java.util
Class Vector<E>

java.lang.Object
  java.util.AbstractCollection<E>
      java.util.AbstractList<E>
          java.util.Vector<E>

All Implemented Interfaces:

Serializable, Cloneable, Iterable<E>, Collection<E>, List<E>, RandomAccess

Direct Known Subclasses:

Stack

public class Vector<E>
extends AbstractList<E>
implements List<E>, RandomAccess, Cloneable, Serializable

Vector is a variable size contiguous indexable array of Objects. The size of the Vector is the number of Objects it contains. The capacity of the Vector is the number of Objects it can hold.

Objects may be inserted at any position up to the size of the Vector, increasing the size of the Vector. Objects at any position in the Vector may be removed, shrinking the size of the Vector. Objects at any position in the Vector may be replaced, which does not affect the Vector size.

The capacity of a Vector may be specified when the Vector is created. If the capacity of the Vector is exceeded, the capacity is increased, doubling by default.

See Also:

StringBuffer, Serialized Form

Field Summary

protected int	capacityIncrement The amount by which the capacity of the vector is increased.
protected int	elementCount The number of elements or the size of the vector.
protected Object[]	elementData The elements of the vector.

Fields inherited from class java.util.AbstractList

modCount

Constructor Summary

Vector()
Constructs a new Vector using the default capacity.

Vector(Collection<? extends E> collection)
Constructs a new instance of Vector containing the elements in the specified collection.

Vector(int capacity)
Constructs a new Vector using the specified capacity.

Vector(int capacity, int capacityIncrement)
Constructs a new Vector using the specified capacity and capacity increment.

Method Summary

boolean	add(E object) Adds the specified object at the end of this Vector.
void	add(int location, E object) Adds the specified object into this Vector at the specified location.
boolean	addAll(Collection<? extends E> collection) Adds the objects in the specified Collection to the end of this Vector.
boolean	addAll(int location, Collection<? extends E> collection) Inserts the objects in the specified Collection at the specified location in this Vector.
void	addElement(E object) Adds the specified object at the end of this Vector.
int	capacity() Answers the number of elements this Vector can hold without growing.
void	clear() Removes all elements from this Vector, leaving it empty.
Object	clone() Answers a new Vector with the same elements, size, capacity and capacity increment as this Vector.
boolean	contains(Object object) Searches this Vector for the specified object.
boolean	containsAll(Collection<?> collection) Searches this Vector for all objects in the specified Collection.
void	copyInto(Object[] elements) Copies the elements of this Vector into the specified Object array.
E	elementAt(int location) Answers the element at the specified location in this Vector.
Enumeration<E>	elements() Answers an Enumeration on the elements of this Vector.
void	ensureCapacity(int minimumCapacity) Ensures that this Vector can hold the specified number of elements without growing.
boolean	equals(Object object) Compares the specified object to this Vector and answer if they are equal.
E	firstElement() Answers the first element in this Vector.
E	get(int location) Answers the element at the specified location in this Vector.
int	hashCode() Answers an integer hash code for the receiver.
int	indexOf(Object object) Searches in this Vector for the index of the specified object.
int	indexOf(Object object, int location) Searches in this Vector for the index of the specified object.
void	insertElementAt(E object, int location) Inserts the specified object into this Vector at the specified location.
boolean	isEmpty() Answers if this Vector has no elements, a size of zero.
E	lastElement() Answers the last element in this Vector.
int	lastIndexOf(Object object) Searches in this Vector for the index of the specified object.
int	lastIndexOf(Object object, int location) Searches in this Vector for the index of the specified object.
E	remove(int location) Removes the element at the specified location from this Vector.
boolean	remove(Object object) Removes the first occurrence, starting at the beginning and moving towards the end, of the specified object from this Vector.
boolean	removeAll(Collection<?> collection) Removes all occurrences in this Vector of each object in the specified Collection.
void	removeAllElements() Removes all elements from this Vector, leaving the size zero and the capacity unchanged.
boolean	removeElement(Object object) Removes the first occurrence, starting at the beginning and moving towards the end, of the specified object from this Vector.
void	removeElementAt(int location) Removes the element at the specified location from this Vector.
protected void	removeRange(int start, int end) Removes the objects in the specified range from the start to the, but not including, end index.
boolean	retainAll(Collection<?> collection) Removes all objects from this Vector that are not contained in the specified Collection.
E	set(int location, E object) Replaces the element at the specified location in this Vector with the specified object.
void	setElementAt(E object, int location) Replaces the element at the specified location in this Vector with the specified object.
void	setSize(int length) Sets the size of this Vector to the specified size.
int	size() Answers the number of elements in this Vector.
List<E>	subList(int start, int end) Answers a List of the specified portion of this Vector from the start index to one less than the end index.
Object[]	toArray() Answers a new array containing all elements contained in this Vector.
<T> T[]	toArray(T[] contents) Answers an array containing all elements contained in this Vector.
String	toString() Answers the string representation of this Vector.
void	trimToSize() Sets the capacity of this Vector to be the same as the size.

