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1 : dl 1.1 /*
2 :     * %W% %E%
3 :     *
4 :     * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
5 :     * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6 :     */
7 :    
8 :     package java.util;
9 :     import java.util.*; // for javadoc (till 6280605 is fixed)
10 :    
11 :     /**
12 :     * The <code>Vector</code> class implements a growable array of
13 :     * objects. Like an array, it contains components that can be
14 :     * accessed using an integer index. However, the size of a
15 :     * <code>Vector</code> can grow or shrink as needed to accommodate
16 :     * adding and removing items after the <code>Vector</code> has been created.<p>
17 :     *
18 :     * Each vector tries to optimize storage management by maintaining a
19 :     * <code>capacity</code> and a <code>capacityIncrement</code>. The
20 :     * <code>capacity</code> is always at least as large as the vector
21 :     * size; it is usually larger because as components are added to the
22 :     * vector, the vector's storage increases in chunks the size of
23 :     * <code>capacityIncrement</code>. An application can increase the
24 :     * capacity of a vector before inserting a large number of
25 :     * components; this reduces the amount of incremental reallocation. <p>
26 :     *
27 :     * As of the Java 2 platform v1.2, this class has been retrofitted to
28 :     * implement List, so that it becomes a part of Java's collection framework.
29 :     * Unlike the new collection implementations, Vector is synchronized.<p>
30 :     *
31 :     * The Iterators returned by Vector's iterator and listIterator
32 :     * methods are <em>fail-fast</em>: if the Vector is structurally modified
33 :     * at any time after the Iterator is created, in any way except through the
34 :     * Iterator's own remove or add methods, the Iterator will throw a
35 :     * ConcurrentModificationException. Thus, in the face of concurrent
36 :     * modification, the Iterator fails quickly and cleanly, rather than risking
37 :     * arbitrary, non-deterministic behavior at an undetermined time in the future.
38 :     * The Enumerations returned by Vector's elements method are <em>not</em>
39 :     * fail-fast.
40 :     *
41 :     * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed
42 :     * as it is, generally speaking, impossible to make any hard guarantees in the
43 :     * presence of unsynchronized concurrent modification. Fail-fast iterators
44 :     * throw <tt>ConcurrentModificationException</tt> on a best-effort basis.
45 :     * Therefore, it would be wrong to write a program that depended on this
46 :     * exception for its correctness: <i>the fail-fast behavior of iterators
47 :     * should be used only to detect bugs.</i><p>
48 :     *
49 :     * This class is a member of the
50 :     * <a href="{@docRoot}/../guide/collections/index.html">
51 :     * Java Collections Framework</a>.
52 :     *
53 :     * @author Lee Boynton
54 :     * @author Jonathan Payne
55 :     * @version %I%, %G%
56 :     * @see Collection
57 :     * @see List
58 :     * @see ArrayList
59 :     * @see LinkedList
60 :     * @since JDK1.0
61 :     */
62 :     public class Vector<E>
63 :     extends AbstractList<E>
64 :     implements List<E>, RandomAccess, Cloneable, java.io.Serializable
65 :     {
66 :     /**
67 :     * The array buffer into which the components of the vector are
68 :     * stored. The capacity of the vector is the length of this array buffer,
69 :     * and is at least large enough to contain all the vector's elements.<p>
70 :     *
71 :     * Any array elements following the last element in the Vector are null.
72 :     *
73 :     * @serial
74 :     */
75 :     protected Object[] elementData;
76 :    
77 :     /**
78 :     * The number of valid components in this <tt>Vector</tt> object.
79 :     * Components <tt>elementData[0]</tt> through
80 :     * <tt>elementData[elementCount-1]</tt> are the actual items.
81 :     *
82 :     * @serial
83 :     */
84 :     protected int elementCount;
85 :    
86 :     /**
87 :     * The amount by which the capacity of the vector is automatically
88 :     * incremented when its size becomes greater than its capacity. If
89 :     * the capacity increment is less than or equal to zero, the capacity
90 :     * of the vector is doubled each time it needs to grow.
91 :     *
92 :     * @serial
93 :     */
94 :     protected int capacityIncrement;
95 :    
96 :     /** use serialVersionUID from JDK 1.0.2 for interoperability */
97 :     private static final long serialVersionUID = -2767605614048989439L;
98 :    
99 :     /**
100 :     * Constructs an empty vector with the specified initial capacity and
101 :     * capacity increment.
102 :     *
103 :     * @param initialCapacity the initial capacity of the vector
104 :     * @param capacityIncrement the amount by which the capacity is
105 :     * increased when the vector overflows
106 :     * @exception IllegalArgumentException if the specified initial capacity
107 :     * is negative
108 :     */
109 :     public Vector(int initialCapacity, int capacityIncrement) {
110 :     super();
111 :     if (initialCapacity < 0)
112 :     throw new IllegalArgumentException("Illegal Capacity: "+
113 :     initialCapacity);
114 :     this.elementData = new Object[initialCapacity];
115 :     this.capacityIncrement = capacityIncrement;
116 :     }
117 :    
118 :     /**
119 :     * Constructs an empty vector with the specified initial capacity and
120 :     * with its capacity increment equal to zero.
121 :     *
122 :     * @param initialCapacity the initial capacity of the vector
123 :     * @exception IllegalArgumentException if the specified initial capacity
124 :     * is negative
125 :     */
126 :     public Vector(int initialCapacity) {
127 :     this(initialCapacity, 0);
128 :     }
129 :    
130 :     /**
131 :     * Constructs an empty vector so that its internal data array
132 :     * has size <tt>10</tt> and its standard capacity increment is
133 :     * zero.
134 :     */
135 :     public Vector() {
136 :     this(10);
137 :     }
138 :    
139 :     /**
140 :     * Constructs a vector containing the elements of the specified
141 :     * collection, in the order they are returned by the collection's
142 :     * iterator.
