1 /*
2 * Copyright (c) 1994, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.util;
27
28 import java.io.IOException;
29 import java.io.ObjectInputStream;
30 import java.io.StreamCorruptedException;
31 import java.util.function.Consumer;
32 import java.util.function.Predicate;
33 import java.util.function.UnaryOperator;
34
35 import jdk.internal.util.ArraysSupport;
36
37 /**
38 * The {@code Vector} class implements a growable array of
39 * objects. Like an array, it contains components that can be
40 * accessed using an integer index. However, the size of a
41 * {@code Vector} can grow or shrink as needed to accommodate
42 * adding and removing items after the {@code Vector} has been created.
43 *
44 * <p>Each vector tries to optimize storage management by maintaining a
45 * {@code capacity} and a {@code capacityIncrement}. The
46 * {@code capacity} is always at least as large as the vector
47 * size; it is usually larger because as components are added to the
48 * vector, the vector's storage increases in chunks the size of
49 * {@code capacityIncrement}. An application can increase the
50 * capacity of a vector before inserting a large number of
51 * components; this reduces the amount of incremental reallocation.
52 *
53 * <p id="fail-fast">
54 * The iterators returned by this class's {@link #iterator() iterator} and
55 * {@link #listIterator(int) listIterator} methods are <em>fail-fast</em>:
56 * if the vector is structurally modified at any time after the iterator is
57 * created, in any way except through the iterator's own
58 * {@link ListIterator#remove() remove} or
59 * {@link ListIterator#add(Object) add} methods, the iterator will throw a
60 * {@link ConcurrentModificationException}. Thus, in the face of
61 * concurrent modification, the iterator fails quickly and cleanly, rather
62 * than risking arbitrary, non-deterministic behavior at an undetermined
63 * time in the future. The {@link Enumeration Enumerations} returned by
64 * the {@link #elements() elements} method are <em>not</em> fail-fast; if the
65 * Vector is structurally modified at any time after the enumeration is
66 * created then the results of enumerating are undefined.
67 *
68 * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed
69 * as it is, generally speaking, impossible to make any hard guarantees in the
70 * presence of unsynchronized concurrent modification. Fail-fast iterators
71 * throw {@code ConcurrentModificationException} on a best-effort basis.
72 * Therefore, it would be wrong to write a program that depended on this
73 * exception for its correctness: <i>the fail-fast behavior of iterators
74 * should be used only to detect bugs.</i>
75 *
76 * <p>As of the Java 2 platform v1.2, this class was retrofitted to
77 * implement the {@link List} interface, making it a member of the
78 * <a href="{@docRoot}/java.base/java/util/package-summary.html#CollectionsFramework">
79 * Java Collections Framework</a>. Unlike the new collection
80 * implementations, {@code Vector} is synchronized. If a thread-safe
81 * implementation is not needed, it is recommended to use {@link
82 * ArrayList} in place of {@code Vector}.
83 *
84 * @param <E> Type of component elements
85 *
86 * @author Lee Boynton
87 * @author Jonathan Payne
88 * @see Collection
89 * @see LinkedList
90 * @since 1.0
91 */
92 public class Vector<E>
93 extends AbstractList<E>
94 implements List<E>, RandomAccess, Cloneable, java.io.Serializable
95 {
96 /**
97 * The array buffer into which the components of the vector are
98 * stored. The capacity of the vector is the length of this array buffer,
99 * and is at least large enough to contain all the vector's elements.
100 *
101 * <p>Any array elements following the last element in the Vector are null.
102 *
103 * @serial
104 */
105 protected Object[] elementData;
106
107 /**
108 * The number of valid components in this {@code Vector} object.
109 * Components {@code elementData[0]} through
110 * {@code elementData[elementCount-1]} are the actual items.
111 *
112 * @serial
113 */
114 protected int elementCount;
115
116 /**
117 * The amount by which the capacity of the vector is automatically
118 * incremented when its size becomes greater than its capacity. If
119 * the capacity increment is less than or equal to zero, the capacity
120 * of the vector is doubled each time it needs to grow.
121 *
122 * @serial
123 */
124 protected int capacityIncrement;
125
126 /** use serialVersionUID from JDK 1.0.2 for interoperability */
127 @java.io.Serial
128 private static final long serialVersionUID = -2767605614048989439L;
129
130 /**
131 * Constructs an empty vector with the specified initial capacity and
132 * capacity increment.
133 *
134 * @param initialCapacity the initial capacity of the vector
135 * @param capacityIncrement the amount by which the capacity is
136 * increased when the vector overflows
137 * @throws IllegalArgumentException if the specified initial capacity
138 * is negative
139 */
140 public Vector(int initialCapacity, int capacityIncrement) {
141 super();
142 if (initialCapacity < 0)
143 throw new IllegalArgumentException("Illegal Capacity: "+
144 initialCapacity);
145 this.elementData = new Object[initialCapacity];
146 this.capacityIncrement = capacityIncrement;
147 }
148
149 /**
150 * Constructs an empty vector with the specified initial capacity and
151 * with its capacity increment equal to zero.
152 *
153 * @param initialCapacity the initial capacity of the vector
154 * @throws IllegalArgumentException if the specified initial capacity
155 * is negative
156 */
157 public Vector(int initialCapacity) {
158 this(initialCapacity, 0);
159 }
160
161 /**
162 * Constructs an empty vector so that its internal data array
163 * has size {@code 10} and its standard capacity increment is
164 * zero.
165 */
166 public Vector() {
167 this(10);
168 }
169
170 /**
171 * Constructs a vector containing the elements of the specified
172 * collection, in the order they are returned by the collection's
173 * iterator.
174 *
175 * @param c the collection whose elements are to be placed into this
176 * vector
177 * @throws NullPointerException if the specified collection is null
178 * @since 1.2
179 */
180 public Vector(Collection<? extends E> c) {
181 elementData = c.toArray();
182 elementCount = elementData.length;
183 // defend against c.toArray (incorrectly) not returning Object[]
184 // (see e.g. https://bugs.openjdk.java.net/browse/JDK-6260652)
185 if (elementData.getClass() != Object[].class)
186 elementData = Arrays.copyOf(elementData, elementCount, Object[].class);
187 }
188
189 /**
190 * Copies the components of this vector into the specified array.
