BlockingDeque (Java Platform SE 6) (original) (raw)
java.util.concurrent
Interface BlockingDeque
Type Parameters:
E - the type of elements held in this collection
All Superinterfaces:
BlockingQueue, Collection, Deque, Iterable, Queue
All Known Implementing Classes:
public interface BlockingDeque
extends BlockingQueue, Deque
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 (eithernull 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 | addFirst(e) | offerFirst(e) | putFirst(e) | [offerFirst(e, time, unit)](../../../java/util/concurrent/BlockingDeque.html#offerFirst%28E, long, java.util.concurrent.TimeUnit%29) |
| Remove | removeFirst() | [pollFirst()](../../../java/util/concurrent/BlockingDeque.html#pollFirst%28long, java.util.concurrent.TimeUnit%29) | takeFirst() | [pollFirst(time, unit)](../../../java/util/concurrent/BlockingDeque.html#pollFirst%28long, java.util.concurrent.TimeUnit%29) |
| 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)](../../../java/util/concurrent/BlockingDeque.html#offerLast%28E, long, java.util.concurrent.TimeUnit%29) |
| Remove | removeLast() | pollLast() | takeLast() | [pollLast(time, unit)](../../../java/util/concurrent/BlockingDeque.html#pollLast%28long, java.util.concurrent.TimeUnit%29) |
| 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 FIFOBlockingQueue. The methods inherited from theBlockingQueue interface are precisely equivalent toBlockingDeque methods as indicated in the following table:
| BlockingQueue Method | Equivalent BlockingDeque Method |
|---|---|
| Insert | |
| add(e) | addLast(e) |
| offer(e) | offerLast(e) |
| put(e) | putLast(e) |
| [offer(e, time, unit)](../../../java/util/concurrent/BlockingDeque.html#offer%28E, long, java.util.concurrent.TimeUnit%29) | [offerLast(e, time, unit)](../../../java/util/concurrent/BlockingDeque.html#offerLast%28E, long, java.util.concurrent.TimeUnit%29) |
| Remove | |
| remove() | removeFirst() |
| poll() | pollFirst() |
| take() | takeFirst() |
| [poll(time, unit)](../../../java/util/concurrent/BlockingDeque.html#poll%28long, java.util.concurrent.TimeUnit%29) | [pollFirst(time, unit)](../../../java/util/concurrent/BlockingDeque.html#pollFirst%28long, java.util.concurrent.TimeUnit%29) |
| Examine | |
| element() | getFirst() |
| peek() | peekFirst() |
Memory consistency effects: As with other concurrent collections, actions in a thread prior to placing an object into aBlockingDeque 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
| 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, returningtrue upon success and throwing anIllegalStateException 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, returningtrue upon success and false if no space is currently available. |
| boolean | [offer](../../../java/util/concurrent/BlockingDeque.html#offer%28E, long, java.util.concurrent.TimeUnit%29)(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](../../../java/util/concurrent/BlockingDeque.html#offerFirst%28E, long, java.util.concurrent.TimeUnit%29)(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](../../../java/util/concurrent/BlockingDeque.html#offerLast%28E, long, java.util.concurrent.TimeUnit%29)(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 returnsnull if this deque is empty. |
| E | [poll](../../../java/util/concurrent/BlockingDeque.html#poll%28long, java.util.concurrent.TimeUnit%29)(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](../../../java/util/concurrent/BlockingDeque.html#pollFirst%28long, java.util.concurrent.TimeUnit%29)(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](../../../java/util/concurrent/BlockingDeque.html#pollLast%28long, java.util.concurrent.TimeUnit%29)(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. |
| 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. |
| Methods inherited from interface java.util.concurrent.BlockingQueue |
|---|
| drainTo, [drainTo](../../../java/util/concurrent/BlockingQueue.html#drainTo%28java.util.Collection, int%29), remainingCapacity |
| Methods inherited from interface java.util.Deque |
|---|
| descendingIterator, getFirst, getLast, peekFirst, peekLast, pollFirst, pollLast, pop, removeFirst, removeLast |
| Methods inherited from interface java.util.Collection |
|---|
| addAll, clear, containsAll, equals, hashCode, isEmpty, removeAll, retainAll, toArray, toArray |
| Method Detail |
|---|
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.
