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java.util.concurrent
public class: LinkedBlockingQueue [javadoc | source]
java.lang.Object
   java.util.AbstractCollection<E>
      java.util.AbstractQueue<E>
         java.util.concurrent.LinkedBlockingQueue

All Implemented Interfaces:
    BlockingQueue, java$io$Serializable, Queue, Collection

An optionally-bounded {@linkplain BlockingQueue blocking queue} 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.

Nested Class Summary:
static class  LinkedBlockingQueue.Node  Linked list node class 
Constructor:
 public LinkedBlockingQueue() 
 public LinkedBlockingQueue(int capacity) 
 public LinkedBlockingQueue(Collection<? extends E> c) 
    Creates a {@code 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 any of its elements are null
Method from java.util.concurrent.LinkedBlockingQueue Summary:
clear,   contains,   drainTo,   drainTo,   fullyLock,   fullyUnlock,   iterator,   offer,   offer,   peek,   poll,   poll,   put,   remainingCapacity,   remove,   size,   take,   toArray,   toArray,   toString,   unlink
Methods from java.util.AbstractQueue:
add,   addAll,   clear,   element,   remove
Methods from java.util.AbstractCollection:
add,   addAll,   clear,   contains,   containsAll,   isEmpty,   iterator,   remove,   removeAll,   retainAll,   size,   toArray,   toArray,   toString
Methods from java.lang.Object:
clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait
Method from java.util.concurrent.LinkedBlockingQueue Detail:
 public  void clear() 
    Atomically removes all of the elements from this queue. The queue will be empty after this call returns.
 public boolean contains(Object o) 
    Returns {@code true} if this queue contains the specified element. More formally, returns {@code true} if and only if this queue contains at least one element {@code e} such that {@code o.equals(e)}.
 public int drainTo(Collection<? super E> c) 
 public int drainTo(Collection<? super E> c,
    int maxElements) 
  void fullyLock() 
    Lock to prevent both puts and takes.
  void fullyUnlock() 
    Unlock to allow both puts and takes.
 public Iterator<E> iterator() 
    Returns an iterator over the elements in this queue 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.

 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 {@code true} upon success and {@code false} if this queue is full. When using a capacity-restricted queue, this method is generally preferable to method add , which can fail to insert an element only by throwing an exception.
 public boolean offer(E e,
    long timeout,
    TimeUnit unit) throws InterruptedException 
    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 E peek() 
 public E poll() 
 public E poll(long timeout,
    TimeUnit unit) throws InterruptedException 
 public  void put(E e) throws InterruptedException 
    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. This is always equal to the initial capacity of this queue less the current {@code size} of this queue.

    Note that you cannot always tell if an attempt to insert an element will succeed by inspecting {@code remainingCapacity} because it may be the case that another thread is about to insert or remove an element.

 public boolean remove(Object o) 
    Removes a single instance of the specified element from this queue, if it is present. More formally, removes an element {@code e} such that {@code o.equals(e)}, if this queue contains one or more such elements. Returns {@code true} if this queue contained the specified element (or equivalently, if this queue changed as a result of the call).
 public int size() 
    Returns the number of elements in this queue.
 public E take() throws InterruptedException 
 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. (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.

 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. 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 {@code 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 {@code 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 {@code String}:

        String[] y = x.toArray(new String[0]);
    Note that {@code toArray(new Object[0])} is identical in function to {@code toArray()}.
 public String toString() 
  void unlink(Node<E> p,
    Node<E> trail) 
    Unlinks interior Node p with predecessor trail.