Vector源码阅读(基于jdk1.8)
前几天看了ArrayList，今天再来看看Vector，这两个其实大同小异，基本结构都差不多，只是一些细节上有区别：比如线程安全与否，扩容的大小等，Vector的线程安全通过在方法上直接加synchronized实现。扩容默认扩大为原来的2倍。
还是先来看类的定义，搞清类的结构层次：
可以看到Vector继承了AbstractList，实现了List，RandomAccess，Cloneable，Serializable接口。
从上面我们就可以得出Vector是一个矢量队列，支持一些增加、删除、修改、遍历等功能，可以快速随机访问，可以被克隆，支持序列化等
public class Vector<E>
extends AbstractList<E>
implements List<E>, RandomAccess, Cloneable, java.io.Serializable
接下来看一些变量定义
//底层结构为object数组，和ArrayList一样，不过我们可以注意到访问修饰符有所不同，Vector用protected修饰，而ArrayList用private修饰。我们知道private变量只能被当前类的方法访问，而protected可以被同一包中的所有类和其他包的子类访问
protected Object[] elementData;
//动态数组的实际有效大小
protected int elementCount;
//动态数组的增长系数：若开始没有人为指定，则默认增加一倍的大小
protected int capacityIncrement;
//Vector的序列版本号
private static final long serialVersionUID = -2767605614048989439L;
Vector的四种构造函数
// 默认构造函数
Vector()
// capacity是Vector的默认容量大小。当由于增加数据导致容量增加时，每次容量会增加一倍。
Vector(int capacity)
// capacity是Vector的默认容量大小，capacityIncrement是每次Vector容量增加时的增量值。
Vector(int capacity, int capacityIncrement)
// 创建一个包含collection的Vector
Vector(Collection<? extends E> collection)
/**
* 构造一个空的Vector，输入参数为自定义的初始容量和增长系数
*/
public Vector(int initialCapacity, int capacityIncrement) {
super();
//如果初始容量参数<0，抛出异常
if (initialCapacity < 0)
throw new IllegalArgumentException("Illegal Capacity: "+
initialCapacity);
this.elementData = new Object[initialCapacity];
this.capacityIncrement = capacityIncrement;
}
/**
* 构造一个初始容量为initialCapacity的空的Vector，默认增加一倍大小
*/
public Vector(int initialCapacity) {
this(initialCapacity, 0);
}
/**
* 默认构造函数
*/
public Vector() {
this(10);
}
/**
* 创建一个包含collection的Vector
*/
public Vector(Collection<? extends E> c) {
elementData = c.toArray();
elementCount = elementData.length;
// c.toArray might (incorrectly) not return Object[] (see 6260652)
if (elementData.getClass() != Object[].class)
elementData = Arrays.copyOf(elementData, elementCount, Object[].class);
}
Vector扩容
Vector扩容默认扩容为原来的2倍
/**
* 确定Vector数组当前的容量大小
*/
public synchronized void ensureCapacity(int minCapacity) {
if (minCapacity > 0) {
modCount++;
ensureCapacityHelper(minCapacity);
}
}
/**
* 如果当前容量>当前数组长度，那么调用grow(minCapacity)进行扩容，注意这个方法并没有用synchronized修饰，因为他是在ensureCapacity()中被调用的，而ensureCapacity()已经被加锁了
*/
private void ensureCapacityHelper(int minCapacity) {
// overflow-conscious code
if (minCapacity - elementData.length > 0)
grow(minCapacity);
}
/**
* 设置能够扩展的最大数组大小
*/
private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
//扩容核心函数
private void grow(int minCapacity) {
// overflow-conscious code
//将旧的容量赋值为数组长度
int oldCapacity = elementData.length;
//如果容量增量系数>0那么设置新容量为oldCapacity+capacityIncrement，否则为oldCapacity + oldCapacity
int newCapacity = oldCapacity + ((capacityIncrement > 0) ?