143 :     *
144 :     * @param c the collection whose elements are to be placed into this
145 :     * vector
146 :     * @throws NullPointerException if the specified collection is null
147 :     * @since 1.2
148 :     */
149 :     public Vector(Collection<? extends E> c) {
150 :     Object[] a = c.toArray();
151 :     elementCount = a.length;
152 :     // If c.toArray incorrectly doesn't return Object[], copy it.
153 :     if (a.getClass() == Object[].class)
154 :     elementData = a;
155 :     else
156 :     elementData = Arrays.copyOf(a, a.length, Object[].class);
157 :     }
158 :    
159 :     /**
160 :     * Copies the components of this vector into the specified array.
161 :     * The item at index <tt>k</tt> in this vector is copied into
162 :     * component <tt>k</tt> of <tt>anArray</tt>.
163 :     *
164 :     * @param anArray the array into which the components get copied
165 :     * @throws NullPointerException if the given array is null
166 :     * @throws IndexOutOfBoundsException if the specified array is not
167 :     * large enough to hold all the components of this vector
168 :     * @throws ArrayStoreException if a component of this vector is not of
169 :     * a runtime type that can be stored in the specified array
170 :     * @see #toArray(Object[])
171 :     */
172 :     public synchronized void copyInto(Object[] anArray) {
173 :     System.arraycopy(elementData, 0, anArray, 0, elementCount);
174 :     }
175 :    
176 :     /**
177 :     * Trims the capacity of this vector to be the vector's current
178 :     * size. If the capacity of this vector is larger than its current
179 :     * size, then the capacity is changed to equal the size by replacing
180 :     * its internal data array, kept in the field <tt>elementData</tt>,
181 :     * with a smaller one. An application can use this operation to
182 :     * minimize the storage of a vector.
183 :     */
184 :     public synchronized void trimToSize() {
185 :     modCount++;
186 :     int oldCapacity = elementData.length;
187 :     if (elementCount < oldCapacity) {
188 :     elementData = Arrays.copyOf(elementData, elementCount);
189 :     }
190 :     }
191 :    
192 :     /**
193 :     * Increases the capacity of this vector, if necessary, to ensure
194 :     * that it can hold at least the number of components specified by
195 :     * the minimum capacity argument.
196 :     *
197 :     * <p>If the current capacity of this vector is less than
198 :     * <tt>minCapacity</tt>, then its capacity is increased by replacing its
199 :     * internal data array, kept in the field <tt>elementData</tt>, with a
200 :     * larger one. The size of the new data array will be the old size plus
201 :     * <tt>capacityIncrement</tt>, unless the value of
202 :     * <tt>capacityIncrement</tt> is less than or equal to zero, in which case
203 :     * the new capacity will be twice the old capacity; but if this new size
204 :     * is still smaller than <tt>minCapacity</tt>, then the new capacity will
205 :     * be <tt>minCapacity</tt>.
206 :     *
207 :     * @param minCapacity the desired minimum capacity
208 :     */
209 :     public synchronized void ensureCapacity(int minCapacity) {
210 :     modCount++;
211 :     ensureCapacityHelper(minCapacity);
212 :     }
213 :    
214 :     /**
215 :     * This implements the unsynchronized semantics of ensureCapacity.
216 :     * Synchronized methods in this class can internally call this
217 :     * method for ensuring capacity without incurring the cost of an
218 :     * extra synchronization.
219 :     *
220 :     * @see java.util.Vector#ensureCapacity(int)
221 :     */
222 :     private void ensureCapacityHelper(int minCapacity) {
223 :     int oldCapacity = elementData.length;
224 :     if (minCapacity > oldCapacity) {
225 :     Object[] oldData = elementData;
226 :     int newCapacity = (capacityIncrement > 0) ?
227 :     (oldCapacity + capacityIncrement) : (oldCapacity * 2);
228 :     if (newCapacity < minCapacity) {
229 :     newCapacity = minCapacity;
230 :     }
231 :     elementData = Arrays.copyOf(elementData, newCapacity);
232 :     }
233 :     }
234 :    
235 :     /**
236 :     * Sets the size of this vector. If the new size is greater than the
237 :     * current size, new <code>null</code> items are added to the end of
238 :     * the vector. If the new size is less than the current size, all
239 :     * components at index <code>newSize</code> and greater are discarded.
240 :     *
241 :     * @param newSize the new size of this vector
242 :     * @throws ArrayIndexOutOfBoundsException if new size is negative
243 :     */
244 :     public synchronized void setSize(int newSize) {
245 :     modCount++;
246 :     if (newSize > elementCount) {
247 :     ensureCapacityHelper(newSize);
248 :     } else {
249 :     for (int i = newSize ; i < elementCount ; i++) {
250 :     elementData[i] = null;
251 :     }
252 :     }
253 :     elementCount = newSize;
254 :     }
255 :    
256 :     /**
257 :     * Returns the current capacity of this vector.
258 :     *
259 :     * @return the current capacity (the length of its internal
260 :     * data array, kept in the field <tt>elementData</tt>
261 :     * of this vector)
262 :     */
263 :     public synchronized int capacity() {
264 :     return elementData.length;
265 :     }
266 :    
267 :     /**
268 :     * Returns the number of components in this vector.
269 :     *
270 :     * @return the number of components in this vector
271 :     */
272 :     public synchronized int size() {
273 :     return elementCount;
274 :     }
275 :    
276 :     /**
277 :     * Tests if this vector has no components.
278 :     *
279 :     * @return <code>true</code> if and only if this vector has
280 :     * no components, that is, its size is zero;
281 :     * <code>false</code> otherwise.
282 :     */
283 :     public synchronized boolean isEmpty() {
284 :     return elementCount == 0;
285 :     }
286 :    
287 :     /**
288 :     * Returns an enumeration of the components of this vector. The
289 :     * returned <tt>Enumeration</tt> object will generate all items in
290 :     * this vector. The first item generated is the item at index <tt>0</tt>,
291 :     * then the item at index <tt>1</tt>, and so on.