Specified by:
[addFirst](../../../java/util/Deque.html#addFirst%28E%29) in interface [Deque](../../../java/util/Deque.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Parameters:
e - the element to add
Throws:
[IllegalStateException](../../../java/lang/IllegalStateException.html "class in java.lang") - if the element cannot be added at this time due to capacity restrictions
[ClassCastException](../../../java/lang/ClassCastException.html "class in java.lang") - if the class of the specified element prevents it from being added to this deque
[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if the specified element is null
[IllegalArgumentException](../../../java/lang/IllegalArgumentException.html "class in java.lang") - 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.
Specified by:
[addLast](../../../java/util/Deque.html#addLast%28E%29) in interface [Deque](../../../java/util/Deque.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Parameters:
e - the element to add
Throws:
[IllegalStateException](../../../java/lang/IllegalStateException.html "class in java.lang") - if the element cannot be added at this time due to capacity restrictions
[ClassCastException](../../../java/lang/ClassCastException.html "class in java.lang") - if the class of the specified element prevents it from being added to this deque
[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if the specified element is null
[IllegalArgumentException](../../../java/lang/IllegalArgumentException.html "class in java.lang") - 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.
Specified by:
[offerFirst](../../../java/util/Deque.html#offerFirst%28E%29) in interface [Deque](../../../java/util/Deque.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Parameters:
e - the element to add
Returns:
true if the element was added to this deque, elsefalse
Throws:
[ClassCastException](../../../java/lang/ClassCastException.html "class in java.lang") - if the class of the specified element prevents it from being added to this deque
[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if the specified element is null
[IllegalArgumentException](../../../java/lang/IllegalArgumentException.html "class in java.lang") - 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.
Specified by:
[offerLast](../../../java/util/Deque.html#offerLast%28E%29) in interface [Deque](../../../java/util/Deque.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Parameters:
e - the element to add
Returns:
true if the element was added to this deque, elsefalse
Throws:
[ClassCastException](../../../java/lang/ClassCastException.html "class in java.lang") - if the class of the specified element prevents it from being added to this deque
[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if the specified element is null
[IllegalArgumentException](../../../java/lang/IllegalArgumentException.html "class in java.lang") - 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.
Parameters:
e - the element to add
Throws:
[InterruptedException](../../../java/lang/InterruptedException.html "class in java.lang") - if interrupted while waiting
[ClassCastException](../../../java/lang/ClassCastException.html "class in java.lang") - if the class of the specified element prevents it from being added to this deque
[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if the specified element is null
[IllegalArgumentException](../../../java/lang/IllegalArgumentException.html "class in java.lang") - 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.
Parameters:
e - the element to add
Throws:
[InterruptedException](../../../java/lang/InterruptedException.html "class in java.lang") - if interrupted while waiting
[ClassCastException](../../../java/lang/ClassCastException.html "class in java.lang") - if the class of the specified element prevents it from being added to this deque
[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if the specified element is null
[IllegalArgumentException](../../../java/lang/IllegalArgumentException.html "class in java.lang") - 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.
Parameters:
e - the element to add
timeout - how long to wait before giving up, in units ofunit
unit - a TimeUnit determining how to interpret thetimeout parameter
Returns:
true if successful, or false if the specified waiting time elapses before space is available
Throws:
[InterruptedException](../../../java/lang/InterruptedException.html "class in java.lang") - if interrupted while waiting
[ClassCastException](../../../java/lang/ClassCastException.html "class in java.lang") - if the class of the specified element prevents it from being added to this deque
[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if the specified element is null
[IllegalArgumentException](../../../java/lang/IllegalArgumentException.html "class in java.lang") - 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.
