E - the type of elements held in this collectionpublic class LinkedBlockingDeque<E> extends AbstractQueue<E> implements BlockingDeque<E>, Serializable
An optionally-bounded blocking deque based on linked nodes.
The optional capacity bound constructor argument serves as a way to prevent excessive expansion. The capacity, if unspecified, is equal to Integer.MAX_VALUE. Linked nodes are dynamically created upon each insertion unless this would bring the deque above capacity.
Most operations run in constant time (ignoring time spent blocking). Exceptions include remove, removeFirstOccurrence, removeLastOccurrence, contains, iterator.remove(), and the bulk operations, all of which run in linear time.
This class and its iterator implement all of the optional methods of the Collection and Iterator interfaces.
This class is a member of the Java Collections Framework.
public LinkedBlockingDeque()
Creates a LinkedBlockingDeque with a capacity of Integer.MAX_VALUE.
public LinkedBlockingDeque(int capacity)
Creates a LinkedBlockingDeque with the given (fixed) capacity.
capacity - the capacity of this dequeIllegalArgumentException - if capacity is less than 1public LinkedBlockingDeque(Collection<? extends E> c)
Creates a LinkedBlockingDeque with a capacity of Integer.MAX_VALUE, initially containing the elements of the given collection, added in traversal order of the collection's iterator.
c - the collection of elements to initially containNullPointerException - if the specified collection or any of its elements are nullpublic void addFirst(E e)
Description copied from interface: BlockingDeque
Inserts the specified element at the front of this deque if it is possible to do so immediately without violating capacity restrictions, throwing an IllegalStateException if no space is currently available. When using a capacity-restricted deque, it is generally preferable to use offerFirst.
addFirst in interface BlockingDeque<E>
addFirst in interface Deque<E>
e - the element to addIllegalStateException - if this deque is fullNullPointerException - if the specified element is nullpublic void addLast(E e)
Description copied from interface: BlockingDeque
Inserts the specified element at the end of this deque if it is possible to do so immediately without violating capacity restrictions, throwing an IllegalStateException if no space is currently available. When using a capacity-restricted deque, it is generally preferable to use offerLast.
addLast in interface BlockingDeque<E>
addLast in interface Deque<E>
e - the element to addIllegalStateException - if this deque is fullNullPointerException - if the specified element is nullpublic boolean offerFirst(E e)
Description copied from interface: BlockingDeque
Inserts the specified element at the front of this deque if it is possible to do so immediately without violating capacity restrictions, returning true upon success and false if no space is currently available. When using a capacity-restricted deque, this method is generally preferable to the addFirst method, which can fail to insert an element only by throwing an exception.
offerFirst in interface BlockingDeque<E>
offerFirst in interface Deque<E>
e - the element to addtrue if the element was added to this deque, else false
NullPointerException - if the specified element is nullpublic boolean offerLast(E e)
Description copied from interface: BlockingDeque
Inserts the specified element at the end of this deque if it is possible to do so immediately without violating capacity restrictions, 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.
offerLast in interface BlockingDeque<E>
offerLast in interface Deque<E>
e - the element to addtrue if the element was added to this deque, else false
NullPointerException - if the specified element is nullpublic void putFirst(E e)
throws InterruptedException Description copied from interface: BlockingDeque
Inserts the specified element at the front of this deque, waiting if necessary for space to become available.
putFirst in interface BlockingDeque<E>
e - the element to addNullPointerException - if the specified element is nullInterruptedException - if interrupted while waitingpublic void putLast(E e)
throws InterruptedException Description copied from interface: BlockingDeque
Inserts the specified element at the end of this deque, waiting if necessary for space to become available.
putLast in interface BlockingDeque<E>
e - the element to addNullPointerException - if the specified element is nullInterruptedException - if interrupted while waitingpublic boolean offerFirst(E e,
long timeout,
TimeUnit unit)
throws InterruptedException Description copied from interface: BlockingDeque
Inserts the specified element at the front of this deque, waiting up to the specified wait time if necessary for space to become available.
offerFirst in interface BlockingDeque<E>
e - the element to addtimeout - how long to wait before giving up, in units of unit
unit - a TimeUnit determining how to interpret the timeout parametertrue if successful, or false if the specified waiting time elapses before space is availableNullPointerException - if the specified element is nullInterruptedException - if interrupted while waitingpublic boolean offerLast(E e,
long timeout,
TimeUnit unit)
throws InterruptedException Description copied from interface: BlockingDeque
Inserts the specified element at the end of this deque, waiting up to the specified wait time if necessary for space to become available.