292 :     *
293 :     * @return an enumeration of the components of this vector
294 :     * @see Enumeration
295 :     * @see Iterator
296 :     */
297 :     public Enumeration<E> elements() {
298 :     return new Enumeration<E>() {
299 :     int count = 0;
300 :    
301 :     public boolean hasMoreElements() {
302 :     return count < elementCount;
303 :     }
304 :    
305 :     public E nextElement() {
306 :     synchronized (Vector.this) {
307 :     if (count < elementCount) {
308 :     return (E)elementData[count++];
309 :     }
310 :     }
311 :     throw new NoSuchElementException("Vector Enumeration");
312 :     }
313 :     };
314 :     }
315 :    
316 :     /**
317 :     * Returns <tt>true</tt> if this vector contains the specified element.
318 :     * More formally, returns <tt>true</tt> if and only if this vector
319 :     * contains at least one element <tt>e</tt> such that
320 :     * <tt>(o==null&nbsp;?&nbsp;e==null&nbsp;:&nbsp;o.equals(e))</tt>.
321 :     *
322 :     * @param o element whose presence in this vector is to be tested
323 :     * @return <tt>true</tt> if this vector contains the specified element
324 :     */
325 :     public boolean contains(Object o) {
326 :     return indexOf(o, 0) >= 0;
327 :     }
328 :    
329 :     /**
330 :     * Returns the index of the first occurrence of the specified element
331 :     * in this vector, or -1 if this vector does not contain the element.
332 :     * More formally, returns the lowest index <tt>i</tt> such that
333 :     * <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>,
334 :     * or -1 if there is no such index.
335 :     *
336 :     * @param o element to search for
337 :     * @return the index of the first occurrence of the specified element in
338 :     * this vector, or -1 if this vector does not contain the element
339 :     */
340 :     public int indexOf(Object o) {
341 :     return indexOf(o, 0);
342 :     }
343 :    
344 :     /**
345 :     * Returns the index of the first occurrence of the specified element in
346 :     * this vector, searching forwards from <tt>index</tt>, or returns -1 if
347 :     * the element is not found.
348 :     * More formally, returns the lowest index <tt>i</tt> such that
349 :     * <tt>(i&nbsp;&gt;=&nbsp;index&nbsp;&amp;&amp;&nbsp;(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i))))</tt>,
350 :     * or -1 if there is no such index.
351 :     *
352 :     * @param o element to search for
353 :     * @param index index to start searching from
354 :     * @return the index of the first occurrence of the element in
355 :     * this vector at position <tt>index</tt> or later in the vector;
356 :     * <tt>-1</tt> if the element is not found.
357 :     * @throws IndexOutOfBoundsException if the specified index is negative
358 :     * @see Object#equals(Object)
359 :     */
360 :     public synchronized int indexOf(Object o, int index) {
361 :     if (o == null) {
362 :     for (int i = index ; i < elementCount ; i++)
363 :     if (elementData[i]==null)
364 :     return i;
365 :     } else {
366 :     for (int i = index ; i < elementCount ; i++)
367 :     if (o.equals(elementData[i]))
368 :     return i;
369 :     }
370 :     return -1;
371 :     }
372 :    
373 :     /**
374 :     * Returns the index of the last occurrence of the specified element
375 :     * in this vector, or -1 if this vector does not contain the element.
376 :     * More formally, returns the highest index <tt>i</tt> such that
377 :     * <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>,
378 :     * or -1 if there is no such index.
379 :     *
380 :     * @param o element to search for
381 :     * @return the index of the last occurrence of the specified element in
382 :     * this vector, or -1 if this vector does not contain the element
383 :     */
384 :     public synchronized int lastIndexOf(Object o) {
385 :     return lastIndexOf(o, elementCount-1);
386 :     }
387 :    
388 :     /**
389 :     * Returns the index of the last occurrence of the specified element in
390 :     * this vector, searching backwards from <tt>index</tt>, or returns -1 if
391 :     * the element is not found.
392 :     * More formally, returns the highest index <tt>i</tt> such that
393 :     * <tt>(i&nbsp;&lt;=&nbsp;index&nbsp;&amp;&amp;&nbsp;(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i))))</tt>,
394 :     * or -1 if there is no such index.
395 :     *
396 :     * @param o element to search for
397 :     * @param index index to start searching backwards from
398 :     * @return the index of the last occurrence of the element at position
399 :     * less than or equal to <tt>index</tt> in this vector;
400 :     * -1 if the element is not found.
401 :     * @throws IndexOutOfBoundsException if the specified index is greater
402 :     * than or equal to the current size of this vector
403 :     */
404 :     public synchronized int lastIndexOf(Object o, int index) {
405 :     if (index >= elementCount)
406 :     throw new IndexOutOfBoundsException(index + " >= "+ elementCount);
407 :    
408 :     if (o == null) {
409 :     for (int i = index; i >= 0; i--)
410 :     if (elementData[i]==null)
411 :     return i;
412 :     } else {
413 :     for (int i = index; i >= 0; i--)
414 :     if (o.equals(elementData[i]))
415 :     return i;
416 :     }
417 :     return -1;
418 :     }
419 :    
420 :     /**
421 :     * Returns the component at the specified index.<p>
422 :     *
423 :     * This method is identical in functionality to the get method
424 :     * (which is part of the List interface).
425 :     *
426 :     * @param index an index into this vector
427 :     * @return the component at the specified index
428 :     * @exception ArrayIndexOutOfBoundsException if the <tt>index</tt>
429 :     * is negative or not less than the current size of this
430 :     * <tt>Vector</tt> object.
431 :     * @see #get(int)
432 :     * @see List
433 :     */
434 :     public synchronized E elementAt(int index) {
435 :     if (index >= elementCount) {
436 :     throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount);
437 :     }
438 :    
439 :     return (E)elementData[index];
440 :     }
441 :    
442 :     /**
443 :     * Returns the first component (the item at index <tt>0</tt>) of
444 :     * this vector.