191 * The item at index {@code k} in this vector is copied into
192 * component {@code k} of {@code anArray}.
193 *
194 * @param anArray the array into which the components get copied
195 * @throws NullPointerException if the given array is null
196 * @throws IndexOutOfBoundsException if the specified array is not
197 * large enough to hold all the components of this vector
198 * @throws ArrayStoreException if a component of this vector is not of
199 * a runtime type that can be stored in the specified array
200 * @see #toArray(Object[])
201 */
202 public synchronized void copyInto(Object[] anArray) {
203 System.arraycopy(elementData, 0, anArray, 0, elementCount);
204 }
205
206 /**
207 * Trims the capacity of this vector to be the vector's current
208 * size. If the capacity of this vector is larger than its current
209 * size, then the capacity is changed to equal the size by replacing
210 * its internal data array, kept in the field {@code elementData},
211 * with a smaller one. An application can use this operation to
212 * minimize the storage of a vector.
213 */
214 public synchronized void trimToSize() {
215 modCount++;
216 int oldCapacity = elementData.length;
217 if (elementCount < oldCapacity) {
218 elementData = Arrays.copyOf(elementData, elementCount);
219 }
220 }
221
222 /**
223 * Increases the capacity of this vector, if necessary, to ensure
224 * that it can hold at least the number of components specified by
225 * the minimum capacity argument.
226 *
227 * <p>If the current capacity of this vector is less than
228 * {@code minCapacity}, then its capacity is increased by replacing its
229 * internal data array, kept in the field {@code elementData}, with a
230 * larger one. The size of the new data array will be the old size plus
231 * {@code capacityIncrement}, unless the value of
232 * {@code capacityIncrement} is less than or equal to zero, in which case
233 * the new capacity will be twice the old capacity; but if this new size
234 * is still smaller than {@code minCapacity}, then the new capacity will
235 * be {@code minCapacity}.
236 *
237 * @param minCapacity the desired minimum capacity
238 */
239 public synchronized void ensureCapacity(int minCapacity) {
240 if (minCapacity > 0) {
241 modCount++;
242 if (minCapacity > elementData.length)
243 grow(minCapacity);
244 }
245 }
246
247 /**
248 * Increases the capacity to ensure that it can hold at least the
249 * number of elements specified by the minimum capacity argument.
250 *
251 * @param minCapacity the desired minimum capacity
252 * @throws OutOfMemoryError if minCapacity is less than zero
253 */
254 private Object[] grow(int minCapacity) {
255 int oldCapacity = elementData.length;
256 int newCapacity = ArraysSupport.newLength(oldCapacity,
257 minCapacity - oldCapacity, /* minimum growth */
258 capacityIncrement > 0 ? capacityIncrement : oldCapacity
259 /* preferred growth */);
260 return elementData = Arrays.copyOf(elementData, newCapacity);
261 }
262
263 private Object[] grow() {
264 return grow(elementCount + 1);
265 }
266
267 /**
268 * Sets the size of this vector. If the new size is greater than the
269 * current size, new {@code null} items are added to the end of
270 * the vector. If the new size is less than the current size, all
271 * components at index {@code newSize} and greater are discarded.
272 *
273 * @param newSize the new size of this vector
274 * @throws ArrayIndexOutOfBoundsException if the new size is negative
275 */
276 public synchronized void setSize(int newSize) {
277 modCount++;
278 if (newSize > elementData.length)
279 grow(newSize);
280 final Object[] es = elementData;
281 for (int to = elementCount, i = newSize; i < to; i++)
282 es[i] = null;
283 elementCount = newSize;
284 }
285
286 /**
287 * Returns the current capacity of this vector.
288 *
289 * @return the current capacity (the length of its internal
290 * data array, kept in the field {@code elementData}
291 * of this vector)
292 */
293 public synchronized int capacity() {
294 return elementData.length;
295 }
296
297 /**
298 * Returns the number of components in this vector.
299 *
300 * @return the number of components in this vector
301 */
302 public synchronized int size() {
303 return elementCount;
304 }
305
306 /**
307 * Tests if this vector has no components.
308 *
309 * @return {@code true} if and only if this vector has
310 * no components, that is, its size is zero;
311 * {@code false} otherwise.
312 */
313 public synchronized boolean isEmpty() {
314 return elementCount == 0;
315 }
316
317 /**
318 * Returns an enumeration of the components of this vector. The
319 * returned {@code Enumeration} object will generate all items in
320 * this vector. The first item generated is the item at index {@code 0},
321 * then the item at index {@code 1}, and so on. If the vector is
322 * structurally modified while enumerating over the elements then the
323 * results of enumerating are undefined.
324 *
325 * @return an enumeration of the components of this vector
326 * @see Iterator
327 */
328 public Enumeration<E> elements() {
329 return new Enumeration<E>() {
330 int count = 0;
331
332 public boolean hasMoreElements() {
333 return count < elementCount;
334 }
335
336 public E nextElement() {
337 synchronized (Vector.this) {
338 if (count < elementCount) {
339 return elementData(count++);
340 }
341 }
342 throw new NoSuchElementException("Vector Enumeration");
343 }
344 };
345 }
346
347 /**
348 * Returns {@code true} if this vector contains the specified element.
349 * More formally, returns {@code true} if and only if this vector
350 * contains at least one element {@code e} such that
351 * {@code Objects.equals(o, e)}.
352 *
353 * @param o element whose presence in this vector is to be tested
354 * @return {@code true} if this vector contains the specified element
355 */
356 public boolean contains(Object o) {
357 return indexOf(o, 0) >= 0;
358 }
359
360 /**
361 * Returns the index of the first occurrence of the specified element
362 * in this vector, or -1 if this vector does not contain the element.
363 * More formally, returns the lowest index {@code i} such that
364 * {@code Objects.equals(o, get(i))},
365 * or -1 if there is no such index.
366 *
367 * @param o element to search for
368 * @return the index of the first occurrence of the specified element in
369 * this vector, or -1 if this vector does not contain the element
370 */
371 public int indexOf(Object o) {
372 return indexOf(o, 0);
373 }
374
375 /**
376 * Returns the index of the first occurrence of the specified element in
377 * this vector, searching forwards from {@code index}, or returns -1 if
378 * the element is not found.
379 * More formally, returns the lowest index {@code i} such that
380 * {@code (i >= index && Objects.equals(o, get(i)))},
381 * or -1 if there is no such index.
