CopyOnWriteArrayList (Java SE 9 & JDK 9 ) (original) (raw)

Constructor Summary

Constructors

Constructor	Description
CopyOnWriteArrayList()	Creates an empty list.
CopyOnWriteArrayList(E[] toCopyIn)	Creates a list holding a copy of the given array.
CopyOnWriteArrayList(Collection<? extends E> c)	Creates a list containing the elements of the specified collection, in the order they are returned by the collection's iterator.

Method Summary

All Methods Instance Methods Concrete Methods

Modifier and Type	Method	Description
void	add(int index,E element)	Inserts the specified element at the specified position in this list.
boolean	add(E e)	Appends the specified element to the end of this list.
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.
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.
int	addAllAbsent(Collection<? extends E> c)	Appends all of the elements in the specified collection that are not already contained in this list, to the end of this list, in the order that they are returned by the specified collection's iterator.
boolean	addIfAbsent(E e)	Appends the element, if not present.
void	clear()	Removes all of the elements from this list.
Object	clone()	Returns a shallow copy of this list.
boolean	contains(Object o)	Returns true if this list contains the specified element.
boolean	containsAll(Collection<?> c)	Returns true if this list contains all of the elements of the specified collection.
boolean	equals(Object o)	Compares the specified object with this list for equality.
void	forEach(Consumer<? super E> action)	Performs the given action for each element of the Iterable until all elements have been processed or the action throws an exception.
E	get(int index)	Returns the element at the specified position in this list.
int	hashCode()	Returns the hash code value for this list.
int	indexOf(E e, int index)	Returns the index of the first occurrence of the specified element in this list, searching forwards from index, or returns -1 if the element is not found.
int	indexOf(Object o)	Returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element.
boolean	isEmpty()	Returns true if this list contains no elements.
Iterator<E>	iterator()	Returns an iterator over the elements in this list in proper sequence.
int	lastIndexOf(E e, int index)	Returns the index of the last occurrence of the specified element in this list, searching backwards from index, or returns -1 if the element is not found.
int	lastIndexOf(Object o)	Returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element.
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 list.
boolean	remove(Object o)	Removes the first occurrence of the specified element from this list, if it is present.
boolean	removeAll(Collection<?> c)	Removes from this list all of its elements that are contained in the specified collection.
boolean	removeIf(Predicate<? super E> filter)	Removes all of the elements of this collection that satisfy the given predicate.
void	replaceAll(UnaryOperator<E> operator)	Replaces each element of this list with the result of applying the operator to that element.
boolean	retainAll(Collection<?> c)	Retains only the elements in this list that are contained in the specified collection.
E	set(int index,E element)	Replaces the element at the specified position in this list with the specified element.
int	size()	Returns the number of elements in this list.
void	sort(Comparator<? super E> c)	Sorts this list according to the order induced by the specifiedComparator.
Spliterator<E>	spliterator()	Returns a Spliterator over the elements in this list.
List<E>	subList(int fromIndex, int toIndex)	Returns a view of the portion of this list betweenfromIndex, inclusive, and toIndex, exclusive.
Object[]	toArray()	Returns an array containing all of the elements in this list in proper sequence (from first to last element).
T[]	toArray(T[] a)	Returns an array containing all of the elements in this list in proper sequence (from first to last element); the runtime type of the returned array is that of the specified array.
String	toString()	Returns a string representation of this list.

   * ### Methods inherited from interface java.util.[Collection](../../../java/util/Collection.html "interface in java.util")  
   `[parallelStream](../../../java/util/Collection.html#parallelStream--), [stream](../../../java/util/Collection.html#stream--)`  
   * ### Methods inherited from interface java.util.[List](../../../java/util/List.html "interface in java.util")  
   `[of](../../../java/util/List.html#of--), [of](../../../java/util/List.html#of-E-), [of](../../../java/util/List.html#of-E...-), [of](../../../java/util/List.html#of-E-E-), [of](../../../java/util/List.html#of-E-E-E-), [of](../../../java/util/List.html#of-E-E-E-E-), [of](../../../java/util/List.html#of-E-E-E-E-E-), [of](../../../java/util/List.html#of-E-E-E-E-E-E-), [of](../../../java/util/List.html#of-E-E-E-E-E-E-E-), [of](../../../java/util/List.html#of-E-E-E-E-E-E-E-E-), [of](../../../java/util/List.html#of-E-E-E-E-E-E-E-E-E-), [of](../../../java/util/List.html#of-E-E-E-E-E-E-E-E-E-E-)`  
   * ### Methods inherited from class java.lang.[Object](../../../java/lang/Object.html "class in java.lang")  
   `[finalize](../../../java/lang/Object.html#finalize--), [getClass](../../../java/lang/Object.html#getClass--), [notify](../../../java/lang/Object.html#notify--), [notifyAll](../../../java/lang/Object.html#notifyAll--), [wait](../../../java/lang/Object.html#wait--), [wait](../../../java/lang/Object.html#wait-long-), [wait](../../../java/lang/Object.html#wait-long-int-)`

