This documentation differs from the official API. Jadeite adds extra features to the API including: variable font sizes, constructions examples, placeholders for classes and methods, and auto-generated “See Also” links. Additionally it is missing some items found in standard Javadoc documentation, including: generics type information, “Deprecated” tags and comments, “See Also” links, along with other minor differences. Please send any questions or feedback to bam@cs.cmu.edu.


java.util.concurrent
interface BlockingDeque

All Superinterfaces:
Collection, Deque, Iterable, Queue
All Known Implementing Classes:
LinkedBlockingDeque

public interface BlockingDeque
extends Deque

A {@link Deque} that additionally supports blocking operations that wait for the deque to become non-empty when retrieving an element, and wait for space to become available in the deque when storing an element.

BlockingDeque methods come in four forms, with different ways of handling operations that cannot be satisfied immediately, but may be satisfied at some point in the future: one throws an exception, the second returns a special value (either null or false, depending on the operation), the third blocks the current thread indefinitely until the operation can succeed, and the fourth blocks for only a given maximum time limit before giving up. These methods are summarized in the following table:

First Element (Head)
Throws exception Special value Blocks Times out
Insert {@link #addFirst addFirst(e)} {@link #offerFirst(Object) offerFirst(e)} {@link #putFirst putFirst(e)} {@link #offerFirst(Object, long, TimeUnit) offerFirst(e, time, unit)}
Remove {@link #removeFirst removeFirst()} {@link #pollFirst pollFirst()} {@link #takeFirst takeFirst()} {@link #pollFirst(long, TimeUnit) pollFirst(time, unit)}
Examine {@link #getFirst getFirst()} {@link #peekFirst peekFirst()} not applicable not applicable
Last Element (Tail)
Throws exception Special value Blocks Times out
Insert {@link #addLast addLast(e)} {@link #offerLast(Object) offerLast(e)} {@link #putLast putLast(e)} {@link #offerLast(Object, long, TimeUnit) offerLast(e, time, unit)}
Remove {@link #removeLast() removeLast()} {@link #pollLast() pollLast()} {@link #takeLast takeLast()} {@link #pollLast(long, TimeUnit) pollLast(time, unit)}
Examine {@link #getLast getLast()} {@link #peekLast peekLast()} not applicable not applicable

Like any {@link BlockingQueue}, a BlockingDeque is thread safe, does not permit null elements, and may (or may not) be capacity-constrained.

A BlockingDeque implementation may be used directly as a FIFO BlockingQueue. The methods inherited from the BlockingQueue interface are precisely equivalent to BlockingDeque methods as indicated in the following table:

BlockingQueue Method Equivalent BlockingDeque Method
Insert
{@link #add(Object) add(e)} {@link #addLast(Object) addLast(e)}
{@link #offer(Object) offer(e)} {@link #offerLast(Object) offerLast(e)}
{@link #put(Object) put(e)} {@link #putLast(Object) putLast(e)}
{@link #offer(Object, long, TimeUnit) offer(e, time, unit)} {@link #offerLast(Object, long, TimeUnit) offerLast(e, time, unit)}
Remove
{@link #remove() remove()} {@link #removeFirst() removeFirst()}
{@link #poll() poll()} {@link #pollFirst() pollFirst()}
{@link #take() take()} {@link #takeFirst() takeFirst()}
{@link #poll(long, TimeUnit) poll(time, unit)} {@link #pollFirst(long, TimeUnit) pollFirst(time, unit)}
Examine
{@link #element() element()} {@link #getFirst() getFirst()}
{@link #peek() peek()} {@link #peekFirst() peekFirst()}

Memory consistency effects: As with other concurrent collections, actions in a thread prior to placing an object into a {@code BlockingDeque} happen-before actions subsequent to the access or removal of that element from the {@code BlockingDeque} in another thread.

This interface is a member of the Java Collections Framework.


Method Summary
 boolean

          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 throwing an IllegalStateException if no space is currently available.
 void

          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

          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.
 boolean

          Returns true if this deque contains the specified element.
 Object

          Retrieves, but does not remove, the head of the queue represented by this deque (in other words, the first element of this deque).
 Iterator

          Returns an iterator over the elements in this deque in proper sequence.
 boolean

          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(Object 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

          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(Object 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

          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(Object 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.
 Object

          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.
 Object

          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.
 Object
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.
 Object
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.
 Object
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.
 void

          Pushes an element onto the stack represented by this deque.
 void

          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

          Inserts the specified element at the front of this deque, waiting if necessary for space to become available.
 void

          Inserts the specified element at the end of this deque, waiting if necessary for space to become available.
 Object

          Retrieves and removes the head of the queue represented by this deque (in other words, the first element of this deque).
 boolean

          Removes the first occurrence of the specified element from this deque.
 boolean

          Removes the first occurrence of the specified element from this deque.
 boolean

          Removes the last occurrence of the specified element from this deque.
 int

          Returns the number of elements in this deque.
 Object

          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.
 Object

          Retrieves and removes the first element of this deque, waiting if necessary until an element becomes available.
 Object

          Retrieves and removes the last element of this deque, waiting if necessary until an element becomes available.
 
