| java.util.concurrent.LinkedBlockingQueue
| LinkedBlockingQueue | | public class LinkedBlockingQueue extends AbstractQueue implements BlockingQueue<E>,java.io.Serializable(Code) | | An optionally-bounded
based on
linked nodes.
This queue orders elements FIFO (first-in-first-out).
The head of the queue is that element that has been on the
queue the longest time.
The tail of the queue is that element that has been on the
queue the shortest time. New elements
are inserted at the tail of the queue, and the queue retrieval
operations obtain elements at the head of the queue.
Linked queues typically have higher throughput than array-based queues but
less predictable performance in most concurrent applications.
The optional capacity bound constructor argument serves as a
way to prevent excessive queue expansion. The capacity, if unspecified,
is equal to
Integer.MAX_VALUE . Linked nodes are
dynamically created upon each insertion unless this would bring the
queue above capacity.
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.
since:
1.5
author:
Doug Lea<
Parameters:
E - > the type of elements held in this collection |
| Inner Class :static class Node | |
| Method Summary | |
| public void | clear()
Atomically removes all of the elements from this queue. | | public int | drainTo(Collection<? super E> c)
| | public int | drainTo(Collection<? super E> c, int maxElements)
| | public Iterator<E> | iterator()
Returns an iterator over the elements in this queue in proper sequence. | | public boolean | offer(E e, long timeout, TimeUnit unit)
Inserts the specified element at the tail of this queue, waiting if
necessary up to the specified wait time for space to become available. | | public boolean | offer(E e)
Inserts the specified element at the tail of this queue if it is
possible to do so immediately without exceeding the queue's capacity,
returning true upon success and false if this queue
is full. | | public E | peek()
| | public E | poll(long timeout, TimeUnit unit)
| | public E | poll()
| | public void | put(E e)
Inserts the specified element at the tail of this queue, waiting if
necessary for space to become available. | | public int | remainingCapacity()
Returns the number of additional elements that this queue can ideally
(in the absence of memory or resource constraints) accept without
blocking. | | public boolean | remove(Object o)
Removes a single instance of the specified element from this queue,
if it is present. | | public int | size()
Returns the number of elements in this queue. | | public E | take()
| | public Object[] | toArray()
Returns an array containing all of the elements in this queue, in
proper sequence.
The returned array will be "safe" in that no references to it are
maintained by this queue. | | public T[] | toArray(T[] a)
Returns an array containing all of the elements in this queue, in
proper sequence; the runtime type of the returned array is that of
the specified array. | | public String | toString()
|
| LinkedBlockingQueue | | public LinkedBlockingQueue()(Code) | | Creates a LinkedBlockingQueue with a capacity of
Integer.MAX_VALUE .
|
| LinkedBlockingQueue | | public LinkedBlockingQueue(int capacity)(Code) | | Creates a LinkedBlockingQueue with the given (fixed) capacity.
Parameters:
capacity - the capacity of this queue
throws:
IllegalArgumentException - if capacity is not greaterthan zero |
| LinkedBlockingQueue | | public LinkedBlockingQueue(Collection<? extends E> c)(Code) | | Creates a LinkedBlockingQueue with a capacity of
Integer.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 anyof its elements are null |
| clear | | public void clear()(Code) | | Atomically removes all of the elements from this queue.
The queue will be empty after this call returns.
|
| iterator | | public Iterator<E> iterator()(Code) | | Returns an iterator over the elements in this queue in proper sequence.
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.
an iterator over the elements in this queue in proper sequence |
| offer | | public boolean offer(E e, long timeout, TimeUnit unit) throws InterruptedException(Code) | | Inserts the specified element at the tail of this queue, waiting if
necessary up to the specified wait time for space to become available.
true if successful, or false ifthe specified waiting time elapses before space is available.
throws:
InterruptedException -
throws:
NullPointerException - |
| offer | | public boolean offer(E e)(Code) | | Inserts the specified element at the tail of this queue if it is
possible to do so immediately without exceeding the queue's capacity,
returning true upon success and false if this queue
is full.
When using a capacity-restricted queue, this method is generally
preferable to method
BlockingQueue.add add , which can fail to
insert an element only by throwing an exception.
throws:
NullPointerException - if the specified element is null |
| remainingCapacity | | public int remainingCapacity()(Code) | | Returns the number of additional elements that this queue can ideally
(in the absence of memory or resource constraints) accept without
blocking. This is always equal to the initial capacity of this queue
less the current size of this queue.
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.
|
| remove | | public boolean remove(Object o)(Code) | | Removes a single instance of the specified element from this queue,
if it is present. More formally, removes an element e such
that o.equals(e), if this queue contains one or more such
elements.
Returns true if this queue contained the specified element
(or equivalently, if this queue changed as a result of the call).
Parameters:
o - element to be removed from this queue, if present true if this queue changed as a result of the call |
| size | | public int size()(Code) | | Returns the number of elements in this queue.
the number of elements in this queue |
| toArray | | public Object[] toArray()(Code) | | Returns an array containing all of the elements in this queue, in
proper sequence.
The returned array will be "safe" in that no references to it are
maintained by this queue. (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.
an array containing all of the elements in this queue |
| toArray | | public T[] toArray(T[] a)(Code) | | Returns an array containing all of the elements in this queue, in
proper sequence; the runtime type of the returned array is that of
the specified array. If the queue 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 queue.
If this queue fits in the specified array with room to spare
(i.e., the array has more elements than this queue), the element in
the array immediately following the end of the queue is set to
null.
Like the
LinkedBlockingQueue.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 queue known to contain only strings.
The following code can be used to dump the queue 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().
Parameters:
a - the array into which the elements of the queue are tobe stored, if it is big enough; otherwise, a new array of thesame runtime type is allocated for this purpose an array containing all of the elements in this queue
throws:
ArrayStoreException - if the runtime type of the specified arrayis not a supertype of the runtime type of every element inthis queue
throws:
NullPointerException - if the specified array is null |
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