offerLast in interface BlockingDeque<E>
e - the element to addtimeout - how long to wait before giving up, in units of unit
unit - a TimeUnit determining how to interpret the timeout parametertrue if successful, or false if the specified waiting time elapses before space is availableNullPointerException - if the specified element is nullInterruptedException - if interrupted while waitingpublic E removeFirst()
Description copied from interface: Deque
Retrieves and removes the first element of this deque. This method differs from pollFirst only in that it throws an exception if this deque is empty.
removeFirst in interface Deque<E>
NoSuchElementException - if this deque is emptypublic E removeLast()
Description copied from interface: Deque
Retrieves and removes the last element of this deque. This method differs from pollLast only in that it throws an exception if this deque is empty.
removeLast in interface Deque<E>
NoSuchElementException - if this deque is emptypublic E pollFirst()
Description copied from interface: Deque
Retrieves and removes the first element of this deque, or returns null if this deque is empty.
pollFirst in interface Deque<E>
null if this deque is emptypublic E pollLast()
Description copied from interface: Deque
Retrieves and removes the last element of this deque, or returns null if this deque is empty.
pollLast in interface Deque<E>
null if this deque is emptypublic E takeFirst()
throws InterruptedException Description copied from interface: BlockingDeque
Retrieves and removes the first element of this deque, waiting if necessary until an element becomes available.
takeFirst in interface BlockingDeque<E>
InterruptedException - if interrupted while waitingpublic E takeLast()
throws InterruptedException Description copied from interface: BlockingDeque
Retrieves and removes the last element of this deque, waiting if necessary until an element becomes available.
takeLast in interface BlockingDeque<E>
InterruptedException - if interrupted while waitingpublic E pollFirst(long timeout,
TimeUnit unit)
throws InterruptedException Description copied from interface: BlockingDeque
Retrieves and removes the first element of this deque, waiting up to the specified wait time if necessary for an element to become available.
pollFirst in interface BlockingDeque<E>
timeout - how long to wait before giving up, in units of unit
unit - a TimeUnit determining how to interpret the timeout parameternull if the specified waiting time elapses before an element is availableInterruptedException - if interrupted while waitingpublic E pollLast(long timeout,
TimeUnit unit)
throws InterruptedException Description copied from interface: BlockingDeque
Retrieves and removes the last element of this deque, waiting up to the specified wait time if necessary for an element to become available.
pollLast in interface BlockingDeque<E>
timeout - how long to wait before giving up, in units of unit
unit - a TimeUnit determining how to interpret the timeout parameternull if the specified waiting time elapses before an element is availableInterruptedException - if interrupted while waitingpublic E getFirst()
Description copied from interface: Deque
Retrieves, but does not remove, the first element of this deque. This method differs from peekFirst only in that it throws an exception if this deque is empty.
getFirst in interface Deque<E>
NoSuchElementException - if this deque is emptypublic E getLast()
Description copied from interface: Deque
Retrieves, but does not remove, the last element of this deque. This method differs from peekLast only in that it throws an exception if this deque is empty.
getLast in interface Deque<E>
NoSuchElementException - if this deque is emptypublic E peekFirst()
Description copied from interface: Deque
Retrieves, but does not remove, the first element of this deque, or returns null if this deque is empty.
peekFirst in interface Deque<E>
null if this deque is emptypublic E peekLast()
Description copied from interface: Deque
Retrieves, but does not remove, the last element of this deque, or returns null if this deque is empty.
peekLast in interface Deque<E>
null if this deque is emptypublic boolean removeFirstOccurrence(Object o)
Description copied from interface: BlockingDeque
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).
removeFirstOccurrence in interface BlockingDeque<E>
removeFirstOccurrence in interface Deque<E>
o - element to be removed from this deque, if presenttrue if an element was removed as a result of this callpublic boolean removeLastOccurrence(Object o)
Description copied from interface: BlockingDeque
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).
removeLastOccurrence in interface BlockingDeque<E>
removeLastOccurrence in interface Deque<E>
o - element to be removed from this deque, if presenttrue if an element was removed as a result of this callpublic boolean add(E e)
Inserts the specified element at the end of this deque unless it would violate capacity restrictions. When using a capacity-restricted deque, it is generally preferable to use method offer.
