Java集合源碼解析系列博客
轉載請標明出處：
https://blog.csdn.net/u011035026/article/details/83990055
1、Vector簡介？
- 繼承與AbstractList，實現了List, RandomAccess, Cloneable, java.io.Serializable。
- 可以看成線程安全版本的ArrayList（其實也不絕對，在使用還是會加鎖操作）。
- 基於泛型的一維數組實現，支持動態擴容，默認容量爲10，增長係數爲0，兩個值都是可以通過構造函數傳遞，擴容時，如果增長係數大於0，擴容的大小爲現有容量大小加上增長係數值，如果增長係數小於0，則擴容2倍，如果還是不夠則直接擴容要其需求之。
- 允許元素爲null，不支持序列化，單線程安全，加入了同步代碼塊，多線程安全（但不絕對）。
- 查看效率高，插入和刪除元素效率低，因爲插入和刪除會導致大量的元素移動。
- 相比於ArrayList其效率低，因爲加入了synchronized操作。
2、源碼解析
/**
* Vector源碼解析
*
* @param <E>
*/
public class Vector<E> extends AbstractList<E> implements List<E>
, RandomAccess, Cloneable, java.io.Serializable {
/**
* 保存Vector中數據的數組
*/
protected Object[] elementData;
/**
* 實際數據的數量
*/
protected int elementCount;
/**
* 容量增長係數
*/
protected int capacityIncrement;
/**
* Vector的序列版本號
*/
private static final long serialVersionUID = -2767605614048989439L;
/**
* 有參構造函數
*
* @param initialCapacity 容量大小
* @param capacityIncrement 增長係數
*/
public Vector(int initialCapacity, int capacityIncrement) {
super();
if (initialCapacity < 0)
throw new IllegalArgumentException("Illegal Capacity: " + initialCapacity);
//新建一個數組，數組容量是initialCapacity
this.elementData = new Object[initialCapacity];
//設置容量增長係數
this.capacityIncrement = capacityIncrement;
}
/**
* 有參構造函數
*
* @param initialCapacity 容量大小
*/
public Vector(int initialCapacity) {
this(initialCapacity, 0);
}
/**
* 無參構造函數，設置默認容量大小爲10
*/
public Vector() {
this(10);
}
/**
* 構造函數，指定集合的Vector
*
* @param c 集合c
*/
public Vector(Collection<? extends E> c) {
//將集合c轉換爲數組，並且賦值給elementData數組
elementData = c.toArray();
//設置數組中數據的數量
elementCount = elementData.length;
// c.toArray might (incorrectly) not return Object[] (see 6260652)
if (elementData.getClass() != Object[].class)
elementData = Arrays.copyOf(elementData, elementCount, Object[].class);
}
/**
* 將anArray數組拷貝到elementData數組中來
*
* @param anArray 待拷貝的數組
*/
public synchronized void copyInto(Object[] anArray) {
System.arraycopy(elementData, 0, anArray, 0, elementCount);
}
/**
* 將當前數組的容量設置爲數組實際元素個數
*/
public synchronized void trimToSize() {
modCount++;
int oldCapacity = elementData.length;
if (elementCount < oldCapacity) {
elementData = Arrays.copyOf(elementData, elementCount);
}
}
/**
* 確定Vector的容量。
*
* @param minCapacity 數組的容量大小
*/
public synchronized void ensureCapacity(int minCapacity) {
//如果傳入的容量大小小於等於0則無效，反之有效
if (minCapacity > 0) {
//將Vector的改變統計數+1
modCount++;
ensureCapacityHelper(minCapacity);
}
}
/**
* 確認“Vector容量”的幫助函數
*
* @param minCapacity 數組的容量大小
*/
private void ensureCapacityHelper(int minCapacity) {
// 判斷重新設置的數組容量是否大於現有的數組容量，這樣纔有效
if (minCapacity - elementData.length > 0)
grow(minCapacity);
}
/**
* The maximum size of array to allocate.
* Some VMs reserve some header words in an array.
