- java.lang.Object
-
- java.util.AbstractCollection<E>
-
- java.util.AbstractQueue<E>
-
- java.util.concurrent.LinkedBlockingDeque<E>
-
- Type Parameters:
E
- the type of elements held in this collection
- All Implemented Interfaces:
- Serializable, Iterable<E>, Collection<E>, BlockingDeque<E>, BlockingQueue<E>, Deque<E>, Queue<E>
public 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
andIterator
interfaces.This class is a member of the Java Collections Framework.
- Since:
- 1.6
- See Also:
- Serialized Form
-
-
Constructor Summary
Constructors Constructor and Description LinkedBlockingDeque()
Creates aLinkedBlockingDeque
with a capacity ofInteger.MAX_VALUE
.LinkedBlockingDeque(Collection<? extends E> c)
Creates aLinkedBlockingDeque
with a capacity ofInteger.MAX_VALUE
, initially containing the elements of the given collection, added in traversal order of the collection's iterator.LinkedBlockingDeque(int capacity)
Creates aLinkedBlockingDeque
with the given (fixed) capacity.
-
Method Summary
Methods 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)
Returnstrue
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.-
Methods inherited from class java.util.AbstractQueue
addAll
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Methods inherited from class java.util.AbstractCollection
containsAll, isEmpty, removeAll, retainAll
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-
-
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Constructor Detail
-
LinkedBlockingDeque
public LinkedBlockingDeque()
Creates aLinkedBlockingDeque
with a capacity ofInteger.MAX_VALUE
.
-
LinkedBlockingDeque
public LinkedBlockingDeque(int capacity)
Creates aLinkedBlockingDeque
with the given (fixed) capacity.- Parameters:
capacity
- the capacity of this deque- Throws:
IllegalArgumentException
- ifcapacity
is less than 1
-
LinkedBlockingDeque
public LinkedBlockingDeque(Collection<? extends E> c)
Creates aLinkedBlockingDeque
with a capacity ofInteger.MAX_VALUE
, initially containing the elements of the given collection, added in traversal order of the collection's iterator.- Parameters:
c
- the collection of elements to initially contain- Throws:
NullPointerException
- if the specified collection or any of its elements are null
-
-
Method Detail
-
addFirst
public 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 useofferFirst
.- Specified by:
addFirst
in interfaceBlockingDeque<E>
- Specified by:
addFirst
in interfaceDeque<E>
- Parameters:
e
- the element to add- Throws:
IllegalStateException
- if the element cannot be added at this time due to capacity restrictionsNullPointerException
- if the specified element is null
-
addLast
public 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 useofferLast
.- Specified by:
addLast
in interfaceBlockingDeque<E>
- Specified by:
addLast
in interfaceDeque<E>
- Parameters:
e
- the element to add- Throws:
IllegalStateException
- if the element cannot be added at this time due to capacity restrictionsNullPointerException
- if the specified element is null
-
offerFirst
public 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 theaddFirst
method, which can fail to insert an element only by throwing an exception.- Specified by:
offerFirst
in interfaceBlockingDeque<E>
- Specified by:
offerFirst
in interfaceDeque<E>
- Parameters:
e
- the element to add- Returns:
- true if the element was added to this deque, else false
- Throws:
NullPointerException
- if the specified element is null
-
offerLast
public 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 theaddLast
method, which can fail to insert an element only by throwing an exception.- Specified by:
offerLast
in interfaceBlockingDeque<E>
- Specified by:
offerLast
in interfaceDeque<E>
- Parameters:
e
- the element to add- Returns:
- true if the element was added to this deque, else false
- Throws:
NullPointerException
- if the specified element is null
-
putFirst
public 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.- Specified by:
putFirst
in interfaceBlockingDeque<E>
- Parameters:
e
- the element to add- Throws:
NullPointerException
- if the specified element is nullInterruptedException
- if interrupted while waiting
-
putLast
public 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.- Specified by:
putLast
in interfaceBlockingDeque<E>
- Parameters:
e
- the element to add- Throws:
NullPointerException
- if the specified element is nullInterruptedException
- if interrupted while waiting
-
offerFirst
