程序包 java.util.concurrent

接口 BlockingDeque<E>

类型参数:

E - the type of elements held in this collection

所有超级接口:

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

所有已知实现类:

LinkedBlockingDeque

public interface BlockingDeque<E>
extends BlockingQueue<E>, Deque<E>

A 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:

Summary of BlockingDeque methods

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

Like any 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:

Comparison of BlockingQueue and BlockingDeque methods

BlockingQueue Method	Equivalent BlockingDeque Method
Insert
add(e)	addLast(e)
offer(e)	offerLast(e)
put(e)	putLast(e)
offer(e, time, unit)	offerLast(e, time, unit)
Remove
remove()	removeFirst()
poll()	pollFirst()
take()	takeFirst()
poll(time, unit)	pollFirst(time, unit)
Examine
element()	getFirst()
peek()	peekFirst()

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

This interface is a member of the Java Collections Framework.

从以下版本开始:

1.6

方法概要

限定符和类型	方法	说明
boolean	add(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 throwing an IllegalStateException if no space is currently available.
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.
boolean	contains(Object o)	Returns true if this deque contains the specified element.
E	element()	Retrieves, but does not remove, the head of the queue represented by this deque (in other words, the first 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	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(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(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	push(E e)	Pushes an element onto the stack represented by this deque (in other words, at the head 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	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.
E	remove()	Retrieves and removes the head of the queue represented by this deque (in other words, the first element of this deque).
boolean	remove(Object o)	Removes the first occurrence of the specified element from this deque.
boolean	removeFirstOccurrence(Object o)	Removes the first occurrence of the specified element from 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.

从接口继承的方法 java.util.concurrent.BlockingQueue

drainTo, drainTo, remainingCapacity

从接口继承的方法 java.util.Collection

addAll, clear, containsAll, equals, hashCode, isEmpty, parallelStream, removeAll, removeIf, retainAll, spliterator, stream, toArray, toArray

从接口继承的方法 java.util.Deque

descendingIterator, getFirst, getLast, peekFirst, peekLast, pollFirst, pollLast, pop, removeFirst, removeLast

从接口继承的方法 java.lang.Iterable

forEach

方法详细资料

addFirst

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. When using a capacity-restricted deque, it is generally preferable to use offerFirst.

指定者:

addFirst 在接口中 Deque<E>

参数:

e - the element to add

抛出:

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

ClassCastException - if the class of the specified element prevents it from being added to this deque

NullPointerException - if the specified element is null

IllegalArgumentException - if some property of the specified element prevents it from being added to this deque

addLast

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. When using a capacity-restricted deque, it is generally preferable to use offerLast.

指定者:

addLast 在接口中 Deque<E>

参数:

e - the element to add

抛出:

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

ClassCastException - if the class of the specified element prevents it from being added to this deque

NullPointerException - if the specified element is null

IllegalArgumentException - if some property of the specified element prevents it from being added to this deque

offerFirst

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. 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.

指定者:

offerFirst 在接口中 Deque<E>

参数:

e - the element to add

返回:

true if the element was added to this deque, else false

抛出:

ClassCastException - if the class of the specified element prevents it from being added to this deque

NullPointerException - if the specified element is null

IllegalArgumentException - if some property of the specified element prevents it from being added to this deque

offerLast

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. When using a capacity-restricted deque, this method is generally preferable to the addLast method, which can fail to insert an element only by throwing an exception.

指定者:

offerLast 在接口中 Deque<E>

参数:

e - the element to add

返回:

true if the element was added to this deque, else false

抛出:

ClassCastException - if the class of the specified element prevents it from being added to this deque

NullPointerException - if the specified element is null

IllegalArgumentException - if some property of the specified element prevents it from being added to this deque

putFirst

void putFirst(E e)
       throws InterruptedException

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

参数:

e - the element to add

抛出:

InterruptedException - if interrupted while waiting

ClassCastException - if the class of the specified element prevents it from being added to this deque

NullPointerException - if the specified element is null

IllegalArgumentException - if some property of the specified element prevents it from being added to this deque

putLast

void putLast(E e)
      throws InterruptedException

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

参数:

e - the element to add

抛出:

InterruptedException - if interrupted while waiting

ClassCastException - if the class of the specified element prevents it from being added to this deque

NullPointerException - if the specified element is null

IllegalArgumentException - if some property of the specified element prevents it from being added to this deque

offerFirst

boolean offerFirst(E 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.

