java.util.concurrent

Class LinkedBlockingDeque<E>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractQueue<E>

java.util.concurrent.LinkedBlockingDeque<E>

Type Parameters:

E - the type of elements held in this collection

All Implemented Interfaces:

Serializable, Iterable<E>, Collection<E>, BlockingDeque<E>, BlockingQueue<E>, Deque<E>, Queue<E>

public class LinkedBlockingDeque<E>
extends AbstractQueue<E>
implements BlockingDeque<E>, Serializable

An optionally-bounded blocking deque based on linked nodes.

The optional capacity bound constructor argument serves as a way to prevent excessive expansion. The capacity, if unspecified, is equal to Integer.MAX_VALUE. Linked nodes are dynamically created upon each insertion unless this would bring the deque above capacity.

Most operations run in constant time (ignoring time spent blocking). Exceptions include remove, removeFirstOccurrence, removeLastOccurrence, contains, iterator.remove(), and the bulk operations, all of which run in linear time.

This class and its iterator implement all of the optional methods of the Collection and Iterator interfaces.

This class is a member of the Java Collections Framework.

Since:

1.6

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
LinkedBlockingDeque() Creates a LinkedBlockingDeque with a capacity of Integer.MAX_VALUE.
LinkedBlockingDeque(Collection<? extends E> c) Creates a LinkedBlockingDeque with a capacity of Integer.MAX_VALUE, initially containing the elements of the given collection, added in traversal order of the collection's iterator.
LinkedBlockingDeque(int capacity) Creates a LinkedBlockingDeque with the given (fixed) capacity.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	add(E e) Inserts the specified element at the end of this deque unless it would violate capacity restrictions.
void	addFirst(E e) Inserts the specified element at the front of this deque if it is possible to do so immediately without violating capacity restrictions, throwing an IllegalStateException if no space is currently available.
void	addLast(E e) Inserts the specified element at the end of this deque if it is possible to do so immediately without violating capacity restrictions, throwing an IllegalStateException if no space is currently available.
void	clear() Atomically removes all of the elements from this deque.
boolean	contains(Object o) Returns true if this deque contains the specified element.
Iterator<E>	descendingIterator() Returns an iterator over the elements in this deque in reverse sequential order.
int	drainTo(Collection<? super E> c) Removes all available elements from this queue and adds them to the given collection.
int	drainTo(Collection<? super E> c, int maxElements) Removes at most the given number of available elements from this queue and adds them to the given collection.
E	element() Retrieves, but does not remove, the head of the queue represented by this deque.
E	getFirst() Retrieves, but does not remove, the first element of this deque.
E	getLast() Retrieves, but does not remove, the last element of this deque.
Iterator<E>	iterator() Returns an iterator over the elements in this deque in proper sequence.
boolean	offer(E e) Inserts the specified element into the queue represented by this deque (in other words, at the tail of this deque) if it is possible to do so immediately without violating capacity restrictions, returning true upon success and false if no space is currently available.
boolean	offer(E e, long timeout, TimeUnit unit) Inserts the specified element into the queue represented by this deque (in other words, at the tail of this deque), waiting up to the specified wait time if necessary for space to become available.
boolean	offerFirst(E e) Inserts the specified element at the front of this deque if it is possible to do so immediately without violating capacity restrictions, returning true upon success and false if no space is currently available.
boolean	offerFirst(E e, long timeout, TimeUnit unit) Inserts the specified element at the front of this deque, waiting up to the specified wait time if necessary for space to become available.
boolean	offerLast(E e) Inserts the specified element at the end of this deque if it is possible to do so immediately without violating capacity restrictions, returning true upon success and false if no space is currently available.
boolean	offerLast(E e, long timeout, TimeUnit unit) Inserts the specified element at the end of this deque, waiting up to the specified wait time if necessary for space to become available.
E	peek() Retrieves, but does not remove, the head of the queue represented by this deque (in other words, the first element of this deque), or returns null if this deque is empty.
E	peekFirst() Retrieves, but does not remove, the first element of this deque, or returns null if this deque is empty.
E	peekLast() Retrieves, but does not remove, the last element of this deque, or returns null if this deque is empty.
E	poll() Retrieves and removes the head of the queue represented by this deque (in other words, the first element of this deque), or returns null if this deque is empty.
E	poll(long timeout, TimeUnit unit) Retrieves and removes the head of the queue represented by this deque (in other words, the first element of this deque), waiting up to the specified wait time if necessary for an element to become available.
E	pollFirst() Retrieves and removes the first element of this deque, or returns null if this deque is empty.
E	pollFirst(long timeout, TimeUnit unit) Retrieves and removes the first element of this deque, waiting up to the specified wait time if necessary for an element to become available.
E	pollLast() Retrieves and removes the last element of this deque, or returns null if this deque is empty.
E	pollLast(long timeout, TimeUnit unit) Retrieves and removes the last element of this deque, waiting up to the specified wait time if necessary for an element to become available.
E	pop() Pops an element from the stack represented by this deque.
void	push(E e) Pushes an element onto the stack represented by this deque.
void	put(E e) Inserts the specified element into the queue represented by this deque (in other words, at the tail of this deque), waiting if necessary for space to become available.
void	putFirst(E e) Inserts the specified element at the front of this deque, waiting if necessary for space to become available.
void	putLast(E e) Inserts the specified element at the end of this deque, waiting if necessary for space to become available.
int	remainingCapacity() Returns the number of additional elements that this deque can ideally (in the absence of memory or resource constraints) accept without blocking.
E	remove() Retrieves and removes the head of the queue represented by this deque.
boolean	remove(Object o) Removes the first occurrence of the specified element from this deque.
E	removeFirst() Retrieves and removes the first element of this deque.
boolean	removeFirstOccurrence(Object o) Removes the first occurrence of the specified element from this deque.
E	removeLast() Retrieves and removes the last element of this deque.
boolean	removeLastOccurrence(Object o) Removes the last occurrence of the specified element from this deque.
int	size() Returns the number of elements in this deque.
E	take() Retrieves and removes the head of the queue represented by this deque (in other words, the first element of this deque), waiting if necessary until an element becomes available.
E	takeFirst() Retrieves and removes the first element of this deque, waiting if necessary until an element becomes available.
E	takeLast() Retrieves and removes the last element of this deque, waiting if necessary until an element becomes available.
Object[]	toArray() Returns an array containing all of the elements in this deque, in proper sequence (from first to last element).
<T> T[]	toArray(T[] a) Returns an array containing all of the elements in this deque, in proper sequence; the runtime type of the returned array is that of the specified array.
String	toString() Returns a string representation of this collection.