* Attempts to allocate larger arrays may result in
* OutOfMemoryError: Requested array size exceeds VM limit
*/
private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
/**
* 數組動態擴容
*
* @param minCapacity 數組的容量大小
*/
private void grow(int minCapacity) {
// overflow-conscious code
int oldCapacity = elementData.length;
//若容量增長係數大於0(即capacityIncrement>0),則將容量增大到現有容量長度+容量增長係數發，
//否則，將原有容量乘2倍處理
int newCapacity = oldCapacity +
((capacityIncrement > 0) ? capacityIncrement : oldCapacity);
//如果擴展後的容量大小newCapacity<傳遞進來的容量大小，則擴展的容量大小設置爲傳遞進來的容量大小
if (newCapacity - minCapacity < 0)
newCapacity = minCapacity;
if (newCapacity - MAX_ARRAY_SIZE > 0)
newCapacity = hugeCapacity(minCapacity);
elementData = Arrays.copyOf(elementData, newCapacity);
}
private static int hugeCapacity(int minCapacity) {
if (minCapacity < 0) // overflow
throw new OutOfMemoryError();
return (minCapacity > MAX_ARRAY_SIZE) ?
Integer.MAX_VALUE :
MAX_ARRAY_SIZE;
}
/**
* 設置容量值爲 newSize
*
* @param newSize
*/
public synchronized void setSize(int newSize) {
modCount++;
if (newSize > elementCount) {
ensureCapacityHelper(newSize);
} else {
for (int i = newSize; i < elementCount; i++) {
elementData[i] = null;
}
}
elementCount = newSize;
}
/**
* 返回"Vector"的總容量的容量大小
*
* @return
*/
public synchronized int capacity() {
return elementData.length;
}
/**
* 返回"Vector"的實際大小。即Vector中元素個數
*
* @return Vector集合中數據大小
*/
public synchronized int size() {
return elementCount;
}
/**
* 判斷"Vector"集合是否爲空
*
* @return true爲空，反之亦然
*/
public synchronized boolean isEmpty() {
return elementCount == 0;
}
/**
* 返回“Vector中全部元素對應的Enumeration”
*
* @return
*/
public Enumeration<E> elements() {
return new Enumeration<E>() {
int count = 0;
public boolean hasMoreElements() {
return count < elementCount;
}
public E nextElement() {
synchronized (Vector.this) {
if (count < elementCount) {
return elementData(count++);
}
}
throw new NoSuchElementException("Vector Enumeration");
}
};
}
/**
* 判斷"Vector"是否包含元素(o)
*
* @param o 元素(o)
* @return true代表包含，false代表不包含
*/
public boolean contains(Object o) {
return indexOf(o, 0) >= 0;
}
/**
* 查找並返回元素(o)在Vector中的索引值
*
* @param o 元素(o)
* @return 返回元素(0)的索引座標，如若不存在返回-1
*/
public int indexOf(Object o) {
return indexOf(o, 0);
}
/**
* 從index位置開始向後查找元素(o)
*
* @param o 元素(o)
* @param index 索引位置
* @return
*/
public synchronized int indexOf(Object o, int index) {
//若查找元素爲null，則正向找出null元素，並返回它對應的序號
if (o == null) {
for (int i = index; i < elementCount; i++)
if (elementData[i] == null)
return i;
} else {
//若查找元素不爲null，則正向找出該元素，並返回它對應的序號
for (int i = index; i < elementCount; i++)
if (o.equals(elementData[i]))
return i;
}
return -1;
}
/**
* 從後向前查找元素(o),並返回元素的索引
*
* @param o 元素(o)
* @return 返回元素的索引座標，如若不存在返回-1
*/
public synchronized int lastIndexOf(Object o) {
return lastIndexOf(o, elementCount - 1);
}
/**
* 從後向前查找元素(o),開始位置是從前向後的第index個數
*
* @param o 元素(o)
* @param index 索引座標
* @return 返回元素的索引座標，如若不存在返回-1
*/
public synchronized int lastIndexOf(Object o, int index) {
if (index >= elementCount)
throw new IndexOutOfBoundsException(index + " >= " + elementCount);
if (o == null) {
for (int i = index; i >= 0; i--)
if (elementData[i] == null)
return i;
} else {
for (int i = index; i >= 0; i--)
if (o.equals(elementData[i]))
return i;
}
return -1;
}
/**
* 返回"Vector"中索引座標爲index位置的元素
*
* @param index 索引座標
* @return 返回對應的元素，失敗則拋出異常
*/
public synchronized E elementAt(int index) {
//判斷index索引座標是否有效
if (index >= elementCount) {
throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount);
}
return elementData(index);
}
/**
* 返回"Vector"中的第一個元素
*
* @return 元素值，若失敗則拋出異常
*/
public synchronized E firstElement() {
if (elementCount == 0) {
throw new NoSuchElementException();
}
return elementData(0);
}
/**
* 返回"Vector"中的最後一個元素
*
* @return 元素值，若失敗則拋出異常
*/
public synchronized E lastElement() {