382 *
383 * @param o element to search for
384 * @param index index to start searching from
385 * @return the index of the first occurrence of the element in
386 * this vector at position {@code index} or later in the vector;
387 * {@code -1} if the element is not found.
388 * @throws IndexOutOfBoundsException if the specified index is negative
389 * @see Object#equals(Object)
390 */
391 public synchronized int indexOf(Object o, int index) {
392 if (o == null) {
393 for (int i = index ; i < elementCount ; i++)
394 if (elementData[i]==null)
395 return i;
396 } else {
397 for (int i = index ; i < elementCount ; i++)
398 if (o.equals(elementData[i]))
399 return i;
400 }
401 return -1;
402 }
403
404 /**
405 * Returns the index of the last occurrence of the specified element
406 * in this vector, or -1 if this vector does not contain the element.
407 * More formally, returns the highest index {@code i} such that
408 * {@code Objects.equals(o, get(i))},
409 * or -1 if there is no such index.
410 *
411 * @param o element to search for
412 * @return the index of the last occurrence of the specified element in
413 * this vector, or -1 if this vector does not contain the element
414 */
415 public synchronized int lastIndexOf(Object o) {
416 return lastIndexOf(o, elementCount-1);
417 }
418
419 /**
420 * Returns the index of the last occurrence of the specified element in
421 * this vector, searching backwards from {@code index}, or returns -1 if
422 * the element is not found.
423 * More formally, returns the highest index {@code i} such that
424 * {@code (i <= index && Objects.equals(o, get(i)))},
425 * or -1 if there is no such index.
426 *
427 * @param o element to search for
428 * @param index index to start searching backwards from
429 * @return the index of the last occurrence of the element at position
430 * less than or equal to {@code index} in this vector;
431 * -1 if the element is not found.
432 * @throws IndexOutOfBoundsException if the specified index is greater
433 * than or equal to the current size of this vector
434 */
435 public synchronized int lastIndexOf(Object o, int index) {
436 if (index >= elementCount)
437 throw new IndexOutOfBoundsException(index + " >= "+ elementCount);
438
439 if (o == null) {
440 for (int i = index; i >= 0; i--)
441 if (elementData[i]==null)
442 return i;
443 } else {
444 for (int i = index; i >= 0; i--)
445 if (o.equals(elementData[i]))
446 return i;
447 }
448 return -1;
449 }
450
451 /**
452 * Returns the component at the specified index.
453 *
454 * <p>This method is identical in functionality to the {@link #get(int)}
455 * method (which is part of the {@link List} interface).
456 *
457 * @param index an index into this vector
458 * @return the component at the specified index
459 * @throws ArrayIndexOutOfBoundsException if the index is out of range
460 * ({@code index < 0 || index >= size()})
461 */
462 public synchronized E elementAt(int index) {
463 if (index >= elementCount) {
464 throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount);
465 }
466
467 return elementData(index);
468 }
469
470 /**
471 * Returns the first component (the item at index {@code 0}) of
472 * this vector.
473 *
474 * @return the first component of this vector
475 * @throws NoSuchElementException if this vector has no components
476 */
477 public synchronized E firstElement() {
478 if (elementCount == 0) {
479 throw new NoSuchElementException();
480 }
481 return elementData(0);
482 }
483
484 /**
485 * Returns the last component of the vector.
486 *
487 * @return the last component of the vector, i.e., the component at index
488 * {@code size() - 1}
489 * @throws NoSuchElementException if this vector is empty
490 */
491 public synchronized E lastElement() {
492 if (elementCount == 0) {
493 throw new NoSuchElementException();
494 }
495 return elementData(elementCount - 1);
496 }
497
498 /**
499 * Sets the component at the specified {@code index} of this
500 * vector to be the specified object. The previous component at that
501 * position is discarded.
502 *
503 * <p>The index must be a value greater than or equal to {@code 0}
504 * and less than the current size of the vector.
505 *
506 * <p>This method is identical in functionality to the
507 * {@link #set(int, Object) set(int, E)}
508 * method (which is part of the {@link List} interface). Note that the
509 * {@code set} method reverses the order of the parameters, to more closely
510 * match array usage. Note also that the {@code set} method returns the
511 * old value that was stored at the specified position.
512 *
513 * @param obj what the component is to be set to
514 * @param index the specified index
515 * @throws ArrayIndexOutOfBoundsException if the index is out of range
516 * ({@code index < 0 || index >= size()})
517 */
518 public synchronized void setElementAt(E obj, int index) {
519 if (index >= elementCount) {
520 throw new ArrayIndexOutOfBoundsException(index + " >= " +
521 elementCount);
522 }
523 elementData[index] = obj;
524 }
525
526 /**
527 * Deletes the component at the specified index. Each component in
528 * this vector with an index greater or equal to the specified
529 * {@code index} is shifted downward to have an index one
530 * smaller than the value it had previously. The size of this vector
531 * is decreased by {@code 1}.
532 *
533 * <p>The index must be a value greater than or equal to {@code 0}
534 * and less than the current size of the vector.
535 *
536 * <p>This method is identical in functionality to the {@link #remove(int)}
537 * method (which is part of the {@link List} interface). Note that the
538 * {@code remove} method returns the old value that was stored at the
539 * specified position.
540 *
541 * @param index the index of the object to remove
542 * @throws ArrayIndexOutOfBoundsException if the index is out of range
543 * ({@code index < 0 || index >= size()})
544 */
545 public synchronized void removeElementAt(int index) {
546 if (index >= elementCount) {
547 throw new ArrayIndexOutOfBoundsException(index + " >= " +
548 elementCount);
549 }
550 else if (index < 0) {
551 throw new ArrayIndexOutOfBoundsException(index);
552 }
553 int j = elementCount - index - 1;
554 if (j > 0) {
555 System.arraycopy(elementData, index + 1, elementData, index, j);
556 }
557 modCount++;
558 elementCount--;
559 elementData[elementCount] = null; /* to let gc do its work */
560 }
561
562 /**
563 * Inserts the specified object as a component in this vector at the
564 * specified {@code index}. Each component in this vector with
565 * an index greater or equal to the specified {@code index} is
566 * shifted upward to have an index one greater than the value it had
567 * previously.