Constructor Detail

 * #### CopyOnWriteArrayList  
 public CopyOnWriteArrayList()  
 Creates an empty list.  
 * #### CopyOnWriteArrayList  
 public CopyOnWriteArrayList([Collection](../../../java/util/Collection.html "interface in java.util")<? extends [E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")> c)  
 Creates a list containing the elements of the specified collection, in the order they are returned by the collection's iterator.  
 Parameters:  
 `c` \- the collection of initially held elements  
 Throws:  
 `[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang")` \- if the specified collection is null  
 * #### CopyOnWriteArrayList  
 public CopyOnWriteArrayList([E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")[] toCopyIn)  
 Creates a list holding a copy of the given array.  
 Parameters:  
 `toCopyIn` \- the array (a copy of this array is used as the internal array)  
 Throws:  
 `[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang")` \- if the specified array is null

Method Detail

* #### size  
public int size()  
Returns the number of elements in this list.  
Specified by:  
`[size](../../../java/util/Collection.html#size--)` in interface `[Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Specified by:  
`[size](../../../java/util/List.html#size--)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Returns:  
the number of elements in this list  
* #### isEmpty  
public boolean isEmpty()  
Returns `true` if this list contains no elements.  
Specified by:  
`[isEmpty](../../../java/util/Collection.html#isEmpty--)` in interface `[Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Specified by:  
`[isEmpty](../../../java/util/List.html#isEmpty--)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Returns:  
`true` if this list contains no elements  
* #### contains  
public boolean contains([Object](../../../java/lang/Object.html "class in java.lang") o)  
Returns `true` if this list contains the specified element. More formally, returns `true` if and only if this list contains at least one element `e` such that `Objects.equals(o, e)`.  
Specified by:  
`[contains](../../../java/util/Collection.html#contains-java.lang.Object-)` in interface `[Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Specified by:  
`[contains](../../../java/util/List.html#contains-java.lang.Object-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`o` \- element whose presence in this list is to be tested  
Returns:  
`true` if this list contains the specified element  
* #### indexOf  
public int indexOf([Object](../../../java/lang/Object.html "class in java.lang") o)  
Returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element. More formally, returns the lowest index `i` such that`Objects.equals(o, get(i))`, or -1 if there is no such index.  
Specified by:  
`[indexOf](../../../java/util/List.html#indexOf-java.lang.Object-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`o` \- element to search for  
Returns:  
the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element  
* #### indexOf  
public int indexOf([E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList") e,  
                   int index)  
Returns the index of the first occurrence of the specified element in this list, searching forwards from `index`, or returns -1 if the element is not found. More formally, returns the lowest index `i` such that`i >= index && Objects.equals(get(i), e)`, or -1 if there is no such index.  
Parameters:  
`e` \- element to search for  
`index` \- index to start searching from  
Returns:  
the index of the first occurrence of the element in this list at position `index` or later in the list;`-1` if the element is not found.  
Throws:  
`[IndexOutOfBoundsException](../../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the specified index is negative  
* #### lastIndexOf  
public int lastIndexOf([Object](../../../java/lang/Object.html "class in java.lang") o)  
Returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element. More formally, returns the highest index `i` such that`Objects.equals(o, get(i))`, or -1 if there is no such index.  
Specified by:  
`[lastIndexOf](../../../java/util/List.html#lastIndexOf-java.lang.Object-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`o` \- element to search for  
Returns:  
the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element  
* #### lastIndexOf  
public int lastIndexOf([E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList") e,  
                       int index)  
Returns the index of the last occurrence of the specified element in this list, searching backwards from `index`, or returns -1 if the element is not found. More formally, returns the highest index `i` such that`i <= index && Objects.equals(get(i), e)`, or -1 if there is no such index.  
Parameters:  
`e` \- element to search for  
`index` \- index to start searching backwards from  
Returns:  
the index of the last occurrence of the element at position less than or equal to `index` in this list; -1 if the element is not found.  
Throws:  
`[IndexOutOfBoundsException](../../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the specified index is greater than or equal to the current size of this list  
* #### clone  
public [Object](../../../java/lang/Object.html "class in java.lang") clone()  
