E - the type of elements held in this collectionpublic class LinkedBlockingDeque<E> extends AbstractQueue<E> implements BlockingDeque<E>, Serializable
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.
| Constructor and Description |
|---|
LinkedBlockingDeque()
Creates a
LinkedBlockingDeque with a capacity of
Integer.MAX_VALUE. |
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. |
LinkedBlockingDeque(int capacity)
Creates a
LinkedBlockingDeque with the given (fixed) capacity. |
| Modifier and Type | Method and Description |
|---|---|
boolean |
add(E e)
Inserts the specified element at the end of this deque unless it would
violate capacity restrictions.
|
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.
|
void |
clear()
Atomically removes all of the elements from this deque.
|
boolean |
contains(Object o)
Returns
true if this deque contains the specified element. |
Iterator<E> |
descendingIterator()
Returns an iterator over the elements in this deque in reverse
sequential order.
|
int |
drainTo(Collection<? super E> c)
Removes all available elements from this queue and adds them
to the given collection.
|
int |
drainTo(Collection<? super E> c,
int maxElements)
Removes at most the given number of available elements from
this queue and adds them to the given collection.
|
E |
element()
Retrieves, but does not remove, the head of the queue represented by
this deque.
|
E |
getFirst()
Retrieves, but does not remove, the first element of this deque.
|
E |
getLast()
Retrieves, but does not remove, the last 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 |
peekFirst()
Retrieves, but does not remove, the first element of this deque,
or returns null if this deque is empty.
|
E |
peekLast()
Retrieves, but does not remove, the last 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()
Retrieves and removes the first element of this deque,
or returns null if this deque is empty.
|
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()
Retrieves and removes the last element of this deque,
or returns null if this deque is empty.
|
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.
|
E |
pop()
Pops an element from the stack represented by this deque.
|
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.
|
int |
remainingCapacity()
Returns the number of additional elements that this deque can ideally
(in the absence of memory or resource constraints) accept without
blocking.
|
E |
remove()
Retrieves and removes the head of the queue represented by this deque.
|
boolean |
remove(Object o)
Removes the first occurrence of the specified element from this deque.
|
E |
removeFirst()
Retrieves and removes the first element of this deque.
|
boolean |
removeFirstOccurrence(Object o)
Removes the first occurrence of the specified element from this deque.
|
E |
removeLast()
Retrieves and removes the last element of 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.
|
Object[] |
toArray()
Returns an array containing all of the elements in this deque, in
proper sequence (from first to last element).
|
<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.
|
String |
toString()
Returns a string representation of this collection.
|
addAllcontainsAll, isEmpty, removeAll, retainAllclone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, waitaddAll, containsAll, equals, hashCode, isEmpty, removeAll, retainAllpublic LinkedBlockingDeque()
LinkedBlockingDeque with a capacity of
Integer.MAX_VALUE.public LinkedBlockingDeque(int capacity)
LinkedBlockingDeque with the given (fixed) capacity.capacity - the capacity of this dequeIllegalArgumentException - if capacity is less than 1public LinkedBlockingDeque(Collection<? extends E> c)
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)
BlockingDequeofferFirst.addFirst in interface BlockingDeque<E>addFirst in interface Deque<E>e - the element to addIllegalStateException - if the element cannot be added at this
time due to capacity restrictionsNullPointerException - if the specified element is nullpublic void addLast(E e)
BlockingDequeofferLast.addLast in interface BlockingDeque<E>addLast in interface Deque<E>e - the element to addIllegalStateException - if the element cannot be added at this
time due to capacity restrictionsNullPointerException - if the specified element is nullpublic boolean offerFirst(E e)
BlockingDequeaddFirst 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 addNullPointerException - if the specified element is nullpublic boolean offerLast(E e)
BlockingDequeaddLast 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 addNullPointerException - if the specified element is nullpublic void putFirst(E e) throws InterruptedException
BlockingDequeputFirst 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
BlockingDequeputLast 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
BlockingDequeofferFirst in interface BlockingDeque<E>e - the element to addtimeout - how long to wait before giving up, in units of
unitunit - a TimeUnit determining how to interpret the
timeout parameterNullPointerException - if the specified element is nullInterruptedException - if interrupted while waitingpublic boolean offerLast(E e, long timeout, TimeUnit unit) throws InterruptedException