568 *
569 * <p>The index must be a value greater than or equal to {@code 0}
570 * and less than or equal to the current size of the vector. (If the
571 * index is equal to the current size of the vector, the new element
572 * is appended to the Vector.)
573 *
574 * <p>This method is identical in functionality to the
575 * {@link #add(int, Object) add(int, E)}
576 * method (which is part of the {@link List} interface). Note that the
577 * {@code add} method reverses the order of the parameters, to more closely
578 * match array usage.
579 *
580 * @param obj the component to insert
581 * @param index where to insert the new component
582 * @throws ArrayIndexOutOfBoundsException if the index is out of range
583 * ({@code index < 0 || index > size()})
584 */
585 public synchronized void insertElementAt(E obj, int index) {
586 if (index > elementCount) {
587 throw new ArrayIndexOutOfBoundsException(index
588 + " > " + elementCount);
589 }
590 modCount++;
591 final int s = elementCount;
592 Object[] elementData = this.elementData;
593 if (s == elementData.length)
594 elementData = grow();
595 System.arraycopy(elementData, index,
596 elementData, index + 1,
597 s - index);
598 elementData[index] = obj;
599 elementCount = s + 1;
600 }
601
602 /**
603 * Adds the specified component to the end of this vector,
604 * increasing its size by one. The capacity of this vector is
605 * increased if its size becomes greater than its capacity.
606 *
607 * <p>This method is identical in functionality to the
608 * {@link #add(Object) add(E)}
609 * method (which is part of the {@link List} interface).
610 *
611 * @param obj the component to be added
612 */
613 public synchronized void addElement(E obj) {
614 modCount++;
615 add(obj, elementData, elementCount);
616 }
617
618 /**
619 * Removes the first (lowest-indexed) occurrence of the argument
620 * from this vector. If the object is found in this vector, each
621 * component in the vector with an index greater or equal to the
622 * object's index is shifted downward to have an index one smaller
623 * than the value it had previously.
624 *
625 * <p>This method is identical in functionality to the
626 * {@link #remove(Object)} method (which is part of the
627 * {@link List} interface).
628 *
629 * @param obj the component to be removed
630 * @return {@code true} if the argument was a component of this
631 * vector; {@code false} otherwise.
632 */
633 public synchronized boolean removeElement(Object obj) {
634 modCount++;
635 int i = indexOf(obj);
636 if (i >= 0) {
637 removeElementAt(i);
638 return true;
639 }
640 return false;
641 }
642
643 /**
644 * Removes all components from this vector and sets its size to zero.
645 *
646 * <p>This method is identical in functionality to the {@link #clear}
647 * method (which is part of the {@link List} interface).
648 */
649 public synchronized void removeAllElements() {
650 final Object[] es = elementData;
651 for (int to = elementCount, i = elementCount = 0; i < to; i++)
652 es[i] = null;
653 modCount++;
654 }
655
656 /**
657 * Returns a clone of this vector. The copy will contain a
658 * reference to a clone of the internal data array, not a reference
659 * to the original internal data array of this {@code Vector} object.
660 *
661 * @return a clone of this vector
662 */
663 public synchronized Object clone() {
664 try {
665 @SuppressWarnings("unchecked")
666 Vector<E> v = (Vector<E>) super.clone();
667 v.elementData = Arrays.copyOf(elementData, elementCount);
668 v.modCount = 0;
669 return v;
670 } catch (CloneNotSupportedException e) {
671 // this shouldn't happen, since we are Cloneable
672 throw new InternalError(e);
673 }
674 }
675
676 /**
677 * Returns an array containing all of the elements in this Vector
678 * in the correct order.
679 *
680 * @since 1.2
681 */
682 public synchronized Object[] toArray() {
683 return Arrays.copyOf(elementData, elementCount);
684 }
685
686 /**
687 * Returns an array containing all of the elements in this Vector in the
688 * correct order; the runtime type of the returned array is that of the
689 * specified array. If the Vector fits in the specified array, it is
690 * returned therein. Otherwise, a new array is allocated with the runtime
691 * type of the specified array and the size of this Vector.
692 *
693 * <p>If the Vector fits in the specified array with room to spare
694 * (i.e., the array has more elements than the Vector),
695 * the element in the array immediately following the end of the
696 * Vector is set to null. (This is useful in determining the length
697 * of the Vector <em>only</em> if the caller knows that the Vector
698 * does not contain any null elements.)
699 *
700 * @param <T> type of array elements. The same type as {@code <E>} or a
701 * supertype of {@code <E>}.
702 * @param a the array into which the elements of the Vector are to
703 * be stored, if it is big enough; otherwise, a new array of the
704 * same runtime type is allocated for this purpose.
705 * @return an array containing the elements of the Vector
706 * @throws ArrayStoreException if the runtime type of a, {@code <T>}, is not
707 * a supertype of the runtime type, {@code <E>}, of every element in this
708 * Vector
709 * @throws NullPointerException if the given array is null
710 * @since 1.2
711 */
712 @SuppressWarnings("unchecked")
713 public synchronized <T> T[] toArray(T[] a) {
714 if (a.length < elementCount)
715 return (T[]) Arrays.copyOf(elementData, elementCount, a.getClass());
716
717 System.arraycopy(elementData, 0, a, 0, elementCount);
718
719 if (a.length > elementCount)
720 a[elementCount] = null;
721
722 return a;
723 }
724
725 // Positional Access Operations
726
727 @SuppressWarnings("unchecked")
728 E elementData(int index) {
729 return (E) elementData[index];
730 }
731
732 @SuppressWarnings("unchecked")
733 static <E> E elementAt(Object[] es, int index) {
734 return (E) es[index];
735 }
736
737 /**
738 * Returns the element at the specified position in this Vector.
739 *
740 * @param index index of the element to return
741 * @return object at the specified index
742 * @throws ArrayIndexOutOfBoundsException if the index is out of range
743 * ({@code index < 0 || index >= size()})
744 * @since 1.2
745 */
746 public synchronized E get(int index) {
747 if (index >= elementCount)
748 throw new ArrayIndexOutOfBoundsException(index);
749
750 return elementData(index);
751 }
752
753 /**
754 * Replaces the element at the specified position in this Vector with the
755 * specified element.
