Class BlockingQueue

java.lang.Object
org.jpos.util.BlockingQueue
public class BlockingQueue extends Object
implements a blocking queue
Since:
1.1
See Also:

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static class 
    BlockingQueue.Closed
    Thrown by queue operations after the queue has been closed.

  • Constructor Summary

    Constructors
    Constructor
    Description
    BlockingQueue()
    Creates an empty, open queue.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    close()
    Closes the queue and wakes all waiting consumers, who will then receive BlockingQueue.Closed.
    int
    consumerCount()
    Returns the number of consumers currently waiting on this queue.
    int
    consumerDeficit()
    Returns the difference between queued items and waiting consumers.
    Object
    dequeue()
    Removes and returns the head of the queue, blocking until an object is available.
    Object
    dequeue(long timeout)
    Removes and returns the head of the queue, blocking up to timeout ms.
    void
    enqueue(Object o)
    Appends an object to the tail of the queue and wakes one waiter.
    LinkedList
    getQueue()
    Returns the underlying list backing this queue.
    int
    pending()
    Returns the number of items currently in the queue.
    boolean
    ready()
    Indicates whether the queue is open for new operations.
    void
    requeue(Object o)
    Inserts an object at the head of the queue and wakes one waiter.
    void
    setQueue(LinkedList queue)
    Replaces the underlying list backing this queue.

    Methods inherited from class Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • BlockingQueue

      public BlockingQueue()
      Creates an empty, open queue.

  • Method Details

    • enqueue

      public void enqueue(Object o) throws BlockingQueue.Closed
      Appends an object to the tail of the queue and wakes one waiter.
      Parameters:
      o - the object to enqueue
      Throws:
      BlockingQueue.Closed - if the queue has been closed

    • requeue

      public void requeue(Object o) throws BlockingQueue.Closed
      Inserts an object at the head of the queue and wakes one waiter.
      Parameters:
      o - the object to requeue
      Throws:
      BlockingQueue.Closed - if the queue has been closed

    • dequeue

      public Object dequeue() throws InterruptedException, BlockingQueue.Closed
      Removes and returns the head of the queue, blocking until an object is available.
      Returns:
      the object at the head of the queue
      Throws:
      InterruptedException - if the thread is interrupted while waiting
      BlockingQueue.Closed - if the queue is closed while waiting

    • dequeue

      public Object dequeue(long timeout) throws InterruptedException, BlockingQueue.Closed
      Removes and returns the head of the queue, blocking up to timeout ms.
      Parameters:
      timeout - maximum wait in milliseconds; 0 blocks indefinitely
      Returns:
      the object at the head of the queue, or null if the wait elapsed
      Throws:
      InterruptedException - if the thread is interrupted while waiting
      BlockingQueue.Closed - if the queue is closed while waiting

    • close

      public void close()
      Closes the queue and wakes all waiting consumers, who will then receive BlockingQueue.Closed.

    • consumerCount

      public int consumerCount()
      Returns the number of consumers currently waiting on this queue.
      Returns:
      the live consumer count

    • consumerDeficit

      public int consumerDeficit()
      Returns the difference between queued items and waiting consumers.
      Returns:
      queue size minus consumer count (negative when consumers exceed items)

    • ready

      public boolean ready()
      Indicates whether the queue is open for new operations.
      Returns:
      true if the queue has not been closed

    • pending

      public int pending()
      Returns the number of items currently in the queue.
      Returns:
      the queue size

    • getQueue

      public LinkedList getQueue()
      Returns the underlying list backing this queue.
      Returns:
      the internal list (live reference, not a copy)

    • setQueue

      public void setQueue(LinkedList queue)
      Replaces the underlying list backing this queue.
      Parameters:
      queue - the list to use as the new backing store