Type Parameters:

S - The incoming object type of the step

E - The outgoing object type of the step

All Superinterfaces:

Cloneable, Iterator<Traverser.Admin<E>>, Serializable

All Known Implementing Classes:

AbstractStep, AddEdgeStartStep, AddEdgeStep, AddPropertyStep, AddVertexStartStep, AddVertexStep, AggregateGlobalStep, AggregateLocalStep, AllStep, AndStep, AnyStep, AsDateStep, AsStringStep, BranchStep, CallStep, ChooseStep, ClassFilterStep, CoalesceStep, CoinStep, CollectingBarrierStep, CombineStep, ComputerAwareStep, ComputerAwareStep.EndStep, ComputerResultStep, ConcatStep, ConjoinStep, ConnectedComponentVertexProgramStep, ConnectiveStep, ConstantStep, CountGlobalStep, CountLocalStep, DateAddStep, DateDiffStep, DedupGlobalStep, DedupLocalStep, DifferenceStep, DisjunctStep, DropStep, EdgeOtherVertexStep, EdgeVertexStep, ElementMapStep, ElementStep, EmptyStep, FailStep, FilterStep, FlatMapStep, FoldStep, GraphStep, GroupCountSideEffectStep, GroupCountStep, GroupSideEffectStep, GroupStep, HasNextStep, HasStep, IdentityStep, IdStep, IndexStep, InjectStep, IntersectStep, IoStep, IsStep, LabelStep, LambdaCollectingBarrierStep, LambdaFilterStep, LambdaFlatMapStep, LambdaMapStep, LambdaSideEffectStep, LengthStep, LocalStep, LoopsStep, LTrimStep, MapStep, MatchStep, MatchStep.MatchEndStep, MatchStep.MatchStartStep, MathStep, MaxGlobalStep, MaxLocalStep, MeanGlobalStep, MeanLocalStep, MergeEdgeStep, MergeStep, MergeVertexStep, MinGlobalStep, MinLocalStep, NoneStep, NoOpBarrierStep, NotStep, OptionalStep, OrderGlobalStep, OrderLocalStep, OrStep, PageRankVertexProgramStep, PathFilterStep, PathStep, PeerPressureVertexProgramStep, ProductStep, ProfileSideEffectStep, ProfileStep, ProfileTest.MockStep, ProgramVertexProgramStep, ProjectStep, PropertiesStep, PropertyKeyStep, PropertyMapStep, PropertyValueStep, RangeGlobalStep, RangeLocalStep, ReducingBarrierStep, ReferenceElementStrategy.ReferenceElementStep, RemoteStep, RepeatStep, RepeatStep.RepeatEndStep, ReplaceStep, RequirementsStep, ReverseStep, RTrimStep, SackStep, SackValueStep, SampleGlobalStep, SampleLocalStep, ScalarMapStep, SelectOneStep, SelectStep, ShortestPathVertexProgramStep, SideEffectCapStep, SideEffectStep, SplitStep, StartStep, SubgraphStep, SubstringStep, SumGlobalStep, SumLocalStep, SupplyingBarrierStep, TailGlobalStep, TailLocalStep, TimeLimitStep, TinkerCountGlobalStep, TinkerGraphStep, ToLowerStep, ToUpperStep, TraversalFilterStep, TraversalFlatMapStep, TraversalMapStep, TraversalMergeStep, TraversalSelectStep, TraversalSideEffectStep, TraversalVertexProgramStep, TreeSideEffectStep, TreeStep, TrimStep, UnfoldStep, UnionStep, VertexProgramStep, VertexStep, WherePredicateStep, WhereTraversalStep, WhereTraversalStep.WhereEndStep, WhereTraversalStep.WhereStartStep
```
public interface Step<S,E>
extends Iterator<Traverser.Admin<E>>, Serializable, Cloneable
```
A Step denotes a unit of computation within a Traversal. A step takes an incoming object and yields an outgoing object. Steps are chained together in a Traversal to yield a lazy function chain of computation.
In the constructor of a Step, never store explicit sideEffect objects in TraversalSideEffects. If a sideEffect needs to be registered with the Traversal, use SideEffects.registerSupplier().

