co.cask.cdap.data2.queue

Interface DequeueResult<T>

Type Parameters:

T - type of dequeue result

All Superinterfaces:

Iterable<T>

public interface DequeueResult<T>
extends Iterable<T>

Represents result of an dequeue. The iterable gives dequeued data entries in the order of dequeue.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	DequeueResult.Empty Static helper class for creating empty result of different result type.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	isEmpty() Returns true if there is no data in the queue.
void	reclaim() Reclaim all dequeue entries represented by this result.
int	size() Returns number of entries in this result.

Methods inherited from interface java.lang.Iterable

iterator

Method Detail

isEmpty

boolean isEmpty()

Returns true if there is no data in the queue.

reclaim

void reclaim()

Reclaim all dequeue entries represented by this result. The effect is to put entries represented by this result back to the dequeued set of the queue consumer. Note that call to this method is transactional and requires a new transaction on the QueueConsumer instance who provides the instance of this DequeueResult. E.g.

   startTransaction();
   DequeueResult result;
   try {
     result = consumer.dequeue();
     commitTransaction();
   } catch (Exception e) {
     rollbackTransaction();

     // Skip the result.
     startTransaction();
     result.reclaim();
     commitTransaction();
   }

 

size

int size()

Returns number of entries in this result.