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

Class UnorderedStreamElementQueue

java.lang.Object

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

All Implemented Interfaces:

StreamElementQueue

@Internal
public class UnorderedStreamElementQueue
extends Object
implements StreamElementQueue

Unordered implementation of the StreamElementQueue. The unordered stream element queue emits asynchronous results as soon as they are completed. Additionally it maintains the watermark-stream record order. This means that no stream record can be overtaken by a watermark and no watermark can overtake a stream record. However, stream records falling in the same segment between two watermarks can overtake each other (their emission order is not guaranteed).

Constructor Summary

Constructors

Constructor and Description
UnorderedStreamElementQueue(int capacity, Executor executor, OperatorActions operatorActions)

Method Summary

Modifier and Type	Method and Description
boolean	isEmpty() True if the queue is empty; otherwise false.
void	onCompleteHandler(StreamElementQueueEntry<?> streamElementQueueEntry) Callback for onComplete events for the given stream element queue entry.
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.

Methods inherited from class java.lang.Object

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

Constructor Detail

UnorderedStreamElementQueue

public UnorderedStreamElementQueue(int capacity,
                                   Executor executor,
                                   OperatorActions operatorActions)

Method Detail

put

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

Description copied from interface: StreamElementQueue

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

Specified by:

put in interface StreamElementQueue

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

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

Description copied from interface: StreamElementQueue

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.

Specified by:

tryPut in interface StreamElementQueue

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

public AsyncResult peekBlockingly()
                           throws InterruptedException

Description copied from interface: StreamElementQueue

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.

Specified by:

peekBlockingly in interface StreamElementQueue

Returns:

Completed AsyncResult

Throws:

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

poll

public AsyncResult poll()
                 throws InterruptedException

Description copied from interface: StreamElementQueue

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.

Specified by:

poll in interface StreamElementQueue

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

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

Description copied from interface: StreamElementQueue

Return the collection of StreamElementQueueEntry currently contained in this queue.

Specified by:

values in interface StreamElementQueue

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

public boolean isEmpty()

Description copied from interface: StreamElementQueue

True if the queue is empty; otherwise false.

Specified by:

isEmpty in interface StreamElementQueue

Returns:

True if the queue is empty; otherwise false.

size

public int size()

Description copied from interface: StreamElementQueue

Return the size of the queue.

Specified by:

size in interface StreamElementQueue

Returns:

The number of elements contained in this queue.

onCompleteHandler

public void onCompleteHandler(StreamElementQueueEntry<?> streamElementQueueEntry)
                       throws InterruptedException

Callback for onComplete events for the given stream element queue entry. Whenever a queue entry is completed, it is checked whether this entry belongs to the first set. If this is the case, then the element is added to the completed entries queue from where it can be consumed. If the first set becomes empty, then the next set is polled from the uncompleted entries queue. Completed entries from this new set are then added to the completed entries queue.

Parameters:

streamElementQueueEntry - which has been completed

Throws:

InterruptedException - if the current thread has been interrupted while performing the on complete callback.