BlockingDequeofferLast in interface BlockingDeque<E>e - the element to addtimeout - how long to wait before giving up, in units of
unitunit - a TimeUnit determining how to interpret the
timeout parameterNullPointerException - if the specified element is nullInterruptedException - if interrupted while waitingpublic E removeFirst()
DequepollFirst 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()
DequepollLast 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()
Dequepublic E pollLast()
Dequepublic E takeFirst() throws InterruptedException
BlockingDequetakeFirst in interface BlockingDeque<E>InterruptedException - if interrupted while waitingpublic E takeLast() throws InterruptedException
BlockingDequetakeLast in interface BlockingDeque<E>InterruptedException - if interrupted while waitingpublic E pollFirst(long timeout, TimeUnit unit) throws InterruptedException
BlockingDequepollFirst in interface BlockingDeque<E>timeout - how long to wait before giving up, in units of
unitunit - a TimeUnit determining how to interpret the
timeout parameterInterruptedException - if interrupted while waitingpublic E pollLast(long timeout, TimeUnit unit) throws InterruptedException
BlockingDequepollLast in interface BlockingDeque<E>timeout - how long to wait before giving up, in units of
unitunit - a TimeUnit determining how to interpret the
timeout parameterInterruptedException - if interrupted while waitingpublic E getFirst()
DequepeekFirst 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()
DequepeekLast 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()
Dequepublic E peekLast()
Dequepublic boolean removeFirstOccurrence(Object o)
BlockingDequeremoveFirstOccurrence in interface BlockingDeque<E>removeFirstOccurrence in interface Deque<E>o - element to be removed from this deque, if presentpublic boolean removeLastOccurrence(Object o)
BlockingDequeremoveLastOccurrence in interface BlockingDeque<E>removeLastOccurrence in interface Deque<E>o - element to be removed from this deque, if presentpublic boolean add(E e)
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 addCollection.add(E))IllegalStateException - if the element cannot be added at this
time due to capacity restrictionsNullPointerException - if the specified element is nullpublic boolean offer(E e)
BlockingDequeBlockingDeque.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 addNullPointerException - if the specified element is nullpublic void put(E e) throws InterruptedException
BlockingDequeThis 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
BlockingDequeThis 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
unitunit - a TimeUnit determining how to interpret the
timeout parameterNullPointerException - if the specified element is nullInterruptedException - if interrupted while waitingpublic E remove()
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()
BlockingDequeThis method is equivalent to Deque.pollFirst().
public E take() throws InterruptedException
BlockingDequeThis 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
BlockingDequeThis 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
unitunit - a TimeUnit determining how to interpret the
timeout parameterInterruptedException - if interrupted while waitingpublic E element()
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()
BlockingDequeThis method is equivalent to peekFirst.
public int remainingCapacity()
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)
BlockingQueuedrainTo 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)
BlockingQueuedrainTo 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)
BlockingDequeThis method is equivalent to addFirst.
push in interface BlockingDeque<E>push in interface Deque<E>e - the element to pushIllegalStateException - if the element cannot be added at this
time due to capacity restrictionsNullPointerException - if the specified element is nullpublic E pop()
DequeThis method is equivalent to Deque.removeFirst().
pop in interface Deque<E>NoSuchElementException - if this deque is emptypublic boolean remove(Object o)
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()
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)
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()
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)
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>a - 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()
AbstractCollectionString.valueOf(Object).toString in class AbstractCollection<E>public void clear()
clear in interface Collection<E>clear in class AbstractQueue<E>public Iterator<E> iterator()
The returned iterator is a "weakly consistent" iterator that
will never throw ConcurrentModificationException, and guarantees to traverse
elements as they existed upon construction of the iterator, and
may (but is not guaranteed to) reflect any modifications
subsequent to construction.
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()
The returned iterator is a "weakly consistent" iterator that
will never throw ConcurrentModificationException, and guarantees to traverse
elements as they existed upon construction of the iterator, and
may (but is not guaranteed to) reflect any modifications
subsequent to construction.
descendingIterator in interface Deque<E>