756 *
757 * @param index index of the element to replace
758 * @param element element to be stored at the specified position
759 * @return the element previously at the specified position
760 * @throws ArrayIndexOutOfBoundsException if the index is out of range
761 * ({@code index < 0 || index >= size()})
762 * @since 1.2
763 */
764 public synchronized E set(int index, E element) {
765 if (index >= elementCount)
766 throw new ArrayIndexOutOfBoundsException(index);
767
768 E oldValue = elementData(index);
769 elementData[index] = element;
770 return oldValue;
771 }
772
773 /**
774 * This helper method split out from add(E) to keep method
775 * bytecode size under 35 (the -XX:MaxInlineSize default value),
776 * which helps when add(E) is called in a C1-compiled loop.
777 */
778 private void add(E e, Object[] elementData, int s) {
779 if (s == elementData.length)
780 elementData = grow();
781 elementData[s] = e;
782 elementCount = s + 1;
783 }
784
785 /**
786 * Appends the specified element to the end of this Vector.
787 *
788 * @param e element to be appended to this Vector
789 * @return {@code true} (as specified by {@link Collection#add})
790 * @since 1.2
791 */
792 public synchronized boolean add(E e) {
793 modCount++;
794 add(e, elementData, elementCount);
795 return true;
796 }
797
798 /**
799 * Removes the first occurrence of the specified element in this Vector
800 * If the Vector does not contain the element, it is unchanged. More
801 * formally, removes the element with the lowest index i such that
802 * {@code Objects.equals(o, get(i))} (if such
803 * an element exists).
804 *
805 * @param o element to be removed from this Vector, if present
806 * @return true if the Vector contained the specified element
807 * @since 1.2
808 */
809 public boolean remove(Object o) {
810 return removeElement(o);
811 }
812
813 /**
814 * Inserts the specified element at the specified position in this Vector.
815 * Shifts the element currently at that position (if any) and any
816 * subsequent elements to the right (adds one to their indices).
817 *
818 * @param index index at which the specified element is to be inserted
819 * @param element element to be inserted
820 * @throws ArrayIndexOutOfBoundsException if the index is out of range
821 * ({@code index < 0 || index > size()})
822 * @since 1.2
823 */
824 public void add(int index, E element) {
825 insertElementAt(element, index);
826 }
827
828 /**
829 * Removes the element at the specified position in this Vector.
830 * Shifts any subsequent elements to the left (subtracts one from their
831 * indices). Returns the element that was removed from the Vector.
832 *
833 * @param index the index of the element to be removed
834 * @return element that was removed
835 * @throws ArrayIndexOutOfBoundsException if the index is out of range
836 * ({@code index < 0 || index >= size()})
837 * @since 1.2
838 */
839 public synchronized E remove(int index) {
840 modCount++;
841 if (index >= elementCount)
842 throw new ArrayIndexOutOfBoundsException(index);
843 E oldValue = elementData(index);
844
845 int numMoved = elementCount - index - 1;
846 if (numMoved > 0)
847 System.arraycopy(elementData, index+1, elementData, index,
848 numMoved);
849 elementData[--elementCount] = null; // Let gc do its work
850
851 return oldValue;
852 }
853
854 /**
855 * Removes all of the elements from this Vector. The Vector will
856 * be empty after this call returns (unless it throws an exception).
857 *
858 * @since 1.2
859 */
860 public void clear() {
861 removeAllElements();
862 }
863
864 // Bulk Operations
865
866 /**
867 * Returns true if this Vector contains all of the elements in the
868 * specified Collection.
869 *
870 * @param c a collection whose elements will be tested for containment
871 * in this Vector
872 * @return true if this Vector contains all of the elements in the
873 * specified collection
874 * @throws NullPointerException if the specified collection is null
875 */
876 public synchronized boolean containsAll(Collection<?> c) {
877 return super.containsAll(c);
878 }
879
880 /**
881 * Appends all of the elements in the specified Collection to the end of
882 * this Vector, in the order that they are returned by the specified
883 * Collection's Iterator. The behavior of this operation is undefined if
884 * the specified Collection is modified while the operation is in progress.
885 * (This implies that the behavior of this call is undefined if the
886 * specified Collection is this Vector, and this Vector is nonempty.)
887 *
888 * @param c elements to be inserted into this Vector
889 * @return {@code true} if this Vector changed as a result of the call
890 * @throws NullPointerException if the specified collection is null
891 * @since 1.2
892 */
893 public boolean addAll(Collection<? extends E> c) {
894 Object[] a = c.toArray();
895 modCount++;
896 int numNew = a.length;
897 if (numNew == 0)
898 return false;
899 synchronized (this) {
900 Object[] elementData = this.elementData;
901 final int s = elementCount;
902 if (numNew > elementData.length - s)
903 elementData = grow(s + numNew);
904 System.arraycopy(a, 0, elementData, s, numNew);
905 elementCount = s + numNew;
906 return true;
907 }
908 }
909
910 /**
911 * Removes from this Vector all of its elements that are contained in the
912 * specified Collection.
913 *
914 * @param c a collection of elements to be removed from the Vector
915 * @return true if this Vector changed as a result of the call
916 * @throws ClassCastException if the types of one or more elements
917 * in this vector are incompatible with the specified
918 * collection
919 * (<a href="Collection.html#optional-restrictions">optional</a>)
920 * @throws NullPointerException if this vector contains one or more null
921 * elements and the specified collection does not support null
922 * elements
923 * (<a href="Collection.html#optional-restrictions">optional</a>),
924 * or if the specified collection is null
925 * @since 1.2
926 */
927 public boolean removeAll(Collection<?> c) {
928 Objects.requireNonNull(c);
929 return bulkRemove(e -> c.contains(e));
930 }
931
932 /**
933 * Retains only the elements in this Vector that are contained in the
934 * specified Collection. In other words, removes from this Vector all
935 * of its elements that are not contained in the specified Collection.
