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1 : dl 1.1 /*
2 :     * %W% %E%
3 :     *
4 : jsr166 1.7 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
5 : dl 1.1 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6 :     */
7 :    
8 :     package java.util;
9 :    
10 :     /**
11 :     * The <code>Vector</code> 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</code> can grow or shrink as needed to accommodate
15 : jsr166 1.9 * adding and removing items after the <code>Vector</code> has been created.
16 : dl 1.1 *
17 : jsr166 1.9 * <p>Each vector tries to optimize storage management by maintaining a
18 : dl 1.1 * <code>capacity</code> and a <code>capacityIncrement</code>. The
19 :     * <code>capacity</code> 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</code>. An application can increase the
23 :     * capacity of a vector before inserting a large number of
24 : jsr166 1.9 * components; this reduces the amount of incremental reallocation.
25 : dl 1.1 *
26 : jsr166 1.9 * <p>The Iterators returned by Vector's iterator and listIterator
27 : dl 1.1 * 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 <tt>ConcurrentModificationException</tt> 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 : jsr166 1.9 * should be used only to detect bugs.</i>
43 : dl 1.1 *
44 : jsr166 1.9 * <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}/../guide/collections/index.html"> Java
47 :     * Collections Framework</a>. Unlike the new collection
48 :     * implementations, {@code Vector} is synchronized.
49 : dl 1.1 *
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.<p>
67 :     *
68 :     * 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 <tt>Vector</tt> object.
76 :     * Components <tt>elementData[0]</tt> through
77 :     * <tt>elementData[elementCount-1]</tt> 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 :     * @exception 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 :     * @exception 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 <tt>10</tt> 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 : jsr166 1.6 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 : dl 1.1 }
153 :    
154 :     /**
155 :     * Copies the components of this vector into the specified array.
156 :     * The item at index <tt>k</tt> in this vector is copied into
157 :     * component <tt>k</tt> of <tt>anArray</tt>.
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 <tt>elementData</tt>,
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 :     * <tt>minCapacity</tt>, then its capacity is increased by replacing its
194 :     * internal data array, kept in the field <tt>elementData</tt>, with a
195 :     * larger one. The size of the new data array will be the old size plus
196 :     * <tt>capacityIncrement</tt>, unless the value of
197 :     * <tt>capacityIncrement</tt> 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 <tt>minCapacity</tt>, then the new capacity will
200 :     * be <tt>minCapacity</tt>.
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 java.util.Vector#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</code> 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</code> and greater are discarded.
235 :     *
236 :     * @param newSize the new size of this vector
237 :     * @throws ArrayIndexOutOfBoundsException if 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 <tt>elementData</tt>
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</code> if and only if this vector has
275 :     * no components, that is, its size is zero;
276 :     * <code>false</code> 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 <tt>Enumeration</tt> object will generate all items in
285 :     * this vector. The first item generated is the item at index <tt>0</tt>,
286 :     * then the item at index <tt>1</tt>, and so on.
287 :     *
288 :     * @return an enumeration of the components of this vector
289 :     * @see Enumeration
290 :     * @see Iterator
291 :     */
292 :     public Enumeration<E> elements() {
293 :     return new Enumeration<E>() {
294 :     int count = 0;
295 :    
296 :     public boolean hasMoreElements() {
297 :     return count < elementCount;
298 :     }
299 :    
300 :     public E nextElement() {
301 :     synchronized (Vector.this) {
302 :     if (count < elementCount) {
303 :     return (E)elementData[count++];
304 :     }
305 :     }
306 :     throw new NoSuchElementException("Vector Enumeration");
307 :     }
308 :     };
309 :     }
310 :    
311 :     /**
312 :     * Returns <tt>true</tt> if this vector contains the specified element.
313 :     * More formally, returns <tt>true</tt> if and only if this vector
314 :     * contains at least one element <tt>e</tt> such that
315 :     * <tt>(o==null&nbsp;?&nbsp;e==null&nbsp;:&nbsp;o.equals(e))</tt>.
316 :     *
317 :     * @param o element whose presence in this vector is to be tested
318 :     * @return <tt>true</tt> if this vector contains the specified element
319 :     */
320 :     public boolean contains(Object o) {
321 :     return indexOf(o, 0) >= 0;
322 :     }
323 :    
324 :     /**
325 :     * Returns the index of the first occurrence of the specified element
326 :     * in this vector, or -1 if this vector does not contain the element.
327 :     * More formally, returns the lowest index <tt>i</tt> such that
328 :     * <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>,
329 :     * or -1 if there is no such index.
330 :     *
331 :     * @param o element to search for
332 :     * @return the index of the first occurrence of the specified element in
333 :     * this vector, or -1 if this vector does not contain the element
334 :     */
335 :     public int indexOf(Object o) {
336 :     return indexOf(o, 0);
337 :     }
338 :    
339 :     /**
340 :     * Returns the index of the first occurrence of the specified element in
341 :     * this vector, searching forwards from <tt>index</tt>, or returns -1 if
342 :     * the element is not found.