public 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.- Specified by:
offerFirst
in interfaceBlockingDeque<E>
- Parameters:
e
- the element to addtimeout
- how long to wait before giving up, in units of unitunit
- a TimeUnit determining how to interpret the timeout parameter- Returns:
- true if successful, or false if the specified waiting time elapses before space is available
- Throws:
NullPointerException
- if the specified element is nullInterruptedException
- if interrupted while waiting
-
offerLast
public 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.- Specified by:
offerLast
in interfaceBlockingDeque<E>
- Parameters:
e
- the element to addtimeout
- how long to wait before giving up, in units of unitunit
- a TimeUnit determining how to interpret the timeout parameter- Returns:
- true if successful, or false if the specified waiting time elapses before space is available
- Throws:
NullPointerException
- if the specified element is nullInterruptedException
- if interrupted while waiting
-
removeFirst
public E removeFirst()
Description copied from interface:Deque
Retrieves and removes the first element of this deque. This method differs frompollFirst
only in that it throws an exception if this deque is empty.- Specified by:
removeFirst
in interfaceDeque<E>
- Returns:
- the head of this deque
- Throws:
NoSuchElementException
- if this deque is empty
-
removeLast
public E removeLast()
Description copied from interface:Deque
Retrieves and removes the last element of this deque. This method differs frompollLast
only in that it throws an exception if this deque is empty.- Specified by:
removeLast
in interfaceDeque<E>
- Returns:
- the tail of this deque
- Throws:
NoSuchElementException
- if this deque is empty
-
pollFirst
public E pollFirst()
Description copied from interface:Deque
Retrieves and removes the first element of this deque, or returns null if this deque is empty.
-
pollLast
public E pollLast()
Description copied from interface:Deque
Retrieves and removes the last element of this deque, or returns null if this deque is empty.
-
takeFirst
public 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.- Specified by:
takeFirst
in interfaceBlockingDeque<E>
- Returns:
- the head of this deque
- Throws:
InterruptedException
- if interrupted while waiting
-
takeLast
public 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.- Specified by:
takeLast
in interfaceBlockingDeque<E>
- Returns:
- the tail of this deque
- Throws:
InterruptedException
- if interrupted while waiting
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pollFirst
public 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.- Specified by:
pollFirst
in interfaceBlockingDeque<E>
- Parameters:
timeout
- how long to wait before giving up, in units of unitunit
- a TimeUnit determining how to interpret the timeout parameter- Returns:
- the head of this deque, or null if the specified waiting time elapses before an element is available
- Throws:
InterruptedException
- if interrupted while waiting
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pollLast
public 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.- Specified by:
pollLast
in interfaceBlockingDeque<E>
- Parameters:
timeout
- how long to wait before giving up, in units of unitunit
- a TimeUnit determining how to interpret the timeout parameter- Returns:
- the tail of this deque, or null if the specified waiting time elapses before an element is available
- Throws:
InterruptedException
- if interrupted while waiting
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getFirst
public E getFirst()
Description copied from interface:Deque
Retrieves, but does not remove, the first element of this deque. This method differs frompeekFirst
only in that it throws an exception if this deque is empty.- Specified by:
getFirst
in interfaceDeque<E>
- Returns:
- the head of this deque
- Throws:
NoSuchElementException
- if this deque is empty
-
getLast
public E getLast()
Description copied from interface:Deque
Retrieves, but does not remove, the last element of this deque. This method differs frompeekLast
only in that it throws an exception if this deque is empty.- Specified by:
getLast
in interfaceDeque<E>
- Returns:
- the tail of this deque
- Throws:
NoSuchElementException
- if this deque is empty
-
peekFirst
public 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.
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peekLast
public 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.