Methods inherited from class java.util.Deque
add, addFirst, addLast, contains, descendingIterator, element, getFirst, getLast, iterator, offer, offerFirst, offerLast, peek, peekFirst, peekLast, poll, pollFirst, pollLast, pop, push, remove, remove, removeFirst, removeFirstOccurrence, removeLast, removeLastOccurrence, size
 
Methods inherited from class java.util.Queue
add, element, offer, peek, poll, remove
 
Methods inherited from class java.util.Collection
add, addAll, clear, contains, containsAll, equals, hashCode, isEmpty, iterator, remove, removeAll, retainAll, size, toArray, toArray
 
Methods inherited from class java.lang.Iterable
iterator
 

Method Detail

add

public boolean add(Object 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 throwing an IllegalStateException if no space is currently available. When using a capacity-restricted deque, it is generally preferable to use {@link #offer(Object) offer}.

This method is equivalent to {@link #addLast(Object) addLast}.

Parameters:
e - the element to add

addFirst

public void addFirst(Object 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. When using a capacity-restricted deque, it is generally preferable to use {@link #offerFirst(Object) offerFirst}.

Parameters:
e - the element to add

addLast

public void addLast(Object 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. When using a capacity-restricted deque, it is generally preferable to use {@link #offerLast(Object) offerLast}.

Parameters:
e - the element to add

contains

public boolean contains(Object o)
Returns true if this deque contains the specified element. More formally, returns true if and only if this deque contains at least one element e such that o.equals(e).

Parameters:
o - object to be checked for containment in this deque
Returns:
true if this deque contains the specified element

element

public Object element()
Retrieves, but does not remove, the head of the queue represented by this deque (in other words, the first element of this deque). This method differs from {@link #peek peek} only in that it throws an exception if this deque is empty.

This method is equivalent to {@link #getFirst() getFirst}.

Returns:
the head of this deque

iterator

public Iterator iterator()
Returns an iterator over the elements in this deque in proper sequence. The elements will be returned in order from first (head) to last (tail).

Returns:
an iterator over the elements in this deque in proper sequence

offer

public boolean offer(Object 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. When using a capacity-restricted deque, this method is generally preferable to the {@link #add} method, which can fail to insert an element only by throwing an exception.

This method is equivalent to {@link #offerLast(Object) offerLast}.

Parameters:
e - the element to add

offer

public boolean offer(Object e,
                     long timeout,
                     TimeUnit unit)
              throws InterruptedException
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.

This method is equivalent to {@link #offerLast(Object,long,TimeUnit) offerLast}.

Parameters:
e - the element to add
timeout
unit
Returns:
true if the element was added to this deque, else false
Throws:
InterruptedException - {@inheritDoc}

offerFirst

public boolean offerFirst(Object 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. When using a capacity-restricted deque, this method is generally preferable to the {@link #addFirst(Object) addFirst} method, which can fail to insert an element only by throwing an exception.

Parameters:
e - the element to add

offerFirst

public boolean offerFirst(Object e,
                          long timeout,
                          TimeUnit unit)
                   throws InterruptedException
Inserts the specified element at the front of this deque, waiting up to the specified wait time if necessary for space to become available.

Parameters:
e - the element to add
timeout - how long to wait before giving up, in units of unit
unit - a TimeUnit determining how to interpret the timeout parameter
Returns:
true if successful, or false if the specified waiting time elapses before space is available
Throws:
InterruptedException - if interrupted while waiting

offerLast

public boolean offerLast(Object 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. When using a capacity-restricted deque, this method is generally preferable to the {@link #addLast(Object) addLast} method, which can fail to insert an element only by throwing an exception.

Parameters:
e - the element to add

offerLast

public boolean offerLast(Object e,
                         long timeout,
                         TimeUnit unit)
                  throws InterruptedException
Inserts the specified element at the end of this deque, waiting up to the specified wait time if necessary for space to become available.

Parameters:
e - the element to add
timeout - how long to wait before giving up, in units of unit
unit - a TimeUnit determining how to interpret the timeout parameter
Returns:
true if successful, or false if the specified waiting time elapses before space is available
Throws:
InterruptedException - if interrupted while waiting

peek

public Object 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.

This method is equivalent to {@link #peekFirst() peekFirst}.

Returns:
the head of this deque, or null if this deque is empty

poll

public Object 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.

This method is equivalent to {@link #pollFirst()}.

Returns:
the head of this deque, or null if this deque is empty

poll

public Object poll(long timeout,
                   TimeUnit unit)
            throws InterruptedException
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.

This method is equivalent to {@link #pollFirst(long,TimeUnit) pollFirst}.