343 :     * More formally, returns the lowest index <tt>i</tt> such that
344 :     * <tt>(i&nbsp;&gt;=&nbsp;index&nbsp;&amp;&amp;&nbsp;(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i))))</tt>,
345 :     * or -1 if there is no such index.
346 :     *
347 :     * @param o element to search for
348 :     * @param index index to start searching from
349 :     * @return the index of the first occurrence of the element in
350 :     * this vector at position <tt>index</tt> or later in the vector;
351 :     * <tt>-1</tt> if the element is not found.
352 :     * @throws IndexOutOfBoundsException if the specified index is negative
353 :     * @see Object#equals(Object)
354 :     */
355 :     public synchronized int indexOf(Object o, int index) {
356 :     if (o == null) {
357 :     for (int i = index ; i < elementCount ; i++)
358 :     if (elementData[i]==null)
359 :     return i;
360 :     } else {
361 :     for (int i = index ; i < elementCount ; i++)
362 :     if (o.equals(elementData[i]))
363 :     return i;
364 :     }
365 :     return -1;
366 :     }
367 :    
368 :     /**
369 :     * Returns the index of the last occurrence of the specified element
370 :     * in this vector, or -1 if this vector does not contain the element.
371 :     * More formally, returns the highest index <tt>i</tt> such that
372 :     * <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>,
373 :     * or -1 if there is no such index.
374 :     *
375 :     * @param o element to search for
376 :     * @return the index of the last occurrence of the specified element in
377 :     * this vector, or -1 if this vector does not contain the element
378 :     */
379 :     public synchronized int lastIndexOf(Object o) {
380 :     return lastIndexOf(o, elementCount-1);
381 :     }
382 :    
383 :     /**
384 :     * Returns the index of the last occurrence of the specified element in
385 :     * this vector, searching backwards from <tt>index</tt>, or returns -1 if
386 :     * the element is not found.
387 :     * More formally, returns the highest index <tt>i</tt> such that
388 :     * <tt>(i&nbsp;&lt;=&nbsp;index&nbsp;&amp;&amp;&nbsp;(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i))))</tt>,
389 :     * or -1 if there is no such index.
390 :     *
391 :     * @param o element to search for
392 :     * @param index index to start searching backwards from
393 :     * @return the index of the last occurrence of the element at position
394 :     * less than or equal to <tt>index</tt> in this vector;
395 :     * -1 if the element is not found.
396 :     * @throws IndexOutOfBoundsException if the specified index is greater
397 :     * than or equal to the current size of this vector
398 :     */
399 :     public synchronized int lastIndexOf(Object o, int index) {
400 :     if (index >= elementCount)
401 :     throw new IndexOutOfBoundsException(index + " >= "+ elementCount);
402 :    
403 :     if (o == null) {
404 :     for (int i = index; i >= 0; i--)
405 :     if (elementData[i]==null)
406 :     return i;
407 :     } else {
408 :     for (int i = index; i >= 0; i--)
409 :     if (o.equals(elementData[i]))
410 :     return i;
411 :     }
412 :     return -1;
413 :     }
414 :    
415 :     /**
416 :     * Returns the component at the specified index.<p>
417 :     *
418 :     * This method is identical in functionality to the get method
419 :     * (which is part of the List interface).
420 :     *
421 :     * @param index an index into this vector
422 :     * @return the component at the specified index
423 :     * @exception ArrayIndexOutOfBoundsException if the <tt>index</tt>
424 :     * is negative or not less than the current size of this
425 :     * <tt>Vector</tt> object.
426 :     * @see #get(int)
427 :     * @see List
428 :     */
429 :     public synchronized E elementAt(int index) {
430 :     if (index >= elementCount) {
431 :     throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount);
432 :     }
433 :    
434 :     return (E)elementData[index];
435 :     }
436 :    
437 :     /**
438 :     * Returns the first component (the item at index <tt>0</tt>) of
439 :     * this vector.
440 :     *
441 :     * @return the first component of this vector
442 :     * @exception NoSuchElementException if this vector has no components
443 :     */
444 :     public synchronized E firstElement() {
445 :     if (elementCount == 0) {
446 :     throw new NoSuchElementException();
447 :     }
448 :     return (E)elementData[0];
449 :     }
450 :    
451 :     /**
452 :     * Returns the last component of the vector.
453 :     *
454 :     * @return the last component of the vector, i.e., the component at index
455 :     * <code>size()&nbsp;-&nbsp;1</code>.