Methods inherited from class java.util.AbstractList

iterator, listIterator, listIterator

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.List

iterator, listIterator, listIterator

Field Detail

elementCount

protected int elementCount

The number of elements or the size of the vector.

elementData

protected Object[] elementData

The elements of the vector.

capacityIncrement

protected int capacityIncrement

The amount by which the capacity of the vector is increased.

Constructor Detail

Vector

public Vector()

Constructs a new Vector using the default capacity.

Vector

public Vector(int capacity)

Constructs a new Vector using the specified capacity.

Parameters:

capacity - the initial capacity of the new vector

Vector

public Vector(int capacity,
              int capacityIncrement)

Constructs a new Vector using the specified capacity and capacity increment.

Parameters:

capacity - the initial capacity of the new Vector

capacityIncrement - the amount to increase the capacity when this Vector is full

Vector

public Vector(Collection<? extends E> collection)

Constructs a new instance of Vector containing the elements in the specified collection. The order of the elements in this Vector is the order they are returned by the collection iterator.

Parameters:

collection - the collection of elements to add

Method Detail

add

public void add(int location,
                E object)

Adds the specified object into this Vector at the specified location. The object is inserted before any previous element at the specified location. If the location is equal to the size of this Vector, the object is added at the end.

Specified by:

add in interface List<E>

Overrides:

add in class AbstractList<E>

Parameters:

location - the index at which to insert the element

object - the object to insert in this Vector

Throws:

ArrayIndexOutOfBoundsException - when location < 0 || > size()

See Also:

addElement(E), size()

add

public boolean add(E object)

Adds the specified object at the end of this Vector.

Specified by:

add in interface Collection<E>

Specified by:

add in interface List<E>

Overrides:

add in class AbstractList<E>

Parameters:

object - the object to add to the Vector

Returns:

true

addAll

public boolean addAll(int location,
                      Collection<? extends E> collection)

Inserts the objects in the specified Collection at the specified location in this Vector. The objects are inserted in the order in which they are returned from the Collection iterator.

Specified by:

addAll in interface List<E>

Overrides:

addAll in class AbstractList<E>

Parameters:

location - the location to insert the objects

collection - the Collection of objects

Returns:

true if this Vector is modified, false otherwise

Throws:

ArrayIndexOutOfBoundsException - when location < 0 or location > size()

addAll

public boolean addAll(Collection<? extends E> collection)

Adds the objects in the specified Collection to the end of this Vector.

Specified by:

addAll in interface Collection<E>

Specified by:

addAll in interface List<E>

Overrides:

addAll in class AbstractCollection<E>

Parameters:

collection - the Collection of objects

Returns:

true if this Vector is modified, false otherwise

addElement

public void addElement(E object)

Adds the specified object at the end of this Vector.

Parameters:

object - the object to add to the Vector

capacity

public int capacity()

Answers the number of elements this Vector can hold without growing.

