org.apache.beam.sdk.transforms.splittabledofn

Class ByteKeyRangeTracker

java.lang.Object

org.apache.beam.sdk.transforms.splittabledofn.RestrictionTracker<ByteKeyRange,ByteKey>

org.apache.beam.sdk.transforms.splittabledofn.ByteKeyRangeTracker

public class ByteKeyRangeTracker
extends RestrictionTracker<ByteKeyRange,ByteKey>

A RestrictionTracker for claiming ByteKeys in a ByteKeyRange in a monotonically increasing fashion. The range is a semi-open bounded interval [startKey, endKey) where the limits are both represented by ByteKey.EMPTY.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.beam.sdk.transforms.splittabledofn.RestrictionTracker

RestrictionTracker.ClaimObserver<PositionT>

Method Summary

Modifier and Type	Method and Description
void	checkDone() Called by the runner after DoFn.ProcessElement returns.
ByteKeyRange	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 RestrictionTracker.checkDone() MUST succeed.
ByteKeyRange	currentRestriction() Returns a restriction accurately describing the full range of work the current DoFn.ProcessElement call will do, including already completed work.
void	markDone() Marks that there are no more keys to be claimed in the range.
static ByteKeyRangeTracker	of(ByteKeyRange range)
java.lang.String	toString()
protected boolean	tryClaimImpl(ByteKey key) Attempts to claim the given key.

Methods inherited from class org.apache.beam.sdk.transforms.splittabledofn.RestrictionTracker

setClaimObserver, tryClaim

Methods inherited from class java.lang.Object

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

Method Detail

of

public static ByteKeyRangeTracker of(ByteKeyRange range)

currentRestriction

public ByteKeyRange currentRestriction()

Description copied from class: RestrictionTracker

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

Specified by:

currentRestriction in class RestrictionTracker<ByteKeyRange,ByteKey>

checkpoint

public ByteKeyRange checkpoint()

Description copied from class: RestrictionTracker

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 RestrictionTracker.checkDone() MUST succeed.

Modifies RestrictionTracker.currentRestriction(). Returns a restriction representing the rest of the work: the old value of RestrictionTracker.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. Must not be called before the first successful RestrictionTracker.tryClaim(PositionT) call.

Specified by:

checkpoint in class RestrictionTracker<ByteKeyRange,ByteKey>

tryClaimImpl

protected boolean tryClaimImpl(ByteKey key)

Attempts to claim the given key.

Must be larger than the last successfully claimed key.

Specified by:

tryClaimImpl in class RestrictionTracker<ByteKeyRange,ByteKey>

Returns:

true if the key was successfully claimed, false if it is outside the current ByteKeyRange of this tracker (in that case this operation is a no-op).

markDone

public void markDone()

Marks that there are no more keys to be claimed in the range.

E.g., a DoFn reading a file and claiming the key of each record in the file might call this if it hits EOF - even though the last attempted claim was before the end of the range, there are no more keys to claim.

checkDone

public void checkDone()
               throws java.lang.IllegalStateException

Description copied from class: RestrictionTracker

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.

Specified by:

checkDone in class RestrictionTracker<ByteKeyRange,ByteKey>

Throws:

java.lang.IllegalStateException

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object