456 :     * @exception NoSuchElementException if this vector is empty
457 :     */
458 :     public synchronized E lastElement() {
459 :     if (elementCount == 0) {
460 :     throw new NoSuchElementException();
461 :     }
462 :     return (E)elementData[elementCount - 1];
463 :     }
464 :    
465 :     /**
466 :     * Sets the component at the specified <code>index</code> of this
467 :     * vector to be the specified object. The previous component at that
468 :     * position is discarded.<p>
469 :     *
470 :     * The index must be a value greater than or equal to <code>0</code>
471 :     * and less than the current size of the vector. <p>
472 :     *
473 :     * This method is identical in functionality to the set method
474 :     * (which is part of the List interface). Note that the set method reverses
475 :     * the order of the parameters, to more closely match array usage. Note
476 :     * also that the set method returns the old value that was stored at the
477 :     * specified position.
478 :     *
479 :     * @param obj what the component is to be set to
480 :     * @param index the specified index
481 :     * @exception ArrayIndexOutOfBoundsException if the index was invalid
482 :     * @see #size()
483 :     * @see List
484 :     * @see #set(int, java.lang.Object)
485 :     */
486 :     public synchronized void setElementAt(E obj, int index) {
487 :     if (index >= elementCount) {
488 :     throw new ArrayIndexOutOfBoundsException(index + " >= " +
489 :     elementCount);
490 :     }
491 :     elementData[index] = obj;
492 :     }
493 :    
494 :     /**
495 :     * Deletes the component at the specified index. Each component in
496 :     * this vector with an index greater or equal to the specified
497 :     * <code>index</code> is shifted downward to have an index one
498 :     * smaller than the value it had previously. The size of this vector
499 :     * is decreased by <tt>1</tt>.<p>
500 :     *
501 :     * The index must be a value greater than or equal to <code>0</code>
502 :     * and less than the current size of the vector. <p>
503 :     *
504 :     * This method is identical in functionality to the remove method
505 :     * (which is part of the List interface). Note that the remove method
506 :     * returns the old value that was stored at the specified position.
507 :     *
508 :     * @param index the index of the object to remove
509 :     * @exception ArrayIndexOutOfBoundsException if the index was invalid
510 :     * @see #size()
511 :     * @see #remove(int)
512 :     * @see List
513 :     */
514 :     public synchronized void removeElementAt(int index) {
515 :     modCount++;
516 :     if (index >= elementCount) {
517 :     throw new ArrayIndexOutOfBoundsException(index + " >= " +
518 :     elementCount);
519 :     }
520 :     else if (index < 0) {
521 :     throw new ArrayIndexOutOfBoundsException(index);
522 :     }
523 :     int j = elementCount - index - 1;
524 :     if (j > 0) {
525 :     System.arraycopy(elementData, index + 1, elementData, index, j);
526 :     }
527 :     elementCount--;
528 :     elementData[elementCount] = null; /* to let gc do its work */
529 :     }
530 :    
531 :     /**
532 :     * Inserts the specified object as a component in this vector at the
533 :     * specified <code>index</code>. Each component in this vector with
534 :     * an index greater or equal to the specified <code>index</code> is
535 :     * shifted upward to have an index one greater than the value it had
536 :     * previously. <p>
537 :     *
538 :     * The index must be a value greater than or equal to <code>0</code>
539 :     * and less than or equal to the current size of the vector. (If the
540 :     * index is equal to the current size of the vector, the new element
541 :     * is appended to the Vector.)<p>
542 :     *
543 :     * This method is identical in functionality to the add(Object, int) method
544 :     * (which is part of the List interface). Note that the add method reverses
545 :     * the order of the parameters, to more closely match array usage.
546 :     *
547 :     * @param obj the component to insert
548 :     * @param index where to insert the new component
549 :     * @exception ArrayIndexOutOfBoundsException if the index was invalid
550 :     * @see #size()
551 :     * @see #add(int, Object)
552 :     * @see List
553 :     */
554 :     public synchronized void insertElementAt(E obj, int index) {
555 :     modCount++;
556 :     if (index > elementCount) {
557 :     throw new ArrayIndexOutOfBoundsException(index
558 :     + " > " + elementCount);
559 :     }
560 :     ensureCapacityHelper(elementCount + 1);
561 :     System.arraycopy(elementData, index, elementData, index + 1, elementCount - index);
562 :     elementData[index] = obj;
563 :     elementCount++;
564 :     }
565 :    
566 :     /**
567 :     * Adds the specified component to the end of this vector,
568 :     * increasing its size by one. The capacity of this vector is
569 :     * increased if its size becomes greater than its capacity. <p>
570 :     *
571 :     * This method is identical in functionality to the add(Object) method
572 :     * (which is part of the List interface).
