All Packages  Class Hierarchy  This Package  Previous  Next  Index

Class com.sun.java.util.collections.Vector

java.lang.Object
   |
   +----com.sun.java.util.collections.AbstractCollection
           |
           +----com.sun.java.util.collections.AbstractList
                   |
                   +----com.sun.java.util.collections.Vector

public class Vector
extends AbstractList
implements List, Cloneable, Serializable
The Vector class implements a 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 tries to optimize storage management by maintaining a capacity and a capacityIncrement. The capacity is always at least as large as the vector size; it is usually larger because as components are added to the vector, the vector's storage increases in chunks the size of capacityIncrement. An application can increase the capacity of a vector before inserting a large number of components; this reduces the amount of incremental reallocation.

As of JDK1.2, this class has been retrofitted to implement List, so that it becomes a part of Java's collection framework. Unlike the new collection implementations, Vector is synchronized.

The Iterators returned by Vector's iterator and listIterator methods are fail-fast: if the Vector is structurally modified at any time after the Iterator is created, in any way except through the Iterator's own remove or add methods, the Iterator will throw a ConcurrentModificationException. Thus, in the face of concurrent modification, the Iterator fails quickly and cleanly, rather than risking arbitrary, non-deterministic behavior at an undetermined time in the future. The java.util.Enumerations returned by Vector's elements method are not fail-fast.

See Also:
Collection, List, ArrayList, LinkedList

Variable Index

 o capacityIncrement
The amount by which the capacity of the vector is automatically incremented when its size becomes greater than its capacity.
 o elementCount
The number of valid components in this Vector object.
 o elementData
The array buffer into which the components of the vector are stored.

Constructor Index

 o Vector()
Constructs an empty vector so that its internal data array has size 10 and its standard capacity increment is zero.
 o Vector(Collection)
Constructs a vector containing the elements of the specified collection, in the order they are returned by the collection's iterator.
 o Vector(int)
Constructs an empty vector with the specified initial capacity and with its capacity increment equal to zero.
 o Vector(int, int)
Constructs an empty vector with the specified initial capacity and capacity increment.

Method Index

 o add(int, Object)
Inserts the specified element at the specified position in this Vector.
 o add(Object)
Appends the specified element to the end of this Vector.
 o addAll(Collection)
Appends all of the elements in the specified Collection to the end of this this Vector, in the order that they are returned by the specified Collection's Iterator.
 o addAll(int, Collection)
Inserts all of the elements in in the specified Collection into this Vector at the specified position.
 o addElement(Object)
Adds the specified component to the end of this vector, increasing its size by one.
 o capacity()
Returns the current capacity of this vector.
 o clear()
Removes all of the elements from this Vector.
 o clone()
Returns a clone of this vector.
 o contains(Object)
Tests if the specified object is a component in this vector.
 o containsAll(Collection)
Returns true if this Vector contains all of the elements in the specified Collection.
 o copyInto(Object[])
Copies the components of this vector into the specified array.
 o elementAt(int)
Returns the component at the specified index.
 o elements()
Returns an enumeration of the components of this vector.
 o ensureCapacity(int)
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.
 o equals(Object)
Compares the specified Object with this Vector for equality.
 o firstElement()
Returns the first component (the item at index 0) of this vector.
 o get(int)
Returns the element at the specified position in this Vector.
 o hashCode()
Returns the hash code value for this Vector.
 o indexOf(Object)
Searches for the first occurence of the given argument, testing for equality using the equals method.
 o indexOf(Object, int)
Searches for the first occurence of the given argument, beginning the search at index, and testing for equality using the equals method.
 o insertElementAt(Object, int)
Inserts the specified object as a component in this vector at the specified index.
 o isEmpty()
Tests if this vector has no components.
 o lastElement()
Returns the last component of the vector.
 o lastIndexOf(Object)
Returns the index of the last occurrence of the specified object in this vector.
 o lastIndexOf(Object, int)
Searches backwards for the specified object, starting from the specified index, and returns an index to it.
 o remove(int)
Removes the element at the specified position in this Vector.
 o remove(Object)
Removes the first occurrence of the specified element in this Vector If the Vector does not contain the element, it is unchanged.
 o removeAll(Collection)
Removes from this Vector all of its elements that are contained in the specified Collection.
 o removeAllElements()
Removes all components from this vector and sets its size to zero.
 o removeElement(Object)
Removes the first (lowest-indexed) occurrence of the argument from this vector.
 o removeElementAt(int)
Deletes the component at the specified index.
 o retainAll(Collection)
Retains only the elements in this Vector that are contained in the specified Collection.
 o set(int, Object)
Replaces the element at the specified position in this Vector with the specified element.
 o setElementAt(Object, int)
Sets the component at the specified index of this vector to be the specified object.
 o setSize(int)
Sets the size of this vector.
 o size()
Returns the number of components in this vector.
 o toArray()
Returns an array containing all of the elements in this Vector in the correct order.
 o toArray(Object[])
Returns an array containing all of the elements in this Vector in the correct order.
 o toString()
Returns a string representation of this Vector, containing the String representation of each element.
 o trimToSize()
Trims the capacity of this vector to be the vector's current size.