Parameters:
timeout
unit
Returns:
the head of this deque, or null if the specified waiting time elapses before an element is available
Throws:
InterruptedException - if interrupted while waiting

pollFirst

public Object pollFirst(long timeout,
                        TimeUnit unit)
                 throws InterruptedException
Retrieves and removes the first element of this deque, waiting up to the specified wait time if necessary for an element to become available.

Parameters:
timeout - how long to wait before giving up, in units of unit
unit - a TimeUnit determining how to interpret the timeout parameter
Returns:
the head of this deque, or null if the specified waiting time elapses before an element is available
Throws:
InterruptedException - if interrupted while waiting

pollLast

public Object pollLast(long timeout,
                       TimeUnit unit)
                throws InterruptedException
Retrieves and removes the last element of this deque, waiting up to the specified wait time if necessary for an element to become available.

Parameters:
timeout - how long to wait before giving up, in units of unit
unit - a TimeUnit determining how to interpret the timeout parameter
Returns:
the tail of this deque, or null if the specified waiting time elapses before an element is available
Throws:
InterruptedException - if interrupted while waiting

push

public void push(Object e)
Pushes an element onto the stack represented by this deque. In other words, inserts the element at the front of this deque unless it would violate capacity restrictions.

This method is equivalent to {@link #addFirst(Object) addFirst}.

Parameters:
e

put

public void put(Object e)
         throws InterruptedException
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.

This method is equivalent to {@link #putLast(Object) putLast}.

Parameters:
e - the element to add
Throws:
InterruptedException - {@inheritDoc}

putFirst

public void putFirst(Object e)
              throws InterruptedException
Inserts the specified element at the front of this deque, waiting if necessary for space to become available.

Parameters:
e - the element to add
Throws:
InterruptedException - if interrupted while waiting

putLast

public void putLast(Object e)
             throws InterruptedException
Inserts the specified element at the end of this deque, waiting if necessary for space to become available.

Parameters:
e - the element to add
Throws:
InterruptedException - if interrupted while waiting

remove

public Object remove()
Retrieves and removes the head of the queue represented by this deque (in other words, the first element of this deque). This method differs from {@link #poll poll} only in that it throws an exception if this deque is empty.

This method is equivalent to {@link #removeFirst() removeFirst}.

Returns:
the head of the queue represented by this deque

remove

public boolean remove(Object o)
Removes the first occurrence of the specified element from this deque. If the deque does not contain the element, it is unchanged. More formally, removes the first element e such that o.equals(e) (if such an element exists). Returns true if this deque contained the specified element (or equivalently, if this deque changed as a result of the call).

This method is equivalent to {@link #removeFirstOccurrence(Object) removeFirstOccurrence}.

Parameters:
o - element to be removed from this deque, if present
Returns:
true if this deque changed as a result of the call

removeFirstOccurrence

public boolean removeFirstOccurrence(Object o)
Removes the first occurrence of the specified element from this deque. If the deque does not contain the element, it is unchanged. More formally, removes the first element e such that o.equals(e) (if such an element exists). Returns true if this deque contained the specified element (or equivalently, if this deque changed as a result of the call).

Parameters:
o - element to be removed from this deque, if present
Returns:
true if an element was removed as a result of this call

removeLastOccurrence

public boolean removeLastOccurrence(Object o)
Removes the last occurrence of the specified element from this deque. If the deque does not contain the element, it is unchanged. More formally, removes the last element e such that o.equals(e) (if such an element exists). Returns true if this deque contained the specified element (or equivalently, if this deque changed as a result of the call).

Parameters:
o - element to be removed from this deque, if present
Returns:
true if an element was removed as a result of this call

size

public int size()
Returns the number of elements in this deque.

Returns:
the number of elements in this deque

take

public Object take()
            throws InterruptedException
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.

This method is equivalent to {@link #takeFirst() takeFirst}.

Returns:
the head of this deque
Throws:
InterruptedException - if interrupted while waiting

takeFirst

public Object takeFirst()
                 throws InterruptedException
Retrieves and removes the first element of this deque, waiting if necessary until an element becomes available.

Returns:
the head of this deque
Throws:
InterruptedException - if interrupted while waiting

takeLast

public Object takeLast()
                throws InterruptedException
Retrieves and removes the last element of this deque, waiting if necessary until an element becomes available.

Returns:
the tail of this deque
Throws:
InterruptedException - if interrupted while waiting


This documentation differs from the official API. Jadeite adds extra features to the API including: variable font sizes, constructions examples, placeholders for classes and methods, and auto-generated “See Also” links. Additionally it is missing some items found in standard Javadoc documentation, including: generics type information, “Deprecated” tags and comments, “See Also” links, along with other minor differences. Please send any questions or feedback to bam@cs.cmu.edu.
This page displays the Jadeite version of the documention, which is derived from the offical documentation that contains this copyright notice:
Copyright 2008 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.
The official Sun™ documentation can be found here at http://java.sun.com/javase/6/docs/api/.