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`void`	`addLabel(String label)`	Add a label to this step.
`void`	`addStart(Traverser.Admin<S> start)`	Add a single `Traverser.Admin` to the step.
`void`	`addStarts(Iterator<Traverser.Admin<S>> starts)`	Add an iterator of `Traverser.Admin` objects of type S to the step.
`void`	`clearLabels()`	Removes all labels on the step.
`Step<S,E>`	`clone()`	Cloning is used to duplicate steps for the purpose of traversal optimization and OLTP replication.
`default boolean`	`equals(Step other, boolean compareIds)`	Compare the current step with another step.
`String`	`getId()`	Get the unique id of this step.
`Set<String>`	`getLabels()`	Get the labels of this step.
`Step<E,?>`	`getNextStep()`	Get the next step to the current step.
`Step<?,S>`	`getPreviousStep()`	Get the step prior to the current step.
`default Set<TraverserRequirement>`	`getRequirements()`	Provide the necessary `TraverserRequirement` that must be met by the traverser in order for the step to function properly.
`<A,B> Traversal.Admin<A,B>`	`getTraversal()`	Get the `Traversal.Admin` that this step is contained within.
`boolean`	`hasStarts()`	Determines if starts objects are present without iterating forward.
`void`	`removeLabel(String label)`	Remove a label from this step.
`void`	`reset()`	Reset the state of the step such that it has no incoming starts.
`void`	`setId(String id)`	Get the unique id of the step.
`void`	`setNextStep(Step<E,?> step)`	Set the step that is next to the current step.
`void`	`setPreviousStep(Step<?,S> step)`	Set the step that is previous to the current step.
`void`	`setTraversal(Traversal.Admin<?,?> traversal)`	Set the `Traversal` that this step is contained within.

Methods inherited from interface java.util.Iterator
forEachRemaining, hasNext, next, remove

- Method Detail
  - addStarts
```
void addStarts(Iterator<Traverser.Admin<S>> starts)
```
    Add an iterator of Traverser.Admin objects of type S to the step.
    
    Parameters:
    
    starts - The iterator of objects to add
  - addStart
```
void addStart(Traverser.Admin<S> start)
```
    Add a single Traverser.Admin to the step.
    
    Parameters:
    
    start - The traverser to add
  - hasStarts
```
boolean hasStarts()
```
    Determines if starts objects are present without iterating forward. This function has special applicability around ReducingBarrierStep implementations where they always return true for calls to Iterator.hasNext(). Using this function gives insight to what the step itself is holding in its iterator without performing any sort of processing on the step itself.
  - setPreviousStep
```
void setPreviousStep(Step<?,S> step)
```
    Set the step that is previous to the current step. Used for linking steps together to form a function chain.
    
    Parameters:
    
    step - the previous step of this step
  - getPreviousStep
```
Step<?,S> getPreviousStep()
```
    Get the step prior to the current step.
    
    Returns:
    
    The previous step
  - setNextStep
```
void setNextStep(Step<E,?> step)
```
    Set the step that is next to the current step. Used for linking steps together to form a function chain.
    
    Parameters:
    
    step - the next step of this step
  - getNextStep
```
Step<E,?> getNextStep()
```
    Get the next step to the current step.
    
    Returns:
    
    The next step
  - getTraversal
```
<A,B> Traversal.Admin<A,B> getTraversal()
```
    Get the Traversal.Admin that this step is contained within.
    
    Type Parameters:
    
    A - The incoming object type of the traversal
    
    B - The outgoing object type of the traversal
    
    Returns:
    
    The traversal of this step
  - setTraversal
```
void setTraversal(Traversal.Admin<?,?> traversal)
```
    Set the Traversal that this step is contained within.
    
    Parameters:
    
    traversal - the new traversal for this step
  - reset
```
void reset()
```
    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.
  - clone
```
Step<S,E> clone()
```
    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.
    
    Returns:
    
    The cloned step
  - getLabels
```
Set<String> getLabels()
```
    Get the labels of this step. The labels are ordered by the order of the calls to addLabel(java.lang.String).
    
    Returns:
    
    the set of labels for this step
  - addLabel
```
void addLabel(String label)
```
    Add a label to this step.
    
    Parameters:
    
    label - the label to add to this step
  - removeLabel
```
void removeLabel(String label)
```
    Remove a label from this step.
    
    Parameters:
    
    label - the label to remove from this step
  - clearLabels
```
void clearLabels()
```
    Removes all labels on the step.
  - setId
```
void setId(String id)
```
    Get the unique id of the step. These ids can change when strategies are applied and anonymous traversals are embedded in the parent traversal. A developer should typically not need to call this method.
    
    Parameters:
    
    id - the unique id of the step
  - getId
```
String getId()
```
    Get the unique id of this step.
    
    Returns:
    
    the unique id of the step
  - getRequirements
```
default Set<TraverserRequirement> getRequirements()
```
    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.
    
    Returns:
    
    the set of requirements
  - equals
```
default boolean equals(Step other,
                       boolean compareIds)
```
    Compare the current step with another step.
    
    Parameters:
    
    other - the other step
    
    compareIds - whether to compare step IDs or not
    
    Returns:
    
    true if the steps are equal, otherwise false

Interface Step<S,​E>

Method Summary

Methods inherited from interface java.util.Iterator

Method Detail

addStarts

addStart

hasStarts

setPreviousStep

getPreviousStep

setNextStep

getNextStep

getTraversal

setTraversal

reset

clone

getLabels

addLabel

removeLabel

clearLabels

setId

getId

getRequirements

equals

Interface Step<S,E>