573 :     *
574 :     * @param obj the component to be added
575 :     * @see #add(Object)
576 :     * @see List
577 :     */
578 :     public synchronized void addElement(E obj) {
579 :     modCount++;
580 :     ensureCapacityHelper(elementCount + 1);
581 :     elementData[elementCount++] = obj;
582 :     }
583 :    
584 :     /**
585 :     * Removes the first (lowest-indexed) occurrence of the argument
586 :     * from this vector. If the object is found in this vector, each
587 :     * component in the vector with an index greater or equal to the
588 :     * object's index is shifted downward to have an index one smaller
589 :     * than the value it had previously.<p>
590 :     *
591 :     * This method is identical in functionality to the remove(Object)
592 :     * method (which is part of the List interface).
593 :     *
594 :     * @param obj the component to be removed
595 :     * @return <code>true</code> if the argument was a component of this
596 :     * vector; <code>false</code> otherwise.
597 :     * @see List#remove(Object)
598 :     * @see List
599 :     */
600 :     public synchronized boolean removeElement(Object obj) {
601 :     modCount++;
602 :     int i = indexOf(obj);
603 :     if (i >= 0) {
604 :     removeElementAt(i);
605 :     return true;
606 :     }
607 :     return false;
608 :     }
609 :    
610 :     /**
611 :     * Removes all components from this vector and sets its size to zero.<p>
612 :     *
613 :     * This method is identical in functionality to the clear method
614 :     * (which is part of the List interface).
615 :     *
616 :     * @see #clear
617 :     * @see List
618 :     */
619 :     public synchronized void removeAllElements() {
620 :     modCount++;
621 :     // Let gc do its work
622 :     for (int i = 0; i < elementCount; i++)
623 :     elementData[i] = null;
624 :    
625 :     elementCount = 0;
626 :     }
627 :    
628 :     /**
629 :     * Returns a clone of this vector. The copy will contain a
630 :     * reference to a clone of the internal data array, not a reference
631 :     * to the original internal data array of this <tt>Vector</tt> object.
632 :     *
633 :     * @return a clone of this vector
634 :     */
635 :     public synchronized Object clone() {
636 :     try {
637 :     Vector<E> v = (Vector<E>) super.clone();
638 :     v.elementData = Arrays.copyOf(elementData, elementCount);
639 :     v.modCount = 0;
640 :     return v;
641 :     } catch (CloneNotSupportedException e) {
642 :     // this shouldn't happen, since we are Cloneable
643 :     throw new InternalError();
644 :     }
645 :     }
646 :    
647 :     /**
648 :     * Returns an array containing all of the elements in this Vector
649 :     * in the correct order.
650 :     *
651 :     * @since 1.2
652 :     */
653 :     public synchronized Object[] toArray() {
654 :     return Arrays.copyOf(elementData, elementCount);
655 :     }
656 :    
657 :     /**
658 :     * Returns an array containing all of the elements in this Vector in the
659 :     * correct order; the runtime type of the returned array is that of the
660 :     * specified array. If the Vector fits in the specified array, it is
661 :     * returned therein. Otherwise, a new array is allocated with the runtime
662 :     * type of the specified array and the size of this Vector.<p>
663 :     *
664 :     * If the Vector fits in the specified array with room to spare
665 :     * (i.e., the array has more elements than the Vector),
666 :     * the element in the array immediately following the end of the
667 :     * Vector is set to null. (This is useful in determining the length
668 :     * of the Vector <em>only</em> if the caller knows that the Vector
669 :     * does not contain any null elements.)
670 :     *
671 :     * @param a the array into which the elements of the Vector are to
672 :     * be stored, if it is big enough; otherwise, a new array of the
673 :     * same runtime type is allocated for this purpose.
674 :     * @return an array containing the elements of the Vector
675 :     * @exception ArrayStoreException the runtime type of a is not a supertype
676 :     * of the runtime type of every element in this Vector
677 :     * @throws NullPointerException if the given array is null
678 :     * @since 1.2
679 :     */
680 :     public synchronized <T> T[] toArray(T[] a) {
681 :     if (a.length < elementCount)
682 :     return (T[]) Arrays.copyOf(elementData, elementCount, a.getClass());
683 :    
684 :     System.arraycopy(elementData, 0, a, 0, elementCount);
685 :    
686 :     if (a.length > elementCount)
687 :     a[elementCount] = null;
688 :    
689 :     return a;
690 :     }
691 :    
692 :     // Positional Access Operations
693 :    
694 :     /**
695 :     * Returns the element at the specified position in this Vector.
696 :     *
697 :     * @param index index of the element to return
698 :     * @return object at the specified index
699 :     * @exception ArrayIndexOutOfBoundsException index is out of range (index
700 :     * &lt; 0 || index &gt;= size())
701 :     * @since 1.2
702 :     */
703 :     public synchronized E get(int index) {
704 :     if (index >= elementCount)
705 :     throw new ArrayIndexOutOfBoundsException(index);
706 :    
707 :     return (E)elementData[index];
708 :     }
709 :    
710 :     /**
711 :     * Replaces the element at the specified position in this Vector with the
712 :     * specified element.