if (elementCount == 0) {
throw new NoSuchElementException();
}
return elementData(elementCount - 1);
}
/**
* 設置索引座標爲index的元素值obj
*
* @param obj 元素值
* @param index 索引座標
*/
public synchronized void setElementAt(E obj, int index) {
if (index >= elementCount) {
throw new ArrayIndexOutOfBoundsException(index + " >= " +
elementCount);
}
elementData[index] = obj;
}
/**
* 刪除索引座標爲index的元素
*
* @param index 索引座標
*/
public synchronized void removeElementAt(int index) {
modCount++;
if (index >= elementCount) {
throw new ArrayIndexOutOfBoundsException(index + " >= " +
elementCount);
} else if (index < 0) {
throw new ArrayIndexOutOfBoundsException(index);
}
int j = elementCount - index - 1;
if (j > 0) {
System.arraycopy(elementData, index + 1, elementData, index, j);
}
elementCount--;
elementData[elementCount] = null; /* to let gc do its work */
}
/**
* 在索引座標爲index的位置插入元素obj
*
* @param obj 元素
* @param index 索引位置
*/
public synchronized void insertElementAt(E obj, int index) {
modCount++;
if (index > elementCount) {
throw new ArrayIndexOutOfBoundsException(index
+ " > " + elementCount);
}
ensureCapacityHelper(elementCount + 1);
System.arraycopy(elementData, index, elementData, index + 1, elementCount - index);
elementData[index] = obj;
elementCount++;
}
/**
* 將某個元素添加到"Vector"末尾位置
*
* @param obj 待添加的元素
*/
public synchronized void addElement(E obj) {
modCount++;
ensureCapacityHelper(elementCount + 1);
elementData[elementCount++] = obj;
}
/**
* 在Vector中查找並刪除元素obj。
*
* @param obj 待刪除的元素
* @return 返回true成功，返回false則失敗
*/
public synchronized boolean removeElement(Object obj) {
modCount++;
int i = indexOf(obj);
if (i >= 0) {
removeElementAt(i);
return true;
}
return false;
}
/**
* 刪除Vector中的全部元素
*/
public synchronized void removeAllElements() {
modCount++;
// Let gc do its work
for (int i = 0; i < elementCount; i++)
elementData[i] = null;
elementCount = 0;
}
/**
* 克隆函數
* 可以將當前集合克隆給另外一個相同類型的集合
*/
public synchronized Object clone() {
try {
@SuppressWarnings("unchecked")
Vector<E> v = (Vector<E>) super.clone();
v.elementData = Arrays.copyOf(elementData, elementCount);
v.modCount = 0;
return v;
} catch (CloneNotSupportedException e) {
// this shouldn't happen, since we are Cloneable
throw new InternalError(e);
}
}
/**
* 將集合轉換爲數組
*
* @return 返回轉換後的數組對象
*/
public synchronized Object[] toArray() {
return Arrays.copyOf(elementData, elementCount);
}
/**
* 返回Vector的模板數組。
* 所謂模板數組，即可以將T設爲任意的數據類型
*
* @param a 數組
* @param <T> 泛型
* @return
*/
@SuppressWarnings("unchecked")
public synchronized <T> T[] toArray(T[] a) {
if (a.length < elementCount)
return (T[]) Arrays.copyOf(elementData, elementCount, a.getClass());
System.arraycopy(elementData, 0, a, 0, elementCount);
if (a.length > elementCount)
a[elementCount] = null;
return a;
}
// Positional Access Operations
@SuppressWarnings("unchecked")
E elementData(int index) {
return (E) elementData[index];
}
/**
* 獲取index位置的元素
*
* @param index
* @return
*/
public synchronized E get(int index) {
if (index >= elementCount)
throw new ArrayIndexOutOfBoundsException(index);
return elementData(index);
}
/**
* 設置index位置的值爲element,並返回index位置的原始值
*
* @param index
* @param element
* @return
*/
public synchronized E set(int index, E element) {
if (index >= elementCount)
throw new ArrayIndexOutOfBoundsException(index);
E oldValue = elementData(index);
elementData[index] = element;
return oldValue;
}
/**
* 將元素e添加到Vector集合最後位置
*
* @param e
* @return
*/
public synchronized boolean add(E e) {
modCount++;
ensureCapacityHelper(elementCount + 1);
elementData[elementCount++] = e;
return true;
}
/**
* 刪除Vector中元素o
*
* @param o
* @return
*/
public boolean remove(Object o) {
return removeElement(o);
}
/**
* 在index位置添加元素element
*
* @param index
* @param element
*/
public void add(int index, E element) {
insertElementAt(element, index);
}
/**
