Previously we have discussed about
Here we learn what is Vector In Java.But before that we must know, What is Collection Interface in Java ?
Class Vector<E>
All Implemented Interfaces:
Direct Known Subclasses:
Declaration of Vector:
public class Vector<E>
extends AbstractList<E>
Vector class supports growable array of objects, like an array, it contains components that can be accessed using an integer index.However, the size of a Vector can grow or shrink as needed to accommodate adding and removing items after the Vector has been created.
Each vector optimize storage by maintaining a capacity and a capacityIncrement.The capacity is always same as vector size; it is usually larger because as component are added to the vector,the vector's storage increases the size of capacityIncrement.
Vector is an example of fail-fast iterator and ListIterator, if the vector is modified structurally at any time after the iterator is created,except throgh the iterator's own remove() or add() method, the iterator will throw a ConcurrentModificationException.
Vector implementation is synchronized.If a thread-safe implementation is not required, it is recommended to use ArrayList in place of Vector.
Form Java 1.2 this class retrofitted to implement the List interface,and making it a member of the Java Collections Framework.
Constructor Summary of Vector:
Constructor
|
Description
|
Vector()
|
Constructs an empty
vector so that its internal data array has size 10 and its standard capacity
increment is zero.
|
Vector(Collection<?
extends E> c)
|
Constructs a vector
containing the elements of the specified collection, in the order they are
returned by the collection's iterator.
|
Vector(int
initialCapacity)
|
Constructs an empty
vector with the specified initial capacity and with its capacity increment
equal to zero.
|
Vector(int
initialCapacity, int capacityIncrement)
|
Constructs an empty
vector with the specified initial capacity and capacity increment.
|
Modifier and Method Name
|
Description
|
boolean add(E e)
|
Appends the specified element to the end of this
list.
|
void add(int index, E element)
|
Inserts the specified element at the specified
position in this list.
|
boolean addAll(Collection<? extends E> c)
|
Appends all of the elements in the specified
collection to the end of this list, in the order that they are returned by
the specified collection's Iterator.
|
boolean addAll(int index, Collection<? extends E> c)
|
Inserts all of the elements in the specified
collection into this list, starting at the specified position.
|
void addElement(E obj)
|
Adds the specified component to the end of this
vector, increasing its size by one.
|
int capacity()
|
Returns the current capacity of this vector.
|
void clear()
|
Removes all of the elements from this list.
|
Object clone()
|
Returns a shallow copy of this ArrayList
instance.
|
boolean containsAll(Collection<?> c)
|
Returns true if this Vector contains all of the
elements in the specified Collection.
|
boolean contains(Object o)
|
Returns true if this list contains the specified
element.
|
void copyInto(Object[] anArray)
|
Copies the components of this vector into the
specified array.
|
E elementAt(int index)
|
Returns the component at the specified index.
|
Enumeration<E> elements()
|
Returns an enumeration of the components of this
vector.
|
void ensureCapacity(int minCapacity)
|
Increases the capacity of this vector, if
necessary, to ensure that it can hold at least the number of components
specified by the minimum capacity argument.
|
boolean equals(Object o)
|
Compares the specified Object with this Vector for
equality.
|
E firstElement()
|
Returns the first component (the item at index 0)
of this vector.
|
E get(int index)
|
Returns the element at the specified position in
this Vector.
|
int hashCode()
|
Returns the hash code value for this Vector.
|
int indexOf(Object o)
|
Returns the index of the first occurrence of the
specified element in this vector, or -1 if this vector does not contain the
element.
|
int indexOf(Object o, int index)
|
Returns the index of the first occurrence of the
specified element in this vector, searching forwards from index, or returns
-1 if the element is not found.
|
void insertElementAt(E obj, int index)
|
Inserts the specified object as a component in
this vector at the specified index.
|
boolean isEmpty()
|
Tests if this vector has no components.
|
Iterator<E> iterator()
|
Returns an iterator over the elements in this
list in proper sequence.
|
E lastElement()
|
Returns the last component of the vector.
|
int lastIndexOf(Object o)
|
Returns the index of the last occurrence of the
specified element in this vector, or -1 if this vector does not contain the
element.
|
int lastIndexOf(Object o, int index)
|
Returns the index of the last occurrence of the
specified element in this vector, searching backwards from index, or returns
-1 if the element is not found.
|
ListIterator<E> listIterator()
|
Returns a list iterator over the elements in this
list (in proper sequence).
|
ListIterator<E> listIterator(int index)
|
Returns a list iterator over the elements in this
list (in proper sequence), starting at the specified position in the list.
|
E remove(int index)
|
Removes the element at the specified position in
this Vector.
|
boolean remove(Object o)
|
Removes the first occurrence of the specified
element in this Vector If the Vector does not contain the element, it is
unchanged.
|
boolean removeAll(Collection<?> c)
|
Removes from this Vector all of its elements that
are contained in the specified Collection.
|
void removeAllElements()
|
Removes all components from this vector and sets
its size to zero.
|
boolean removeElement(Object obj)
|
Removes the first (lowest-indexed) occurrence of
the argument from this vector.