713 :     *
714 :     * @param index index of the element to replace
715 :     * @param element element to be stored at the specified position
716 :     * @return the element previously at the specified position
717 :     * @exception ArrayIndexOutOfBoundsException index out of range
718 :     * (index &lt; 0 || index &gt;= size())
719 :     * @since 1.2
720 :     */
721 :     public synchronized E set(int index, E element) {
722 :     if (index >= elementCount)
723 :     throw new ArrayIndexOutOfBoundsException(index);
724 :    
725 :     Object oldValue = elementData[index];
726 :     elementData[index] = element;
727 :     return (E)oldValue;
728 :     }
729 :    
730 :     /**
731 :     * Appends the specified element to the end of this Vector.
732 :     *
733 :     * @param e element to be appended to this Vector
734 :     * @return <tt>true</tt> (as specified by {@link Collection#add})
735 :     * @since 1.2
736 :     */
737 :     public synchronized boolean add(E e) {
738 :     modCount++;
739 :     ensureCapacityHelper(elementCount + 1);
740 :     elementData[elementCount++] = e;
741 :     return true;
742 :     }
743 :    
744 :     /**
745 :     * Removes the first occurrence of the specified element in this Vector
746 :     * If the Vector does not contain the element, it is unchanged. More
747 :     * formally, removes the element with the lowest index i such that
748 :     * <code>(o==null ? get(i)==null : o.equals(get(i)))</code> (if such
749 :     * an element exists).
750 :     *
751 :     * @param o element to be removed from this Vector, if present
752 :     * @return true if the Vector contained the specified element
753 :     * @since 1.2
754 :     */
755 :     public boolean remove(Object o) {
756 :     return removeElement(o);
757 :     }
758 :    
759 :     /**
760 :     * Inserts the specified element at the specified position in this Vector.
761 :     * Shifts the element currently at that position (if any) and any
762 :     * subsequent elements to the right (adds one to their indices).
763 :     *
764 :     * @param index index at which the specified element is to be inserted
765 :     * @param element element to be inserted
766 :     * @exception ArrayIndexOutOfBoundsException index is out of range
767 :     * (index &lt; 0 || index &gt; size())
768 :     * @since 1.2
769 :     */
770 :     public void add(int index, E element) {
771 :     insertElementAt(element, index);
772 :     }
773 :    
774 :     /**
775 :     * Removes the element at the specified position in this Vector.
776 :     * Shifts any subsequent elements to the left (subtracts one from their
777 :     * indices). Returns the element that was removed from the Vector.
778 :     *
779 :     * @exception ArrayIndexOutOfBoundsException index out of range (index
780 :     * &lt; 0 || index &gt;= size())
781 :     * @param index the index of the element to be removed
782 :     * @return element that was removed
783 :     * @since 1.2
784 :     */
785 :     public synchronized E remove(int index) {
786 :     modCount++;
787 :     if (index >= elementCount)
788 :     throw new ArrayIndexOutOfBoundsException(index);
789 :     Object oldValue = elementData[index];
790 :    
791 :     int numMoved = elementCount - index - 1;
792 :     if (numMoved > 0)
793 :     System.arraycopy(elementData, index+1, elementData, index,
794 :     numMoved);
795 :     elementData[--elementCount] = null; // Let gc do its work
796 :    
797 :     return (E)oldValue;
798 :     }
799 :    
800 :     /**
801 :     * Removes all of the elements from this Vector. The Vector will
802 :     * be empty after this call returns (unless it throws an exception).
803 :     *
804 :     * @since 1.2
805 :     */
806 :     public void clear() {
807 :     removeAllElements();
808 :     }
809 :    
810 :     // Bulk Operations
811 :    
812 :     /**
813 :     * Returns true if this Vector contains all of the elements in the
814 :     * specified Collection.
815 :     *
816 :     * @param c a collection whose elements will be tested for containment
817 :     * in this Vector
818 :     * @return true if this Vector contains all of the elements in the
819 :     * specified collection
820 :     * @throws NullPointerException if the specified collection is null
821 :     */
822 :     public synchronized boolean containsAll(Collection<?> c) {
823 :     return super.containsAll(c);
824 :     }
825 :    
826 :     /**
827 :     * Appends all of the elements in the specified Collection to the end of
828 :     * this Vector, in the order that they are returned by the specified
829 :     * Collection's Iterator. The behavior of this operation is undefined if
830 :     * the specified Collection is modified while the operation is in progress.
831 :     * (This implies that the behavior of this call is undefined if the
832 :     * specified Collection is this Vector, and this Vector is nonempty.)