capacityIncrement : oldCapacity);
//如果新容量<数组实际所需容量，令newCapacity = minCapacity
if (newCapacity - minCapacity < 0)
newCapacity = minCapacity;
//如果新容量大于数组最大扩容大小，如果当前所需容量>MAX_ARRAY_SIZE，那么新容量设为 Integer.MAX_VALUE，否则设为 MAX_ARRAY_SIZE
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;
}
Vector遍历方式
Vector主要支持4中遍历方式
- 通过迭代器遍历元素
- 通过for-each循环遍历
- 利用下标访问随机遍历
- 使用Enumeration遍历
测试代码
package Collection;
import java.util.*;
public class TestVector {
public static void main(String[] args) {
Vector v = new Vector();
v.add(1);
v.add(2);
v.add(3);
v.add(4);
v.add(5);
Enumeration enu = v.elements();
while(enu.hasMoreElements()) {
System.out.println(enu.nextElement());
}
Integer value = null;
for( Object val : v) {
System.out.println(val);
}
Iterator<Integer> iter = v.iterator();
while(iter.hasNext()) {
System.out.println(iter.next());
}
for(int i = 0; i < v.size(); i++) {
System.out.println(v.get(i));
}
}
}
剩余主要方法源码
/**
* 将数组Vector中的全部元素都拷贝到数组anArray中去，调用本地方法arraycopy实现
*/
public synchronized void copyInto(Object[] anArray) {
System.arraycopy(elementData, 0, anArray, 0, elementCount);
}
/**
* 将当前容量设为实际元素个数
*/
public synchronized void trimToSize() {
modCount++;
int oldCapacity = elementData.length;
if (elementCount < oldCapacity) {
elementData = Arrays.copyOf(elementData, elementCount);
}
}
/**
*设置Vector数组的大小
*/
public synchronized void setSize(int newSize) {
modCount++;
// 若 "newSize 大于 Vector容量"，则调整Vector的大小。
if (newSize > elementCount) {
ensureCapacityHelper(newSize);
} else {
// 若 "newSize 小于/等于 Vector容量"，则将newSize位置开始的元素都设置为null
for (int i = newSize ; i < elementCount ; i++) {
elementData[i] = null;
}
}
elementCount = newSize;
}
/**
* 返回Vector的当前容量
*/
public synchronized int capacity() {
return elementData.length;
}
/**
* 返回Vector里面的元素个数
*/
public synchronized int size() {
return elementCount;
}
/**
* 判断Vector是否为空
*/
public synchronized boolean isEmpty() {
return elementCount == 0;
}
// 返回“Vector中全部元素对应的Enumeration” public Enumeration<E> elements() {
return new Enumeration<E>() {
int count = 0;
//判断是否存在下一个元素
public boolean hasMoreElements() {
return count < elementCount;
}
//获取下一个元素
public E nextElement() {
synchronized (Vector.this) {
if (count < elementCount) {
return elementData(count++);
}
}
throw new NoSuchElementException("Vector Enumeration");
}
};
}
/**
* 返回Vector数组里面是否包含对象o
*/
public boolean contains(Object o) {
return indexOf(o, 0) >= 0;
}
/**
* 返回Vector数组中第一次出现对象o的下标，如果不存在，那么返回-1
*/
public int indexOf(Object o) {
return indexOf(o, 0);
}
/**
* 返回从index出开始第一次出现对象o的下标，如果不存在，那么返回-1
*/
public synchronized int indexOf(Object o, int index) {
if (o == null) {
for (int i = index ; i < elementCount ; i++)
if (elementData[i]==null)
return i;
} else {
for (int i = index ; i < elementCount ; i++)
if (o.equals(elementData[i]))
return i;
}
return -1;
}
/**
* 返回对象o在数组中最后一次出现的下标，如果不存在，返回-1
*/
public synchronized int lastIndexOf(Object o) {
return lastIndexOf(o, elementCount-1);
}
/**
* 返回从index开始对象o在数组中最后一次出现的下标，如果不存在，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;
}
/**
* 返回数组指定下标位置的元素，如果index>=elementCount，则抛出数组越界异常
* ({@code index < 0 || index >= size()})
*/
public synchronized E elementAt(int index) {
if (index >= elementCount) {
throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount);
}
return elementData(index);
}
/**
* 返回数组的第一个元素
*/
public synchronized E firstElement() {
if (elementCount == 0) {
throw new NoSuchElementException();
}
return elementData(0);
}
/**
* 返回数组的最后一个元素
*/
public synchronized E lastElement() {
if (elementCount == 0) {
throw new NoSuchElementException();
}
return elementData(elementCount - 1);
}
/**
* 将数组下标为index位置的元素设置为给定obj对象
*/
public synchronized void setElementAt(E obj, int index) {
if (index >= elementCount) {
throw new ArrayIndexOutOfBoundsException(index + " >= " +
elementCount);
}
elementData[index] = obj;
}
/**
* 删除指定下标位置的元素
*/
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) {
//将数组index+1开始往后元素全都往前移一位
System.arraycopy(elementData, index + 1, elementData, index, j);
}
elementCount--;
//让最后一个元素指向null，方便GC工作
elementData[elementCount] = null; /* to let gc do its work */
}
/**
* 在指定位置插入元素
*/
public synchronized void insertElementAt(E obj, int index) {
modCount++;
if (index > elementCount) {
throw new ArrayIndexOutOfBoundsException(index
+ " > " + elementCount);
}
//增加数组容量
ensureCapacityHelper(elementCount + 1);
//从index开始将数组所以元素都往后移一位
System.arraycopy(elementData, index, elementData, index + 1, elementCount - index);
//复制新对象
elementData[index] = obj;
//元素个数+1
elementCount++;
}
/**