445 :     *
446 :     * @return the first component of this vector
447 :     * @exception NoSuchElementException if this vector has no components
448 :     */
449 :     public synchronized E firstElement() {
450 :     if (elementCount == 0) {
451 :     throw new NoSuchElementException();
452 :     }
453 :     return (E)elementData[0];
454 :     }
455 :    
456 :     /**
457 :     * Returns the last component of the vector.
458 :     *
459 :     * @return the last component of the vector, i.e., the component at index
460 :     * <code>size()&nbsp;-&nbsp;1</code>.
461 :     * @exception NoSuchElementException if this vector is empty
462 :     */
463 :     public synchronized E lastElement() {
464 :     if (elementCount == 0) {
465 :     throw new NoSuchElementException();
466 :     }
467 :     return (E)elementData[elementCount - 1];
468 :     }
469 :    
470 :     /**
471 :     * Sets the component at the specified <code>index</code> of this
472 :     * vector to be the specified object. The previous component at that
473 :     * position is discarded.<p>
474 :     *
475 :     * The index must be a value greater than or equal to <code>0</code>
476 :     * and less than the current size of the vector. <p>
477 :     *
478 :     * This method is identical in functionality to the set method
479 :     * (which is part of the List interface). Note that the set method reverses
480 :     * the order of the parameters, to more closely match array usage. Note
481 :     * also that the set method returns the old value that was stored at the
482 :     * specified position.
483 :     *
484 :     * @param obj what the component is to be set to
485 :     * @param index the specified index
486 :     * @exception ArrayIndexOutOfBoundsException if the index was invalid
487 :     * @see #size()
488 :     * @see List
489 :     * @see #set(int, java.lang.Object)
490 :     */
491 :     public synchronized void setElementAt(E obj, int index) {
492 :     if (index >= elementCount) {
493 :     throw new ArrayIndexOutOfBoundsException(index + " >= " +
494 :     elementCount);
495 :     }
496 :     elementData[index] = obj;
497 :     }
498 :    
499 :     /**
500 :     * Deletes the component at the specified index. Each component in
501 :     * this vector with an index greater or equal to the specified
502 :     * <code>index</code> is shifted downward to have an index one
503 :     * smaller than the value it had previously. The size of this vector
504 :     * is decreased by <tt>1</tt>.<p>
505 :     *
506 :     * The index must be a value greater than or equal to <code>0</code>
507 :     * and less than the current size of the vector. <p>
508 :     *
509 :     * This method is identical in functionality to the remove method
510 :     * (which is part of the List interface). Note that the remove method
511 :     * returns the old value that was stored at the specified position.
512 :     *
513 :     * @param index the index of the object to remove
514 :     * @exception ArrayIndexOutOfBoundsException if the index was invalid
515 :     * @see #size()
516 :     * @see #remove(int)
517 :     * @see List
518 :     */
519 :     public synchronized void removeElementAt(int index) {
520 :     modCount++;
521 :     if (index >= elementCount) {
522 :     throw new ArrayIndexOutOfBoundsException(index + " >= " +
523 :     elementCount);
524 :     }
525 :     else if (index < 0) {
526 :     throw new ArrayIndexOutOfBoundsException(index);
527 :     }
528 :     int j = elementCount - index - 1;
529 :     if (j > 0) {
530 :     System.arraycopy(elementData, index + 1, elementData, index, j);
531 :     }
532 :     elementCount--;
533 :     elementData[elementCount] = null; /* to let gc do its work */
534 :     }
535 :    
536 :     /**
537 :     * Inserts the specified object as a component in this vector at the
538 :     * specified <code>index</code>. Each component in this vector with
539 :     * an index greater or equal to the specified <code>index</code> is
540 :     * shifted upward to have an index one greater than the value it had
541 :     * previously. <p>
542 :     *
543 :     * The index must be a value greater than or equal to <code>0</code>
544 :     * and less than or equal to the current size of the vector. (If the
545 :     * index is equal to the current size of the vector, the new element
546 :     * is appended to the Vector.)<p>
547 :     *
548 :     * This method is identical in functionality to the add(Object, int) method
549 :     * (which is part of the List interface). Note that the add method reverses
550 :     * the order of the parameters, to more closely match array usage.
551 :     *
552 :     * @param obj the component to insert
553 :     * @param index where to insert the new component
554 :     * @exception ArrayIndexOutOfBoundsException if the index was invalid
555 :     * @see #size()
556 :     * @see #add(int, Object)
557 :     * @see List
558 :     */
559 :     public synchronized void insertElementAt(E obj, int index) {
560 :     modCount++;
561 :     if (index > elementCount) {
562 :     throw new ArrayIndexOutOfBoundsException(index
563 :     + " > " + elementCount);
564 :     }
565 :     ensureCapacityHelper(elementCount + 1);
566 :     System.arraycopy(elementData, index, elementData, index + 1, elementCount - index);
567 :     elementData[index] = obj;
568 :     elementCount++;
569 :     }
570 :    
571 :     /**
572 :     * Adds the specified component to the end of this vector,
573 :     * increasing its size by one. The capacity of this vector is
574 :     * increased if its size becomes greater than its capacity. <p>
575 :     *
576 :     * This method is identical in functionality to the add(Object) method
577 :     * (which is part of the List interface).
578 :     *
579 :     * @param obj the component to be added
580 :     * @see #add(Object)
581 :     * @see List
582 :     */
583 :     public synchronized void addElement(E obj) {
584 :     modCount++;
585 :     ensureCapacityHelper(elementCount + 1);
586 :     elementData[elementCount++] = obj;
587 :     }
588 :    
589 :     /**
590 :     * Removes the first (lowest-indexed) occurrence of the argument
591 :     * from this vector. If the object is found in this vector, each
592 :     * component in the vector with an index greater or equal to the
593 :     * object's index is shifted downward to have an index one smaller
594 :     * than the value it had previously.<p>
595 :     *
596 :     * This method is identical in functionality to the remove(Object)
597 :     * method (which is part of the List interface).