Parameters:
e - the element to add
timeout - how long to wait before giving up, in units ofunit
unit - a TimeUnit determining how to interpret thetimeout parameter
Returns:
true if successful, or false if the specified waiting time elapses before space is available
Throws:
[InterruptedException](../../../java/lang/InterruptedException.html "class in java.lang") - if interrupted while waiting
[ClassCastException](../../../java/lang/ClassCastException.html "class in java.lang") - if the class of the specified element prevents it from being added to this deque
[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if the specified element is null
[IllegalArgumentException](../../../java/lang/IllegalArgumentException.html "class in java.lang") - 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.
Returns:
the head of this deque
Throws:
[InterruptedException](../../../java/lang/InterruptedException.html "class in java.lang") - 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.
Returns:
the tail of this deque
Throws:
[InterruptedException](../../../java/lang/InterruptedException.html "class in java.lang") - 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.
Parameters:
timeout - how long to wait before giving up, in units ofunit
unit - a TimeUnit determining how to interpret thetimeout parameter
Returns:
the head of this deque, or null if the specified waiting time elapses before an element is available
Throws:
[InterruptedException](../../../java/lang/InterruptedException.html "class in java.lang") - 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.
Parameters:
timeout - how long to wait before giving up, in units ofunit
unit - a TimeUnit determining how to interpret thetimeout parameter
Returns:
the tail of this deque, or null if the specified waiting time elapses before an element is available
Throws:
[InterruptedException](../../../java/lang/InterruptedException.html "class in java.lang") - 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 thato.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).
Specified by:
[removeFirstOccurrence](../../../java/util/Deque.html#removeFirstOccurrence%28java.lang.Object%29) in interface [Deque](../../../java/util/Deque.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Parameters:
o - element to be removed from this deque, if present
Returns:
true if an element was removed as a result of this call
Throws:
[ClassCastException](../../../java/lang/ClassCastException.html "class in java.lang") - if the class of the specified element is incompatible with this deque (optional)
[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - 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 thato.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).
Specified by:
[removeLastOccurrence](../../../java/util/Deque.html#removeLastOccurrence%28java.lang.Object%29) in interface [Deque](../../../java/util/Deque.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Parameters:
o - element to be removed from this deque, if present
Returns:
true if an element was removed as a result of this call
Throws:
[ClassCastException](../../../java/lang/ClassCastException.html "class in java.lang") - if the class of the specified element is incompatible with this deque (optional)
[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - 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, returningtrue upon success and throwing anIllegalStateException 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.
Specified by:
[add](../../../java/util/concurrent/BlockingQueue.html#add%28E%29) in interface [BlockingQueue](../../../java/util/concurrent/BlockingQueue.html "interface in java.util.concurrent")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Specified by:
[add](../../../java/util/Collection.html#add%28E%29) in interface [Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Specified by:
[add](../../../java/util/Deque.html#add%28E%29) in interface [Deque](../../../java/util/Deque.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Specified by:
[add](../../../java/util/Queue.html#add%28E%29) in interface [Queue](../../../java/util/Queue.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Parameters:
e - the element to add
Returns:
true (as specified by Collection.add(E))
Throws:
[IllegalStateException](../../../java/lang/IllegalStateException.html "class in java.lang") - if the element cannot be added at this time due to capacity restrictions
[ClassCastException](../../../java/lang/ClassCastException.html "class in java.lang") - if the class of the specified element prevents it from being added to this deque
[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if the specified element is null
[IllegalArgumentException](../../../java/lang/IllegalArgumentException.html "class in java.lang") - 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, returningtrue 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.