833 :     *
834 :     * @param c elements to be inserted into this Vector
835 :     * @return <tt>true</tt> if this Vector changed as a result of the call
836 :     * @throws NullPointerException if the specified collection is null
837 :     * @since 1.2
838 :     */
839 :     public synchronized boolean addAll(Collection<? extends E> c) {
840 :     modCount++;
841 :     Object[] a = c.toArray();
842 :     int numNew = a.length;
843 :     ensureCapacityHelper(elementCount + numNew);
844 :     System.arraycopy(a, 0, elementData, elementCount, numNew);
845 :     elementCount += numNew;
846 :     return numNew != 0;
847 :     }
848 :    
849 :     /**
850 :     * Removes from this Vector all of its elements that are contained in the
851 :     * specified Collection.
852 :     *
853 :     * @param c a collection of elements to be removed from the Vector
854 :     * @return true if this Vector changed as a result of the call
855 :     * @throws ClassCastException if the types of one or more elements
856 :     * in this vector are incompatible with the specified
857 :     * collection (optional)
858 :     * @throws NullPointerException if this vector contains one or more null
859 :     * elements and the specified collection does not support null
860 :     * elements (optional), or if the specified collection is null
861 :     * @since 1.2
862 :     */
863 :     public synchronized boolean removeAll(Collection<?> c) {
864 :     return super.removeAll(c);
865 :     }
866 :    
867 :     /**
868 :     * Retains only the elements in this Vector that are contained in the
869 :     * specified Collection. In other words, removes from this Vector all
870 :     * of its elements that are not contained in the specified Collection.
871 :     *
872 :     * @param c a collection of elements to be retained in this Vector
873 :     * (all other elements are removed)
874 :     * @return true if this Vector changed as a result of the call
875 :     * @throws ClassCastException if the types of one or more elements
876 :     * in this vector are incompatible with the specified
877 :     * collection (optional)
878 :     * @throws NullPointerException if this vector contains one or more null
879 :     * elements and the specified collection does not support null
880 :     * elements (optional), or if the specified collection is null
881 :     * @since 1.2
882 :     */
883 :     public synchronized boolean retainAll(Collection<?> c) {
884 :     return super.retainAll(c);
885 :     }
886 :    
887 :     /**
888 :     * Inserts all of the elements in the specified Collection into this
889 :     * Vector at the specified position. Shifts the element currently at
890 :     * that position (if any) and any subsequent elements to the right
891 :     * (increases their indices). The new elements will appear in the Vector
892 :     * in the order that they are returned by the specified Collection's
893 :     * iterator.
894 :     *
895 :     * @param index index at which to insert the first element from the
896 :     * specified collection
897 :     * @param c elements to be inserted into this Vector
898 :     * @return <tt>true</tt> if this Vector changed as a result of the call
899 :     * @exception ArrayIndexOutOfBoundsException index out of range (index
900 :     * &lt; 0 || index &gt; size())
901 :     * @throws NullPointerException if the specified collection is null
902 :     * @since 1.2
903 :     */
904 :     public synchronized boolean addAll(int index, Collection<? extends E> c) {
905 :     modCount++;
906 :     if (index < 0 || index > elementCount)
907 :     throw new ArrayIndexOutOfBoundsException(index);
908 :    
909 :     Object[] a = c.toArray();
910 :     int numNew = a.length;
911 :     ensureCapacityHelper(elementCount + numNew);
912 :    
913 :     int numMoved = elementCount - index;
914 :     if (numMoved > 0)
915 :     System.arraycopy(elementData, index, elementData, index + numNew,
916 :     numMoved);
917 :    
918 :     System.arraycopy(a, 0, elementData, index, numNew);
919 :     elementCount += numNew;
920 :     return numNew != 0;
921 :     }
922 :    
923 :     /**
924 :     * Compares the specified Object with this Vector for equality. Returns
925 :     * true if and only if the specified Object is also a List, both Lists
926 :     * have the same size, and all corresponding pairs of elements in the two
927 :     * Lists are <em>equal</em>. (Two elements <code>e1</code> and
928 :     * <code>e2</code> are <em>equal</em> if <code>(e1==null ? e2==null :
929 :     * e1.equals(e2))</code>.) In other words, two Lists are defined to be
930 :     * equal if they contain the same elements in the same order.
931 :     *
932 :     * @param o the Object to be compared for equality with this Vector
933 :     * @return true if the specified Object is equal to this Vector
934 :     */
935 :     public synchronized boolean equals(Object o) {
936 :     return super.equals(o);
937 :     }
938 :    
939 :     /**
940 :     * Returns the hash code value for this Vector.
941 :     */
942 :     public synchronized int hashCode() {
943 :     return super.hashCode();
944 :     }
945 :    
946 :     /**
947 :     * Returns a string representation of this Vector, containing
948 :     * the String representation of each element.