936 *
937 * @param c a collection of elements to be retained in this Vector
938 * (all other elements are removed)
939 * @return true if this Vector changed as a result of the call
940 * @throws ClassCastException if the types of one or more elements
941 * in this vector are incompatible with the specified
942 * collection
943 * (<a href="Collection.html#optional-restrictions">optional</a>)
944 * @throws NullPointerException if this vector contains one or more null
945 * elements and the specified collection does not support null
946 * elements
947 * (<a href="Collection.html#optional-restrictions">optional</a>),
948 * or if the specified collection is null
949 * @since 1.2
950 */
951 public boolean retainAll(Collection<?> c) {
952 Objects.requireNonNull(c);
953 return bulkRemove(e -> !c.contains(e));
954 }
955
956 /**
957 * @throws NullPointerException {@inheritDoc}
958 */
959 @Override
960 public boolean removeIf(Predicate<? super E> filter) {
961 Objects.requireNonNull(filter);
962 return bulkRemove(filter);
963 }
964
965 // A tiny bit set implementation
966
967 private static long[] nBits(int n) {
968 return new long[((n - 1) >> 6) + 1];
969 }
970 private static void setBit(long[] bits, int i) {
971 bits[i >> 6] |= 1L << i;
972 }
973 private static boolean isClear(long[] bits, int i) {
974 return (bits[i >> 6] & (1L << i)) == 0;
975 }
976
977 private synchronized boolean bulkRemove(Predicate<? super E> filter) {
978 int expectedModCount = modCount;
979 final Object[] es = elementData;
980 final int end = elementCount;
981 int i;
982 // Optimize for initial run of survivors
983 for (i = 0; i < end && !filter.test(elementAt(es, i)); i++)
984 ;
985 // Tolerate predicates that reentrantly access the collection for
986 // read (but writers still get CME), so traverse once to find
987 // elements to delete, a second pass to physically expunge.
988 if (i < end) {
989 final int beg = i;
990 final long[] deathRow = nBits(end - beg);
991 deathRow[0] = 1L; // set bit 0
992 for (i = beg + 1; i < end; i++)
993 if (filter.test(elementAt(es, i)))
994 setBit(deathRow, i - beg);
995 if (modCount != expectedModCount)
996 throw new ConcurrentModificationException();
997 modCount++;
998 int w = beg;
999 for (i = beg; i < end; i++)
1000 if (isClear(deathRow, i - beg))
1001 es[w++] = es[i];
1002 for (i = elementCount = w; i < end; i++)
1003 es[i] = null;
1004 return true;
1005 } else {
1006 if (modCount != expectedModCount)
1007 throw new ConcurrentModificationException();
1008 return false;
1009 }
1010 }
1011
1012 /**
1013 * Inserts all of the elements in the specified Collection into this
1014 * Vector at the specified position. Shifts the element currently at
1015 * that position (if any) and any subsequent elements to the right
1016 * (increases their indices). The new elements will appear in the Vector
1017 * in the order that they are returned by the specified Collection's
1018 * iterator.
1019 *
1020 * @param index index at which to insert the first element from the
1021 * specified collection
1022 * @param c elements to be inserted into this Vector
1023 * @return {@code true} if this Vector changed as a result of the call
1024 * @throws ArrayIndexOutOfBoundsException if the index is out of range
1025 * ({@code index < 0 || index > size()})
1026 * @throws NullPointerException if the specified collection is null
1027 * @since 1.2
1028 */
1029 public synchronized boolean addAll(int index, Collection<? extends E> c) {
1030 if (index < 0 || index > elementCount)
1031 throw new ArrayIndexOutOfBoundsException(index);
1032
1033 Object[] a = c.toArray();
1034 modCount++;
1035 int numNew = a.length;
1036 if (numNew == 0)
1037 return false;
1038 Object[] elementData = this.elementData;
1039 final int s = elementCount;
1040 if (numNew > elementData.length - s)
1041 elementData = grow(s + numNew);
1042
1043 int numMoved = s - index;
1044 if (numMoved > 0)
1045 System.arraycopy(elementData, index,
1046 elementData, index + numNew,
1047 numMoved);
1048 System.arraycopy(a, 0, elementData, index, numNew);
1049 elementCount = s + numNew;
1050 return true;
1051 }
1052
1053 /**
1054 * Compares the specified Object with this Vector for equality. Returns
1055 * true if and only if the specified Object is also a List, both Lists
1056 * have the same size, and all corresponding pairs of elements in the two
1057 * Lists are <em>equal</em>. (Two elements {@code e1} and
1058 * {@code e2} are <em>equal</em> if {@code Objects.equals(e1, e2)}.)
1059 * In other words, two Lists are defined to be
1060 * equal if they contain the same elements in the same order.
1061 *
1062 * @param o the Object to be compared for equality with this Vector
1063 * @return true if the specified Object is equal to this Vector
1064 */
1065 public synchronized boolean equals(Object o) {
1066 return super.equals(o);
1067 }
1068
1069 /**
1070 * Returns the hash code value for this Vector.
1071 */
1072 public synchronized int hashCode() {
1073 return super.hashCode();
1074 }
1075
1076 /**
1077 * Returns a string representation of this Vector, containing
1078 * the String representation of each element.
1079 */
1080 public synchronized String toString() {
1081 return super.toString();
1082 }
1083
1084 /**
1085 * Returns a view of the portion of this List between fromIndex,
1086 * inclusive, and toIndex, exclusive. (If fromIndex and toIndex are
1087 * equal, the returned List is empty.) The returned List is backed by this
1088 * List, so changes in the returned List are reflected in this List, and
1089 * vice-versa. The returned List supports all of the optional List
1090 * operations supported by this List.
1091 *
1092 * <p>This method eliminates the need for explicit range operations (of
1093 * the sort that commonly exist for arrays). Any operation that expects
1094 * a List can be used as a range operation by operating on a subList view
1095 * instead of a whole List. For example, the following idiom
1096 * removes a range of elements from a List:
1097 * <pre>
1098 * list.subList(from, to).clear();
1099 * </pre>
1100 * Similar idioms may be constructed for indexOf and lastIndexOf,
1101 * and all of the algorithms in the Collections class can be applied to
1102 * a subList.
1103 *
1104 * <p>The semantics of the List returned by this method become undefined if
1105 * the backing list (i.e., this List) is <i>structurally modified</i> in
1106 * any way other than via the returned List. (Structural modifications are
1107 * those that change the size of the List, or otherwise perturb it in such
1108 * a fashion that iterations in progress may yield incorrect results.)