Returns:

the capacity of this Vector

See Also:

ensureCapacity(int), size()

clear

public void clear()

Removes all elements from this Vector, leaving it empty.

Specified by:

clear in interface Collection<E>

Specified by:

clear in interface List<E>

Overrides:

clear in class AbstractList<E>

See Also:

isEmpty(), size()

clone

public Object clone()

Answers a new Vector with the same elements, size, capacity and capacity increment as this Vector.

Overrides:

clone in class Object

Returns:

a shallow copy of this Vector

See Also:

Cloneable

contains

public boolean contains(Object object)

Searches this Vector for the specified object.

Specified by:

contains in interface Collection<E>

Specified by:

contains in interface List<E>

Overrides:

contains in class AbstractCollection<E>

Parameters:

object - the object to look for in this Vector

Returns:

true if object is an element of this Vector, false otherwise

See Also:

indexOf(Object), indexOf(Object, int), Object.equals(java.lang.Object)

containsAll

public boolean containsAll(Collection<?> collection)

Searches this Vector for all objects in the specified Collection.

Specified by:

containsAll in interface Collection<E>

Specified by:

containsAll in interface List<E>

Overrides:

containsAll in class AbstractCollection<E>

Parameters:

collection - the Collection of objects

Returns:

true if all objects in the specified Collection are elements of this Vector, false otherwise

copyInto

public void copyInto(Object[] elements)

Copies the elements of this Vector into the specified Object array.

Parameters:

elements - the Object array into which the elements of this Vector are copied

See Also:

clone()

elementAt

public E elementAt(int location)

Answers the element at the specified location in this Vector.

Parameters:

location - the index of the element to return in this Vector

Returns:

the element at the specified location

Throws:

ArrayIndexOutOfBoundsException - when location < 0 || >= size()

See Also:

size()

elements

public Enumeration<E> elements()

Answers an Enumeration on the elements of this Vector. The results of the Enumeration may be affected if the contents of this Vector are modified.

Returns:

an Enumeration of the elements of this Vector

See Also:

elementAt(int), Enumeration

ensureCapacity

public void ensureCapacity(int minimumCapacity)

Ensures that this Vector can hold the specified number of elements without growing.

Parameters:

minimumCapacity - the minimum number of elements that this vector will hold before growing

See Also:

capacity()

equals

public boolean equals(Object object)

Compares the specified object to this Vector and answer if they are equal. The object must be a List which contains the same objects in the same order.

Specified by:

equals in interface Collection<E>

Specified by:

equals in interface List<E>

Overrides:

equals in class AbstractList<E>

Parameters:

object - the object to compare with this object

Returns:

true if the specified object is equal to this Vector, false otherwise

See Also:

hashCode()

firstElement

public E firstElement()

Answers the first element in this Vector.

Returns:

the element at the first position

Throws:

NoSuchElementException - when this vector is empty

See Also:

elementAt(int), lastElement(), size()

get

public E get(int location)

Answers the element at the specified location in this Vector.

Specified by:

get in interface List<E>

Specified by:

get in class AbstractList<E>

Parameters:

location - the index of the element to return in this Vector

Returns:

the element at the specified location

Throws:

ArrayIndexOutOfBoundsException - when location < 0 || >= size()

See Also:

size()

hashCode

public int hashCode()

Answers an integer hash code for the receiver. Objects which are equal answer the same value for this method.

Specified by:

hashCode in interface Collection<E>

Specified by:

hashCode in interface List<E>

Overrides:

hashCode in class AbstractList<E>

Returns:

the receiver's hash

See Also:

equals(java.lang.Object)

indexOf

public int indexOf(Object object)

Searches in this Vector for the index of the specified object. The search for the object starts at the beginning and moves towards the end of this Vector.

Specified by:

indexOf in interface List<E>

Overrides:

indexOf in class AbstractList<E>

Parameters:

object - the object to find in this Vector

Returns:

the index in this Vector of the specified element, -1 if the element isn't found

See Also:

contains(java.lang.Object), lastIndexOf(Object), lastIndexOf(Object, int)

indexOf

public int indexOf(Object object,
                   int location)

Searches in this Vector for the index of the specified object. The search for the object starts at the specified location and moves towards the end of this Vector.