Variables

 o elementData
 protected Object elementData[]
The array buffer into which the components of the vector are stored. The capacity of the vector is the length of this array buffer, and is at least large enough to contain all the vector's elements.

Any array elements following the last element in the Vector are null.

 o elementCount
 protected int elementCount
The number of valid components in this Vector object. Components elementData[0] through elementData[elementCount-1] are the actual items.

 o capacityIncrement
 protected int capacityIncrement
The amount by which the capacity of the vector is automatically incremented when its size becomes greater than its capacity. If the capacity increment is 0, the capacity of the vector is doubled each time it needs to grow.

Constructors

 o Vector
 public Vector(int initialCapacity,
               int capacityIncrement)
Constructs an empty vector with the specified initial capacity and capacity increment.

Parameters:
initialCapacity - the initial capacity of the vector.
capacityIncrement - the amount by which the capacity is increased when the vector overflows.
Throws: IllegalArgumentException
if the specified initial capacity is negative
 o Vector
 public Vector(int initialCapacity)
Constructs an empty vector with the specified initial capacity and with its capacity increment equal to zero.

Parameters:
initialCapacity - the initial capacity of the vector.
Throws: IllegalArgumentException
if the specified initial capacity is negative
 o Vector
 public Vector()
Constructs an empty vector so that its internal data array has size 10 and its standard capacity increment is zero.

 o Vector
 public Vector(Collection c)
Constructs a vector containing the elements of the specified collection, in the order they are returned by the collection's iterator.

Methods

 o copyInto
 public synchronized void copyInto(Object anArray[])
Copies the components of this vector into the specified array. The item at index k in this vector is copied into component k of anArray. The array must be big enough to hold all the objects in this vector, else an IndexOutOfBoundsException is thrown.

Parameters:
anArray - the array into which the components get copied.
 o trimToSize
 public synchronized void trimToSize()
Trims the capacity of this vector to be the vector's current size. If the capacity of this cector is larger than its current size, then the capacity is changed to equal the size by replacing its internal data array, kept in the field elementData, with a smaller one. An application can use this operation to minimize the storage of a vector.

 o ensureCapacity
 public synchronized 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.

If the current capacity of this vector is less than minCapacity, then its capacity is increased by replacing its internal data array, kept in the field elementData, with a larger one. The size of the new data array will be the old size plus capacityIncrement, unless the value of capacityIncrement is nonpositive, in which case the new capacity will be twice the old capacity; but if this new size is still smaller than minCapacity, then the new capacity will be minCapacity.

Parameters:
minCapacity - the desired minimum capacity.
 o setSize
 public synchronized void setSize(int newSize)
Sets the size of this vector. If the new size is greater than the current size, new null items are added to the end of the vector. If the new size is less than the current size, all components at index newSize and greater are discarded.

Parameters:
newSize - the new size of this vector.
 o capacity
 public int capacity()
Returns the current capacity of this vector.

Returns:
the current capacity (the length of its internal data arary, kept in the field elementData of this vector.
 o size
 public int size()
Returns the number of components in this vector.

