org.apache.flink.streaming.runtime.io

Interface CheckpointBarrierHandler

All Known Implementing Classes:

BarrierBuffer, BarrierTracker

@Internal
public interface CheckpointBarrierHandler

The CheckpointBarrierHandler reacts to checkpoint barrier arriving from the input channels. Different implementations may either simply track barriers, or block certain inputs on barriers.

Method Summary

Modifier and Type	Method and Description
void	cleanup() Cleans up all internally held resources.
BufferOrEvent	getNextNonBlocked() Returns the next BufferOrEvent that the operator may consume.
boolean	isEmpty() Checks if the barrier handler has buffered any data internally.
void	registerCheckpointEventHandler(EventListener<CheckpointBarrier> checkpointHandler) Registers the given event handler to be notified on successful checkpoints.

Method Detail

getNextNonBlocked

BufferOrEvent getNextNonBlocked()
                         throws IOException,
                                InterruptedException

Returns the next BufferOrEvent that the operator may consume. This call blocks until the next BufferOrEvent is available, ir until the stream has been determined to be finished.

Returns:

The next BufferOrEvent, or null, if the stream is finished.

Throws:

IOException - Thrown, if the network or local disk I/O fails.

InterruptedException - Thrown, if the thread is interrupted while blocking during waiting for the next BufferOrEvent to become available.

registerCheckpointEventHandler

void registerCheckpointEventHandler(EventListener<CheckpointBarrier> checkpointHandler)

Registers the given event handler to be notified on successful checkpoints.

Parameters:

checkpointHandler - The handler to register.

cleanup

void cleanup()
      throws IOException

Cleans up all internally held resources.

Throws:

IOException - Thrown, if the cleanup of I/O resources failed.

isEmpty

boolean isEmpty()

Checks if the barrier handler has buffered any data internally.

Returns:

True, if no data is buffered internally, false otherwise.