参数:

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

返回:

true if successful, or false if the specified waiting time elapses before space is available

抛出:

InterruptedException - if interrupted while waiting

ClassCastException - if the class of the specified element prevents it from being added to this deque

NullPointerException - if the specified element is null

IllegalArgumentException - if some property of the specified element prevents it from being added to this deque

offerLast

boolean offerLast(E 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.

参数:

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

返回:

true if successful, or false if the specified waiting time elapses before space is available

抛出:

InterruptedException - if interrupted while waiting

ClassCastException - if the class of the specified element prevents it from being added to this deque

NullPointerException - if the specified element is null

IllegalArgumentException - if some property of the specified element prevents it from being added to this deque

takeFirst

E takeFirst()
     throws InterruptedException

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

返回:

the head of this deque

抛出:

InterruptedException - if interrupted while waiting

takeLast

E takeLast()
    throws InterruptedException

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

返回:

the tail of this deque

抛出:

InterruptedException - if interrupted while waiting

pollFirst

E 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.

参数:

timeout - how long to wait before giving up, in units of unit

unit - a TimeUnit determining how to interpret the timeout parameter

返回:

the head of this deque, or null if the specified waiting time elapses before an element is available

抛出:

InterruptedException - if interrupted while waiting

pollLast

E 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.

参数:

timeout - how long to wait before giving up, in units of unit

unit - a TimeUnit determining how to interpret the timeout parameter

返回:

the tail of this deque, or null if the specified waiting time elapses before an element is available

抛出:

InterruptedException - if interrupted while waiting

removeFirstOccurrence

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).

指定者:

removeFirstOccurrence 在接口中 Deque<E>

参数:

o - element to be removed from this deque, if present

返回:

true if an element was removed as a result of this call

抛出:

ClassCastException - if the class of the specified element is incompatible with this deque (optional)

NullPointerException - if the specified element is null (optional)

removeLastOccurrence

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).

指定者:

removeLastOccurrence 在接口中 Deque<E>

参数:

o - element to be removed from this deque, if present

返回:

true if an element was removed as a result of this call

抛出:

ClassCastException - if the class of the specified element is incompatible with this deque (optional)

NullPointerException - if the specified element is null (optional)

add

boolean add(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 throwing an IllegalStateException if no space is currently available. When using a capacity-restricted deque, it is generally preferable to use offer.

This method is equivalent to addLast.

指定者:

add 在接口中 BlockingQueue<E>

指定者:

add 在接口中 Collection<E>

指定者:

add 在接口中 Deque<E>

指定者:

add 在接口中 Queue<E>

参数:

e - the element to add

返回:

true (as specified by Collection#add)

抛出:

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

ClassCastException - if the class of the specified element prevents it from being added to this deque

NullPointerException - if the specified element is null

IllegalArgumentException - if some property of the specified element prevents it from being added to this deque

offer

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. When using a capacity-restricted deque, this method is generally preferable to the add(E) method, which can fail to insert an element only by throwing an exception.

This method is equivalent to offerLast.

指定者:

offer 在接口中 BlockingQueue<E>

指定者:

offer 在接口中 Deque<E>

指定者:

offer 在接口中 Queue<E>

参数:

e - the element to add

返回:

true if the element was added to this queue, else false

抛出:

ClassCastException - if the class of the specified element prevents it from being added to this deque

NullPointerException - if the specified element is null

IllegalArgumentException - if some property of the specified element prevents it from being added to this deque

put

void put(E 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 putLast.