Returns:
the number of components in this vector.
Overrides:
size in class AbstractCollection
 o isEmpty
 public boolean isEmpty()
Tests if this vector has no components.

Returns:
true if and only if this vector has no components, that is, its size is zero; false otherwise.
Overrides:
isEmpty in class AbstractCollection
 o elements
 public Enumeration elements()
Returns an enumeration of the components of this vector. The returned java.util.Enumeration object will generate all items in this vector. The first item generated is the item at index 0, then the item at index 1, and so on.

Returns:
an enumeration of the components of this vector.
See Also:
Enumeration, Iterator
 o contains
 public boolean contains(Object elem)
Tests if the specified object is a component in this vector.

Parameters:
elem - an object.
Returns:
true if and only if the specified object is the same as a component in this vector, as determined by the equals method; false otherwise.
Overrides:
contains in class AbstractCollection
 o indexOf
 public int indexOf(Object elem)
Searches for the first occurence of the given argument, testing for equality using the equals method.

Parameters:
elem - an object.
Returns:
the index of the first occurrence of the argument in this vector, that is, the smallest value k such that elem.equals(elementData[k]) is true; returns -1 if the object is not found.
Overrides:
indexOf in class AbstractList
See Also:
equals
 o indexOf
 public synchronized int indexOf(Object elem,
                                 int index)
Searches for the first occurence of the given argument, beginning the search at index, and testing for equality using the equals method.

Parameters:
elem - an object.
index - the index to start searching from.
Returns:
the index of the first occurrence of the object argument in this vector at position index or later in the vector, that is, the smallest value k such that elem.equals(elementData[k]) && (k >= index) is true; returns -1 if the object is not found.
See Also:
equals
 o lastIndexOf
 public int lastIndexOf(Object elem)
Returns the index of the last occurrence of the specified object in this vector.

Parameters:
elem - the desired component.
Returns:
the index of the last occurrence of the specified object in this vector, that is, the largest value k such that elem.equals(elementData[k]) is true; returns -1 if the object is not found.
Overrides:
lastIndexOf in class AbstractList
 o lastIndexOf
 public synchronized int lastIndexOf(Object elem,
                                     int index)
Searches backwards for the specified object, starting from the specified index, and returns an index to it.

Parameters:
elem - the desired component.
index - the index to start searching from.
Returns:
the index of the last occurrence of the specified object in this vector at position less than index in the vector, that is, the largest value k such that elem.equals(elementData[k]) && (k <= index) is true; -1 if the object is not found.
 o elementAt
 public synchronized Object elementAt(int index)
Returns the component at the specified index.

This method is identical in functionality to the get method (which is part of the List interface).

Parameters:
index - an index into this vector.
Returns:
the component at the specified index.
Throws: ArrayIndexOutOfBoundsException
if the index is negative or not less than the current size of this Vector object. given.
See Also:
get, List
 o firstElement
 public synchronized Object firstElement()
Returns the first component (the item at index 0) of this vector.

Returns:
the first component of this vector.
Throws: NoSuchElementException
if this vector has no components.
 o lastElement
 public synchronized Object lastElement()
Returns the last component of the vector.

Returns:
the last component of the vector, i.e., the component at index size() - 1.
Throws: NoSuchElementException
if this vector is empty.
 o setElementAt
 public synchronized void setElementAt(Object obj,
                                       int index)
Sets the component at the specified index of this vector to be the specified object. The previous component at that position is discarded.

The index must be a value greater than or equal to 0 and less than the current size of the vector.

This method is identical in functionality to the set method (which is part of the List interface). Note that the set method reverses the order of the parameters, to more closely match array usage. Note also that the set method returns the old value that was stored at the specified position.

Parameters:
obj - what the component is to be set to.
index - the specified index.
Throws: ArrayIndexOutOfBoundsException
if the index was invalid.
See Also:
size, List, set
 o removeElementAt
 public synchronized void removeElementAt(int index)
Deletes the component at the specified index. Each component in this vector with an index greater or equal to the specified index is shifted downward to have an index one smaller than the value it had previously. The size of this vector is decreased by 1.

