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

Class GroupStep<S,K,V,R>

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<K,R>>

org.apache.tinkerpop.gremlin.process.traversal.step.map.GroupStep<S,K,V,R>

All Implemented Interfaces:

Serializable, Cloneable, Iterator<Traverser<Map<K,R>>>, Step<S,Map<K,R>>, EngineDependent, MapReducer, TraversalParent

public final class GroupStep<S,K,V,R>
extends ReducingBarrierStep<S,Map<K,R>>
implements MapReducer, TraversalParent

Author:

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

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	GroupStep.GroupMapReduce<K,V,R>

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

ReducingBarrierStep.DefaultMapReduce, ReducingBarrierStep.FinalGet<A>

Field Summary

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

byPass, REDUCING, reducingBiFunction, seedSupplier

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

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

Constructor Summary

Constructors

Constructor and Description
GroupStep(Traversal.Admin traversal)

Method Summary

Modifier and Type	Method and Description
void	addLocalChild(Traversal.Admin<?,?> kvrTraversal)
GroupStep<S,K,V,R>	clone() Cloning is used to duplicate steps for the purpose of traversal optimization and OLTP replication.
<A,B> List<Traversal.Admin<A,B>>	getLocalChildren()
MapReduce<K,Collection<V>,K,R,Map<K,R>>	getMapReduce()
Traversal.Admin<Collection<V>,R>	getReduceTraversal()
Set<TraverserRequirement>	getRequirements() Provide the necessary TraverserRequirement that must be met by the traverser in order for the step to function properly.
int	hashCode()
Traverser<Map<K,R>>	processNextStart()
String	toString()

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

onEngine, reset, setBiFunction, setSeedSupplier

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

addLabel, addStart, addStarts, equals, getId, getLabels, getNextStep, getPreviousStep, getTraversal, hasNext, next, removeLabel, setId, setNextStep, setPreviousStep, setTraversal

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.TraversalParent

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

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

equals

Methods inherited from interface java.util.Iterator

forEachRemaining, remove

Constructor Detail

GroupStep

public GroupStep(Traversal.Admin traversal)

Method Detail

getLocalChildren

public <A,B> List<Traversal.Admin<A,B>> getLocalChildren()

Specified by:

getLocalChildren in interface TraversalParent

getReduceTraversal

public Traversal.Admin<Collection<V>,R> getReduceTraversal()

addLocalChild

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

Specified by:

addLocalChild 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,Map<K,R>>

Returns:

the set of requirements

clone

public GroupStep<S,K,V,R> 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 reset() is called. Moreover, the previous and next steps should be set to EmptyStep.

Specified by:

clone in interface Step<S,Map<K,R>>

Overrides:

clone in class ReducingBarrierStep<S,Map<K,R>>

Returns:

The cloned step

hashCode

public int hashCode()

Overrides:

hashCode in class AbstractStep<S,Map<K,R>>

getMapReduce

public MapReduce<K,Collection<V>,K,R,Map<K,R>> getMapReduce()

Specified by:

getMapReduce in interface MapReducer

Overrides:

getMapReduce in class ReducingBarrierStep<S,Map<K,R>>

processNextStart

public Traverser<Map<K,R>> processNextStart()

Overrides:

processNextStart in class ReducingBarrierStep<S,Map<K,R>>

toString

public String toString()

Overrides:

toString in class AbstractStep<S,Map<K,R>>