* 刪除index位置的元素，並返回index位置的原始值
*
* @param index
* @return
*/
public synchronized E remove(int index) {
modCount++;
if (index >= elementCount)
throw new ArrayIndexOutOfBoundsException(index);
E oldValue = elementData(index);
int numMoved = elementCount - index - 1;
if (numMoved > 0)
System.arraycopy(elementData, index + 1, elementData, index,
numMoved);
elementData[--elementCount] = null; // Let gc do its work
return oldValue;
}
/**
* 清空Vector
*/
public void clear() {
removeAllElements();
}
/**
* 返回Vector是否包含集合c
*
* @param c
* @return
*/
public synchronized boolean containsAll(Collection<?> c) {
return super.containsAll(c);
}
/**
* 將集合c添加到Vector中
*
* @param c
* @return
*/
public synchronized boolean addAll(Collection<? extends E> c) {
modCount++;
Object[] a = c.toArray();
int numNew = a.length;
ensureCapacityHelper(elementCount + numNew);
System.arraycopy(a, 0, elementData, elementCount, numNew);
elementCount += numNew;
return numNew != 0;
}
/**
* 刪除集合c的全部元素
*
* @param c
* @return
*/
public synchronized boolean removeAll(Collection<?> c) {
return super.removeAll(c);
}
/**
* 刪除"非集合c中的元素"
*
* @param c
* @return
*/
public synchronized boolean retainAll(Collection<?> c) {
return super.retainAll(c);
}
/**
* 從index位置開始，將集合c添加到Vector中
* @param index
* @param c
* @return
*/
public synchronized boolean addAll(int index, Collection<? extends E> c) {
modCount++;
if (index < 0 || index > elementCount)
throw new ArrayIndexOutOfBoundsException(index);
Object[] a = c.toArray();
int numNew = a.length;
ensureCapacityHelper(elementCount + numNew);
int numMoved = elementCount - index;
if (numMoved > 0)
System.arraycopy(elementData, index, elementData, index + numNew,
numMoved);
System.arraycopy(a, 0, elementData, index, numNew);
elementCount += numNew;
return numNew != 0;
}
/**
* 返回兩個對象是否相等
*
* @param o
* @return
*/
public synchronized boolean equals(Object o) {
return super.equals(o);
}
/**
* 計算哈希值
*
* @return
*/
public synchronized int hashCode() {
return super.hashCode();
}
/**
* 調用父類的toString()方法
*/
public synchronized String toString() {
return super.toString();
}
/**
* 獲取Vector中fromIndex(包括)到toIndex(不包括)的子集
*
* @param fromIndex
* @param toIndex
* @return
*/
public synchronized List<E> subList(int fromIndex, int toIndex) {
return Collections.synchronizedList(super.subList(fromIndex, toIndex),
this);
}
/**
* 刪除Vector中fromIndex到toIndex的元素
*
* @param fromIndex
* @param toIndex
*/
protected synchronized void removeRange(int fromIndex, int toIndex) {
modCount++;
int numMoved = elementCount - toIndex;
System.arraycopy(elementData, toIndex, elementData, fromIndex,
numMoved);
// Let gc do its work
int newElementCount = elementCount - (toIndex - fromIndex);
while (elementCount != newElementCount)
elementData[--elementCount] = null;
}
/**
* Save the state of the {@code Vector} instance to a stream (that
* is, serialize it).
* This method performs synchronization to ensure the consistency
* of the serialized data.
*/
private void writeObject(java.io.ObjectOutputStream s)
throws java.io.IOException {
final java.io.ObjectOutputStream.PutField fields = s.putFields();
final Object[] data;
synchronized (this) {
fields.put("capacityIncrement", capacityIncrement);
fields.put("elementCount", elementCount);
data = elementData.clone();
}
fields.put("elementData", data);
s.writeFields();
}
/**
* Returns a list iterator over the elements in this list (in proper
* sequence), starting at the specified position in the list.
* The specified index indicates the first element that would be
* returned by an initial call to {@link ListIterator#next next}.
* An initial call to {@link ListIterator#previous previous} would
* return the element with the specified index minus one.
* <p>
* <p>The returned list iterator is <a href="#fail-fast"><i>fail-fast</i></a>.
