java.util.concurrent

Class CopyOnWriteArrayList<E>

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

Since: 1.5

Constructor Summary
	CopyOnWriteArrayList() Construct a new ArrayList with the default capacity (16).
	CopyOnWriteArrayList(Collection<? extends E> c) Construct a new ArrayList, and initialize it with the elements in the supplied Collection.
	CopyOnWriteArrayList(E[] array) Construct a new ArrayList, and initialize it with the elements in the supplied array.

Method Summary
boolean	add(E e) Appends the supplied element to the end of this list.
void	add(int index, E e) Adds the supplied element at the specified index, shifting all elements currently at that index or higher one to the right.
boolean	addAll(Collection<? extends E> c) Add each element in the supplied Collection to this List.
boolean	addAll(int index, Collection<? extends E> c) Add all elements in the supplied collection, inserting them beginning at the specified index. c can contain objects of any type, as well as null values.
int	addAllAbsent(Collection<? extends E> c)
boolean	addIfAbsent(E val)
void	clear() Removes all elements from this List
Object	clone() Creates a shallow copy of this ArrayList (elements are not cloned).
boolean	contains(Object e) Returns true iff element is in this ArrayList.
E	get(int index) Retrieves the element at the user-supplied index.
int	indexOf(Object e) Returns the lowest index at which element appears in this List, or -1 if it does not appear.
int	indexOf(E e, int index) Return the lowest index greater equal `index` at which `e` appears in this List, or -1 if it does not appear.
boolean	isEmpty() Checks if the list is empty.
int	lastIndexOf(Object e) Returns the highest index at which element appears in this List, or -1 if it does not appear.
int	lastIndexOf(E e, int index) Returns the highest index lesser equal `index` at which `e` appears in this List, or -1 if it does not appear.
E	remove(int index) Removes the element at the user-supplied index.
E	set(int index, E e) Sets the element at the specified index.
int	size() Returns the number of elements in this list.
Object[]	toArray() Returns an Object array containing all of the elements in this ArrayList.
<T> T[]	toArray(T[] a) Returns an Array whose component type is the runtime component type of the passed-in Array.

Constructor Detail

CopyOnWriteArrayList

public CopyOnWriteArrayList()

Construct a new ArrayList with the default capacity (16).

CopyOnWriteArrayList

public CopyOnWriteArrayList(Collection<? extends E> c)

Construct a new ArrayList, and initialize it with the elements in the supplied Collection. The initial capacity is 110% of the Collection's size.

Parameters: c the collection whose elements will initialize this list

Throws: NullPointerException if c is null

CopyOnWriteArrayList

public CopyOnWriteArrayList(E[] array)

Construct a new ArrayList, and initialize it with the elements in the supplied array.

Parameters: array the array used to initialize this list

Throws: NullPointerException if array is null

Method Detail

add

public boolean add(E e)

Appends the supplied element to the end of this list. The element, e, can be an object of any type or null.

Parameters: e the element to be appended to this list

Returns: true, the add will always succeed

add

public void add(int index, E e)

Adds the supplied element at the specified index, shifting all elements currently at that index or higher one to the right. The element, e, can be an object of any type or null.

Parameters: index the index at which the element is being added e the item being added

Throws: IndexOutOfBoundsException if index < 0 || index > size()

addAll

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

Add each element in the supplied Collection to this List. It is undefined what happens if you modify the list while this is taking place; for example, if the collection contains this list. c can contain objects of any type, as well as null values.

Parameters: c a Collection containing elements to be added to this List

Returns: true if the list was modified, in other words c is not empty

Throws: NullPointerException if c is null

addAll

public boolean addAll(int index, Collection<? extends E> c)

Add all elements in the supplied collection, inserting them beginning at the specified index. c can contain objects of any type, as well as null values.

Parameters: index the index at which the elements will be inserted c the Collection containing the elements to be inserted

Throws: IndexOutOfBoundsException if index < 0 || index > 0 NullPointerException if c is null

addAllAbsent

public int addAllAbsent(Collection<? extends E> c)

addIfAbsent

public boolean addIfAbsent(E val)

clear

public void clear()

Removes all elements from this List

clone

public Object clone()

Creates a shallow copy of this ArrayList (elements are not cloned).

Returns: the cloned object

contains

public boolean contains(Object e)

Returns true iff element is in this ArrayList.

Parameters: e the element whose inclusion in the List is being tested

Returns: true if the list contains e

get

public E get(int index)

Retrieves the element at the user-supplied index.

Parameters: index the index of the element we are fetching

Throws: IndexOutOfBoundsException if index < 0 || index >= size()

indexOf

public int indexOf(Object e)

Returns the lowest index at which element appears in this List, or -1 if it does not appear.

Parameters: e the element whose inclusion in the List is being tested

Returns: the index where e was found

indexOf

public int indexOf(E e, int index)

Return the lowest index greater equal index at which e appears in this List, or -1 if it does not appear.

Parameters: e the element whose inclusion in the list is being tested index the index at which the search begins

Returns: the index where e was found

isEmpty

public boolean isEmpty()

Checks if the list is empty.

Returns: true if there are no elements

lastIndexOf

public int lastIndexOf(Object e)

Returns the highest index at which element appears in this List, or -1 if it does not appear.

Parameters: e the element whose inclusion in the List is being tested

Returns: the index where e was found

lastIndexOf

public int lastIndexOf(E e, int index)

Returns the highest index lesser equal index at which e appears in this List, or -1 if it does not appear.

Parameters: e the element whose inclusion in the list is being tested index the index at which the search begins

Returns: the index where e was found

remove

public E remove(int index)

Removes the element at the user-supplied index.

Parameters: index the index of the element to be removed

Returns: the removed Object

Throws: IndexOutOfBoundsException if index < 0 || index >= size()

set

public E set(int index, E e)

Sets the element at the specified index. The new element, e, can be an object of any type or null.

Parameters: index the index at which the element is being set e the element to be set

Returns: the element previously at the specified index

Throws: IndexOutOfBoundsException if index < 0 || index >= 0

size

public int size()

Returns the number of elements in this list.

Returns: the list size

toArray

public Object[] toArray()

Returns an Object array containing all of the elements in this ArrayList. The array is independent of this list.

Returns: an array representation of this list

toArray

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

Returns an Array whose component type is the runtime component type of the passed-in Array. The returned Array is populated with all of the elements in this ArrayList. If the passed-in Array is not large enough to store all of the elements in this List, a new Array will be created and returned; if the passed-in Array is larger than the size of this List, then size() index will be set to null.

Parameters: a the passed-in Array

Returns: an array representation of this list

Throws: ArrayStoreException if the runtime type of a does not allow an element in this list NullPointerException if a is null