This method is equivalent to addLast(E).
add in interface Collection<E>
add in interface BlockingDeque<E>
add in interface BlockingQueue<E>
add in interface Deque<E>
add in interface Queue<E>
add in class AbstractQueue<E>
e - the element to addtrue (as specified by Collection.add(E))IllegalStateException - if this deque is fullNullPointerException - if the specified element is nullpublic boolean offer(E e)
Description copied from interface: BlockingDeque
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(E) method, which can fail to insert an element only by throwing an exception.
This method is equivalent to offerLast.
offer in interface BlockingDeque<E>
offer in interface BlockingQueue<E>
offer in interface Deque<E>
offer in interface Queue<E>
e - the element to addtrue if the element was added to this queue, else false
NullPointerException - if the specified element is nullpublic void put(E e)
throws InterruptedException Description copied from interface: BlockingDeque
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.
put in interface BlockingDeque<E>
put in interface BlockingQueue<E>
e - the element to addNullPointerException - if the specified element is nullInterruptedException - if interrupted while waitingpublic boolean offer(E e,
long timeout,
TimeUnit unit)
throws InterruptedException Description copied from interface: BlockingDeque
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.
offer in interface BlockingDeque<E>
offer in interface BlockingQueue<E>
e - the element to addtimeout - how long to wait before giving up, in units of unit
unit - a TimeUnit determining how to interpret the timeout parametertrue if the element was added to this deque, else false
NullPointerException - if the specified element is nullInterruptedException - if interrupted while waitingpublic E remove()
Retrieves and removes the head of the queue represented by 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.
remove in interface BlockingDeque<E>
remove in interface Deque<E>
remove in interface Queue<E>
remove in class AbstractQueue<E>
NoSuchElementException - if this deque is emptypublic E poll()
Description copied from interface: BlockingDeque
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().
poll in interface BlockingDeque<E>
poll in interface Deque<E>
poll in interface Queue<E>
null if this deque is emptypublic E take()
throws InterruptedException Description copied from interface: BlockingDeque
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.
take in interface BlockingDeque<E>
take in interface BlockingQueue<E>
InterruptedException - if interrupted while waitingpublic E poll(long timeout,
TimeUnit unit)
throws InterruptedException Description copied from interface: BlockingDeque
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.
poll in interface BlockingDeque<E>
poll in interface BlockingQueue<E>
timeout - how long to wait before giving up, in units of unit
unit - a TimeUnit determining how to interpret the timeout parameternull if the specified waiting time elapses before an element is availableInterruptedException - if interrupted while waitingpublic E element()
Retrieves, but does not remove, the head of the queue represented by 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.
element in interface BlockingDeque<E>
element in interface Deque<E>
element in interface Queue<E>
element in class AbstractQueue<E>
NoSuchElementException - if this deque is emptypublic E peek()
Description copied from interface: BlockingDeque
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.
peek in interface BlockingDeque<E>
peek in interface Deque<E>
peek in interface Queue<E>
null if this deque is emptypublic int remainingCapacity()
Returns the number of additional elements that this deque can ideally (in the absence of memory or resource constraints) accept without blocking. This is always equal to the initial capacity of this deque less the current size of this deque.
Note that you cannot always tell if an attempt to insert an element will succeed by inspecting remainingCapacity because it may be the case that another thread is about to insert or remove an element.
remainingCapacity in interface BlockingQueue<E>
public int drainTo(Collection<? super E> c)
Description copied from interface: BlockingQueue
Removes all available elements from this queue and adds them to the given collection. This operation may be more efficient than repeatedly polling this queue. A failure encountered while attempting to add elements to collection c may result in elements being in neither, either or both collections when the associated exception is thrown. Attempts to drain a queue to itself result in IllegalArgumentException. Further, the behavior of this operation is undefined if the specified collection is modified while the operation is in progress.
drainTo in interface BlockingQueue<E>
c - the collection to transfer elements intoUnsupportedOperationException - if addition of elements is not supported by the specified collectionClassCastException - if the class of an element of this queue prevents it from being added to the specified collectionNullPointerException - if the specified collection is nullIllegalArgumentException - if the specified collection is this queue, or some property of an element of this queue prevents it from being added to the specified collectionpublic int drainTo(Collection<? super E> c,
int maxElements) Description copied from interface: BlockingQueue
Removes at most the given number of available elements from this queue and adds them to the given collection. A failure encountered while attempting to add elements to collection c may result in elements being in neither, either or both collections when the associated exception is thrown. Attempts to drain a queue to itself result in IllegalArgumentException. Further, the behavior of this operation is undefined if the specified collection is modified while the operation is in progress.
