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by Dinesh Thakur

The Vector object store objects of any kind are extremely  although flexible operations on objects of this class are slower than  operations on common vectors (arrays). The capacity of the vector is the maximum amount of  elements that it can hold at a given instant. Its size corresponds to  number of elements actually stored. Having your whole capacity occupied  (size = capacity), adding a new element causes the automatic increase  capacity vector. If an increment is specified via its constructor, this increase occurs with this granularity, otherwise the capacity is doubled.

The main constructors and methods of java.util.Vector class are:

Method

Description

Vector ()

Constructs an initially empty Vector object.

Vector (int)

Constructs a Vector with the ability indicated.

Vector (int, int)

Constructs a Vector with the ability and capacity increase indicated.

addElement (Object)

Adds the object to the vector.

capacity ()

Returns the current capacity of the vector.

elementAt (int)

Returns the object contained in the given position.

insertElementAt (Object, int)

Inserts the given object at the position indicated.

removeAllElements ()

Removes all elements of the vector.

removeElementAt (Int)

Removes the element from the indicated position.

setElementAt (Object, int)

Replaces the element at the position indicated object provided.

setSize (int)

Specifies the capacity of the vector.

size ()

Returns the current number of elements contained in vector.

trim (int)

reduces the ability of the vector to the number of elements in the vector.

 

import java.util.*;

class JavaExampleVector
{
    public static void main(String as[])
    {
        Vector Vctr = new Vector(5);
        System.out.println("Capacity: " + Vctr.capacity());
        Vctr.addElement(new Integer(0));
        Vctr.addElement(new Integer(1));
        Vctr.addElement(new Integer(2));
        Vctr.addElement(new Integer(3));
        Vctr.addElement(new Integer(4));
        Vctr.addElement(new Integer(5));
        Vctr.addElement(new Integer(6));
        Vctr.addElement(new Double(3.14159));
        Vctr.addElement(new Float(3.14159));
        System.out.println("Capacity: " + Vctr.capacity());
        System.out.println("Size: " + Vctr.size());
        System.out.println("First item: " + (Integer) Vctr.firstElement());
        System.out.println("Last item: " + (Float) Vctr.lastElement());
        if(Vctr.contains(new Integer(3)))
            System.out.println("Found a 3.");
    }
}

Java Vector Example