598 :     *
599 :     * @param obj the component to be removed
600 :     * @return <code>true</code> if the argument was a component of this
601 :     * vector; <code>false</code> otherwise.
602 :     * @see List#remove(Object)
603 :     * @see List
604 :     */
605 :     public synchronized boolean removeElement(Object obj) {
606 :     modCount++;
607 :     int i = indexOf(obj);
608 :     if (i >= 0) {
609 :     removeElementAt(i);
610 :     return true;
611 :     }
612 :     return false;
613 :     }
614 :    
615 :     /**
616 :     * Removes all components from this vector and sets its size to zero.<p>
617 :     *
618 :     * This method is identical in functionality to the clear method
619 :     * (which is part of the List interface).
620 :     *
621 :     * @see #clear
622 :     * @see List
623 :     */
624 :     public synchronized void removeAllElements() {
625 :     modCount++;
626 :     // Let gc do its work
627 :     for (int i = 0; i < elementCount; i++)
628 :     elementData[i] = null;
629 :    
630 :     elementCount = 0;
631 :     }
632 :    
633 :     /**
634 :     * Returns a clone of this vector. The copy will contain a
635 :     * reference to a clone of the internal data array, not a reference
636 :     * to the original internal data array of this <tt>Vector</tt> object.
637 :     *
638 :     * @return a clone of this vector
639 :     */
640 :     public synchronized Object clone() {
641 :     try {
642 :     Vector<E> v = (Vector<E>) super.clone();
643 :     v.elementData = Arrays.copyOf(elementData, elementCount);
644 :     v.modCount = 0;
645 :     return v;
646 :     } catch (CloneNotSupportedException e) {
647 :     // this shouldn't happen, since we are Cloneable
648 :     throw new InternalError();
649 :     }
650 :     }
651 :    
652 :     /**
653 :     * Returns an array containing all of the elements in this Vector
654 :     * in the correct order.
655 :     *
656 :     * @since 1.2
657 :     */
658 :     public synchronized Object[] toArray() {
659 :     return Arrays.copyOf(elementData, elementCount);
660 :     }
661 :    
662 :     /**
663 :     * Returns an array containing all of the elements in this Vector in the
664 :     * correct order; the runtime type of the returned array is that of the
665 :     * specified array. If the Vector fits in the specified array, it is
666 :     * returned therein. Otherwise, a new array is allocated with the runtime
667 :     * type of the specified array and the size of this Vector.<p>
668 :     *
669 :     * If the Vector fits in the specified array with room to spare
670 :     * (i.e., the array has more elements than the Vector),
671 :     * the element in the array immediately following the end of the
672 :     * Vector is set to null. (This is useful in determining the length
673 :     * of the Vector <em>only</em> if the caller knows that the Vector
674 :     * does not contain any null elements.)
675 :     *
676 :     * @param a the array into which the elements of the Vector are to
677 :     * be stored, if it is big enough; otherwise, a new array of the
678 :     * same runtime type is allocated for this purpose.
679 :     * @return an array containing the elements of the Vector
680 :     * @exception ArrayStoreException the runtime type of a is not a supertype
681 :     * of the runtime type of every element in this Vector
682 :     * @throws NullPointerException if the given array is null
683 :     * @since 1.2
684 :     */
685 :     public synchronized <T> T[] toArray(T[] a) {
686 :     if (a.length < elementCount)
687 :     return (T[]) Arrays.copyOf(elementData, elementCount, a.getClass());
688 :    
689 :     System.arraycopy(elementData, 0, a, 0, elementCount);
690 :    
691 :     if (a.length > elementCount)
692 :     a[elementCount] = null;
693 :    
694 :     return a;
695 :     }
696 :    
697 :     // Positional Access Operations
698 :    
699 :     /**
700 :     * Returns the element at the specified position in this Vector.
701 :     *
702 :     * @param index index of the element to return
703 :     * @return object at the specified index
704 :     * @exception ArrayIndexOutOfBoundsException index is out of range (index
705 :     * &lt; 0 || index &gt;= size())
706 :     * @since 1.2
707 :     */
708 :     public synchronized E get(int index) {
709 :     if (index >= elementCount)
710 :     throw new ArrayIndexOutOfBoundsException(index);
711 :    
712 :     return (E)elementData[index];
713 :     }
714 :    
715 :     /**
716 :     * Replaces the element at the specified position in this Vector with the
717 :     * specified element.
718 :     *
719 :     * @param index index of the element to replace
720 :     * @param element element to be stored at the specified position
721 :     * @return the element previously at the specified position
722 :     * @exception ArrayIndexOutOfBoundsException index out of range
723 :     * (index &lt; 0 || index &gt;= size())
724 :     * @since 1.2
725 :     */
726 :     public synchronized E set(int index, E element) {
727 :     if (index >= elementCount)
728 :     throw new ArrayIndexOutOfBoundsException(index);
729 :    
730 :     Object oldValue = elementData[index];
731 :     elementData[index] = element;
732 :     return (E)oldValue;
733 :     }
734 :    
735 :     /**
736 :     * Appends the specified element to the end of this Vector.
737 :     *
738 :     * @param e element to be appended to this Vector
739 :     * @return <tt>true</tt> (as specified by {@link Collection#add})
740 :     * @since 1.2
741 :     */
742 :     public synchronized boolean add(E e) {
743 :     modCount++;
744 :     ensureCapacityHelper(elementCount + 1);
745 :     elementData[elementCount++] = e;
746 :     return true;
747 :     }
748 :    
749 :     /**
750 :     * Removes the first occurrence of the specified element in this Vector
751 :     * If the Vector does not contain the element, it is unchanged. More
752 :     * formally, removes the element with the lowest index i such that
753 :     * <code>(o==null ? get(i)==null : o.equals(get(i)))</code> (if such
754 :     * an element exists).