949 :     */
950 :     public synchronized String toString() {
951 :     return super.toString();
952 :     }
953 :    
954 :     /**
955 :     * Returns a view of the portion of this List between fromIndex,
956 :     * inclusive, and toIndex, exclusive. (If fromIndex and toIndex are
957 :     * equal, the returned List is empty.) The returned List is backed by this
958 :     * List, so changes in the returned List are reflected in this List, and
959 :     * vice-versa. The returned List supports all of the optional List
960 :     * operations supported by this List.<p>
961 :     *
962 :     * This method eliminates the need for explicit range operations (of
963 :     * the sort that commonly exist for arrays). Any operation that expects
964 :     * a List can be used as a range operation by operating on a subList view
965 :     * instead of a whole List. For example, the following idiom
966 :     * removes a range of elements from a List:
967 :     * <pre>
968 :     * list.subList(from, to).clear();
969 :     * </pre>
970 :     * Similar idioms may be constructed for indexOf and lastIndexOf,
971 :     * and all of the algorithms in the Collections class can be applied to
972 :     * a subList.<p>
973 :     *
974 :     * The semantics of the List returned by this method become undefined if
975 :     * the backing list (i.e., this List) is <i>structurally modified</i> in
976 :     * any way other than via the returned List. (Structural modifications are
977 :     * those that change the size of the List, or otherwise perturb it in such
978 :     * a fashion that iterations in progress may yield incorrect results.)
979 :     *
980 :     * @param fromIndex low endpoint (inclusive) of the subList
981 :     * @param toIndex high endpoint (exclusive) of the subList
982 :     * @return a view of the specified range within this List
983 :     * @throws IndexOutOfBoundsException endpoint index value out of range
984 :     * <code>(fromIndex &lt; 0 || toIndex &gt; size)</code>
985 :     * @throws IllegalArgumentException endpoint indices out of order
986 :     * <code>(fromIndex &gt; toIndex)</code>
987 :     */
988 :     public synchronized List<E> subList(int fromIndex, int toIndex) {
989 :     return Collections.synchronizedList(super.subList(fromIndex, toIndex),
990 :     this);
991 :     }
992 :    
993 :     /**
994 :     * Removes from this List all of the elements whose index is between
995 :     * fromIndex, inclusive and toIndex, exclusive. Shifts any succeeding
996 :     * elements to the left (reduces their index).
997 :     * This call shortens the ArrayList by (toIndex - fromIndex) elements. (If
998 :     * toIndex==fromIndex, this operation has no effect.)
999 :     *
1000 :     * @param fromIndex index of first element to be removed
1001 :     * @param toIndex index after last element to be removed
1002 :     */
1003 :     protected synchronized void removeRange(int fromIndex, int toIndex) {
1004 :     modCount++;
1005 :     int numMoved = elementCount - toIndex;
1006 :     System.arraycopy(elementData, toIndex, elementData, fromIndex,
1007 :     numMoved);
1008 :    
1009 :     // Let gc do its work
1010 :     int newElementCount = elementCount - (toIndex-fromIndex);
1011 :     while (elementCount != newElementCount)
1012 :     elementData[--elementCount] = null;
1013 :     }
1014 :    
1015 :     /**
1016 :     * Save the state of the <tt>Vector</tt> instance to a stream (that
1017 :     * is, serialize it). This method is present merely for synchronization.
1018 :     * It just calls the default writeObject method.
1019 :     */
1020 :     private synchronized void writeObject(java.io.ObjectOutputStream s)
1021 :     throws java.io.IOException
1022 :     {
1023 :     s.defaultWriteObject();
1024 :     }
1025 :    
1026 :     /**
1027 :     * Returns a list-iterator of the elements in this list (in proper
1028 :     * sequence), starting at the specified position in the list.
1029 :     * Obeys the general contract of <tt>List.listIterator(int)</tt>.<p>
1030 :     *
1031 :     * The list-iterator is <i>fail-fast</i>: if the list is structurally
1032 :     * modified at any time after the Iterator is created, in any way except
1033 :     * through the list-iterator's own <tt>remove</tt> or <tt>add</tt>
1034 :     * methods, the list-iterator will throw a
1035 :     * <tt>ConcurrentModificationException</tt>. Thus, in the face of
1036 :     * concurrent modification, the iterator fails quickly and cleanly, rather
1037 :     * than risking arbitrary, non-deterministic behavior at an undetermined
1038 :     * time in the future.
1039 :     *
1040 :     * @param index index of the first element to be returned from the
1041 :     * list-iterator (by a call to <tt>next</tt>)
1042 :     * @return a ListIterator of the elements in this list (in proper
1043 :     * sequence), starting at the specified position in the list
1044 :     * @throws IndexOutOfBoundsException {@inheritDoc}
1045 :     * @see List#listIterator(int)
1046 :     */
1047 :     public synchronized ListIterator<E> listIterator(int index) {
1048 :     if (index < 0 || index > elementCount)
1049 :     throw new IndexOutOfBoundsException("Index: "+index);
1050 :     return new VectorIterator(index);
1051 :     }
1052 : jsr166 1.2
1053 : dl 1.1 /**
1054 : dl 1.3 * {@inheritDoc}
1055 :     */
1056 :     public synchronized ListIterator<E> listIterator() {
1057 :     return new VectorIterator(0);
1058 :     }
1059 :    
1060 :     /**
1061 : dl 1.1 * Returns an iterator over the elements in this list in proper sequence.