Parameters:

object - the object to find in this Vector

location - the index at which to start searching

Returns:

the index in this Vector of the specified element, -1 if the element isn't found

Throws:

ArrayIndexOutOfBoundsException - when location < 0

See Also:

contains(java.lang.Object), lastIndexOf(Object), lastIndexOf(Object, int)

insertElementAt

public void insertElementAt(E object,
                            int location)

Inserts the specified object into this Vector at the specified location. This object is inserted before any previous element at the specified location. If the location is equal to the size of this Vector, the object is added at the end.

Parameters:

object - the object to insert in this Vector

location - the index at which to insert the element

Throws:

ArrayIndexOutOfBoundsException - when location < 0 || > size()

See Also:

addElement(E), size()

isEmpty

public boolean isEmpty()

Answers if this Vector has no elements, a size of zero.

Specified by:

isEmpty in interface Collection<E>

Specified by:

isEmpty in interface List<E>

Overrides:

isEmpty in class AbstractCollection<E>

Returns:

true if this Vector has no elements, false otherwise

See Also:

size()

lastElement

public E lastElement()

Answers the last element in this Vector.

Returns:

the element at the last position

Throws:

NoSuchElementException - when this vector is empty

See Also:

elementAt(int), firstElement(), size()

lastIndexOf

public int lastIndexOf(Object object)

Searches in this Vector for the index of the specified object. The search for the object starts at the end and moves towards the start of this Vector.

Specified by:

lastIndexOf in interface List<E>

Overrides:

lastIndexOf in class AbstractList<E>

Parameters:

object - the object to find in this Vector

Returns:

the index in this Vector of the specified element, -1 if the element isn't found

See Also:

contains(java.lang.Object), indexOf(Object), indexOf(Object, int)

lastIndexOf

public int lastIndexOf(Object object,
                       int location)

Searches in this Vector for the index of the specified object. The search for the object starts at the specified location and moves towards the start of this Vector.

Parameters:

object - the object to find in this Vector

location - the index at which to start searching

Returns:

the index in this Vector of the specified element, -1 if the element isn't found

Throws:

ArrayIndexOutOfBoundsException - when location >= size()

See Also:

contains(java.lang.Object), indexOf(Object), indexOf(Object, int)

remove

public E remove(int location)

Removes the element at the specified location from this Vector.

Specified by:

remove in interface List<E>

Overrides:

remove in class AbstractList<E>

Parameters:

location - the index of the element to remove

Returns:

the removed element

Throws:

ArrayIndexOutOfBoundsException - when location < 0 || >= size()

See Also:

removeElement(java.lang.Object), removeAllElements(), size()

remove

public boolean remove(Object object)

Removes the first occurrence, starting at the beginning and moving towards the end, of the specified object from this Vector.

Specified by:

remove in interface Collection<E>

Specified by:

remove in interface List<E>

Overrides:

remove in class AbstractCollection<E>

Parameters:

object - the object to remove from this Vector

Returns:

true if the specified object was found, false otherwise

See Also:

removeAllElements(), removeElementAt(int), size()

removeAll

public boolean removeAll(Collection<?> collection)

Removes all occurrences in this Vector of each object in the specified Collection.

Specified by:

removeAll in interface Collection<E>

Specified by:

removeAll in interface List<E>

Overrides:

removeAll in class AbstractCollection<E>

Parameters:

collection - the Collection of objects to remove

Returns:

true if this Vector is modified, false otherwise

removeAllElements

public void removeAllElements()

Removes all elements from this Vector, leaving the size zero and the capacity unchanged.

See Also:

isEmpty(), size()

removeElement

public boolean removeElement(Object object)

Removes the first occurrence, starting at the beginning and moving towards the end, of the specified object from this Vector.