755 :     *
756 :     * @param o element to be removed from this Vector, if present
757 :     * @return true if the Vector contained the specified element
758 :     * @since 1.2
759 :     */
760 :     public boolean remove(Object o) {
761 :     return removeElement(o);
762 :     }
763 :    
764 :     /**
765 :     * Inserts the specified element at the specified position in this Vector.
766 :     * Shifts the element currently at that position (if any) and any
767 :     * subsequent elements to the right (adds one to their indices).
768 :     *
769 :     * @param index index at which the specified element is to be inserted
770 :     * @param element element to be inserted
771 :     * @exception ArrayIndexOutOfBoundsException index is out of range
772 :     * (index &lt; 0 || index &gt; size())
773 :     * @since 1.2
774 :     */
775 :     public void add(int index, E element) {
776 :     insertElementAt(element, index);
777 :     }
778 :    
779 :     /**
780 :     * Removes the element at the specified position in this Vector.
781 :     * Shifts any subsequent elements to the left (subtracts one from their
782 :     * indices). Returns the element that was removed from the Vector.
783 :     *
784 :     * @exception ArrayIndexOutOfBoundsException index out of range (index
785 :     * &lt; 0 || index &gt;= size())
786 :     * @param index the index of the element to be removed
787 :     * @return element that was removed
788 :     * @since 1.2
789 :     */
790 :     public synchronized E remove(int index) {
791 :     modCount++;
792 :     if (index >= elementCount)
793 :     throw new ArrayIndexOutOfBoundsException(index);
794 :     Object oldValue = elementData[index];
795 :    
796 :     int numMoved = elementCount - index - 1;
797 :     if (numMoved > 0)
798 :     System.arraycopy(elementData, index+1, elementData, index,
799 :     numMoved);
800 :     elementData[--elementCount] = null; // Let gc do its work
801 :    
802 :     return (E)oldValue;
803 :     }
804 :    
805 :     /**
806 :     * Removes all of the elements from this Vector. The Vector will
807 :     * be empty after this call returns (unless it throws an exception).
808 :     *
809 :     * @since 1.2
810 :     */
811 :     public void clear() {
812 :     removeAllElements();
813 :     }
814 :    
815 :     // Bulk Operations
816 :    
817 :     /**
818 :     * Returns true if this Vector contains all of the elements in the
819 :     * specified Collection.
820 :     *
821 :     * @param c a collection whose elements will be tested for containment
822 :     * in this Vector
823 :     * @return true if this Vector contains all of the elements in the
824 :     * specified collection
825 :     * @throws NullPointerException if the specified collection is null
826 :     */
827 :     public synchronized boolean containsAll(Collection<?> c) {
828 :     return super.containsAll(c);
829 :     }
830 :    
831 :     /**
832 :     * Appends all of the elements in the specified Collection to the end of
833 :     * this Vector, in the order that they are returned by the specified
834 :     * Collection's Iterator. The behavior of this operation is undefined if
835 :     * the specified Collection is modified while the operation is in progress.
836 :     * (This implies that the behavior of this call is undefined if the
837 :     * specified Collection is this Vector, and this Vector is nonempty.)
838 :     *
839 :     * @param c elements to be inserted into this Vector
840 :     * @return <tt>true</tt> if this Vector changed as a result of the call
841 :     * @throws NullPointerException if the specified collection is null
842 :     * @since 1.2
843 :     */
844 :     public synchronized boolean addAll(Collection<? extends E> c) {
845 :     modCount++;
846 :     Object[] a = c.toArray();
847 :     int numNew = a.length;
848 :     ensureCapacityHelper(elementCount + numNew);
849 :     System.arraycopy(a, 0, elementData, elementCount, numNew);
850 :     elementCount += numNew;
851 :     return numNew != 0;
852 :     }
853 :    
854 :     /**
855 :     * Removes from this Vector all of its elements that are contained in the
856 :     * specified Collection.
857 :     *
858 :     * @param c a collection of elements to be removed from the Vector
859 :     * @return true if this Vector changed as a result of the call
860 :     * @throws ClassCastException if the types of one or more elements
861 :     * in this vector are incompatible with the specified
862 :     * collection (optional)
863 :     * @throws NullPointerException if this vector contains one or more null
864 :     * elements and the specified collection does not support null
865 :     * elements (optional), or if the specified collection is null
866 :     * @since 1.2
867 :     */
868 :     public synchronized boolean removeAll(Collection<?> c) {
869 :     return super.removeAll(c);
870 :     }
871 :    
872 :     /**
873 :     * Retains only the elements in this Vector that are contained in the
874 :     * specified Collection. In other words, removes from this Vector all
875 :     * of its elements that are not contained in the specified Collection.
876 :     *
877 :     * @param c a collection of elements to be retained in this Vector
878 :     * (all other elements are removed)
879 :     * @return true if this Vector changed as a result of the call
880 :     * @throws ClassCastException if the types of one or more elements
881 :     * in this vector are incompatible with the specified
882 :     * collection (optional)
883 :     * @throws NullPointerException if this vector contains one or more null
884 :     * elements and the specified collection does not support null
885 :     * elements (optional), or if the specified collection is null
886 :     * @since 1.2
887 :     */
888 :     public synchronized boolean retainAll(Collection<?> c) {
889 :     return super.retainAll(c);
890 :     }
891 :    
892 :     /**
893 :     * Inserts all of the elements in the specified Collection into this
894 :     * Vector at the specified position. Shifts the element currently at
895 :     * that position (if any) and any subsequent elements to the right
896 :     * (increases their indices). The new elements will appear in the Vector
897 :     * in the order that they are returned by the specified Collection's
898 :     * iterator.
