class Vector<E> is an array (in other words, a set of elements).
Any element can be gotten by integer index.
You can add and delete elements.
Vector is fully synchronized (thread-safe).
Vector is the same as
ArrayList, and the difference is that
Vector is fully synchronized (thread-safe). If not need a thread-safe, it is recommended to use
ArrayList because works faster.
Vector
implements
interface List<E> this array, i.e. you can add and remove elements, get an element by index
Java
Creating a new Java console application ... and write the code
package org.example;
import java.util.Vector;
public class Program {
public static void main(String[] args)
{
Vector<String> myList1 = new Vector<String>();
// Add an element to the end
myList1.add("Car");
// myList1 = ["Car"]
// Add an element to the end
myList1.add("House");
// myList1 = ["Car", "House"]
// Add an element to the end
myList1.add("Notebook");
// myList1 = ["Car", "House", "Notebook"]
// View item by index
String elem = myList1.get(1);
// elem = "House"
// myList1 = ["Car", "House", "Notebook"]
// Insert element by index 1
myList1.add(1, "Airplane");
// myList1 = ["Car", "Airplane", "House", "Notebook"]
// Delete item by index
myList1.remove(1);
// myList1 = ["Car", "House", "Notebook"]
}
}
Kotlin
Creating a new Kotlin console application ... and write the code
import java.util.Vector;
fun main() {
val myList1 = Vector<String>()
// добавляем элемент в конец
myList1.add("Car")
// myList1 = ["Car"]
// добавляем элемент в конец
myList1.add("House")
// myList1 = ["Car", "House"]
// добавляем элемент в конец
myList1.add("Notebook")
// myList1 = ["Car", "House", "Notebook"]
// посмотреть элемент по индексу
val elem = myList1[1]
// elem = "House"
// myList1 = ["Car", "House", "Notebook"]
// вставить элемент по индексу 1
myList1.add(1, "Airplane")
// myList1 = ["Car", "Airplane", "House", "Notebook"]
// удалить элемент по индексу
myList1.removeAt(1)
// myList1 = ["Car", "House", "Notebook"]
}
Java
class Vector<E> extends AbstractList<E> implements List<E>, RandomAccess, Cloneable, java.io.Serializable
{
@SuppressWarnings("serial") // Conditionally serializable
protected Object[] elementData;
protected int elementCount;
protected int capacityIncrement;
public Vector(int initialCapacity, int capacityIncrement) {
super();
if (initialCapacity < 0)
throw new IllegalArgumentException("Illegal Capacity: "+ initialCapacity);
this.elementData = new Object[initialCapacity];
this.capacityIncrement = capacityIncrement;
}
public Vector(int initialCapacity) {
this(initialCapacity, 0);
}
public Vector() {
this(10);
}
public Vector(Collection<? extends E> c) {
Object[] a = c.toArray();
elementCount = a.length;
if (c.getClass() == ArrayList.class) {
elementData = a;
} else {
elementData = Arrays.copyOf(a, elementCount, Object[].class);
}
}
public synchronized void copyInto(Object[] anArray) {
System.arraycopy(elementData, 0, anArray, 0, elementCount);
}
public synchronized void trimToSize() {
modCount++;
int oldCapacity = elementData.length;
if (elementCount < oldCapacity) {
elementData = Arrays.copyOf(elementData, elementCount);
}
}
public synchronized void ensureCapacity(int minCapacity) {
if (minCapacity > 0) {
modCount++;
if (minCapacity > elementData.length)
grow(minCapacity);
}
}
private Object[] grow(int minCapacity) {
int oldCapacity = elementData.length;
int newCapacity = ArraysSupport.newLength(oldCapacity,
minCapacity - oldCapacity, /* minimum growth */
capacityIncrement > 0 ? capacityIncrement : oldCapacity
/* preferred growth */);
return elementData = Arrays.copyOf(elementData, newCapacity);
}
private Object[] grow() {
return grow(elementCount + 1);
}
public synchronized void setSize(int newSize) {
modCount++;
if (newSize > elementData.length)
grow(newSize);
final Object[] es = elementData;
for (int to = elementCount, i = newSize; i < to; i++)
es[i] = null;
elementCount = newSize;
}
public synchronized int capacity() {
return elementData.length;
}
public synchronized int size() {
return elementCount;
}
public synchronized boolean isEmpty() {
return elementCount == 0;
}
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");
}
};
}
public boolean contains(Object o) {
return indexOf(o, 0) >= 0;
}
public int indexOf(Object o) {
return indexOf(o, 0);
}
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;
}
public synchronized int lastIndexOf(Object o) {
return lastIndexOf(o, elementCount-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;
}
public synchronized E elementAt(int index) {
if (index >= elementCount) {
throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount);
}
return elementData(index);
}
public synchronized E firstElement() {
if (elementCount == 0) {
throw new NoSuchElementException();
}
return elementData(0);
}
public synchronized E lastElement() {
if (elementCount == 0) {
throw new NoSuchElementException();
}
return elementData(elementCount - 1);
}
public synchronized void setElementAt(E obj, int index) {
if (index >= elementCount) {
throw new ArrayIndexOutOfBoundsException(index + " >= " +
elementCount);
}
elementData[index] = obj;
}
public synchronized void removeElementAt(int index) {
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);
}
modCount++;
elementCount--;
elementData[elementCount] = null; /* to let gc do its work */
}
public synchronized void insertElementAt(E obj, int index) {