Methods inherited from class java.util.AbstractQueue

addAll

Methods inherited from class java.util.AbstractCollection

containsAll, isEmpty, removeAll, retainAll

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection

addAll, containsAll, equals, hashCode, isEmpty, removeAll, retainAll

Constructor Detail

LinkedBlockingDeque

public LinkedBlockingDeque()

Creates a LinkedBlockingDeque with a capacity of Integer.MAX_VALUE.

LinkedBlockingDeque

public LinkedBlockingDeque(int capacity)

Creates a LinkedBlockingDeque with the given (fixed) capacity.

Parameters:

capacity - the capacity of this deque

Throws:

IllegalArgumentException - if capacity is less than 1

LinkedBlockingDeque

public LinkedBlockingDeque(Collection<? extends E> c)

Creates a LinkedBlockingDeque with a capacity of Integer.MAX_VALUE, initially containing the elements of the given collection, added in traversal order of the collection's iterator.

Parameters:

c - the collection of elements to initially contain

Throws:

NullPointerException - if the specified collection or any of its elements are null

Method Detail

addFirst

public void addFirst(E e)

Description copied from interface: BlockingDeque

Inserts the specified element at the front of this deque if it is possible to do so immediately without violating capacity restrictions, throwing an IllegalStateException if no space is currently available. When using a capacity-restricted deque, it is generally preferable to use offerFirst.

Specified by:

addFirst in interface BlockingDeque<E>

Specified by:

addFirst in interface Deque<E>

Parameters:

e - the element to add

Throws:

IllegalStateException - if the element cannot be added at this time due to capacity restrictions

NullPointerException - if the specified element is null

addLast

public void addLast(E e)

Description copied from interface: BlockingDeque

Inserts the specified element at the end of this deque if it is possible to do so immediately without violating capacity restrictions, throwing an IllegalStateException if no space is currently available. When using a capacity-restricted deque, it is generally preferable to use offerLast.

Specified by:

addLast in interface BlockingDeque<E>

Specified by:

addLast in interface Deque<E>

Parameters:

e - the element to add

Throws:

IllegalStateException - if the element cannot be added at this time due to capacity restrictions

NullPointerException - if the specified element is null

offerFirst

public boolean offerFirst(E e)

Description copied from interface: BlockingDeque

Inserts the specified element at the front of this deque if it is possible to do so immediately without violating capacity restrictions, returning true upon success and false if no space is currently available. When using a capacity-restricted deque, this method is generally preferable to the addFirst method, which can fail to insert an element only by throwing an exception.

Specified by:

offerFirst in interface BlockingDeque<E>

Specified by:

offerFirst in interface Deque<