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removeFirstOccurrence
public 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).- Specified by:
removeFirstOccurrence
in interfaceBlockingDeque<E>
- Specified by:
removeFirstOccurrence
in interfaceDeque<E>
- Parameters:
o
- element to be removed from this deque, if present- Returns:
- true if an element was removed as a result of this call
-
removeLastOccurrence
public 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).- Specified by:
removeLastOccurrence
in interfaceBlockingDeque<E>
- Specified by:
removeLastOccurrence
in interfaceDeque<E>
- Parameters:
o
- element to be removed from this deque, if present- Returns:
- true if an element was removed as a result of this call
-
add
public 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 methodoffer
.This method is equivalent to
addLast(E)
.- Specified by:
add
in interfaceCollection<E>
- Specified by:
add
in interfaceBlockingDeque<E>
- Specified by:
add
in interfaceBlockingQueue<E>
- Specified by:
add
in interfaceDeque<E>
- Specified by:
add
in interfaceQueue<E>
- Overrides:
add
in classAbstractQueue<E>
- Parameters:
e
- the element to add- Returns:
- true (as specified by
Collection.add(E)
) - Throws:
IllegalStateException
- if the element cannot be added at this time due to capacity restrictionsNullPointerException
- if the specified element is null
-
offer
public 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 theBlockingDeque.add(E)
method, which can fail to insert an element only by throwing an exception.This method is equivalent to
offerLast
.- Specified by:
offer
in interfaceBlockingDeque<E>
- Specified by:
offer
in interfaceBlockingQueue<E>
- Specified by:
offer
in interfaceDeque<E>
- Specified by:
offer
in interfaceQueue<E>
- Parameters:
e
- the element to add- Returns:
- true if the element was added to this queue, else false
- Throws:
NullPointerException
- if the specified element is null
-
put
public 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
.- Specified by:
put
in interfaceBlockingDeque<E>
- Specified by:
put
in interfaceBlockingQueue<E>
- Parameters:
e
- the element to add- Throws:
NullPointerException
- if the specified element is nullInterruptedException
- if interrupted while waiting
-
offer
public 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
.- Specified by:
offer
in interfaceBlockingDeque<E>
- Specified by:
offer
in interfaceBlockingQueue<E>
- Parameters:
e
- the element to addtimeout
- how long to wait before giving up, in units of unitunit
- a TimeUnit determining how to interpret the timeout parameter- Returns:
- true if the element was added to this deque, else false
- Throws:
NullPointerException
- if the specified element is nullInterruptedException
- if interrupted while waiting
-
remove
public E remove()
Retrieves and removes the head of the queue represented by this deque. This method differs frompoll
only in that it throws an exception if this deque is empty.This method is equivalent to
removeFirst
.- Specified by:
remove
in interfaceBlockingDeque<E>
- Specified by:
remove
in interfaceDeque<E>
- Specified by:
remove
in interfaceQueue<E>
- Overrides:
remove
in classAbstractQueue<E>
- Returns:
- the head of the queue represented by this deque
- Throws:
NoSuchElementException
- if this deque is empty
-
poll
public 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()
.
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take
public 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
.- Specified by:
take
in interfaceBlockingDeque<E>
- Specified by:
take
in interfaceBlockingQueue<E>
- Returns:
- the head of this deque
- Throws:
InterruptedException
- if interrupted while waiting
-
poll
public 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
.- Specified by:
poll
in interfaceBlockingDeque<E>
- Specified by:
poll
in interfaceBlockingQueue<E>
- Parameters:
timeout
- how long to wait before giving up, in units of unitunit
- a TimeUnit determining how to interpret the timeout parameter- Returns:
- the head of this deque, or null if the specified waiting time elapses before an element is available
- Throws:
InterruptedException
- if interrupted while waiting
-
element
public E element()
Retrieves, but does not remove, the head of the queue represented by this deque. This method differs frompeek
only in that it throws an exception if this deque is empty.This method is equivalent to
getFirst
.- Specified by:
element
in interfaceBlockingDeque<E>
- Specified by:
element
in interfaceDeque<E>
- Specified by:
element
in interfaceQueue<E>
- Overrides:
element
in classAbstractQueue<E>
- Returns:
- the head of the queue represented by this deque
- Throws:
NoSuchElementException
- if this deque is empty
-
peek
public 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
.