*
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
public synchronized ListIterator<E> listIterator(int index) {
if (index < 0 || index > elementCount)
throw new IndexOutOfBoundsException("Index: " + index);
return new ListItr(index);
}
/**
* Returns a list iterator over the elements in this list (in proper
* sequence).
* <p>
* <p>The returned list iterator is <a href="#fail-fast"><i>fail-fast</i></a>.
*
* @see #listIterator(int)
*/
public synchronized ListIterator<E> listIterator() {
return new ListItr(0);
}
/**
* Returns an iterator over the elements in this list in proper sequence.
* <p>
* <p>The returned iterator is <a href="#fail-fast"><i>fail-fast</i></a>.
*
* @return an iterator over the elements in this list in proper sequence
*/
public synchronized Iterator<E> iterator() {
return new Itr();
}
/**
* An optimized version of AbstractList.Itr
*/
private class Itr implements Iterator<E> {
// Android-changed: changes around elementCount, introduced limit.
// b/27430229 AOSP commit 6e5b758a4438d2c154dd11a5c04d14a5d2fc907c
//
// The "limit" of this iterator. This is the size of the list at the time the
// iterator was created. Adding & removing elements will invalidate the iteration
// anyway (and cause next() to throw) so saving this value will guarantee that the
// value of hasNext() remains stable and won't flap between true and false when elements
// are added and removed from the list.
protected int limit = Vector.this.elementCount;
int cursor; // index of next element to return
int lastRet = -1; // index of last element returned; -1 if no such
int expectedModCount = modCount;
public boolean hasNext() {
return cursor < limit;
}
public E next() {
synchronized (Vector.this) {
checkForComodification();
int i = cursor;
if (i >= limit)
throw new NoSuchElementException();
cursor = i + 1;
return elementData(lastRet = i);
}
}
public void remove() {
if (lastRet == -1)
throw new IllegalStateException();
synchronized (Vector.this) {
checkForComodification();
Vector.this.remove(lastRet);
expectedModCount = modCount;
limit--;
}
cursor = lastRet;
lastRet = -1;
}
@Override
public void forEachRemaining(Consumer<? super E> action) {
Objects.requireNonNull(action);
synchronized (Vector.this) {
final int size = limit;
int i = cursor;
if (i >= size) {
return;
}
@SuppressWarnings("unchecked") final E[] elementData = (E[]) Vector.this.elementData;
if (i >= elementData.length) {
throw new ConcurrentModificationException();
}
while (i != size && modCount == expectedModCount) {
action.accept(elementData[i++]);
}
// update once at end of iteration to reduce heap write traffic
cursor = i;
lastRet = i - 1;
checkForComodification();
}
}
final void checkForComodification() {
if (modCount != expectedModCount)
throw new ConcurrentModificationException();
}
}
/**
* An optimized version of AbstractList.ListItr
*/
final class ListItr extends Itr implements ListIterator<E> {
ListItr(int index) {
super();
cursor = index;
}
public boolean hasPrevious() {
return cursor != 0;
}
public int nextIndex() {
return cursor;
}
public int previousIndex() {
return cursor - 1;
}
public E previous() {
synchronized (Vector.this) {
checkForComodification();
int i = cursor - 1;
if (i < 0)
throw new NoSuchElementException();
cursor = i;
return elementData(lastRet = i);
}
}
public void set(E e) {
if (lastRet == -1)
throw new IllegalStateException();
synchronized (Vector.this) {
checkForComodification();
Vector.this.set(lastRet, e);
}
}
public void add(E e) {
int i = cursor;
synchronized (Vector.this) {
checkForComodification();
Vector.this.add(i, e);
expectedModCount = modCount;
limit++;
}
cursor = i + 1;
lastRet = -1;
}
}
@Override
public synchronized void forEach(Consumer<? super E> action) {
Objects.requireNonNull(action);
final int expectedModCount = modCount;
@SuppressWarnings("unchecked") final E[] elementData = (E[]) this.elementData;
final int elementCount = this.elementCount;
for (int i = 0; modCount == expectedModCount && i < elementCount; i++) {
action.accept(elementData[i]);
}
if (modCount != expectedModCount) {
throw new ConcurrentModificationException();
}
}
@Override
@SuppressWarnings("unchecked")
public synchronized boolean removeIf(Predicate<? super E> filter) {
Objects.requireNonNull(filter);
// figure out which elements are to be removed
// any exception thrown from the filter predicate at this stage
// will leave the collection unmodified