指定者:

put 在接口中 BlockingQueue<E>

参数:

e - the element to add

抛出:

InterruptedException - if interrupted while waiting

ClassCastException - if the class of the specified element prevents it from being added to this deque

NullPointerException - if the specified element is null

IllegalArgumentException - if some property of the specified element prevents it from being added to this deque

offer

boolean offer(E 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 offerLast.

指定者:

offer 在接口中 BlockingQueue<E>

参数:

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

返回:

true if the element was added to this deque, else false

抛出:

InterruptedException - if interrupted while waiting

ClassCastException - if the class of the specified element prevents it from being added to this deque

NullPointerException - if the specified element is null

IllegalArgumentException - if some property of the specified element prevents it from being added to this deque

remove

E 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 poll only in that it throws an exception if this deque is empty.

This method is equivalent to removeFirst.

指定者:

remove 在接口中 Deque<E>

指定者:

remove 在接口中 Queue<E>

返回:

the head of the queue represented by this deque

抛出:

NoSuchElementException - if this deque is empty

poll

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.

This method is equivalent to Deque.pollFirst().

指定者:

poll 在接口中 Deque<E>

指定者:

poll 在接口中 Queue<E>

返回:

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

take

E 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 takeFirst.

指定者:

take 在接口中 BlockingQueue<E>

返回:

the head of this deque

抛出:

InterruptedException - if interrupted while waiting

poll

E 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 pollFirst.

指定者:

poll 在接口中 BlockingQueue<E>

参数:

timeout - how long to wait before giving up, in units of unit

unit - a TimeUnit determining how to interpret the timeout parameter

返回:

the head of this deque, or null if the specified waiting time elapses before an element is available

抛出:

InterruptedException - if interrupted while waiting

element

E 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 peek only in that it throws an exception if this deque is empty.

This method is equivalent to getFirst.

指定者:

element 在接口中 Deque<E>

指定者:

element 在接口中 Queue<E>

返回:

the head of this deque

抛出:

NoSuchElementException - if this deque is empty

peek

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.

This method is equivalent to peekFirst.

指定者:

peek 在接口中 Deque<E>

指定者:

peek 在接口中 Queue<E>

返回:

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

remove

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 removeFirstOccurrence.

指定者:

remove 在接口中 BlockingQueue<E>

指定者:

remove 在接口中 Collection<E>

指定者:

remove 在接口中 Deque<E>

参数:

o - element to be removed from this deque, if present

返回:

true if this deque changed as a result of the call

抛出:

ClassCastException - if the class of the specified element is incompatible with this deque (optional)

NullPointerException - if the specified element is null (optional)

contains

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).

指定者:

contains 在接口中 BlockingQueue<E>

指定者:

contains 在接口中 Collection<E>

指定者:

contains 在接口中 Deque<E>

参数:

o - object to be checked for containment in this deque

返回:

true if this deque contains the specified element

抛出:

ClassCastException - if the class of the specified element is incompatible with this deque (optional)

NullPointerException - if the specified element is null (optional)

size

int size()

Returns the number of elements in this deque.

指定者:

size 在接口中 Collection<E>

指定者:

size 在接口中 Deque<E>

返回:

the number of elements in this deque

iterator

Iterator<E> 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).

指定者:

iterator 在接口中 Collection<E>

指定者:

iterator 在接口中 Deque<E>

指定者:

iterator 在接口中 Iterable<E>

返回:

an iterator over the elements in this deque in proper sequence

push

void push(E e)

Pushes an element onto the stack represented by this deque (in other words, at the head of this deque) if it is possible to do so immediately without violating capacity restrictions, throwing an IllegalStateException if no space is currently available.

This method is equivalent to addFirst.

指定者:

push 在接口中 Deque<E>

参数:

e - the element to push

抛出:

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

ClassCastException - if the class of the specified element prevents it from being added to this deque

NullPointerException - if the specified element is null

IllegalArgumentException - if some property of the specified element prevents it from being added to this deque