* 在数组末尾增加一个元素，首先数组的容量增加1
*/
public synchronized void addElement(E obj) {
modCount++;
ensureCapacityHelper(elementCount + 1);
elementData[elementCount++] = obj;
}
/**
* 删除数组中第一次出现的obj对象
*/
public synchronized boolean removeElement(Object obj) {
modCount++;
int i = indexOf(obj);
if (i >= 0) {
removeElementAt(i);
return true;
}
return false;
}
/**
* 删除数组中所有元素，为了便于GC，让每个位置都指向null
*/
public synchronized void removeAllElements() {
modCount++;
// Let gc do its work
for (int i = 0; i < elementCount; i++)
elementData[i] = null;
elementCount = 0;
}
/**
* 返回一个object的克隆
*/
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);
}
}
/**
* 返回一个数组包含Vector中的所有元素
* @since 1.2
*/
public synchronized Object[] toArray() {
return Arrays.copyOf(elementData, elementCount);
}
/**
* 返回Vector的模板数组。所谓模板数组，即可以将T设为任意的数据类型
* @since 1.2
*/
@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];
}
/**
* 返回指定下标位置的元素
* @since 1.2
*/
public synchronized E get(int index) {
if (index >= elementCount)
throw new ArrayIndexOutOfBoundsException(index);
return elementData(index);
}
/**
* 用element替换数组中指定下标位置的元素
* @since 1.2
*/
public synchronized E set(int index, E element) {
if (index >= elementCount)
throw new ArrayIndexOutOfBoundsException(index);
E oldValue = elementData(index);
elementData[index] = element;
return oldValue;
}
/**
* 在数组末尾添加指定元素
* @since 1.2
*/
public synchronized boolean add(E e) {
modCount++;
ensureCapacityHelper(elementCount + 1);
elementData[elementCount++] = e;
return true;
}
/**
* 删除数组中第一次出现的指定对象
* @since 1.2
*/
public boolean remove(Object o) {
return removeElement(o);
}
/**
* 在数组指定位置插入元素
* @since 1.2
*/
public void add(int index, E element) {
insertElementAt(element, index);
}
/**
* 删除数组指定位置的元素
* @since 1.2
*/
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;
}
/**
*删除数组所有元素
* @since 1.2
*/
public void clear() {
removeAllElements();
}
// Bulk Operations
/**
* 返回一个数组是否包含给定集合中的所有元素
*/
public synchronized boolean containsAll(Collection<?> c) {
return super.containsAll(c);
}
/**
* 在Vector数组末尾添加特定集合中的所有元素
* @since 1.2
*/
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;
}
/**
* 删除Vector中在给定集合中存在的所有元素
* @since 1.2
*/
public synchronized boolean removeAll(Collection<?> c) {
return super.removeAll(c);
}
/**
* 删除Vector中在给定集合中不存在的元素
* @since 1.2
*/
public synchronized boolean retainAll(Collection<?> c) {
return super.retainAll(c);
}
/**
* 将给定集合的所有元素插入到Vector的特定位置
* @since 1.2
*/
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;
}
/**
* 比较两个数组是否相等
*/
public synchronized boolean equals(Object o) {
return super.equals(o);
}
/**
* 返回哈希值
*/
public synchronized int hashCode() {
return super.hashCode();
}
/**
* 返回数组的字符串表示
*/
public synchronized String toString() {
return super.toString();
}
/**
* 获取Vector中fromIndex(包括)到toIndex(不包括)的子集
*/
public synchronized List<E> subList(int fromIndex, int toIndex) {
return Collections.synchronizedList(super.subList(fromIndex, toIndex),
this);
}
/**
* 删除Vector中fromIndex到toIndex的元素
*/
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;
}
/**
* 从二进制流中读取对象实例
*/
private void readObject(ObjectInputStream in)
throws IOException, ClassNotFoundException {
ObjectInputStream.GetField gfields = in.readFields();
int count = gfields.get("elementCount", 0);
Object[] data = (Object[])gfields.get("elementData", null);
if (count < 0 || data == null || count > data.length) {
throw new StreamCorruptedException("Inconsistent vector internals");
}
elementCount = count;
elementData = data.clone();
}
/**
* 序列化保存一个对象的状态
*/
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();
}
/**
* 返回一个列表迭代器
* @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>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>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> {
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() {
// Racy but within spec, since modifications are checked
// within or after synchronization in next/previous
return cursor != elementCount;
}
public E next() {
synchronized (Vector.this) {
checkForComodification();
int i = cursor;
if (i >= elementCount)
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;
}
cursor = lastRet;
lastRet = -1;
}
@Override
public void forEachRemaining(Consumer<? super E> action) {
Objects.requireNonNull(action);
synchronized (Vector.this) {
final int size = elementCount;
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;
}
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>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;
}
}
}
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