int removeCount = 0;
final int size = elementCount;
final BitSet removeSet = new BitSet(size);
final int expectedModCount = modCount;
for (int i = 0; modCount == expectedModCount && i < size; i++) {
@SuppressWarnings("unchecked") final E element = (E) elementData[i];
if (filter.test(element)) {
removeSet.set(i);
removeCount++;
}
}
if (modCount != expectedModCount) {
throw new ConcurrentModificationException();
}
// shift surviving elements left over the spaces left by removed elements
final boolean anyToRemove = removeCount > 0;
if (anyToRemove) {
final int newSize = size - removeCount;
for (int i = 0, j = 0; (i < size) && (j < newSize); i++, j++) {
i = removeSet.nextClearBit(i);
elementData[j] = elementData[i];
}
for (int k = newSize; k < size; k++) {
elementData[k] = null; // Let gc do its work
}
elementCount = newSize;
if (modCount != expectedModCount) {
throw new ConcurrentModificationException();
}
modCount++;
}
return anyToRemove;
}
@Override
@SuppressWarnings("unchecked")
public synchronized void replaceAll(UnaryOperator<E> operator) {
Objects.requireNonNull(operator);
final int expectedModCount = modCount;
final int size = elementCount;
for (int i = 0; modCount == expectedModCount && i < size; i++) {
elementData[i] = operator.apply((E) elementData[i]);
}
if (modCount != expectedModCount) {
throw new ConcurrentModificationException();
}
modCount++;
}
@SuppressWarnings("unchecked")
@Override
public synchronized void sort(Comparator<? super E> c) {
final int expectedModCount = modCount;
Arrays.sort((E[]) elementData, 0, elementCount, c);
if (modCount != expectedModCount) {
throw new ConcurrentModificationException();
}
modCount++;
}
/**
* Creates a <em><a href="Spliterator.html#binding">late-binding</a></em>
* and <em>fail-fast</em> {@link Spliterator} over the elements in this
* list.
* <p>
* <p>The {@code Spliterator} reports {@link Spliterator#SIZED},
* {@link Spliterator#SUBSIZED}, and {@link Spliterator#ORDERED}.
* Overriding implementations should document the reporting of additional
* characteristic values.
*
* @return a {@code Spliterator} over the elements in this list
* @since 1.8
*/
@Override
public Spliterator<E> spliterator() {
return new VectorSpliterator<>(this, null, 0, -1, 0);
}
/**
* Similar to ArrayList Spliterator
*/
static final class VectorSpliterator<E> implements Spliterator<E> {
private final Vector<E> list;
private Object[] array;
private int index; // current index, modified on advance/split
private int fence; // -1 until used; then one past last index
private int expectedModCount; // initialized when fence set
/**
* Create new spliterator covering the given range
*/
VectorSpliterator(Vector<E> list, Object[] array, int origin, int fence,
int expectedModCount) {
this.list = list;
this.array = array;
this.index = origin;
this.fence = fence;
this.expectedModCount = expectedModCount;
}
private int getFence() { // initialize on first use
int hi;
if ((hi = fence) < 0) {
synchronized (list) {
array = list.elementData;
expectedModCount = list.modCount;
hi = fence = list.elementCount;
}
}
return hi;
}
public Spliterator<E> trySplit() {
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
return (lo >= mid) ? null :
new VectorSpliterator<E>(list, array, lo, index = mid,
expectedModCount);
}
@SuppressWarnings("unchecked")
public boolean tryAdvance(Consumer<? super E> action) {
int i;
if (action == null)
throw new NullPointerException();
if (getFence() > (i = index)) {
index = i + 1;
action.accept((E) array[i]);
if (list.modCount != expectedModCount)
throw new ConcurrentModificationException();
return true;
}
return false;
}
@SuppressWarnings("unchecked")
public void forEachRemaining(Consumer<? super E> action) {
int i, hi; // hoist accesses and checks from loop
Vector<E> lst;
Object[] a;
if (action == null)
throw new NullPointerException();
if ((lst = list) != null) {
if ((hi = fence) < 0) {
synchronized (lst) {
expectedModCount = lst.modCount;
a = array = lst.elementData;
hi = fence = lst.elementCount;
}
} else
a = array;
if (a != null && (i = index) >= 0 && (index = hi) <= a.length) {
while (i < hi)
action.accept((E) a[i++]);
if (lst.modCount == expectedModCount)
return;
}
}
throw new ConcurrentModificationException();
}
public long estimateSize() {
return (long) (getFence() - index);
}
public int characteristics() {
return Spliterator.ORDERED | Spliterator.SIZED | Spliterator.SUBSIZED;
}
}
}