org.apache.flink.streaming.api.operators.async.queue

Interface StreamElementQueue

All Known Implementing Classes:

OrderedStreamElementQueue, UnorderedStreamElementQueue

@Internal
public interface StreamElementQueue

Interface for blocking stream element queues for the AsyncWaitOperator.

Method Summary

Modifier and Type	Method and Description
boolean	isEmpty() True if the queue is empty; otherwise false.
AsyncResult	peekBlockingly() Peek at the head of the queue and return the first completed AsyncResult.
AsyncResult	poll() Poll the first completed AsyncResult from the head of this queue.
<T> void	put(StreamElementQueueEntry<T> streamElementQueueEntry) Put the given element in the queue if capacity is left.
int	size() Return the size of the queue.
<T> boolean	tryPut(StreamElementQueueEntry<T> streamElementQueueEntry) Try to put the given element in the queue.
Collection<StreamElementQueueEntry<?>>	values() Return the collection of StreamElementQueueEntry currently contained in this queue.

Method Detail

put

<T> void put(StreamElementQueueEntry<T> streamElementQueueEntry)
      throws InterruptedException

Put the given element in the queue if capacity is left. If not, then block until this is the case.

Type Parameters:

T - Type of the entries future value

Parameters:

streamElementQueueEntry - to be put into the queue

Throws:

InterruptedException - if the calling thread has been interrupted while waiting to insert the given element

tryPut

<T> boolean tryPut(StreamElementQueueEntry<T> streamElementQueueEntry)
            throws InterruptedException

Try to put the given element in the queue. This operation succeeds if the queue has capacity left and fails if the queue is full.

Type Parameters:

T - Type of the entries future value

Parameters:

streamElementQueueEntry - to be inserted

Returns:

True if the entry could be inserted; otherwise false

Throws:

InterruptedException - if the calling thread has been interrupted while waiting to insert the given element

peekBlockingly

AsyncResult peekBlockingly()
                    throws InterruptedException

Peek at the head of the queue and return the first completed AsyncResult. This operation is a blocking operation and only returns once a completed async result has been found.

Returns:

Completed AsyncResult

Throws:

InterruptedException - if the current thread has been interrupted while waiting for a completed async result.

poll

AsyncResult poll()
          throws InterruptedException

Poll the first completed AsyncResult from the head of this queue. This operation is blocking and only returns once a completed async result has been found.

Returns:

Completed AsyncResult which has been removed from the queue

Throws:

InterruptedException - if the current thread has been interrupted while waiting for a completed async result.

values

Collection<StreamElementQueueEntry<?>> values()
                                       throws InterruptedException

Return the collection of StreamElementQueueEntry currently contained in this queue.

Returns:

Collection of currently contained StreamElementQueueEntry.

Throws:

InterruptedException - if the current thread has been interrupted while retrieving the stream element queue entries of this queue.

isEmpty

boolean isEmpty()

True if the queue is empty; otherwise false.

Returns:

True if the queue is empty; otherwise false.

size

int size()

Return the size of the queue.

Returns:

The number of elements contained in this queue.