The index must be a value greater than or equal to 0 and less than the current size of the vector.

This method is identical in functionality to the remove method (which is part of the List interface). Note that the remove method returns the old value that was stored at the specified position.

Parameters:
index - the index of the object to remove.
Throws: ArrayIndexOutOfBoundsException
if the index was invalid.
See Also:
size, remove, List
 o insertElementAt
 public synchronized void insertElementAt(Object obj,
                                          int index)
Inserts the specified object as a component in this vector at the specified index. Each component in this vector with an index greater or equal to the specified index is shifted upward to have an index one greater than the value it had previously.

The index must be a value greater than or equal to 0 and less than or equal to the current size of the vector.

This method is identical in functionality to the add(Object, int) method (which is part of the List interface). Note that the add method reverses the order of the parameters, to more closely match array usage.

Parameters:
obj - the component to insert.
index - where to insert the new component.
Throws: ArrayIndexOutOfBoundsException
if the index was invalid.
See Also:
size, add, List
 o addElement
 public synchronized void addElement(Object obj)
Adds the specified component to the end of this vector, increasing its size by one. The capacity of this vector is increased if its size becomes greater than its capacity.

This method is identical in functionality to the add(Object) method (which is part of the List interface).

Parameters:
obj - the component to be added.
See Also:
add, List
 o removeElement
 public synchronized boolean removeElement(Object obj)
Removes the first (lowest-indexed) occurrence of the argument from this vector. If the object is found in this vector, each component in the vector with an index greater or equal to the object's index is shifted downward to have an index one smaller than the value it had previously.

This method is identical in functionality to the remove(Object) method (which is part of the List interface).

Parameters:
obj - the component to be removed.
Returns:
true if the argument was a component of this vector; false otherwise.
See Also:
remove, List
 o removeAllElements
 public synchronized void removeAllElements()
Removes all components from this vector and sets its size to zero.

This method is identical in functionality to the clear method (which is part of the List interface).

See Also:
clear, List
 o clone
 public synchronized Object clone()
Returns a clone of this vector. The copy will contain a reference to a clone of the internal data array, not a reference to the original internal data array of this Vector object.

Returns:
a clone of this vector.
Overrides:
clone in class Object
 o toArray
 public synchronized Object[] toArray()
Returns an array containing all of the elements in this Vector in the correct order.

Overrides:
toArray in class AbstractCollection
 o toArray
 public synchronized Object[] toArray(Object 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. If the Vector fits in the specified array, it is returned therein. Otherwise, a new array is allocated with the runtime type of the specified array and the size of this Vector.

If the Vector fits in the specified array with room to spare (i.e., the array has more elements than the Vector), the element in the array immediately following the end of the Vector is set to null. This is useful in determining the length of the Vector only if the caller knows that the Vector does not contain any null elements.

Parameters:
a - the array into which the elements of the Vector are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose.
Returns:
an array containing the elements of the Vector.
Throws: ArrayStoreException
the runtime type of a is not a supertype of the runtime type of every element in this Vector.
Overrides:
toArray in class AbstractCollection
 o get
 public synchronized Object get(int index)
Returns the element at the specified position in this Vector.

Parameters:
index - index of element to return.
Throws: ArrayIndexOutOfBoundsException
index is out of range (index < 0 || index >= size()).
Overrides:
get in class AbstractList
 o set
 public synchronized Object set(int index,
                                Object element)
Replaces the element at the specified position in this Vector with the specified element.

Parameters:
index - index of element to replace.
element - element to be stored at the specified position.
Returns:
the element previously at the specified position.
Throws: ArrayIndexOutOfBoundsException
index out of range (index < 0 || index >= size()).
Throws: IllegalArgumentException
fromIndex > toIndex.
Overrides:
set in class AbstractList
 o add
 public synchronized boolean add(Object o)
Appends the specified element to the end of this Vector.

Parameters:
o - element to be appended to this Vector.
Returns:
true (as per the general contract of Collection.add).
Overrides:
add in class AbstractList
 o remove
 public 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. More formally, removes the element with the lowest index i such that (o==null ? get(i)==null : o.equals(get(i))) (if such an element exists).

