org.apache.beam.sdk.transforms.splittabledofn

Interface RestrictionTracker<RestrictionT>

All Known Implementing Classes:

OffsetRangeTracker

public interface RestrictionTracker<RestrictionT>

Manages concurrent access to the restriction and keeps track of its claimed part for a splittable DoFn.

Method Summary

Modifier and Type	Method and Description
void	checkDone() Called by the runner after DoFn.ProcessElement returns.
RestrictionT	checkpoint() Signals that the current DoFn.ProcessElement call should terminate as soon as possible: after this method returns, the tracker MUST refuse all future claim calls, and checkDone() MUST succeed.
RestrictionT	currentRestriction() Returns a restriction accurately describing the full range of work the current DoFn.ProcessElement call will do, including already completed work.

Method Detail

currentRestriction

RestrictionT currentRestriction()

Returns a restriction accurately describing the full range of work the current DoFn.ProcessElement call will do, including already completed work.

checkpoint

RestrictionT checkpoint()

Signals that the current DoFn.ProcessElement call should terminate as soon as possible: after this method returns, the tracker MUST refuse all future claim calls, and checkDone() MUST succeed.

Modifies currentRestriction(). Returns a restriction representing the rest of the work: the old value of currentRestriction() is equivalent to the new value and the return value of this method combined. Must be called at most once on a given object.

checkDone

void checkDone()
        throws java.lang.IllegalStateException

Called by the runner after DoFn.ProcessElement returns.

Must throw an exception with an informative error message, if there is still any unclaimed work remaining in the restriction.

Throws:

java.lang.IllegalStateException