899 :     *
900 :     * @param index index at which to insert the first element from the
901 :     * specified collection
902 :     * @param c elements to be inserted into this Vector
903 :     * @return <tt>true</tt> if this Vector changed as a result of the call
904 :     * @exception ArrayIndexOutOfBoundsException index out of range (index
905 :     * &lt; 0 || index &gt; size())
906 :     * @throws NullPointerException if the specified collection is null
907 :     * @since 1.2
908 :     */
909 :     public synchronized boolean addAll(int index, Collection<? extends E> c) {
910 :     modCount++;
911 :     if (index < 0 || index > elementCount)
912 :     throw new ArrayIndexOutOfBoundsException(index);
913 :    
914 :     Object[] a = c.toArray();
915 :     int numNew = a.length;
916 :     ensureCapacityHelper(elementCount + numNew);
917 :    
918 :     int numMoved = elementCount - index;
919 :     if (numMoved > 0)
920 :     System.arraycopy(elementData, index, elementData, index + numNew,
921 :     numMoved);
922 :    
923 :     System.arraycopy(a, 0, elementData, index, numNew);
924 :     elementCount += numNew;
925 :     return numNew != 0;
926 :     }
927 :    
928 :     /**
929 :     * Compares the specified Object with this Vector for equality. Returns
930 :     * true if and only if the specified Object is also a List, both Lists
931 :     * have the same size, and all corresponding pairs of elements in the two
932 :     * Lists are <em>equal</em>. (Two elements <code>e1</code> and
933 :     * <code>e2</code> are <em>equal</em> if <code>(e1==null ? e2==null :
934 :     * e1.equals(e2))</code>.) In other words, two Lists are defined to be
935 :     * equal if they contain the same elements in the same order.
936 :     *
937 :     * @param o the Object to be compared for equality with this Vector
938 :     * @return true if the specified Object is equal to this Vector
939 :     */
940 :     public synchronized boolean equals(Object o) {
941 :     return super.equals(o);
942 :     }
943 :    
944 :     /**
945 :     * Returns the hash code value for this Vector.
946 :     */
947 :     public synchronized int hashCode() {
948 :     return super.hashCode();
949 :     }
950 :    
951 :     /**
952 :     * Returns a string representation of this Vector, containing
953 :     * the String representation of each element.
954 :     */
955 :     public synchronized String toString() {
956 :     return super.toString();
957 :     }
958 :    
959 :     /**
960 :     * Returns a view of the portion of this List between fromIndex,
961 :     * inclusive, and toIndex, exclusive. (If fromIndex and toIndex are
962 :     * equal, the returned List is empty.) The returned List is backed by this
963 :     * List, so changes in the returned List are reflected in this List, and
964 :     * vice-versa. The returned List supports all of the optional List
965 :     * operations supported by this List.<p>
966 :     *
967 :     * This method eliminates the need for explicit range operations (of
968 :     * the sort that commonly exist for arrays). Any operation that expects
969 :     * a List can be used as a range operation by operating on a subList view
970 :     * instead of a whole List. For example, the following idiom
971 :     * removes a range of elements from a List:
972 :     * <pre>
973 :     * list.subList(from, to).clear();
974 :     * </pre>
975 :     * Similar idioms may be constructed for indexOf and lastIndexOf,
976 :     * and all of the algorithms in the Collections class can be applied to
977 :     * a subList.<p>
978 :     *
979 :     * The semantics of the List returned by this method become undefined if
980 :     * the backing list (i.e., this List) is <i>structurally modified</i> in
981 :     * any way other than via the returned List. (Structural modifications are
982 :     * those that change the size of the List, or otherwise perturb it in such
983 :     * a fashion that iterations in progress may yield incorrect results.)
984 :     *
985 :     * @param fromIndex low endpoint (inclusive) of the subList
986 :     * @param toIndex high endpoint (exclusive) of the subList
987 :     * @return a view of the specified range within this List
988 :     * @throws IndexOutOfBoundsException endpoint index value out of range
989 :     * <code>(fromIndex &lt; 0 || toIndex &gt; size)</code>
990 :     * @throws IllegalArgumentException endpoint indices out of order
991 :     * <code>(fromIndex &gt; toIndex)</code>
992 :     */
993 :     public synchronized List<E> subList(int fromIndex, int toIndex) {
994 :     return Collections.synchronizedList(super.subList(fromIndex, toIndex),
995 :     this);
996 :     }
997 :    
998 :     /**
999 :     * Removes from this List all of the elements whose index is between
1000 :     * fromIndex, inclusive and toIndex, exclusive. Shifts any succeeding
1001 :     * elements to the left (reduces their index).
1002 :     * This call shortens the ArrayList by (toIndex - fromIndex) elements. (If
1003 :     * toIndex==fromIndex, this operation has no effect.)
1004 :     *
1005 :     * @param fromIndex index of first element to be removed
1006 :     * @param toIndex index after last element to be removed
1007 :     */
1008 :     protected synchronized void removeRange(int fromIndex, int toIndex) {
1009 :     modCount++;
1010 :     int numMoved = elementCount - toIndex;
1011 :     System.arraycopy(elementData, toIndex, elementData, fromIndex,
1012 :     numMoved);
1013 :    
1014 :     // Let gc do its work
1015 :     int newElementCount = elementCount - (toIndex-fromIndex);
1016 :     while (elementCount != newElementCount)
1017 :     elementData[--elementCount] = null;
1018 :     }
1019 :    
1020 :     /**
1021 :     * Save the state of the <tt>Vector</tt> instance to a stream (that
1022 :     * is, serialize it). This method is present merely for synchronization.
1023 :     * It just calls the default writeObject method.
1024 :     */
1025 :     private synchronized void writeObject(java.io.ObjectOutputStream s)
1026 :     throws java.io.IOException
1027 :     {
1028 :     s.defaultWriteObject();
1029 :     }
1030 :    
1031 :     /**
1032 :     * Returns a list-iterator of the elements in this list (in proper
1033 :     * sequence), starting at the specified position in the list.