Parameters:

object - the object to remove from this Vector

Returns:

true if the specified object was found, false otherwise

See Also:

removeAllElements(), removeElementAt(int), size()

removeElementAt

public void removeElementAt(int location)

Removes the element at the specified location from this Vector.

Parameters:

location - the index of the element to remove

Throws:

ArrayIndexOutOfBoundsException - when location < 0 || >= size()

See Also:

removeElement(java.lang.Object), removeAllElements(), size()

removeRange

protected void removeRange(int start,
                           int end)

Removes the objects in the specified range from the start to the, but not including, end index.

Overrides:

removeRange in class AbstractList<E>

Parameters:

start - the index at which to start removing

end - the index one past the end of the range to remove

Throws:

IndexOutOfBoundsException - when start < 0, start > end or end > size()

retainAll

public boolean retainAll(Collection<?> collection)

Removes all objects from this Vector that are not contained in the specified Collection.

Specified by:

retainAll in interface Collection<E>

Specified by:

retainAll in interface List<E>

Overrides:

retainAll in class AbstractCollection<E>

Parameters:

collection - the Collection of objects to retain

Returns:

true if this Vector is modified, false otherwise

set

public E set(int location,
             E object)

Replaces the element at the specified location in this Vector with the specified object.

Specified by:

set in interface List<E>

Overrides:

set in class AbstractList<E>

Parameters:

location - the index at which to put the specified object

object - the object to add to this Vector

Returns:

the previous element at the location

Throws:

ArrayIndexOutOfBoundsException - when location < 0 || >= size()

See Also:

size()

setElementAt

public void setElementAt(E object,
                         int location)

Replaces the element at the specified location in this Vector with the specified object.

Parameters:

object - the object to add to this Vector

location - the index at which to put the specified object

Throws:

ArrayIndexOutOfBoundsException - when location < 0 || >= size()

See Also:

size()

setSize

public void setSize(int length)

Sets the size of this Vector to the specified size. If there are more than length elements in this Vector, the elements at end are lost. If there are less than length elements in the Vector, the additional elements contain null.

Parameters:

length - the new size of this Vector

See Also:

size()

size

public int size()

Answers the number of elements in this Vector.

Specified by:

size in interface Collection<E>

Specified by:

size in interface List<E>

Specified by:

size in class AbstractCollection<E>

Returns:

the number of elements in this Vector

See Also:

elementCount, lastElement()

subList

public List<E> subList(int start,
                       int end)

Answers a List of the specified portion of this Vector from the start index to one less than the end index. The returned List is backed by this Vector so changes to one are reflected by the other.

Specified by:

subList in interface List<E>

Overrides:

subList in class AbstractList<E>

Parameters:

start - the index at which to start the sublist

end - the index one past the end of the sublist

Returns:

a List of a portion of this Vector

Throws:

IndexOutOfBoundsException - when start < 0 or end > size()

IllegalArgumentException - when start > end

toArray

public Object[] toArray()

Answers a new array containing all elements contained in this Vector.

Specified by:

toArray in interface Collection<E>

Specified by:

toArray in interface List<E>

Overrides:

toArray in class AbstractCollection<E>

Returns:

an array of the elements from this Vector

toArray

public <T> T[] toArray(T[] contents)

Answers an array containing all elements contained in this Vector. If the specified array is large enough to hold the elements, the specified array is used, otherwise an array of the same type is created. If the specified array is used and is larger than this Vector, the array element following the collection elements is set to null.

Specified by:

toArray in interface Collection<E>

Specified by:

toArray in interface List<E>

Overrides:

toArray in class AbstractCollection<E>

Parameters:

contents - the array

Returns:

an array of the elements from this Vector

Throws:

ArrayStoreException - when the type of an element in this Vector cannot be stored in the type of the specified array

toString

public String toString()

Answers the string representation of this Vector.

Overrides:

toString in class AbstractCollection<E>

Returns:

the string representation of this Vector

See Also:

elements()

trimToSize

public void trimToSize()

Sets the capacity of this Vector to be the same as the size.

See Also:

capacity(), ensureCapacity(int), size()