| java.util.concurrent.BlockingDeque
| BlockingDeque | | public interface BlockingDeque extends BlockingQueue<E>,Deque<E>(Code) | | 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:
| First Element (Head) |
|
Throws exception |
Special value |
Blocks |
Times out |
| Insert |
BlockingDeque.addFirst addFirst(e) |
BlockingDeque.offerFirst(Object) offerFirst(e) |
BlockingDeque.putFirst putFirst(e) |
BlockingDeque.offerFirst(Object,long,TimeUnit) offerFirst(e, time, unit) |
| Remove |
BlockingDeque.removeFirst removeFirst() |
BlockingDeque.pollFirst pollFirst() |
BlockingDeque.takeFirst takeFirst() |
BlockingDeque.pollFirst(long,TimeUnit) pollFirst(time, unit) |
| Examine |
BlockingDeque.getFirst getFirst() |
BlockingDeque.peekFirst peekFirst() |
not applicable |
not applicable |
| Last Element (Tail) |
|
Throws exception |
Special value |
Blocks |
Times out |
| Insert |
BlockingDeque.addLast addLast(e) |
BlockingDeque.offerLast(Object) offerLast(e) |
BlockingDeque.putLast putLast(e) |
BlockingDeque.offerLast(Object,long,TimeUnit) offerLast(e, time, unit) |
| Remove |
BlockingDeque.removeLast() removeLast() |
BlockingDeque.pollLast() pollLast() |
BlockingDeque.takeLast takeLast() |
BlockingDeque.pollLast(long,TimeUnit) pollLast(time, unit) |
| Examine |
BlockingDeque.getLast getLast() |
BlockingDeque.peekLast 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:
| BlockingQueue Method |
Equivalent BlockingDeque Method |
| Insert |
|
BlockingDeque.add(Object) add(e) |
BlockingDeque.addLast(Object) addLast(e) |
|
BlockingDeque.offer(Object) offer(e) |
BlockingDeque.offerLast(Object) offerLast(e) |
|
BlockingDeque.put(Object) put(e) |
BlockingDeque.putLast(Object) putLast(e) |
|
BlockingDeque.offer(Object,long,TimeUnit) offer(e, time, unit) |
BlockingDeque.offerLast(Object,long,TimeUnit) offerLast(e, time, unit) |
| Remove |
|
BlockingDeque.remove() remove() |
BlockingDeque.removeFirst() removeFirst() |
|
BlockingDeque.poll() poll() |
BlockingDeque.pollFirst() pollFirst() |
|
BlockingDeque.take() take() |
BlockingDeque.takeFirst() takeFirst() |
|
BlockingDeque.poll(long,TimeUnit) poll(time, unit) |
BlockingDeque.pollFirst(long,TimeUnit) pollFirst(time, unit) |
| Examine |
|
BlockingDeque.element() element() |
BlockingDeque.getFirst() getFirst() |
|
BlockingDeque.peek() peek() |
BlockingDeque.peekFirst() 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.
since:
1.6
author:
Doug Lea<
Parameters:
E - > the type of elements held in this collection |
| Method Summary | |
| 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. | | public 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. | | 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. | | public 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. |
| add | | boolean add(E e)(Code) | | 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
BlockingDeque.offer(Object) offer .
This method is equivalent to
BlockingDeque.addLast(Object) addLast .
Parameters:
e - the element to add
throws:
IllegalStateException -
throws:
ClassCastException - if the class of the specified elementprevents it from being added to this deque
throws:
NullPointerException - if the specified element is null
throws:
IllegalArgumentException - if some property of the specifiedelement prevents it from being added to this deque |
| contains | | public boolean contains(Object o)(Code) | | 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 true if this deque contains the specified element
throws:
ClassCastException - if the class of the specified elementis incompatible with this deque (optional)
throws:
NullPointerException - if the specified element is null (optional) |
| element | | E element()(Code) | | 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
BlockingDeque.peek peek only in that it throws an
exception if this deque is empty.
This method is equivalent to
BlockingDeque.getFirst() getFirst .
the head of this deque
throws:
NoSuchElementException - if this deque is empty |
| iterator | | Iterator<E> iterator()(Code) | | 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).
an iterator over the elements in this deque in proper sequence |
| offer | | boolean offer(E e)(Code) | | 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
BlockingDeque.add method, which can fail to
insert an element only by throwing an exception.
This method is equivalent to
BlockingDeque.offerLast(Object) offerLast .
Parameters:
e - the element to add
throws:
ClassCastException - if the class of the specified elementprevents it from being added to this deque
throws:
NullPointerException - if the specified element is null
throws:
IllegalArgumentException - if some property of the specifiedelement prevents it from being added to this deque |
| offerFirst | | boolean offerFirst(E e)(Code) | | 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
BlockingDeque.addFirst(Object) addFirst method, which can
fail to insert an element only by throwing an exception.