Parameters:
o - element to be removed from this Vector, if present.
Returns:
true if the Vector contained the specified element.
Overrides:
remove in class AbstractCollection
 o add
 public void add(int index,
                 Object element)
Inserts the specified element at the specified position in this Vector. Shifts the element currently at that position (if any) and any subsequent elements to the right (adds one to their indices).

Parameters:
index - index at which the specified element is to be inserted.
element - element to be inserted.
Throws: ArrayIndexOutOfBoundsException
index is out of range (index < 0 || index > size()).
Overrides:
add in class AbstractList
 o remove
 public synchronized Object remove(int index)
Removes the element at the specified position in this Vector. shifts any subsequent elements to the left (subtracts one from their indices). Returns the element that was removed from the Vector.

Parameters:
index - the index of the element to removed.
Throws: ArrayIndexOutOfBoundsException
index out of range (index < 0 || index >= size()).
Overrides:
remove in class AbstractList
 o clear
 public void clear()
Removes all of the elements from this Vector. The Vector will be empty after this call returns (unless it throws an exception).

Overrides:
clear in class AbstractCollection
 o containsAll
 public synchronized boolean containsAll(Collection c)
Returns true if this Vector contains all of the elements in the specified Collection.

Returns:
true if this Vector contains all of the elements in the specified collection.
Overrides:
containsAll in class AbstractCollection
 o addAll
 public synchronized boolean addAll(Collection c)
Appends all of the elements in the specified Collection to the end of this this Vector, in the order that they are returned by the specified Collection's Iterator. The behavior of this operation is undefined if the specified Collection is modified while the operation is in progress. (This implies that the behavior of this call is undefined if the specified Collection is this Vector, and this Vector is nonempty.)

Parameters:
index - index at which to insert first element from the specified collection.
c - elements to be inserted into this Vector.
Throws: ArrayIndexOutOfBoundsException
index out of range (index < 0 || index > size()).
Overrides:
addAll in class AbstractCollection
 o removeAll
 public synchronized boolean removeAll(Collection c)
Removes from this Vector all of its elements that are contained in the specified Collection.

Returns:
true if this Vector changed as a result of the call.
Overrides:
removeAll in class AbstractCollection
 o retainAll
 public synchronized boolean retainAll(Collection c)
Retains only the elements in this Vector that are contained in the specified Collection. In other words, removes from this Vector all of its elements that are not contained in the specified Collection.

Returns:
true if this Vector changed as a result of the call.
Overrides:
retainAll in class AbstractCollection
 o addAll
 public synchronized boolean addAll(int index,
                                    Collection c)
Inserts all of the elements in in the specified Collection into this Vector at the specified position. Shifts the element currently at that position (if any) and any subsequent elements to the right (increases their indices). The new elements will appear in the Vector in the order that they are returned by the specified Collection's iterator.

Parameters:
index - index at which to insert first element from the specified collection.
c - elements to be inserted into this Vector.
Throws: ArrayIndexOutOfBoundsException
index out of range (index < 0 || index > size()).
Overrides:
addAll in class AbstractList
 o equals
 public synchronized boolean equals(Object o)
Compares the specified Object with this Vector for equality. Returns true if and only if the specified Object is also a List, both Lists have the same size, and all corresponding pairs of elements in the two Lists are equal. (Two elements e1 and e2 are equal if (e1==null ? e2==null : e1.equals(e2)).) In other words, two Lists are defined to be equal if they contain the same elements in the same order.

Parameters:
o - the Object to be compared for equality with this Vector.
Returns:
true if the specified Object is equal to this Vector
Overrides:
equals in class AbstractList
 o hashCode
 public synchronized int hashCode()
Returns the hash code value for this Vector.

Overrides:
hashCode in class AbstractList
 o toString
 public synchronized String toString()
Returns a string representation of this Vector, containing the String representation of each element.

Overrides:
toString in class AbstractCollection

All Packages  Class Hierarchy  This Package  Previous  Next  Index