Returns a shallow copy of this list. (The elements themselves are not copied.)  
Overrides:  
`[clone](../../../java/lang/Object.html#clone--)` in class `[Object](../../../java/lang/Object.html "class in java.lang")`  
Returns:  
a clone of this list  
See Also:  
[Cloneable](../../../java/lang/Cloneable.html "interface in java.lang")  
* #### toArray  
public [Object](../../../java/lang/Object.html "class in java.lang")[] toArray()  
Returns an array containing all of the elements in this list in proper sequence (from first to last element).  
The returned array will be "safe" in that no references to it are maintained by this list. (In other words, this method must allocate a new array). The caller is thus free to modify the returned array.  
This method acts as bridge between array-based and collection-based APIs.  
Specified by:  
`[toArray](../../../java/util/Collection.html#toArray--)` in interface `[Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Specified by:  
`[toArray](../../../java/util/List.html#toArray--)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Returns:  
an array containing all the elements in this list  
See Also:  
[Arrays.asList(Object\[\])](../../../java/util/Arrays.html#asList-T...-)  
* #### toArray  
public <T> T[] toArray(T[] a)  
Returns an array containing all of the elements in this list in proper sequence (from first to last element); the runtime type of the returned array is that of the specified array. If the list 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 list.  
If this list fits in the specified array with room to spare (i.e., the array has more elements than this list), the element in the array immediately following the end of the list is set to`null`. (This is useful in determining the length of this list _only_ if the caller knows that this list does not contain any null elements.)  
Like the [toArray()](../../../java/util/concurrent/CopyOnWriteArrayList.html#toArray--) method, this method acts as bridge between array-based and collection-based APIs. Further, this method allows precise control over the runtime type of the output array, and may, under certain circumstances, be used to save allocation costs.  
Suppose `x` is a list known to contain only strings. The following code can be used to dump the list into a newly allocated array of `String`:  
 `String[] y = x.toArray(new String[0]);`  
 Note that `toArray(new Object[0])` is identical in function to`toArray()`.  
Specified by:  
`[toArray](../../../java/util/Collection.html#toArray-T:A-)` in interface `[Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Specified by:  
`[toArray](../../../java/util/List.html#toArray-T:A-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Type Parameters:  
`T` \- the runtime type of the array to contain the collection  
Parameters:  
`a` \- the array into which the elements of the list 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 all the elements in this list  
Throws:  
`[ArrayStoreException](../../../java/lang/ArrayStoreException.html "class in java.lang")` \- if the runtime type of the specified array is not a supertype of the runtime type of every element in this list  
`[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang")` \- if the specified array is null  
* #### get  
public [E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList") get(int index)  
Returns the element at the specified position in this list.  
Specified by:  
`[get](../../../java/util/List.html#get-int-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`index` \- index of the element to return  
Returns:  
the element at the specified position in this list  
Throws:  
`[IndexOutOfBoundsException](../../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the index is out of range (`index < 0 || index >= size()`)  
* #### set  
public [E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList") set(int index,  
             [E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList") element)  
Replaces the element at the specified position in this list with the specified element.  
Specified by:  
`[set](../../../java/util/List.html#set-int-E-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`index` \- index of the element to replace  
`element` \- element to be stored at the specified position  
Returns:  
the element previously at the specified position  
Throws:  
`[IndexOutOfBoundsException](../../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the index is out of range (`index < 0 || index >= size()`)  
* #### add  
public boolean add([E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList") e)  
Appends the specified element to the end of this list.  
Specified by:  
`[add](../../../java/util/Collection.html#add-E-)` in interface `[Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Specified by:  
`[add](../../../java/util/List.html#add-E-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`e` \- element to be appended to this list  
Returns:  
`true` (as specified by [Collection.add(E)](../../../java/util/Collection.html#add-E-))  
* #### add  
public void add(int index,  
                [E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList") element)  