1109 *
1110 * @param fromIndex low endpoint (inclusive) of the subList
1111 * @param toIndex high endpoint (exclusive) of the subList
1112 * @return a view of the specified range within this List
1113 * @throws IndexOutOfBoundsException if an endpoint index value is out of range
1114 * {@code (fromIndex < 0 || toIndex > size)}
1115 * @throws IllegalArgumentException if the endpoint indices are out of order
1116 * {@code (fromIndex > toIndex)}
1117 */
1118 public synchronized List<E> subList(int fromIndex, int toIndex) {
1119 return Collections.synchronizedList(super.subList(fromIndex, toIndex),
1120 this);
1121 }
1122
1123 /**
1124 * Removes from this list all of the elements whose index is between
1125 * {@code fromIndex}, inclusive, and {@code toIndex}, exclusive.
1126 * Shifts any succeeding elements to the left (reduces their index).
1127 * This call shortens the list by {@code (toIndex - fromIndex)} elements.
1128 * (If {@code toIndex==fromIndex}, this operation has no effect.)
1129 */
1130 protected synchronized void removeRange(int fromIndex, int toIndex) {
1131 modCount++;
1132 shiftTailOverGap(elementData, fromIndex, toIndex);
1133 }
1134
1135 /** Erases the gap from lo to hi, by sliding down following elements. */
1136 private void shiftTailOverGap(Object[] es, int lo, int hi) {
1137 System.arraycopy(es, hi, es, lo, elementCount - hi);
1138 for (int to = elementCount, i = (elementCount -= hi - lo); i < to; i++)
1139 es[i] = null;
1140 }
1141
1142 /**
1143 * Loads a {@code Vector} instance from a stream
1144 * (that is, deserializes it).
1145 * This method performs checks to ensure the consistency
1146 * of the fields.
1147 *
1148 * @param in the stream
1149 * @throws java.io.IOException if an I/O error occurs
1150 * @throws ClassNotFoundException if the stream contains data
1151 * of a non-existing class
1152 */
1153 @java.io.Serial
1154 private void readObject(ObjectInputStream in)
1155 throws IOException, ClassNotFoundException {
1156 ObjectInputStream.GetField gfields = in.readFields();
1157 int count = gfields.get("elementCount", 0);
1158 Object[] data = (Object[])gfields.get("elementData", null);
1159 if (count < 0 || data == null || count > data.length) {
1160 throw new StreamCorruptedException("Inconsistent vector internals");
1161 }
1162 elementCount = count;
1163 elementData = data.clone();
1164 }
1165
1166 /**
1167 * Saves the state of the {@code Vector} instance to a stream
1168 * (that is, serializes it).
1169 * This method performs synchronization to ensure the consistency
1170 * of the serialized data.
1171 *
1172 * @param s the stream
1173 * @throws java.io.IOException if an I/O error occurs
1174 */
1175 @java.io.Serial
1176 private void writeObject(java.io.ObjectOutputStream s)
1177 throws java.io.IOException {
1178 final java.io.ObjectOutputStream.PutField fields = s.putFields();
1179 final Object[] data;
1180 synchronized (this) {
1181 fields.put("capacityIncrement", capacityIncrement);
1182 fields.put("elementCount", elementCount);
1183 data = elementData.clone();
1184 }
1185 fields.put("elementData", data);
1186 s.writeFields();
1187 }
1188
1189 /**
1190 * Returns a list iterator over the elements in this list (in proper
1191 * sequence), starting at the specified position in the list.
1192 * The specified index indicates the first element that would be
1193 * returned by an initial call to {@link ListIterator#next next}.
1194 * An initial call to {@link ListIterator#previous previous} would
1195 * return the element with the specified index minus one.
1196 *
1197 * <p>The returned list iterator is <a href="#fail-fast"><i>fail-fast</i></a>.
1198 *
1199 * @throws IndexOutOfBoundsException {@inheritDoc}
1200 */
1201 public synchronized ListIterator<E> listIterator(int index) {
1202 if (index < 0 || index > elementCount)
1203 throw new IndexOutOfBoundsException("Index: "+index);
1204 return new ListItr(index);
1205 }
1206
1207 /**
1208 * Returns a list iterator over the elements in this list (in proper
1209 * sequence).
1210 *
1211 * <p>The returned list iterator is <a href="#fail-fast"><i>fail-fast</i></a>.
1212 *
1213 * @see #listIterator(int)
1214 */
1215 public synchronized ListIterator<E> listIterator() {
1216 return new ListItr(0);
1217 }
1218
1219 /**
1220 * Returns an iterator over the elements in this list in proper sequence.
1221 *
1222 * <p>The returned iterator is <a href="#fail-fast"><i>fail-fast</i></a>.