Specified by:
[offer](../../../java/util/concurrent/BlockingQueue.html#offer%28E%29) in interface [BlockingQueue](../../../java/util/concurrent/BlockingQueue.html "interface in java.util.concurrent")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Specified by:
[offer](../../../java/util/Deque.html#offer%28E%29) in interface [Deque](../../../java/util/Deque.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Specified by:
[offer](../../../java/util/Queue.html#offer%28E%29) in interface [Queue](../../../java/util/Queue.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Parameters:
e - the element to add
Returns:
true if the element was added to this queue, elsefalse
Throws:
[ClassCastException](../../../java/lang/ClassCastException.html "class in java.lang") - if the class of the specified element prevents it from being added to this deque
[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if the specified element is null
[IllegalArgumentException](../../../java/lang/IllegalArgumentException.html "class in java.lang") - 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.
Specified by:
[put](../../../java/util/concurrent/BlockingQueue.html#put%28E%29) in interface [BlockingQueue](../../../java/util/concurrent/BlockingQueue.html "interface in java.util.concurrent")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Parameters:
e - the element to add
Throws:
[InterruptedException](../../../java/lang/InterruptedException.html "class in java.lang") - if interrupted while waiting
[ClassCastException](../../../java/lang/ClassCastException.html "class in java.lang") - if the class of the specified element prevents it from being added to this deque
[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if the specified element is null
[IllegalArgumentException](../../../java/lang/IllegalArgumentException.html "class in java.lang") - 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](../../../java/util/concurrent/BlockingDeque.html#offerLast%28E, long, java.util.concurrent.TimeUnit%29).
Specified by:
[offer](../../../java/util/concurrent/BlockingQueue.html#offer%28E, long, java.util.concurrent.TimeUnit%29) in interface [BlockingQueue](../../../java/util/concurrent/BlockingQueue.html "interface in java.util.concurrent")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Parameters:
e - the element to add
timeout - how long to wait before giving up, in units ofunit
unit - a TimeUnit determining how to interpret thetimeout parameter
Returns:
true if the element was added to this deque, elsefalse
Throws:
[InterruptedException](../../../java/lang/InterruptedException.html "class in java.lang") - if interrupted while waiting
[ClassCastException](../../../java/lang/ClassCastException.html "class in java.lang") - if the class of the specified element prevents it from being added to this deque
[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if the specified element is null
[IllegalArgumentException](../../../java/lang/IllegalArgumentException.html "class in java.lang") - 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.
Specified by:
[remove](../../../java/util/Deque.html#remove%28%29) in interface [Deque](../../../java/util/Deque.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Specified by:
[remove](../../../java/util/Queue.html#remove%28%29) in interface [Queue](../../../java/util/Queue.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Returns:
the head of the queue represented by this deque
Throws:
[NoSuchElementException](../../../java/util/NoSuchElementException.html "class in java.util") - 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 returnsnull if this deque is empty.
This method is equivalent to Deque.pollFirst().
Specified by:
[poll](../../../java/util/Deque.html#poll%28%29) in interface [Deque](../../../java/util/Deque.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Specified by:
[poll](../../../java/util/Queue.html#poll%28%29) in interface [Queue](../../../java/util/Queue.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Returns:
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.
Specified by:
[take](../../../java/util/concurrent/BlockingQueue.html#take%28%29) in interface [BlockingQueue](../../../java/util/concurrent/BlockingQueue.html "interface in java.util.concurrent")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Returns:
the head of this deque
Throws:
[InterruptedException](../../../java/lang/InterruptedException.html "class in java.lang") - 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](../../../java/util/concurrent/BlockingDeque.html#pollFirst%28long, java.util.concurrent.TimeUnit%29).
Specified by:
[poll](../../../java/util/concurrent/BlockingQueue.html#poll%28long, java.util.concurrent.TimeUnit%29) in interface [BlockingQueue](../../../java/util/concurrent/BlockingQueue.html "interface in java.util.concurrent")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Parameters:
timeout - how long to wait before giving up, in units ofunit
unit - a TimeUnit determining how to interpret thetimeout parameter
Returns:
the head of this deque, or null if the specified waiting time elapses before an element is available
Throws:
[InterruptedException](../../../java/lang/InterruptedException.html "class in java.lang") - 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.