Inserts the specified element at the specified position in this list. Shifts the element currently at that position (if any) and any subsequent elements to the right (adds one to their indices).  
Specified by:  
`[add](../../../java/util/List.html#add-int-E-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`index` \- index at which the specified element is to be inserted  
`element` \- element to be inserted  
Throws:  
`[IndexOutOfBoundsException](../../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the index is out of range (`index < 0 || index > size()`)  
* #### remove  
public [E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList") remove(int index)  
Removes the element at the specified position in this list. Shifts any subsequent elements to the left (subtracts one from their indices). Returns the element that was removed from the list.  
Specified by:  
`[remove](../../../java/util/List.html#remove-int-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`index` \- the index of the element to be removed  
Returns:  
the element previously at the specified position  
Throws:  
`[IndexOutOfBoundsException](../../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the index is out of range (`index < 0 || index >= size()`)  
* #### remove  
public boolean remove([Object](../../../java/lang/Object.html "class in java.lang") o)  
Removes the first occurrence of the specified element from this list, if it is present. If this list does not contain the element, it is unchanged. More formally, removes the element with the lowest index`i` such that `Objects.equals(o, get(i))` (if such an element exists). Returns `true` if this list contained the specified element (or equivalently, if this list changed as a result of the call).  
Specified by:  
`[remove](../../../java/util/Collection.html#remove-java.lang.Object-)` in interface `[Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Specified by:  
`[remove](../../../java/util/List.html#remove-java.lang.Object-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`o` \- element to be removed from this list, if present  
Returns:  
`true` if this list contained the specified element  
* #### addIfAbsent  
public boolean addIfAbsent([E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList") e)  
Appends the element, if not present.  
Parameters:  
`e` \- element to be added to this list, if absent  
Returns:  
`true` if the element was added  
* #### containsAll  
public boolean containsAll([Collection](../../../java/util/Collection.html "interface in java.util")<?> c)  
Returns `true` if this list contains all of the elements of the specified collection.  
Specified by:  
`[containsAll](../../../java/util/Collection.html#containsAll-java.util.Collection-)` in interface `[Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Specified by:  
`[containsAll](../../../java/util/List.html#containsAll-java.util.Collection-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`c` \- collection to be checked for containment in this list  
Returns:  
`true` if this list contains all of the elements of the specified collection  
Throws:  
`[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang")` \- if the specified collection is null  
See Also:  
[contains(Object)](../../../java/util/concurrent/CopyOnWriteArrayList.html#contains-java.lang.Object-)  
* #### removeAll  
public boolean removeAll([Collection](../../../java/util/Collection.html "interface in java.util")<?> c)  
Removes from this list all of its elements that are contained in the specified collection. This is a particularly expensive operation in this class because of the need for an internal temporary array.  
Specified by:  
`[removeAll](../../../java/util/Collection.html#removeAll-java.util.Collection-)` in interface `[Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Specified by:  
`[removeAll](../../../java/util/List.html#removeAll-java.util.Collection-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`c` \- collection containing elements to be removed from this list  
Returns:  
`true` if this list changed as a result of the call  
Throws:  
`[ClassCastException](../../../java/lang/ClassCastException.html "class in java.lang")` \- if the class of an element of this list is incompatible with the specified collection ([optional](../../../java/util/Collection.html#optional-restrictions))  
`[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang")` \- if this list contains a null element and the specified collection does not permit null elements ([optional](../../../java/util/Collection.html#optional-restrictions)), or if the specified collection is null  
See Also:  
[remove(Object)](../../../java/util/concurrent/CopyOnWriteArrayList.html#remove-java.lang.Object-)  
* #### retainAll  
public boolean retainAll([Collection](../../../java/util/Collection.html "interface in java.util")<?> c)  
Retains only the elements in this list that are contained in the specified collection. In other words, removes from this list all of its elements that are not contained in the specified collection.  
Specified by:  
`[retainAll](../../../java/util/Collection.html#retainAll-java.util.Collection-)` in interface `[Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Specified by:  
`[retainAll](../../../java/util/List.html#retainAll-java.util.Collection-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`c` \- collection containing elements to be retained in this list  