if (index > elementCount) {
throw new ArrayIndexOutOfBoundsException(index
+ " > " + elementCount);
}
modCount++;
final int s = elementCount;
Object[] elementData = this.elementData;
if (s == elementData.length)
elementData = grow();
System.arraycopy(elementData, index,
elementData, index + 1,
s - index);
elementData[index] = obj;
elementCount = s + 1;
}
public synchronized void addElement(E obj) {
modCount++;
add(obj, elementData, elementCount);
}
public synchronized boolean removeElement(Object obj) {
modCount++;
int i = indexOf(obj);
if (i >= 0) {
removeElementAt(i);
return true;
}
return false;
}
public synchronized void removeAllElements() {
final Object[] es = elementData;
for (int to = elementCount, i = elementCount = 0; i < to; i++)
es[i] = null;
modCount++;
}
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);
}
}
public synchronized Object[] toArray() {
return Arrays.copyOf(elementData, elementCount);
}
@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];
}
@SuppressWarnings("unchecked")
static <E> E elementAt(Object[] es, int index) {
return (E) es[index];
}
public synchronized E get(int index) {
if (index >= elementCount)
throw new ArrayIndexOutOfBoundsException(index);
return elementData(index);
}
public synchronized E set(int index, E element) {
if (index >= elementCount)
throw new ArrayIndexOutOfBoundsException(index);
E oldValue = elementData(index);
elementData[index] = element;
return oldValue;
}
private void add(E e, Object[] elementData, int s) {
if (s == elementData.length)
elementData = grow();
elementData[s] = e;
elementCount = s + 1;
}
public synchronized boolean add(E e) {
modCount++;
add(e, elementData, elementCount);
return true;
}
public boolean remove(Object o) {
return removeElement(o);
}
public void add(int index, E element) {
insertElementAt(element, index);
}
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;
}
public void clear() {
removeAllElements();
}
// Bulk Operations
public synchronized boolean containsAll(Collection<?> c) {
return super.containsAll(c);
}
public boolean addAll(Collection<? extends E> c) {
Object[] a = c.toArray();
modCount++;
int numNew = a.length;
if (numNew == 0)
return false;
synchronized (this) {
Object[] elementData = this.elementData;
final int s = elementCount;
if (numNew > elementData.length - s)
elementData = grow(s + numNew);
System.arraycopy(a, 0, elementData, s, numNew);
elementCount = s + numNew;
return true;
}
}
public boolean removeAll(Collection<?> c) {
Objects.requireNonNull(c);
return bulkRemove(e -> c.contains(e));
}
public boolean retainAll(Collection<?> c) {
Objects.requireNonNull(c);
return bulkRemove(e -> !c.contains(e));
}
@Override
public boolean removeIf(Predicate<? super E> filter) {
Objects.requireNonNull(filter);
return bulkRemove(filter);
}
public synchronized boolean addAll(int index, Collection<? extends E> c) {
if (index < 0 || index > elementCount)
throw new ArrayIndexOutOfBoundsException(index);
Object[] a = c.toArray();
modCount++;
int numNew = a.length;
if (numNew == 0)
return false;
Object[] elementData = this.elementData;
final int s = elementCount;
if (numNew > elementData.length - s)
elementData = grow(s + numNew);
int numMoved = s - index;
if (numMoved > 0)
System.arraycopy(elementData, index,
elementData, index + numNew,
numMoved);
System.arraycopy(a, 0, elementData, index, numNew);
elementCount = s + numNew;
return true;
}
public synchronized boolean equals(Object o) {
return super.equals(o);
}
public synchronized int hashCode() {
return super.hashCode();
}
public synchronized String toString() {
return super.toString();
}
public synchronized List<E> subList(int fromIndex, int toIndex) {
return Collections.synchronizedList(super.subList(fromIndex, toIndex),
this);
}
protected synchronized void removeRange(int fromIndex, int toIndex) {
modCount++;
shiftTailOverGap(elementData, fromIndex, toIndex);
}
@java.io.Serial
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();
}
@java.io.Serial
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();
}
public synchronized ListIterator<E> listIterator(int index) {
if (index < 0 || index > elementCount)
throw new IndexOutOfBoundsException("Index: "+index);
return new ListItr(index);
}
public synchronized ListIterator<E> listIterator() {
return new ListItr(0);
}
public synchronized Iterator<E> iterator() {
return new Itr();
}
@Override
public synchronized void forEach(Consumer<? super E> action) {
Objects.requireNonNull(action);
final int expectedModCount = modCount;
final Object[] es = elementData;
final int size = elementCount;
for (int i = 0; modCount == expectedModCount && i < size; i++)
action.accept(elementAt(es, i));
if (modCount != expectedModCount)
throw new ConcurrentModificationException();
}
@Override
public synchronized void replaceAll(UnaryOperator<E> operator) {
Objects.requireNonNull(operator);
final int expectedModCount = modCount;
final Object[] es = elementData;
final int size = elementCount;
for (int i = 0; modCount == expectedModCount && i < size; i++)
es[i] = operator.apply(elementAt(es, i));
if (modCount != expectedModCount)
throw new ConcurrentModificationException();
// TODO(8203662): remove increment of modCount from ...
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++;
}
@Override
public Spliterator<E> spliterator() {
return new VectorSpliterator(null, 0, -1, 0);
}
}