Parameters:
e - the element to add
throws:
ClassCastException -
throws:
NullPointerException - if the specified element is null
throws:
IllegalArgumentException - |
| offerFirst | | boolean offerFirst(E e, long timeout, TimeUnit unit) throws InterruptedException(Code) | | 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
Parameters:
timeout - how long to wait before giving up, in units ofunit
Parameters:
unit - a TimeUnit determining how to interpret thetimeout parameter true if successful, or false ifthe specified waiting time elapses before space is available
throws:
InterruptedException - if interrupted while waiting
throws:
ClassCastException - if the class of the specified elementprevents it from being added to this deque
throws:
NullPointerException - if the specified element is null
throws:
IllegalArgumentException - if some property of the specifiedelement prevents it from being added to this deque |
| offerLast | | boolean offerLast(E e)(Code) | | 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
BlockingDeque.addLast(Object) addLast method, which can
fail to insert an element only by throwing an exception.
Parameters:
e - the element to add
throws:
ClassCastException -
throws:
NullPointerException - if the specified element is null
throws:
IllegalArgumentException - |
| offerLast | | boolean offerLast(E e, long timeout, TimeUnit unit) throws InterruptedException(Code) | | 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
Parameters:
timeout - how long to wait before giving up, in units ofunit
Parameters:
unit - a TimeUnit determining how to interpret thetimeout parameter true if successful, or false ifthe specified waiting time elapses before space is available
throws:
InterruptedException - if interrupted while waiting
throws:
ClassCastException - if the class of the specified elementprevents it from being added to this deque
throws:
NullPointerException - if the specified element is null
throws:
IllegalArgumentException - if some property of the specifiedelement prevents it from being added to this deque |
| peek | | E peek()(Code) | | 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
BlockingDeque.peekFirst() peekFirst .
the head of this deque, or null if this deque is empty |
| poll | | E poll()(Code) | | 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
BlockingDeque.pollFirst() .
the head of this deque, or null if this deque is empty |
| poll | | E poll(long timeout, TimeUnit unit) throws InterruptedException(Code) | | 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
BlockingDeque.pollFirst(long,TimeUnit) pollFirst .
the head of this deque, or null if thespecified waiting time elapses before an element is available
throws:
InterruptedException - if interrupted while waiting |
| pollFirst | | E pollFirst(long timeout, TimeUnit unit) throws InterruptedException(Code) | | 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 ofunit
Parameters:
unit - a TimeUnit determining how to interpret thetimeout parameter the head of this deque, or null if the specifiedwaiting time elapses before an element is available
throws:
InterruptedException - if interrupted while waiting |
| pollLast | | E pollLast(long timeout, TimeUnit unit) throws InterruptedException(Code) | | 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 ofunit
Parameters:
unit - a TimeUnit determining how to interpret thetimeout parameter the tail of this deque, or null if the specifiedwaiting time elapses before an element is available
throws:
InterruptedException - if interrupted while waiting |
| putFirst | | void putFirst(E e) throws InterruptedException(Code) | | 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
throws:
ClassCastException - if the class of the specified elementprevents it from being added to this deque
throws:
NullPointerException - if the specified element is null
throws:
IllegalArgumentException - if some property of the specifiedelement prevents it from being added to this deque |
| putLast | | void putLast(E e) throws InterruptedException(Code) | | 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
throws:
ClassCastException - if the class of the specified elementprevents it from being added to this deque
throws:
NullPointerException - if the specified element is null
throws:
IllegalArgumentException - if some property of the specifiedelement prevents it from being added to this deque |
| remove | | E remove()(Code) | | 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
BlockingDeque.poll poll only in that it
throws an exception if this deque is empty.
This method is equivalent to
BlockingDeque.removeFirst() removeFirst .
the head of the queue represented by this deque
throws:
NoSuchElementException - if this deque is empty |
| remove | | boolean remove(Object o)(Code) | | 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
BlockingDeque.removeFirstOccurrence(Object) removeFirstOccurrence .
Parameters:
o - element to be removed from this deque, if present true if this deque changed as a result of the call
throws:
ClassCastException - if the class of the specified elementis incompatible with this deque (optional)
throws:
NullPointerException - if the specified element is null (optional) |
| removeFirstOccurrence | | boolean removeFirstOccurrence(Object o)(Code) | | 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 true if an element was removed as a result of this call
throws:
ClassCastException - if the class of the specified elementis incompatible with this deque (optional)
throws:
NullPointerException - if the specified element is null (optional) |
| removeLastOccurrence | | boolean removeLastOccurrence(Object o)(Code) | | 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 true if an element was removed as a result of this call
throws:
ClassCastException - if the class of the specified elementis incompatible with this deque (optional)
throws:
NullPointerException - if the specified element is null (optional) |
| size | | public int size()(Code) | | Returns the number of elements in this deque.
the number of elements in this deque |
| take | | E take() throws InterruptedException(Code) | | 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
BlockingDeque.takeFirst() takeFirst .
the head of this deque
throws:
InterruptedException - if interrupted while waiting |
| takeFirst | | E takeFirst() throws InterruptedException(Code) | | Retrieves and removes the first element of this deque, waiting
if necessary until an element becomes available.
the head of this deque
throws:
InterruptedException - if interrupted while waiting |
| takeLast | | E takeLast() throws InterruptedException(Code) | | Retrieves and removes the last element of this deque, waiting
if necessary until an element becomes available.
the tail of this deque
throws:
InterruptedException - if interrupted while waiting |
|
|