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

Class GroupCountStep<S,E>

java.lang.Object

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

org.apache.tinkerpop.gremlin.process.traversal.step.util.ReducingBarrierStep<S,Map<E,Long>>

org.apache.tinkerpop.gremlin.process.traversal.step.map.GroupCountStep<S,E>

All Implemented Interfaces:

Serializable, AutoCloseable, Cloneable, Iterator<Traverser.Admin<Map<E,Long>>>, Step<S,Map<E,Long>>, Barrier<Map<E,Long>>, ByModulating, Generating<Map<E,Long>,Map<E,Long>>, MemoryComputing<Map<E,Long>>, PopContaining, TraversalParent

public class GroupCountStep<S,E>
extends ReducingBarrierStep<S,Map<E,Long>>
implements TraversalParent, ByModulating

Author:

Marko A. Rodriguez (http://markorodriguez.com)

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	GroupCountStep.GroupCountBiOperator<E>

Nested classes/interfaces inherited from class org.apache.tinkerpop.gremlin.process.traversal.step.util.ReducingBarrierStep

ReducingBarrierStep.NonEmittingSeed

Nested classes/interfaces inherited from interface org.apache.tinkerpop.gremlin.process.traversal.step.PopContaining

PopContaining.PopInstruction

Field Summary

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

hasProcessedOnce, NON_EMITTING_SEED, reducingBiOperator, seedSupplier

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
GroupCountStep(Traversal.Admin traversal)

Method Summary

Modifier and Type	Method	Description
void	addLocalChild(Traversal.Admin<?,?> groupTraversal)
GroupCountStep<S,E>	clone()	Cloning is used to duplicate steps for the purpose of traversal optimization and OLTP replication.
List<Traversal.Admin<S,E>>	getLocalChildren()	Gets a list of all "local" child traversals for this step.
Set<TraverserRequirement>	getRequirements()	Provide the necessary TraverserRequirement that must be met by the traverser in order for the step to function properly.
int	hashCode()
void	modulateBy(Traversal.Admin<?,?> keyTraversal)
Map<E,Long>	projectTraverser(Traverser.Admin<S> traverser)
void	replaceLocalChild(Traversal.Admin<?,?> oldTraversal, Traversal.Admin<?,?> newTraversal)
void	setTraversal(Traversal.Admin<?,?> parentTraversal)	Set the Traversal that this step is contained within.
String	toString()

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

addBarrier, done, generateSeedFromStarts, getBiOperator, getEmptyBarrier, getMemoryComputeKey, getSeedSupplier, hasNextBarrier, nextBarrier, processAllStarts, processNextStart, reset, setReducingBiOperator, setSeedSupplier

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

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

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.ByModulating

modulateBy, modulateBy, modulateBy, modulateBy, modulateBy, modulateBy, modulateBy, modulateBy, modulateBy, modulateBy, modulateBy

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

generateFinalResult

Methods inherited from interface java.util.Iterator

forEachRemaining, remove

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

equals

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

addGlobalChild, asStep, close, getGlobalChildren, getPopInstructions, getSelfAndChildRequirements, integrateChild, removeGlobalChild, removeLocalChild

Constructor Detail

GroupCountStep

public GroupCountStep(Traversal.Admin traversal)

Method Detail

projectTraverser

public Map<E,Long> projectTraverser(Traverser.Admin<S> traverser)

Specified by:

projectTraverser in class ReducingBarrierStep<S,Map<E,Long>>

addLocalChild

public void addLocalChild(Traversal.Admin<?,?> groupTraversal)

Specified by:

addLocalChild in interface TraversalParent

getLocalChildren

public List<Traversal.Admin<S,E>> getLocalChildren()

Description copied from interface: TraversalParent

Gets a list of all "local" child traversals for this step. A "local" traversal is one which is evaluated independently for each incoming traverser to the parent step. This is typically used in cases where the child is used to process or augment each traverser individually. See LocalStep or ByModulating as examples.

Specified by:

getLocalChildren in interface TraversalParent

getRequirements

public Set<TraverserRequirement> getRequirements()

Description copied from interface: Step

Provide the necessary TraverserRequirement that must be met by the traverser in order for the step to function properly. The provided default implements returns an empty set.

Specified by:

getRequirements in interface Step<S,E>

Returns:

the set of requirements

modulateBy

public void modulateBy(Traversal.Admin<?,?> keyTraversal)
                throws UnsupportedOperationException

Specified by:

modulateBy in interface ByModulating

Throws:

UnsupportedOperationException

replaceLocalChild

public void replaceLocalChild(Traversal.Admin<?,?> oldTraversal,
                              Traversal.Admin<?,?> newTraversal)

Specified by:

replaceLocalChild in interface TraversalParent

clone

public GroupCountStep<S,E> 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,E>

Overrides:

clone in class ReducingBarrierStep<S,Map<E,Long>>

Returns:

The cloned step

setTraversal

public void setTraversal(Traversal.Admin<?,?> parentTraversal)

Description copied from interface: Step

Set the Traversal that this step is contained within.

Specified by:

setTraversal in interface Step<S,E>

Overrides:

setTraversal in class AbstractStep<S,Map<E,Long>>

Parameters:

parentTraversal - the new traversal for this step

hashCode

public int hashCode()

Overrides:

hashCode in class AbstractStep<S,Map<E,Long>>

toString

public String toString()

Overrides:

toString in class AbstractStep<S,Map<E,Long>>