Returns:  
`true` if this list changed as a result of the call  
Throws:  
`[ClassCastException](../../../java/lang/ClassCastException.html "class in java.lang")` \- if the class of an element of this list is incompatible with the specified collection ([optional](../../../java/util/Collection.html#optional-restrictions))  
`[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang")` \- if this list contains a null element and the specified collection does not permit null elements ([optional](../../../java/util/Collection.html#optional-restrictions)), or if the specified collection is null  
See Also:  
[remove(Object)](../../../java/util/concurrent/CopyOnWriteArrayList.html#remove-java.lang.Object-)  
* #### addAllAbsent  
public int addAllAbsent([Collection](../../../java/util/Collection.html "interface in java.util")<? extends [E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")> c)  
Appends all of the elements in the specified collection that are not already contained in this list, to the end of this list, in the order that they are returned by the specified collection's iterator.  
Parameters:  
`c` \- collection containing elements to be added to this list  
Returns:  
the number of elements added  
Throws:  
`[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang")` \- if the specified collection is null  
See Also:  
[addIfAbsent(Object)](../../../java/util/concurrent/CopyOnWriteArrayList.html#addIfAbsent-E-)  
* #### clear  
public void clear()  
Removes all of the elements from this list. The list will be empty after this call returns.  
Specified by:  
`[clear](../../../java/util/Collection.html#clear--)` in interface `[Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Specified by:  
`[clear](../../../java/util/List.html#clear--)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
* #### addAll  
public boolean addAll([Collection](../../../java/util/Collection.html "interface in java.util")<? extends [E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")> 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.  
Specified by:  
`[addAll](../../../java/util/Collection.html#addAll-java.util.Collection-)` in interface `[Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Specified by:  
`[addAll](../../../java/util/List.html#addAll-java.util.Collection-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`c` \- collection containing elements to be added to this list  
Returns:  
`true` if this list changed as a result of the call  
Throws:  
`[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang")` \- if the specified collection is null  
See Also:  
[add(Object)](../../../java/util/concurrent/CopyOnWriteArrayList.html#add-E-)  
* #### addAll  
public boolean addAll(int index,  
                      [Collection](../../../java/util/Collection.html "interface in java.util")<? extends [E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")> c)  
Inserts all of the elements in the specified collection into this list, starting 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 this list in the order that they are returned by the specified collection's iterator.  
Specified by:  
`[addAll](../../../java/util/List.html#addAll-int-java.util.Collection-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`index` \- index at which to insert the first element from the specified collection  
`c` \- collection containing elements to be added to this list  
Returns:  
`true` if this list changed as a result of the call  
Throws:  
`[IndexOutOfBoundsException](../../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the index is out of range (`index < 0 || index > size()`)  
`[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang")` \- if the specified collection is null  
See Also:  
[add(int,Object)](../../../java/util/concurrent/CopyOnWriteArrayList.html#add-int-E-)  
* #### forEach  
public void forEach([Consumer](../../../java/util/function/Consumer.html "interface in java.util.function")<? super [E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")> action)  
Description copied from interface: `[Iterable](../../../java/lang/Iterable.html#forEach-java.util.function.Consumer-)`  
Performs the given action for each element of the `Iterable` until all elements have been processed or the action throws an exception. Actions are performed in the order of iteration, if that order is specified. Exceptions thrown by the action are relayed to the caller.  
 The behavior of this method is unspecified if the action performs side-effects that modify the underlying source of elements, unless an overriding class has specified a concurrent modification policy.  
Specified by:  
`[forEach](../../../java/lang/Iterable.html#forEach-java.util.function.Consumer-)` in interface `[Iterable](../../../java/lang/Iterable.html "interface in java.lang")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`action` \- The action to be performed for each element  
Throws:  
`[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang")` \- if the specified action is null  
* #### removeIf  
public boolean removeIf([Predicate](../../../java/util/function/Predicate.html "interface in java.util.function")<? super [E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")> filter)  