drainTo in interface BlockingQueue<E>
c - the collection to transfer elements intomaxElements - the maximum number of elements to transferUnsupportedOperationException - if addition of elements is not supported by the specified collectionClassCastException - if the class of an element of this queue prevents it from being added to the specified collectionNullPointerException - if the specified collection is nullIllegalArgumentException - if the specified collection is this queue, or some property of an element of this queue prevents it from being added to the specified collectionpublic void push(E e)
Description copied from interface: BlockingDeque
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.
push in interface BlockingDeque<E>
push in interface Deque<E>
e - the element to pushIllegalStateException - if this deque is fullNullPointerException - if the specified element is nullpublic E pop()
Description copied from interface: Deque
Pops an element from the stack represented by this deque. In other words, removes and returns the first element of this deque.
This method is equivalent to Deque.removeFirst().
pop in interface Deque<E>
NoSuchElementException - if this deque is emptypublic 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.
remove in interface Collection<E>
remove in interface BlockingDeque<E>
remove in interface BlockingQueue<E>
remove in interface Deque<E>
remove in class AbstractCollection<E>
o - element to be removed from this deque, if presenttrue if this deque changed as a result of the callpublic int size()
Returns the number of elements in this deque.
size in interface Collection<E>
size in interface BlockingDeque<E>
size in interface Deque<E>
size in class AbstractCollection<E>
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).
contains in interface Collection<E>
contains in interface BlockingDeque<E>
contains in interface BlockingQueue<E>
contains in interface Deque<E>
contains in class AbstractCollection<E>
o - object to be checked for containment in this dequetrue if this deque contains the specified elementpublic Object[] toArray()
Returns an array containing all of the elements in this deque, in proper sequence (from first to last element).
The returned array will be "safe" in that no references to it are maintained by this deque. (In other words, this method must allocate a new array). The caller is thus free to modify the returned array.
This method acts as bridge between array-based and collection-based APIs.
toArray in interface Collection<E>
toArray in class AbstractCollection<E>
public <T> T[] toArray(T[] a)
Returns an array containing all of the elements in this deque, in proper sequence; the runtime type of the returned array is that of the specified array. If the deque fits in the specified array, it is returned therein. Otherwise, a new array is allocated with the runtime type of the specified array and the size of this deque.
If this deque fits in the specified array with room to spare (i.e., the array has more elements than this deque), the element in the array immediately following the end of the deque is set to null.
Like the toArray() method, this method acts as bridge between array-based and collection-based APIs. Further, this method allows precise control over the runtime type of the output array, and may, under certain circumstances, be used to save allocation costs.
Suppose x is a deque known to contain only strings. The following code can be used to dump the deque into a newly allocated array of String:
String[] y = x.toArray(new String[0]);Note that
toArray(new Object[0]) is identical in function to toArray().toArray in interface Collection<E>
toArray in class AbstractCollection<E>
T - the runtime type of the array to contain the collectiona - the array into which the elements of the deque are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purposeArrayStoreException - if the runtime type of the specified array is not a supertype of the runtime type of every element in this dequeNullPointerException - if the specified array is nullpublic String toString()
Description copied from class: AbstractCollection
Returns a string representation of this collection. The string representation consists of a list of the collection's elements in the order they are returned by its iterator, enclosed in square brackets ("[]"). Adjacent elements are separated by the characters ", " (comma and space). Elements are converted to strings as by String.valueOf(Object).
toString in class AbstractCollection<E>
public void clear()
Atomically removes all of the elements from this deque. The deque will be empty after this call returns.
clear in interface Collection<E>
clear in class AbstractQueue<E>
public 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).
The returned iterator is weakly consistent.
iterator in interface Iterable<E>
iterator in interface Collection<E>
iterator in interface BlockingDeque<E>
iterator in interface Deque<E>
iterator in class AbstractCollection<E>
public Iterator<E> descendingIterator()
Returns an iterator over the elements in this deque in reverse sequential order. The elements will be returned in order from last (tail) to first (head).
The returned iterator is weakly consistent.
descendingIterator in interface Deque<E>
public Spliterator<E> spliterator()
Returns a Spliterator over the elements in this deque.
The returned spliterator is weakly consistent.
The Spliterator reports Spliterator.CONCURRENT, Spliterator.ORDERED, and Spliterator.NONNULL.
spliterator in interface Iterable<E>
spliterator in interface Collection<E>
Spliterator implements trySplit to permit limited parallelism.Spliterator over the elements in this deque
© 1993–2017, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.