1223 *
1224 * @return an iterator over the elements in this list in proper sequence
1225 */
1226 public synchronized Iterator<E> iterator() {
1227 return new Itr();
1228 }
1229
1230 /**
1231 * An optimized version of AbstractList.Itr
1232 */
1233 private class Itr implements Iterator<E> {
1234 int cursor; // index of next element to return
1235 int lastRet = -1; // index of last element returned; -1 if no such
1236 int expectedModCount = modCount;
1237
1238 public boolean hasNext() {
1239 // Racy but within spec, since modifications are checked
1240 // within or after synchronization in next/previous
1241 return cursor != elementCount;
1242 }
1243
1244 public E next() {
1245 synchronized (Vector.this) {
1246 checkForComodification();
1247 int i = cursor;
1248 if (i >= elementCount)
1249 throw new NoSuchElementException();
1250 cursor = i + 1;
1251 return elementData(lastRet = i);
1252 }
1253 }
1254
1255 public void remove() {
1256 if (lastRet == -1)
1257 throw new IllegalStateException();
1258 synchronized (Vector.this) {
1259 checkForComodification();
1260 Vector.this.remove(lastRet);
1261 expectedModCount = modCount;
1262 }
1263 cursor = lastRet;
1264 lastRet = -1;
1265 }
1266
1267 @Override
1268 public void forEachRemaining(Consumer<? super E> action) {
1269 Objects.requireNonNull(action);
1270 synchronized (Vector.this) {
1271 final int size = elementCount;
1272 int i = cursor;
1273 if (i >= size) {
1274 return;
1275 }
1276 final Object[] es = elementData;
1277 if (i >= es.length)
1278 throw new ConcurrentModificationException();
1279 while (i < size && modCount == expectedModCount)
1280 action.accept(elementAt(es, i++));
1281 // update once at end of iteration to reduce heap write traffic
1282 cursor = i;
1283 lastRet = i - 1;
1284 checkForComodification();
1285 }
1286 }
1287
1288 final void checkForComodification() {
1289 if (modCount != expectedModCount)
1290 throw new ConcurrentModificationException();
1291 }
1292 }
1293
1294 /**
1295 * An optimized version of AbstractList.ListItr
1296 */
1297 final class ListItr extends Itr implements ListIterator<E> {
1298 ListItr(int index) {
1299 super();
1300 cursor = index;
1301 }
1302
1303 public boolean hasPrevious() {
1304 return cursor != 0;
1305 }
1306
1307 public int nextIndex() {
1308 return cursor;
1309 }
1310
1311 public int previousIndex() {
1312 return cursor - 1;
1313 }
1314
1315 public E previous() {
1316 synchronized (Vector.this) {
1317 checkForComodification();
1318 int i = cursor - 1;
1319 if (i < 0)
1320 throw new NoSuchElementException();
1321 cursor = i;
1322 return elementData(lastRet = i);
1323 }
1324 }
1325
1326 public void set(E e) {
1327 if (lastRet == -1)
1328 throw new IllegalStateException();
1329 synchronized (Vector.this) {
1330 checkForComodification();
1331 Vector.this.set(lastRet, e);
1332 }
1333 }
1334
1335 public void add(E e) {
1336 int i = cursor;
1337 synchronized (Vector.this) {
1338 checkForComodification();
1339 Vector.this.add(i, e);
1340 expectedModCount = modCount;
1341 }
1342 cursor = i + 1;
1343 lastRet = -1;
1344 }
1345 }
1346
1347 /**
1348 * @throws NullPointerException {@inheritDoc}
1349 */
1350 @Override
1351 public synchronized void forEach(Consumer<? super E> action) {
1352 Objects.requireNonNull(action);
1353 final int expectedModCount = modCount;
1354 final Object[] es = elementData;
1355 final int size = elementCount;
1356 for (int i = 0; modCount == expectedModCount && i < size; i++)
1357 action.accept(elementAt(es, i));
1358 if (modCount != expectedModCount)
1359 throw new ConcurrentModificationException();
1360 }
1361
1362 /**
1363 * @throws NullPointerException {@inheritDoc}
1364 */
1365 @Override
1366 public synchronized void replaceAll(UnaryOperator<E> operator) {
1367 Objects.requireNonNull(operator);
1368 final int expectedModCount = modCount;
1369 final Object[] es = elementData;
1370 final int size = elementCount;
1371 for (int i = 0; modCount == expectedModCount && i < size; i++)
1372 es[i] = operator.apply(elementAt(es, i));
1373 if (modCount != expectedModCount)
1374 throw new ConcurrentModificationException();
1375 // TODO(8203662): remove increment of modCount from ...
1376 modCount++;
1377 }
1378
1379 @SuppressWarnings("unchecked")
1380 @Override
1381 public synchronized void sort(Comparator<? super E> c) {
1382 final int expectedModCount = modCount;
1383 Arrays.sort((E[]) elementData, 0, elementCount, c);
1384 if (modCount != expectedModCount)
1385 throw new ConcurrentModificationException();
1386 modCount++;
1387 }
1388
1389 /**
1390 * Creates a <em><a href="Spliterator.html#binding">late-binding</a></em>
1391 * and <em>fail-fast</em> {@link Spliterator} over the elements in this
1392 * list.
1393 *
1394 * <p>The {@code Spliterator} reports {@link Spliterator#SIZED},
1395 * {@link Spliterator#SUBSIZED}, and {@link Spliterator#ORDERED}.
1396 * Overriding implementations should document the reporting of additional
1397 * characteristic values.
1398 *
1399 * @return a {@code Spliterator} over the elements in this list
1400 * @since 1.8
1401 */
1402 @Override
1403 public Spliterator<E> spliterator() {
1404 return new VectorSpliterator(null, 0, -1, 0);
1405 }
1406
1407 /** Similar to ArrayList Spliterator */
1408 final class VectorSpliterator implements Spliterator<E> {
1409 private Object[] array;
1410 private int index; // current index, modified on advance/split
1411 private int fence; // -1 until used; then one past last index
1412 private int expectedModCount; // initialized when fence set
1413
1414 /** Creates new spliterator covering the given range. */
1415 VectorSpliterator(Object[] array, int origin, int fence,
1416 int expectedModCount) {
1417 this.array = array;
1418 this.index = origin;
1419 this.fence = fence;
1420 this.expectedModCount = expectedModCount;
1421 }
1422
1423 private int getFence() { // initialize on first use
1424 int hi;
1425 if ((hi = fence) < 0) {
1426 synchronized (Vector.this) {
1427 array = elementData;
1428 expectedModCount = modCount;
1429 hi = fence = elementCount;
1430 }
1431 }
1432 return hi;
1433 }
1434
1435 public Spliterator<E> trySplit() {
1436 int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
1437 return (lo >= mid) ? null :
1438 new VectorSpliterator(array, lo, index = mid, expectedModCount);
1439 }
1440
1441 @SuppressWarnings("unchecked")
1442 public boolean tryAdvance(Consumer<? super E> action) {
1443 Objects.requireNonNull(action);
1444 int i;
1445 if (getFence() > (i = index)) {
1446 index = i + 1;
1447 action.accept((E)array[i]);
1448 if (modCount != expectedModCount)
1449 throw new ConcurrentModificationException();
1450 return true;
1451 }
1452 return false;
1453 }
1454
1455 @SuppressWarnings("unchecked")
1456 public void forEachRemaining(Consumer<? super E> action) {
1457 Objects.requireNonNull(action);
1458 final int hi = getFence();
1459 final Object[] a = array;
1460 int i;
1461 for (i = index, index = hi; i < hi; i++)
1462 action.accept((E) a[i]);
1463 if (modCount != expectedModCount)
1464 throw new ConcurrentModificationException();
1465 }
1466
1467 public long estimateSize() {
1468 return getFence() - index;
1469 }
1470
1471 public int characteristics() {
1472 return Spliterator.ORDERED | Spliterator.SIZED | Spliterator.SUBSIZED;
1473 }
1474 }
1475
1476 void checkInvariants() {
1477 // assert elementCount >= 0;
1478 // assert elementCount == elementData.length || elementData[elementCount] == null;
1479 }
1480 }