Description copied from interface: `[Collection](../../../java/util/Collection.html#removeIf-java.util.function.Predicate-)`  
Removes all of the elements of this collection that satisfy the given predicate. Errors or runtime exceptions thrown during iteration or by the predicate are relayed to the caller.  
Specified by:  
`[removeIf](../../../java/util/Collection.html#removeIf-java.util.function.Predicate-)` in interface `[Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`filter` \- a predicate which returns `true` for elements to be removed  
Returns:  
`true` if any elements were removed  
Throws:  
`[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang")` \- if the specified filter is null  
* #### replaceAll  
public void replaceAll([UnaryOperator](../../../java/util/function/UnaryOperator.html "interface in java.util.function")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")> operator)  
Description copied from interface: `[List](../../../java/util/List.html#replaceAll-java.util.function.UnaryOperator-)`  
Replaces each element of this list with the result of applying the operator to that element. Errors or runtime exceptions thrown by the operator are relayed to the caller.  
Specified by:  
`[replaceAll](../../../java/util/List.html#replaceAll-java.util.function.UnaryOperator-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`operator` \- the operator to apply to each element  
* #### sort  
public void sort([Comparator](../../../java/util/Comparator.html "interface in java.util")<? super [E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")> c)  
Description copied from interface: `[List](../../../java/util/List.html#sort-java.util.Comparator-)`  
Sorts this list according to the order induced by the specified[Comparator](../../../java/util/Comparator.html "interface in java.util").  
All elements in this list must be _mutually comparable_ using the specified comparator (that is, `c.compare(e1, e2)` must not throw a `ClassCastException` for any elements `e1` and `e2` in the list).  
If the specified comparator is `null` then all elements in this list must implement the [Comparable](../../../java/lang/Comparable.html "interface in java.lang") interface and the elements'[natural ordering](../../../java/lang/Comparable.html "interface in java.lang") should be used.  
This list must be modifiable, but need not be resizable.  
Specified by:  
`[sort](../../../java/util/List.html#sort-java.util.Comparator-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`c` \- the `Comparator` used to compare list elements. A `null` value indicates that the elements'[natural ordering](../../../java/lang/Comparable.html "interface in java.lang") should be used  
* #### toString  
public [String](../../../java/lang/String.html "class in java.lang") toString()  
Returns a string representation of this list. The string representation consists of the string representations of the list's elements in the order they are returned by its iterator, enclosed in square brackets (`"[]"`). Adjacent elements are separated by the characters `", "` (comma and space). Elements are converted to strings as by [String.valueOf(Object)](../../../java/lang/String.html#valueOf-java.lang.Object-).  
Overrides:  
`[toString](../../../java/lang/Object.html#toString--)` in class `[Object](../../../java/lang/Object.html "class in java.lang")`  
Returns:  
a string representation of this list  
* #### equals  
public boolean equals([Object](../../../java/lang/Object.html "class in java.lang") o)  
Compares the specified object with this list for equality. Returns `true` if the specified object is the same object as this object, or if it is also a [List](../../../java/util/List.html "interface in java.util") and the sequence of elements returned by an [iterator](../../../java/util/List.html#iterator--) over the specified list is the same as the sequence returned by an iterator over this list. The two sequences are considered to be the same if they have the same length and corresponding elements at the same position in the sequence are _equal_. Two elements `e1` and `e2` are considered_equal_ if `Objects.equals(e1, e2)`.  
Specified by:  
`[equals](../../../java/util/Collection.html#equals-java.lang.Object-)` in interface `[Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Specified by:  
`[equals](../../../java/util/List.html#equals-java.lang.Object-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Overrides:  
`[equals](../../../java/lang/Object.html#equals-java.lang.Object-)` in class `[Object](../../../java/lang/Object.html "class in java.lang")`  
Parameters:  
`o` \- the object to be compared for equality with this list  
Returns:  
`true` if the specified object is equal to this list  
See Also:  
[Object.hashCode()](../../../java/lang/Object.html#hashCode--), [HashMap](../../../java/util/HashMap.html "class in java.util")  
* #### hashCode  
public int hashCode()  
Returns the hash code value for this list.  
This implementation uses the definition in [List.hashCode()](../../../java/util/List.html#hashCode--).  
Specified by:  
`[hashCode](../../../java/util/Collection.html#hashCode--)` in interface `[Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Specified by:  
`[hashCode](../../../java/util/List.html#hashCode--)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Overrides:  