-
remainingCapacity
public 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 currentsize
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.- Specified by:
remainingCapacity
in interfaceBlockingQueue<E>
- Returns:
- the remaining capacity
-
drainTo
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.- Specified by:
drainTo
in interfaceBlockingQueue<E>
- Parameters:
c
- the collection to transfer elements into- Returns:
- the number of elements transferred
- Throws:
UnsupportedOperationException
- 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 collection
-
drainTo
public 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.- Specified by:
drainTo
in interfaceBlockingQueue<E>
- Parameters:
c
- the collection to transfer elements intomaxElements
- the maximum number of elements to transfer- Returns:
- the number of elements transferred
- Throws:
UnsupportedOperationException
- 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 collection
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push
public void push(E e)
Description copied from interface:BlockingDeque
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
in interfaceBlockingDeque<E>
- Specified by:
push
in interfaceDeque<E>
- Parameters:
e
- the element to push- Throws:
IllegalStateException
- if the element cannot be added at this time due to capacity restrictionsNullPointerException
- if the specified element is null
-
pop
public 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()
.- Specified by:
pop
in interfaceDeque<E>
- Returns:
- the element at the front of this deque (which is the top of the stack represented by this deque)
- Throws:
NoSuchElementException
- if this deque is empty
-
remove
public 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 elemente
such thato.equals(e)
(if such an element exists). Returnstrue
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
.- Specified by:
remove
in interfaceCollection<E>
- Specified by:
remove
in interfaceBlockingDeque<E>
- Specified by:
remove
in interfaceBlockingQueue<E>
- Specified by:
remove
in interfaceDeque<E>
- Overrides:
remove
in classAbstractCollection<E>
- Parameters:
o
- element to be removed from this deque, if present- Returns:
true
if this deque changed as a result of the call
-
size
public int size()
Returns the number of elements in this deque.- Specified by:
size
in interfaceCollection<E>
- Specified by:
size
in interfaceBlockingDeque<E>
- Specified by:
size
in interfaceDeque<E>
- Specified by:
size
in classAbstractCollection<E>
- Returns:
- the number of elements in this deque
-
contains
public boolean contains(Object o)
Returnstrue
if this deque contains the specified element. More formally, returnstrue
if and only if this deque contains at least one elemente
such thato.equals(e)
.- Specified by:
contains
in interfaceCollection<E>
- Specified by:
contains
in interfaceBlockingDeque<E>
- Specified by:
contains
in interfaceBlockingQueue<E>
- Specified by:
contains
in interfaceDeque<E>
- Overrides:
contains
in classAbstractCollection<E>
- Parameters:
o
- object to be checked for containment in this deque- Returns:
true
if this deque contains the specified element
-
toArray
public 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.
- Specified by:
toArray
in interfaceCollection<E>
- Overrides:
toArray
in classAbstractCollection<E>
- Returns:
- an array containing all of the elements in this deque
-
toArray
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 ofString
:String[] y = x.toArray(new String[0]);
Note thattoArray(new Object[0])
is identical in function totoArray()
.- Specified by:
toArray
in interfaceCollection<E>
- Overrides:
toArray
in classAbstractCollection<E>
- Parameters:
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 purpose- Returns:
- an array containing all of the elements in this deque
- Throws:
ArrayStoreException
- 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 null
-
toString
public 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 byString.valueOf(Object)
.- Overrides:
toString
in classAbstractCollection<E>
- Returns:
- a string representation of this collection
-
clear
public void clear()
Atomically removes all of the elements from this deque. The deque will be empty after this call returns.- Specified by:
clear
in interfaceCollection<E>
- Overrides:
clear
in classAbstractQueue<E>
-
iterator
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 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.- Specified by:
iterator
in interfaceIterable<E>
- Specified by:
iterator
in interfaceCollection<E>
- Specified by:
iterator
in interfaceBlockingDeque<E>
- Specified by:
iterator
in interfaceDeque<E>
- Specified by:
iterator
in classAbstractCollection<E>
- Returns:
- an iterator over the elements in this deque in proper sequence
-
descendingIterator
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 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.- Specified by:
descendingIterator
in interfaceDeque<E>
- Returns:
- an iterator over the elements in this deque in reverse order
-
-
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Bij voorbaat dank.
Document heeft de 11/06/2005 gemaakt, de laatste keer de 04/03/2020 gewijzigd
Bron van het afgedrukte document:https://www.gaudry.be/nl/java-api-rf-java/util/concurrent/linkedblockingdeque.html
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