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.
long	getAlignmentDurationNanos() Gets the time that the latest alignment took, in nanoseconds.
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(AbstractInvokable task) Registers the task be notified once all checkpoint barriers have been received for a checkpoint.

Method Detail

getNextNonBlocked

BufferOrEvent getNextNonBlocked()
                         throws Exception

Returns the next BufferOrEvent that the operator may consume. This call blocks until the next BufferOrEvent is available, or 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.

Exception - Thrown in case that a checkpoint fails that is started as the result of receiving the last checkpoint barrier

registerCheckpointEventHandler

void registerCheckpointEventHandler(AbstractInvokable task)

Registers the task be notified once all checkpoint barriers have been received for a checkpoint.

Parameters:

task - The task to notify

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.

getAlignmentDurationNanos

long getAlignmentDurationNanos()

Gets the time that the latest alignment took, in nanoseconds. If there is currently an alignment in progress, it will return the time spent in the current alignment so far.

Returns:

The duration in nanoseconds