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

All Implemented Interfaces:

Serializable, AutoCloseable, Cloneable, Iterator<E>, Traversal<S,E>, Traversal.Admin<S,E>
```
public final class EmptyTraversal<S,E>
extends Object
implements Traversal.Admin<S,E>
```
Author:

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

See Also:

Serialized Form

Nested Class Summary
- Nested classes/interfaces inherited from interface org.apache.tinkerpop.gremlin.process.traversal.Traversal
  Traversal.Admin<S,E>, Traversal.Exceptions, Traversal.Symbols

Constructor Summary

Constructors
Modifier Constructor Description

protected EmptyTraversal()

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`addStart(Traverser.Admin<S> start)`	Add a single `Traverser.Admin` object to the head of the traversal.
`void`	`addStarts(Iterator<Traverser.Admin<S>> starts)`	Add an iterator of `Traverser.Admin` objects to the head/start of the traversal.
`<S2,E2> Traversal.Admin<S2,E2>`	`addStep(int index, Step<?,?> step)`	Add a `Step` to an arbitrary point in the traversal.
`<E2> Traversal.Admin<S,E2>`	`addStep(Step<?,E2> step)`	Add a `Step` to the end of the traversal.
`void`	`applyStrategies()`	Apply the registered `TraversalStrategies` to the traversal.
`Traversal.Admin<S,E>`	`asAdmin()`	Get access to administrative methods of the traversal via its accompanying `Traversal.Admin`.
`EmptyTraversal<S,E>`	`clone()`	Cloning is used to duplicate the traversal typically in OLAP environments.
`boolean`	`equals(Object object)`
`Bytecode`	`getBytecode()`	Get the `Bytecode` associated with the construction of this traversal.
`Optional<Graph>`	`getGraph()`	Gets the `Graph` instance associated directly to this `Traversal` or through its parent.
`TraversalParent`	`getParent()`	Get the `TraversalParent` `Step` that is the parent of this traversal.
`TraversalSideEffects`	`getSideEffects()`	Get the `TraversalSideEffects` associated with the traversal.
`List<Step>`	`getSteps()`	Get the `Step` instances associated with this traversal.
`TraversalStrategies`	`getStrategies()`	Get the `TraversalStrategies` associated with this traversal.
`TraverserGenerator`	`getTraverserGenerator()`	Get the `TraverserGenerator` associated with this traversal.
`Set<TraverserRequirement>`	`getTraverserRequirements()`	Get the set of all `TraverserRequirement`s for this traversal.
`int`	`hashCode()`
`boolean`	`hasNext()`
`static <A,B> EmptyTraversal<A,B>`	`instance()`
`boolean`	`isLocked()`	When the traversal has had its `TraversalStrategies` applied to it, it is locked.
`void`	`lock()`	Lock the traversal and perform any final adjustments to it after strategy application.
`E`	`next()`
`<S2,E2> Traversal.Admin<S2,E2>`	`removeStep(int index)`	Remove a `Step` from the traversal.
`void`	`setGraph(Graph graph)`
`void`	`setParent(TraversalParent step)`	Set the `TraversalParent` `Step` that is the parent of this traversal.
`void`	`setSideEffects(TraversalSideEffects sideEffects)`	Set the `TraversalSideEffects` of this traversal.
`void`	`setStrategies(TraversalStrategies traversalStrategies)`	Set the `TraversalStrategies` to be used by this traversal at evaluation time.

Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Iterator
remove

Methods inherited from interface org.apache.tinkerpop.gremlin.process.traversal.Traversal
close, explain, fill, forEachRemaining, forEachRemaining, iterate, next, none, notifyClose, profile, promise, toBulkSet, toList, toSet, toStream, tryNext

Methods inherited from interface org.apache.tinkerpop.gremlin.process.traversal.Traversal.Admin
equals, getEndStep, getStartStep, getTraversalSource, getTraverserSetSupplier, isRoot, nextTraverser, removeStep, reset

- Constructor Detail
  - EmptyTraversal
```
protected EmptyTraversal()
```
- Method Detail
  - instance
```
public static <A,B> EmptyTraversal<A,B> instance()
```
  - getBytecode
```
public Bytecode getBytecode()
```
    Description copied from interface: Traversal.Admin
    
    Get the Bytecode associated with the construction of this traversal.
    
    Specified by:
    
    getBytecode in interface Traversal.Admin<S,E>
    
    Returns:
    
    the byte code representation of the traversal
  - asAdmin
```
public Traversal.Admin<S,E> asAdmin()
```
    Description copied from interface: Traversal
    
    Get access to administrative methods of the traversal via its accompanying Traversal.Admin.
    
    Specified by:
    
    asAdmin in interface Traversal<S,E>
    
    Returns:
    
    the admin of this traversal
  - hasNext
```
public boolean hasNext()
```
    Specified by:
    
    hasNext in interface Iterator<S>
  - next
```
public E next()
```
    Specified by:
    
    next in interface Iterator<S>
  - getSideEffects
```
public TraversalSideEffects getSideEffects()
```
    Description copied from interface: Traversal.Admin
    
    Get the TraversalSideEffects associated with the traversal. This method should not be called externally for purposes of retrieving side-effects as traversal results. Traversal results should only be returned by way of the execution of the traversal itself. Should a side-effect of a traversal be needed it should only be obtained by using GraphTraversal.cap(String, String...) so that the side-effect can be included as part of the traversal iteration. Relying on this method to get side-effects in these situations may not result in consistent behavior across all types of executions and environments (e.g. remoting).
    