`[hashCode](../../../java/lang/Object.html#hashCode--)` in class `[Object](../../../java/lang/Object.html "class in java.lang")`  
Returns:  
the hash code value for this list  
See Also:  
[Object.equals(java.lang.Object)](../../../java/lang/Object.html#equals-java.lang.Object-), [System.identityHashCode(java.lang.Object)](../../../java/lang/System.html#identityHashCode-java.lang.Object-)  
* #### iterator  
public [Iterator](../../../java/util/Iterator.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")> iterator()  
Returns an iterator over the elements in this list in proper sequence.  
The returned iterator provides a snapshot of the state of the list when the iterator was constructed. No synchronization is needed while traversing the iterator. The iterator does _NOT_ support the`remove` method.  
Specified by:  
`[iterator](../../../java/util/Collection.html#iterator--)` in interface `[Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Specified by:  
`[iterator](../../../java/lang/Iterable.html#iterator--)` in interface `[Iterable](../../../java/lang/Iterable.html "interface in java.lang")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Specified by:  
`[iterator](../../../java/util/List.html#iterator--)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Returns:  
an iterator over the elements in this list in proper sequence  
* #### listIterator  
public [ListIterator](../../../java/util/ListIterator.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")> listIterator()  
Returns a list iterator over the elements in this list (in proper sequence).  
The returned iterator provides a snapshot of the state of the list when the iterator was constructed. No synchronization is needed while traversing the iterator. The iterator does _NOT_ support the`remove`, `set` or `add` methods.  
Specified by:  
`[listIterator](../../../java/util/List.html#listIterator--)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Returns:  
a list iterator over the elements in this list (in proper sequence)  
* #### listIterator  
public [ListIterator](../../../java/util/ListIterator.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")> listIterator(int index)  
Returns a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list. The specified index indicates the first element that would be returned by an initial call to [next](../../../java/util/ListIterator.html#next--). An initial call to [previous](../../../java/util/ListIterator.html#previous--) would return the element with the specified index minus one.  
The returned iterator provides a snapshot of the state of the list when the iterator was constructed. No synchronization is needed while traversing the iterator. The iterator does _NOT_ support the`remove`, `set` or `add` methods.  
Specified by:  
`[listIterator](../../../java/util/List.html#listIterator-int-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`index` \- index of the first element to be returned from the list iterator (by a call to [next](../../../java/util/ListIterator.html#next--))  
Returns:  
a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list  
Throws:  
`[IndexOutOfBoundsException](../../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the index is out of range (`index < 0 || index > size()`)  
* #### spliterator  
public [Spliterator](../../../java/util/Spliterator.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")> spliterator()  
Specified by:  
`[spliterator](../../../java/util/Collection.html#spliterator--)` in interface `[Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Specified by:  
`[spliterator](../../../java/lang/Iterable.html#spliterator--)` in interface `[Iterable](../../../java/lang/Iterable.html "interface in java.lang")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Specified by:  
`[spliterator](../../../java/util/List.html#spliterator--)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Returns:  
a `Spliterator` over the elements in this list  
Since:  
1.8  
* #### subList  
public [List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")> subList(int fromIndex,  
                       int toIndex)  
Returns a view of the portion of this list between`fromIndex`, inclusive, and `toIndex`, exclusive. The returned list is backed by this list, so changes in the returned list are reflected in this list.  
The semantics of the list returned by this method become undefined if the backing list (i.e., this list) is modified in any way other than via the returned list.  
Specified by:  
`[subList](../../../java/util/List.html#subList-int-int-)` in interface `[List](../../../java/util/List.html "interface in java.util")<[E](../../../java/util/concurrent/CopyOnWriteArrayList.html "type parameter in CopyOnWriteArrayList")>`  
Parameters:  
`fromIndex` \- low endpoint (inclusive) of the subList  
`toIndex` \- high endpoint (exclusive) of the subList  
Returns:  
a view of the specified range within this list  
Throws:  
`[IndexOutOfBoundsException](../../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- for an illegal endpoint index value (`fromIndex < 0 || toIndex > size || fromIndex > toIndex`)

CopyOnWriteArrayList (Java SE 9 & JDK 9 ) (original) (raw)

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