EmptyStep (Apache TinkerPop 3.5.3 API)

java.lang.Object
- org.apache.tinkerpop.gremlin.process.traversal.step.util.EmptyStep<S,E>

All Implemented Interfaces:

Serializable, AutoCloseable, Cloneable, Iterator<Traverser.Admin<E>>, Step<S,E>, TraversalParent
```
public final class EmptyStep<S,E>
extends Object
implements Step<S,E>, TraversalParent
```
Author:

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

See Also:

Serialized Form

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and 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 a iterator of `Traverser.Admin` objects of type S to the step.
`EmptyStep<S,E>`	`clone()` Cloning is used to duplicate steps for the purpose of traversal optimization and OLTP replication.
`boolean`	`equals(Object object)`
`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.
`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.
`int`	`hashCode()`
`boolean`	`hasNext()`
`boolean`	`hasStarts()` Determines if starts objects are present without iterating forward.
`static <S,E> EmptyStep<S,E>`	`instance()`
`Traverser.Admin<E>`	`next()`
`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 class java.lang.Object
finalize, getClass, notify, notifyAll, toString, wait, wait, wait

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

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

Methods inherited from interface org.apache.tinkerpop.gremlin.process.traversal.step.TraversalParent
addGlobalChild, addLocalChild, asStep, close, getGlobalChildren, getLocalChildren, getSelfAndChildRequirements, integrateChild, removeGlobalChild, removeLocalChild, replaceLocalChild

- Method Detail
  - instance
```
public static <S,E> EmptyStep<S,E> instance()
```
  - addStarts
```
public void addStarts(Iterator<Traverser.Admin<S>> starts)
```
    Description copied from interface: Step
    
    Add a iterator of Traverser.Admin objects of type S to the step.
    
    Specified by:
    
    addStarts in interface Step<S,E>
    
    Parameters:
    
    starts - The iterator of objects to add
  - hasStarts
```
public boolean hasStarts()
```
    Description copied from interface: Step
    
    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.
    
    Specified by:
    
    hasStarts in interface Step<S,E>
  - addStart
```
public void addStart(Traverser.Admin<S> start)
```
    Description copied from interface: Step
    
    Add a single Traverser.Admin to the step.
    
    Specified by:
    
    addStart in interface Step<S,E>
    
    Parameters:
    
    start - The traverser to add
  - setPreviousStep
```
public void setPreviousStep(Step<?,S> step)
```
    Description copied from interface: Step
    
    Set the step that is previous to the current step. Used for linking steps together to form a function chain.
    
    Specified by:
    
    setPreviousStep in interface Step<S,E>
    
    Parameters:
    
    step - the previous step of this step
  - 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,E>
  - getPreviousStep
```
public Step<?,S> getPreviousStep()
```
    Description copied from interface: Step
    
    Get the step prior to the current step.
    
    Specified by:
    
    getPreviousStep in interface Step<S,E>
    
    Returns:
    
    The previous step
  - setNextStep
```
public void setNextStep(Step<E,?> step)
```
    Description copied from interface: Step
    
    Set the step that is next to the current step. Used for linking steps together to form a function chain.
    
    Specified by:
    
    setNextStep in interface Step<S,E>
    
    Parameters:
    
    step - the next step of this step
  - getNextStep
```
public Step<E,?> getNextStep()
```
    Description copied from interface: Step
    
    Get the next step to the current step.
    
    Specified by:
    
    getNextStep in interface Step<S,E>
    
    Returns:
    
    The next step
  - getTraversal
```
public <A,B> Traversal.Admin<A,B> getTraversal()
```
    Description copied from interface: Step
    
    Get the Traversal.Admin that this step is contained within.
    
    Specified by:
    
    getTraversal in interface Step<S,E>
    
    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
```
public void setTraversal(Traversal.Admin<?,?> traversal)
```
    Description copied from interface: Step
    
    Set the Traversal that this step is contained within.
    
    Specified by:
    
    setTraversal in interface Step<S,E>
    
    Parameters:
    
    traversal - the new traversal for this step
  - clone
```
public EmptyStep<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 Object
    
    Returns:
    
    The cloned step
  - getLabels
```
public Set<String> getLabels()
```
    Description copied from interface: Step
    
    Get the labels of this step. The labels are ordered by the order of the calls to Step.addLabel(java.lang.String).
    
    Specified by:
    
    getLabels in interface Step<S,E>
    
    Returns:
    
    the set of labels for this step
  - addLabel
```
public void addLabel(String label)
```
    Description copied from interface: Step
    
    Add a label to this step.
    
    Specified by:
    
    addLabel in interface Step<S,E>
    
    Parameters:
    
    label - the label to add to this step
  - removeLabel
```
public void removeLabel(String label)
```
    Description copied from interface: Step
    
    Remove a label from this step.
    
    Specified by:
    
    removeLabel in interface Step<S,E>
    
    Parameters:
    
    label - the label to remove from this step
  - setId
```
public void setId(String id)
```
    Description copied from interface: Step
    
    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.
    
    Specified by:
    
    setId in interface Step<S,E>
    
    Parameters:
    
    id - the unique id of the step
  - getId
```
public String getId()
```
    Description copied from interface: Step
    
    Get the unique id of this step.
    
    Specified by:
    
    getId in interface Step<S,E>
    
    Returns:
    
    the unique id of the step
  - hasNext
```
public boolean hasNext()
```
    Specified by:
    
    hasNext in interface Iterator<Traverser.Admin<E>>
  - next
```
public Traverser.Admin<E> next()
```
    Specified by:
    
    next in interface Iterator<Traverser.Admin<E>>
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - equals
```
public boolean equals(Object object)
```
    Overrides:
    
    equals in class Object
  - 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

Class EmptyStep<S,E>

Method Summary

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

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

Method Detail

instance

addStarts

hasStarts

addStart

setPreviousStep

reset

getPreviousStep

setNextStep

getNextStep

getTraversal

setTraversal

clone

getLabels

addLabel

removeLabel

setId

getId

hasNext

next

hashCode

equals

getRequirements