Specified by:
[element](../../../java/util/Deque.html#element%28%29) in interface [Deque](../../../java/util/Deque.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Specified by:
[element](../../../java/util/Queue.html#element%28%29) in interface [Queue](../../../java/util/Queue.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Returns:
the head of this deque
Throws:
[NoSuchElementException](../../../java/util/NoSuchElementException.html "class in java.util") - 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.
Specified by:
[peek](../../../java/util/Deque.html#peek%28%29) in interface [Deque](../../../java/util/Deque.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Specified by:
[peek](../../../java/util/Queue.html#peek%28%29) in interface [Queue](../../../java/util/Queue.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Returns:
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 thato.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 toremoveFirstOccurrence.
Specified by:
[remove](../../../java/util/concurrent/BlockingQueue.html#remove%28java.lang.Object%29) in interface [BlockingQueue](../../../java/util/concurrent/BlockingQueue.html "interface in java.util.concurrent")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Specified by:
[remove](../../../java/util/Collection.html#remove%28java.lang.Object%29) in interface [Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Specified by:
[remove](../../../java/util/Deque.html#remove%28java.lang.Object%29) in interface [Deque](../../../java/util/Deque.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Parameters:
o - element to be removed from this deque, if present
Returns:
true if this deque changed as a result of the call
Throws:
[ClassCastException](../../../java/lang/ClassCastException.html "class in java.lang") - if the class of the specified element is incompatible with this deque (optional)
[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - 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).
Specified by:
[contains](../../../java/util/concurrent/BlockingQueue.html#contains%28java.lang.Object%29) in interface [BlockingQueue](../../../java/util/concurrent/BlockingQueue.html "interface in java.util.concurrent")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Specified by:
[contains](../../../java/util/Collection.html#contains%28java.lang.Object%29) in interface [Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Specified by:
[contains](../../../java/util/Deque.html#contains%28java.lang.Object%29) in interface [Deque](../../../java/util/Deque.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Parameters:
o - object to be checked for containment in this deque
Returns:
true if this deque contains the specified element
Throws:
[ClassCastException](../../../java/lang/ClassCastException.html "class in java.lang") - if the class of the specified element is incompatible with this deque (optional)
[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if the specified element is null (optional)
size
int size()
Returns the number of elements in this deque.
Specified by:
[size](../../../java/util/Collection.html#size%28%29) in interface [Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Specified by:
[size](../../../java/util/Deque.html#size%28%29) in interface [Deque](../../../java/util/Deque.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Returns:
the number of elements in this deque
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).
Specified by:
[iterator](../../../java/util/Collection.html#iterator%28%29) in interface [Collection](../../../java/util/Collection.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Specified by:
[iterator](../../../java/util/Deque.html#iterator%28%29) in interface [Deque](../../../java/util/Deque.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Specified by:
[iterator](../../../java/lang/Iterable.html#iterator%28%29) in interface [Iterable](../../../java/lang/Iterable.html "interface in java.lang")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Returns:
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, inserts the element at the front of this deque unless it would violate capacity restrictions.
This method is equivalent to addFirst.
Specified by:
[push](../../../java/util/Deque.html#push%28E%29) in interface [Deque](../../../java/util/Deque.html "interface in java.util")<[E](../../../java/util/concurrent/BlockingDeque.html "type parameter in BlockingDeque")>
Parameters:
e - the element to push
Throws:
[IllegalStateException](../../../java/lang/IllegalStateException.html "class in java.lang") - if the element cannot be added at this time due to capacity restrictions
[ClassCastException](../../../java/lang/ClassCastException.html "class in java.lang") - if the class of the specified element prevents it from being added to this deque
[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if the specified element is null
[IllegalArgumentException](../../../java/lang/IllegalArgumentException.html "class in java.lang") - if some property of the specified element prevents it from being added to this deque
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