org.apache.oozie.util
Class PollablePriorityDelayQueue<E>

java.lang.Object
  java.util.AbstractCollection<E>
      java.util.AbstractQueue<PriorityDelayQueue.QueueElement<E>>
          org.apache.oozie.util.PriorityDelayQueue<E>
              org.apache.oozie.util.PollablePriorityDelayQueue<E>

All Implemented Interfaces:

Iterable<PriorityDelayQueue.QueueElement<E>>, Collection<PriorityDelayQueue.QueueElement<E>>, BlockingQueue<PriorityDelayQueue.QueueElement<E>>, Queue<PriorityDelayQueue.QueueElement<E>>

public class PollablePriorityDelayQueue<E>
extends PriorityDelayQueue<E>

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.oozie.util.PriorityDelayQueue

PriorityDelayQueue.QueueElement<E>

Field Summary

Fields inherited from class org.apache.oozie.util.PriorityDelayQueue

ANTI_STARVATION_INTERVAL, currentSize, lock, priorities, queues

Constructor Summary

PollablePriorityDelayQueue(int priorities, long maxWait, TimeUnit unit, int maxSize)

Method Summary

protected boolean	eligibleToPoll(PriorityDelayQueue.QueueElement<?> element) Method for checking the QueueElement eligible to poll before remove it from queue.
PriorityDelayQueue.QueueElement<E>	poll() Retrieve and remove the head of this queue if it is eligible to poll.

Methods inherited from class org.apache.oozie.util.PriorityDelayQueue

add, antiStarvation, clear, debug, drainTo, drainTo, getMaxSize, getMaxWait, getPriorities, iterator, offer, offer, peek, poll, put, remainingCapacity, size, sizes, take

Methods inherited from class java.util.AbstractQueue

addAll, element, remove

Methods inherited from class java.util.AbstractCollection

contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.concurrent.BlockingQueue

contains, remove

Methods inherited from interface java.util.Queue

element, remove

Methods inherited from interface java.util.Collection

addAll, containsAll, equals, hashCode, isEmpty, removeAll, retainAll, toArray, toArray

Constructor Detail

PollablePriorityDelayQueue

public PollablePriorityDelayQueue(int priorities,
                                  long maxWait,
                                  TimeUnit unit,
                                  int maxSize)

Method Detail

poll

public PriorityDelayQueue.QueueElement<E> poll()

Retrieve and remove the head of this queue if it is eligible to poll. If not, iterate next element until find the one which is eligible to poll from queue. Return null if this queue has no elements eligible to run.

Invocations to this method run the anti-starvation (once every interval check).

Specified by:

poll in interface Queue<PriorityDelayQueue.QueueElement<E>>

Overrides:

poll in class PriorityDelayQueue<E>

Returns:

the element of this queue, for which eligibleToPoll is true.

eligibleToPoll

protected boolean eligibleToPoll(PriorityDelayQueue.QueueElement<?> element)

Method for checking the QueueElement eligible to poll before remove it from queue.

This method should be overriden for checking purposes.

Parameters:

element - the element to check