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

Interface Grouping<S,K,V>

All Known Implementing Classes:

GroupSideEffectStep, GroupStep

public interface Grouping<S,K,V>

An interface for common functionality of GroupStep and GroupSideEffectStep.

Method Summary

Modifier and Type	Method and Description
default Traversal.Admin<S,V>	convertValueTraversal(Traversal.Admin<S,V> valueTraversal)
default Barrier	determineBarrierStep(Traversal.Admin<S,V> traversal) Determines the first non-local Barrier step in the provided traversal.
default Map<K,V>	doFinalReduction(Map<K,Object> map, Traversal.Admin<S,V> valueTraversal) When there is a Barrier detected by determineBarrierStep(Traversal.Admin) it is processed in full up to that point and then the remainder of the traversal that follows it is completed.
Traversal.Admin<S,K>	getKeyTraversal() Determines if the provided traversal is equal to the key traversal that the Grouping has.
Traversal.Admin<S,V>	getValueTraversal() Determines if the provided traversal is equal to the value traversal that the Grouping has.
default boolean	hasBarrierInValueTraversal() Checks if there is a non-local Barrier in the value traversal.

Method Detail

getKeyTraversal

Traversal.Admin<S,K> getKeyTraversal()

Determines if the provided traversal is equal to the key traversal that the Grouping has.

getValueTraversal

Traversal.Admin<S,V> getValueTraversal()

Determines if the provided traversal is equal to the value traversal that the Grouping has.

hasBarrierInValueTraversal

default boolean hasBarrierInValueTraversal()

Checks if there is a non-local Barrier in the value traversal.

determineBarrierStep

default Barrier determineBarrierStep(Traversal.Admin<S,V> traversal)

Determines the first non-local Barrier step in the provided traversal. This method is used by GroupStep and GroupSideEffectStep to ultimately determine the reducing bi-operator.

Parameters:

traversal - The traversal to inspect.

Returns:

The first non-local barrier step or null if no such step was found.

convertValueTraversal

default Traversal.Admin<S,V> convertValueTraversal(Traversal.Admin<S,V> valueTraversal)

doFinalReduction

default Map<K,V> doFinalReduction(Map<K,Object> map,
                                  Traversal.Admin<S,V> valueTraversal)

When there is a Barrier detected by determineBarrierStep(Traversal.Admin) it is processed in full up to that point and then the remainder of the traversal that follows it is completed.