1034 :     * Obeys the general contract of <tt>List.listIterator(int)</tt>.<p>
1035 :     *
1036 :     * The list-iterator is <i>fail-fast</i>: if the list is structurally
1037 :     * modified at any time after the Iterator is created, in any way except
1038 :     * through the list-iterator's own <tt>remove</tt> or <tt>add</tt>
1039 :     * methods, the list-iterator will throw a
1040 :     * <tt>ConcurrentModificationException</tt>. Thus, in the face of
1041 :     * concurrent modification, the iterator fails quickly and cleanly, rather
1042 :     * than risking arbitrary, non-deterministic behavior at an undetermined
1043 :     * time in the future.
1044 :     *
1045 :     * @param index index of the first element to be returned from the
1046 :     * list-iterator (by a call to <tt>next</tt>)
1047 :     * @return a ListIterator of the elements in this list (in proper
1048 :     * sequence), starting at the specified position in the list
1049 :     * @throws IndexOutOfBoundsException {@inheritDoc}
1050 :     * @see List#listIterator(int)
1051 :     */
1052 :     public synchronized ListIterator<E> listIterator(int index) {
1053 :     if (index < 0 || index > elementCount)
1054 :     throw new IndexOutOfBoundsException("Index: "+index);
1055 :     return new VectorIterator(index);
1056 :     }
1057 : jsr166 1.2
1058 : dl 1.1 /**
1059 : dl 1.3 * {@inheritDoc}
1060 :     */
1061 :     public synchronized ListIterator<E> listIterator() {
1062 :     return new VectorIterator(0);
1063 :     }
1064 :    
1065 :     /**
1066 : dl 1.1 * Returns an iterator over the elements in this list in proper sequence.
1067 :     *
1068 :     * @return an iterator over the elements in this list in proper sequence
1069 :     */
1070 :     public synchronized Iterator<E> iterator() {
1071 :     return new VectorIterator(0);
1072 :     }
1073 :    
1074 :     /**
1075 : dl 1.3 * A streamlined version of AbstractList.ListItr.
1076 : dl 1.1 */
1077 : dl 1.3 private final class VectorIterator implements ListIterator<E> {
1078 :     int cursor; // current position
1079 :     int lastRet; // index of last returned element
1080 :     int expectedModCount; // to check for CME
1081 : dl 1.1
1082 :     VectorIterator(int index) {
1083 :     cursor = index;
1084 : dl 1.3 expectedModCount = modCount;
1085 : dl 1.1 lastRet = -1;
1086 :     }
1087 :    
1088 :     public boolean hasNext() {
1089 : dl 1.3 // Racy but within spec, since modifications are checked
1090 :     // within or after synchronization in next/previous
1091 :     return cursor < Vector.this.elementCount;
1092 : dl 1.1 }
1093 :    
1094 :     public boolean hasPrevious() {
1095 :     return cursor > 0;
1096 :     }
1097 :    
1098 :     public int nextIndex() {
1099 :     return cursor;
1100 :     }
1101 :    
1102 :     public int previousIndex() {
1103 :     return cursor - 1;
1104 :     }
1105 :    
1106 :     public E next() {
1107 : dl 1.3 try {
1108 :     int i = cursor;
1109 :     E next = get(i);
1110 :     lastRet = i;
1111 :     cursor = i + 1;
1112 :     return next;
1113 :     } catch (IndexOutOfBoundsException ex) {
1114 :     throw new NoSuchElementException();
1115 :     } finally {
1116 :     if (expectedModCount != modCount)
1117 :     throw new ConcurrentModificationException();
1118 : dl 1.1 }
1119 :     }
1120 : jsr166 1.4
1121 :     public E previous() {
1122 : dl 1.3 try {
1123 :     int i = cursor - 1;
1124 :     E prev = get(i);
1125 :     lastRet = i;
1126 :     cursor = i;
1127 :     return prev;
1128 :     } catch (IndexOutOfBoundsException ex) {
1129 :     throw new NoSuchElementException();
1130 :     } finally {
1131 :     if (expectedModCount != modCount)
1132 :     throw new ConcurrentModificationException();
1133 : dl 1.1 }
1134 :     }
1135 :    
1136 :     public void remove() {
1137 : dl 1.3 if (lastRet == -1)
1138 : dl 1.1 throw new IllegalStateException();
1139 : dl 1.3 if (expectedModCount != modCount)
1140 :     throw new ConcurrentModificationException();
1141 :     try {
1142 :     Vector.this.remove(lastRet);
1143 :     if (lastRet < cursor)
1144 :     cursor--;
1145 :     lastRet = -1;
1146 :     expectedModCount = modCount;
1147 : jsr166 1.4 } catch (IndexOutOfBoundsException ex) {
1148 : dl 1.3 throw new ConcurrentModificationException();
1149 :     }
1150 : dl 1.1 }
1151 :    
1152 :     public void set(E e) {
1153 : dl 1.3 if (lastRet == -1)
1154 : dl 1.1 throw new IllegalStateException();
1155 : dl 1.3 if (expectedModCount != modCount)
1156 :     throw new ConcurrentModificationException();
1157 :     try {
1158 :     Vector.this.set(lastRet, e);
1159 :     expectedModCount = modCount;
1160 :     } catch (IndexOutOfBoundsException ex) {
1161 :     throw new ConcurrentModificationException();
1162 :     }
1163 : dl 1.1 }
1164 :    
1165 :     public void add(E e) {
1166 : dl 1.3 if (expectedModCount != modCount)
1167 :     throw new ConcurrentModificationException();
1168 :     try {
1169 :     int i = cursor;
1170 :     Vector.this.add(i, e);
1171 :     cursor = i + 1;
1172 :     lastRet = -1;
1173 :     expectedModCount = modCount;
1174 :     } catch (IndexOutOfBoundsException ex) {
1175 :     throw new ConcurrentModificationException();
1176 :     }
1177 : dl 1.1 }
1178 :     }
1179 :     }

Doug Lea
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