Package org.apache.tinkerpop.gremlin.process.traversal.step.sideEffect

Class SideEffectBarrierStep<S>

java.lang.Object

org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep<S,S>

org.apache.tinkerpop.gremlin.process.traversal.step.sideEffect.SideEffectBarrierStep<S>

All Implemented Interfaces:

Serializable, Cloneable, Iterator<Traverser.Admin<S>>, Step<S,S>, Barrier<TraverserSet<S>>, LocalBarrier<S>, MemoryComputing<TraverserSet<S>>

Direct Known Subclasses:

GroupCountSideEffectStep, GroupSideEffectStep, SubgraphStep, TreeSideEffectStep

public abstract class SideEffectBarrierStep<S>
extends AbstractStep<S,S>
implements LocalBarrier<S>

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected TraverserSet<S>	barrier

Fields inherited from class org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep

id, labels, nextEnd, nextStep, previousStep, starts, traversal, traverserStepIdAndLabelsSetByChild

Constructor Summary

Constructors

Constructor	Description
SideEffectBarrierStep(Traversal.Admin traversal)

Method Summary

Modifier and Type	Method	Description
void	addBarrier(TraverserSet<S> barrier)	Add a barrier to the step.
SideEffectBarrierStep<S>	clone()	Cloning is used to duplicate steps for the purpose of traversal optimization and OLTP replication.
boolean	hasNextBarrier()	Whether or not the step has an accessible barrier.
TraverserSet<S>	nextBarrier()	Get the next barrier within this step.
void	processAllStarts()	Process all left traversers by do not yield the resultant output.
protected Traverser.Admin<S>	processNextStart()
void	reset()	Reset the state of the step such that it has no incoming starts.
protected abstract void	sideEffect(Traverser.Admin<S> traverser)

Methods inherited from class org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep

addLabel, addStart, addStarts, clearLabels, equals, getId, getLabels, getNextStep, getPreviousStep, getStarts, getTraversal, hashCode, hasNext, hasStarts, isTraverserStepIdAndLabelsSetByChild, next, prepareTraversalForNextStep, removeLabel, setId, setNextStep, setPreviousStep, setTraversal, toString

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.tinkerpop.gremlin.process.traversal.step.Barrier

done

Methods inherited from interface java.util.Iterator

forEachRemaining, remove

Methods inherited from interface org.apache.tinkerpop.gremlin.process.traversal.step.LocalBarrier

getEmptyBarrier, getMemoryComputeKey

Methods inherited from interface org.apache.tinkerpop.gremlin.process.traversal.Step

equals, getRequirements

Field Detail

barrier

protected TraverserSet<S> barrier

Constructor Detail

SideEffectBarrierStep

public SideEffectBarrierStep(Traversal.Admin traversal)

Method Detail

sideEffect

protected abstract void sideEffect(Traverser.Admin<S> traverser)

processNextStart

protected Traverser.Admin<S> processNextStart()

Specified by:

processNextStart in class AbstractStep<S,S>

processAllStarts

public void processAllStarts()

Description copied from interface: Barrier

Process all left traversers by do not yield the resultant output. This method is useful for steps like ReducingBarrierStep, where traversers can be processed "on the fly" and thus, reduce memory consumption.

Specified by:

processAllStarts in interface Barrier<S>

hasNextBarrier

public boolean hasNextBarrier()

Description copied from interface: Barrier

Whether or not the step has an accessible barrier.

Specified by:

hasNextBarrier in interface Barrier<S>

Returns:

whether a barrier exists or not

nextBarrier

public TraverserSet<S> nextBarrier()
                            throws NoSuchElementException

Description copied from interface: Barrier

Get the next barrier within this step. Barriers from parallel steps can be the be merged to create a single step with merge barriers.

Specified by:

nextBarrier in interface Barrier<S>

Returns:

the next barrier of the step

Throws:

NoSuchElementException

addBarrier

public void addBarrier(TraverserSet<S> barrier)

Description copied from interface: Barrier

Add a barrier to the step. This typically happens when multiple parallel barriers need to become one barrier at a single step.

Specified by:

addBarrier in interface Barrier<S>

Parameters:

barrier - the barrier to merge in

reset

public void reset()

Description copied from interface: Step

Reset the state of the step such that it has no incoming starts. Internal states are to be reset, but any sideEffect data structures are not to be recreated.

Specified by:

reset in interface Step<S,S>

Overrides:

reset in class AbstractStep<S,S>

clone

public SideEffectBarrierStep<S> clone()

Description copied from interface: Step

Cloning is used to duplicate steps for the purpose of traversal optimization and OLTP replication. When cloning a step, it is important that the steps, the cloned step is equivalent to the state of the step when Step.reset() is called. Moreover, the previous and next steps should be set to EmptyStep.

Specified by:

clone in interface Step<S,S>

Overrides:

clone in class AbstractStep<S,S>

Returns:

The cloned step