1062 :     *
1063 :     * @return an iterator over the elements in this list in proper sequence
1064 :     */
1065 :     public synchronized Iterator<E> iterator() {
1066 :     return new VectorIterator(0);
1067 :     }
1068 :    
1069 :     /**
1070 : dl 1.3 * A streamlined version of AbstractList.ListItr.
1071 : dl 1.1 */
1072 : dl 1.3 private final class VectorIterator implements ListIterator<E> {
1073 :     int cursor; // current position
1074 :     int lastRet; // index of last returned element
1075 :     int expectedModCount; // to check for CME
1076 : dl 1.1
1077 :     VectorIterator(int index) {
1078 :     cursor = index;
1079 : dl 1.3 expectedModCount = modCount;
1080 : dl 1.1 lastRet = -1;
1081 :     }
1082 :    
1083 :     public boolean hasNext() {
1084 : dl 1.3 // Racy but within spec, since modifications are checked
1085 :     // within or after synchronization in next/previous
1086 : dl 1.5 return cursor != elementCount;
1087 : dl 1.1 }
1088 :    
1089 :     public boolean hasPrevious() {
1090 : dl 1.5 return cursor != 0;
1091 : dl 1.1 }
1092 :    
1093 :     public int nextIndex() {
1094 :     return cursor;
1095 :     }
1096 :    
1097 :     public int previousIndex() {
1098 :     return cursor - 1;
1099 :     }
1100 :    
1101 :     public E next() {
1102 : dl 1.3 try {
1103 :     int i = cursor;
1104 :     E next = get(i);
1105 :     lastRet = i;
1106 :     cursor = i + 1;
1107 :     return next;
1108 :     } catch (IndexOutOfBoundsException ex) {
1109 :     throw new NoSuchElementException();
1110 :     } finally {
1111 :     if (expectedModCount != modCount)
1112 :     throw new ConcurrentModificationException();
1113 : dl 1.1 }
1114 :     }
1115 : jsr166 1.4
1116 :     public E previous() {
1117 : dl 1.3 try {
1118 :     int i = cursor - 1;
1119 :     E prev = get(i);
1120 :     lastRet = i;
1121 :     cursor = i;
1122 :     return prev;
1123 :     } catch (IndexOutOfBoundsException ex) {
1124 :     throw new NoSuchElementException();
1125 :     } finally {
1126 :     if (expectedModCount != modCount)
1127 :     throw new ConcurrentModificationException();
1128 : dl 1.1 }
1129 :     }
1130 :    
1131 :     public void remove() {
1132 : dl 1.3 if (lastRet == -1)
1133 : dl 1.1 throw new IllegalStateException();
1134 : dl 1.3 if (expectedModCount != modCount)
1135 :     throw new ConcurrentModificationException();
1136 :     try {
1137 :     Vector.this.remove(lastRet);
1138 :     if (lastRet < cursor)
1139 :     cursor--;
1140 :     lastRet = -1;
1141 :     expectedModCount = modCount;
1142 : jsr166 1.4 } catch (IndexOutOfBoundsException ex) {
1143 : dl 1.3 throw new ConcurrentModificationException();
1144 :     }
1145 : dl 1.1 }
1146 :    
1147 :     public void set(E e) {
1148 : dl 1.3 if (lastRet == -1)
1149 : dl 1.1 throw new IllegalStateException();
1150 : dl 1.3 if (expectedModCount != modCount)
1151 :     throw new ConcurrentModificationException();
1152 :     try {
1153 :     Vector.this.set(lastRet, e);
1154 :     expectedModCount = modCount;
1155 :     } catch (IndexOutOfBoundsException ex) {
1156 :     throw new ConcurrentModificationException();
1157 :     }
1158 : dl 1.1 }
1159 :    
1160 :     public void add(E e) {
1161 : dl 1.3 if (expectedModCount != modCount)
1162 :     throw new ConcurrentModificationException();
1163 :     try {
1164 :     int i = cursor;
1165 :     Vector.this.add(i, e);
1166 :     cursor = i + 1;
1167 :     lastRet = -1;
1168 :     expectedModCount = modCount;
1169 :     } catch (IndexOutOfBoundsException ex) {
1170 :     throw new ConcurrentModificationException();
1171 :     }
1172 : dl 1.1 }
1173 :     }
1174 :     }

Doug Lea
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