|
void removeElementAt(int index)
|
Deletes the component at the specified index.
|
protected void removeRange(int fromIndex, int toIndex)
|
Removes from this list all of the elements whose
index is between fromIndex, inclusive, and toIndex, exclusive.
|
boolean retainAll(Collection<?> c)
|
Retains only the elements in this Vector that are
contained in the specified Collection.
|
E set(int index, E element)
|
Replaces the element at the specified position in
this Vector with the specified element.
|
void setElementAt(E obj, int index)
|
Sets the component at the specified index of this
vector to be the specified object.
|
void setSize(int newSize)
|
Sets the size of this vector.
|
int size()
|
Returns the number of components in this vector.
|
List<E> subList(int
fromIndex, int toIndex)
|
Returns a view of the portion of this List
between fromIndex, inclusive, and toIndex, exclusive.
|
Object[] toArray()
|
Returns an array containing all of the elements
in this Vector in the correct order.
|
<T> T[] toArray(T[] a)
|
Returns an array containing all of the elements
in this Vector in the correct order; the runtime type of the returned array
is that of the specified array.
|
String toString()
|
Returns a string representation of this Vector,
containing the String representation of each element.
|
void trimToSize()
|
Trims the capacity of this vector to be the
vector's current size.
|
Example of Vector:
import java.util.Vector;
public class VectorClassExample {
public static void main(String[] args) {
Vector<String> v = new Vector<String>();
System.out.println("Initial Size of Vector :\t"+v.size());
//Adding Elements in Vector
v.add("Apple");
v.add("Banana");
v.add("Cake");
v.add("Guava");
//This method adds the element at end of vector
v.addElement("Orange");
System.out.println("Displaying Vector :\t"+v);
System.out.println("capacity() ,This method return current capacity :\t"+v.capacity());
System.out.println("clone() ,This method returns clone :\t"+v.clone());
System.out.println("contains() ,This method return true/false if element found :\t"+v.contains("Cake"));
System.out.println("elementAt(e) ,This method return element at specified index :\t"+v.elementAt(2));
System.out.println("firstElement() ,This method return first element :\t"+v.firstElement());
System.out.println("get() ,This method returns element at specified position :\t"+v.get(3));
System.out.println("hashCode() ,This method return hashcode of vector :\t"+v.hashCode());
System.out.println("indexOf() ,This method return index of specified element :\t"+v.indexOf("Orange"));
System.out.println("indexOf(e,int) ,This method returns index at provided index,if not found search forward also :\t"+v.indexOf("Orange", 1));
System.out.println("isEmpty() ,This method return true/false :\t"+v.isEmpty());
System.out.println("lastElement() ,This method return last element :\t"+v.lastElement());
System.out.println("lastIndexOf(e) ,This method return index of last occurence :\t"+v.lastIndexOf(3));
System.out.println("remove(e) ,This method remove element at specified index :\t"+v.remove(2));
System.out.println("remove(o) ,This method remove element :\t"+v.remove("Guava"));
System.out.println("set(int,o) ,This method sets & replace the elements at specified index :\t"+v.set(1, "Pankaj"));
System.out.println("subList(1,3) ,This method return elements sub list between fromIndex & toIndex :\t"+v.subList(1, 3));
//This method set the size of vector
v.setSize(6);
//This method sets the element at specified index
v.setElementAt("Pushkar", 2);
System.out.println("Displaying Vector :\t"+v);
//This method adds element at specified index
v.insertElementAt("Ram Prased", 2);
//This method removes element at specified index
v.removeElementAt(1);
//This method Remove all elements
v.clear();
//This method retains only those element which contained in specified collection
v.retainAll(v);
//This method Removes all elements and set size to 0
v.removeAllElements();
System.out.println("Size of Vector after Elements Addition :\t"+v.size());
}
}
Program Output:
Initial Size of Vector : 0
Displaying Vector : [Apple, Banana, Cake, Guava, Orange]
capacity() ,This method return current capacity : 10
clone() ,This method returns clone : [Apple, Banana, Cake, Guava, Orange]
contains() ,This method return true/false if element found : true
elementAt(e) ,This method return element at specified index : Cake
firstElement() ,This method return first element : Apple
get() ,This method returns element at specified position : Guava
hashCode() ,This method return hashcode of vector : 2109281436
indexOf() ,This method return index of specified element : 4
indexOf(e,int) ,This method returns index at provided index,if not found search forward also : 4
isEmpty() ,This method return true/false : false
lastElement() ,This method return last element : Orange
lastIndexOf(e) ,This method return index of last occurence : -1
remove(e) ,This method remove element at specified index : Cake
remove(o) ,This method remove element : true
set(int,o) ,This method sets & replace the elements at specified index : Banana
subList(1,3) ,This method return elements sub list between fromIndex & toIndex : [Pankaj, Orange]
Displaying Vector : [Apple, Pankaj, Pushkar, null, null, null]
Size of Vector after Elements Addition : 0
Software Developer by Profession with 3.0 Yrs of Experience , through this blog i'am sharing my industrial Java Knowledge to entire world. For any question or query any one can comment below or mail me at pushkar.itsitm52@gmail.com.
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