945 * inclusive, and toIndex, exclusive. (If fromIndex and toIndex are
946 * equal, the returned List is empty.) The returned List is backed by this
947 * List, so changes in the returned List are reflected in this List, and
948 * vice-versa. The returned List supports all of the optional List
949 * operations supported by this List.
950 *
951 * <p>This method eliminates the need for explicit range operations (of
952 * the sort that commonly exist for arrays). Any operation that expects
953 * a List can be used as a range operation by operating on a subList view
954 * instead of a whole List. For example, the following idiom
955 * removes a range of elements from a List:
956 * <pre>
957 * list.subList(from, to).clear();
958 * </pre>
959 * Similar idioms may be constructed for indexOf and lastIndexOf,
960 * and all of the algorithms in the Collections class can be applied to
961 * a subList.
962 *
963 * <p>The semantics of the List returned by this method become undefined if
964 * the backing list (i.e., this List) is <i>structurally modified</i> in
965 * any way other than via the returned List. (Structural modifications are
966 * those that change the size of the List, or otherwise perturb it in such
967 * a fashion that iterations in progress may yield incorrect results.)
968 *
969 * @param fromIndex low endpoint (inclusive) of the subList
970 * @param toIndex high endpoint (exclusive) of the subList
971 * @return a view of the specified range within this List
972 * @throws IndexOutOfBoundsException if an endpoint index value is out of range
973 * {@code (fromIndex < 0 || toIndex > size)}
974 * @throws IllegalArgumentException if the endpoint indices are out of order
975 * {@code (fromIndex > toIndex)}
976 */
977 public synchronized List<E> subList(int fromIndex, int toIndex) {
978 return Collections.synchronizedList(super.subList(fromIndex, toIndex),
979 this);
980 }
981
982 /**
983 * Removes from this List all of the elements whose index is between
984 * fromIndex, inclusive and toIndex, exclusive. Shifts any succeeding
985 * elements to the left (reduces their index).
986 * This call shortens the ArrayList by (toIndex - fromIndex) elements. (If
987 * toIndex==fromIndex, this operation has no effect.)
988 *
989 * @param fromIndex index of first element to be removed
990 * @param toIndex index after last element to be removed
991 */
992 protected synchronized void removeRange(int fromIndex, int toIndex) {
993 modCount++;
994 int numMoved = elementCount - toIndex;
995 System.arraycopy(elementData, toIndex, elementData, fromIndex,
996 numMoved);
997
998 // Let gc do its work
999 int newElementCount = elementCount - (toIndex-fromIndex);
1000 while (elementCount != newElementCount)
1001 elementData[--elementCount] = null;
1002 }
1003
1004 /**
1005 * Save the state of the {@code Vector} instance to a stream (that
1006 * is, serialize it). This method is present merely for synchronization.
1007 * It just calls the default writeObject method.
1008 */
1009 private synchronized void writeObject(java.io.ObjectOutputStream s)
1010 throws java.io.IOException
1011 {
1012 s.defaultWriteObject();
1013 }
1014}
1015