    Specified by:
    
    getSideEffects in interface Traversal.Admin<S,E>
    
    Returns:
    
    The traversal sideEffects
  - applyStrategies
```
public void applyStrategies()
```
    Description copied from interface: Traversal.Admin
    
    Apply the registered TraversalStrategies to the traversal. Once the strategies are applied, the traversal is "locked" and can no longer have steps added to it. The order of operations for strategy applications should be: globally id steps, apply each strategy in turn to root traversal, then recursively to nested traversals.
    
    Specified by:
    
    applyStrategies in interface Traversal.Admin<S,E>
  - addStarts
```
public void addStarts(Iterator<Traverser.Admin<S>> starts)
```
    Description copied from interface: Traversal.Admin
    
    Add an iterator of Traverser.Admin objects to the head/start of the traversal. Users should typically not need to call this method. For dynamic inject of data, they should use InjectStep.
    
    Specified by:
    
    addStarts in interface Traversal.Admin<S,E>
    
    Parameters:
    
    starts - an iterators of traversers
  - addStart
```
public void addStart(Traverser.Admin<S> start)
```
    Description copied from interface: Traversal.Admin
    
    Add a single Traverser.Admin object to the head of the traversal. Users should typically not need to call this method. For dynamic inject of data, they should use InjectStep.
    
    Specified by:
    
    addStart in interface Traversal.Admin<S,E>
    
    Parameters:
    
    start - a traverser to add to the traversal
  - addStep
```
public <E2> Traversal.Admin<S,E2> addStep(Step<?,E2> step)
```
    Description copied from interface: Traversal.Admin
    
    Add a Step to the end of the traversal. This method should link the step to its next and previous step accordingly.
    
    Specified by:
    
    addStep in interface Traversal.Admin<S,E>
    
    Type Parameters:
    
    E2 - the output of the step
    
    Parameters:
    
    step - the step to add
    
    Returns:
    
    the updated traversal
  - getSteps
```
public List<Step> getSteps()
```
    Description copied from interface: Traversal.Admin
    
    Get the Step instances associated with this traversal. The steps are ordered according to their linked list structure as defined by Step.getPreviousStep() and Step.getNextStep().
    
    Specified by:
    
    getSteps in interface Traversal.Admin<S,E>
    
    Returns:
    
    the ordered steps of the traversal
  - clone
```
public EmptyTraversal<S,E> clone()
```
    Description copied from interface: Traversal.Admin
    
    Cloning is used to duplicate the traversal typically in OLAP environments.
    
    Specified by:
    
    clone in interface Traversal.Admin<S,E>
    
    Overrides:
    
    clone in class Object
    
    Returns:
    
    The cloned traversal
  - isLocked
```
public boolean isLocked()
```
    Description copied from interface: Traversal.Admin
    
    When the traversal has had its TraversalStrategies applied to it, it is locked.
    
    Specified by:
    
    isLocked in interface Traversal.Admin<S,E>
    
    Returns:
    
    whether the traversal is locked
  - lock
```
public void lock()
```
    Description copied from interface: Traversal.Admin
    
    Lock the traversal and perform any final adjustments to it after strategy application.
    
    Specified by:
    
    lock in interface Traversal.Admin<S,E>
  - getTraverserGenerator
```
public TraverserGenerator getTraverserGenerator()
```
    Description copied from interface: Traversal.Admin
    
    Get the TraverserGenerator associated with this traversal. The traversal generator creates Traverser instances that are respective of the traversal's TraverserRequirement.
    
    Specified by:
    
    getTraverserGenerator in interface Traversal.Admin<S,E>
    
    Returns:
    
    the generator of traversers
  - setSideEffects
```
public void setSideEffects(TraversalSideEffects sideEffects)
```
    Description copied from interface: Traversal.Admin
    
    Set the TraversalSideEffects of this traversal.
    
    Specified by:
    
    setSideEffects in interface Traversal.Admin<S,E>
    
    Parameters:
    
    sideEffects - the sideEffects to set for this traversal.
  - getStrategies
```
public TraversalStrategies getStrategies()
```
    Description copied from interface: Traversal.Admin
    
    Get the TraversalStrategies associated with this traversal.
    
    Specified by:
    
    getStrategies in interface Traversal.Admin<S,E>
    
    Returns:
    
    the strategies associated with this traversal
  - setParent
```
public void setParent(TraversalParent step)
```
    Description copied from interface: Traversal.Admin
    
    Set the TraversalParent Step that is the parent of this traversal. Traversals can be nested and this is the means by which the traversal tree is connected. If there is no parent, then it should be a EmptyStep.
    
    Specified by:
    
    setParent in interface Traversal.Admin<S,E>
    
    Parameters:
    
    step - the traversal holder parent step or EmptyStep if it has no parent
  - getParent
```
public TraversalParent getParent()
```
    Description copied from interface: Traversal.Admin
    
    Get the TraversalParent Step that is the parent of this traversal. Traversals can be nested and this is the means by which the traversal tree is walked.
    
    Specified by:
    
    getParent in interface Traversal.Admin<S,E>
    
    Returns:
    
    the traversal holder parent step or EmptyStep if it has no parent.
  - setStrategies
```
public void setStrategies(TraversalStrategies traversalStrategies)
```
    Description copied from interface: Traversal.Admin
    
    Set the TraversalStrategies to be used by this traversal at evaluation time.
    
    Specified by:
    
    setStrategies in interface Traversal.Admin<S,E>
    
    Parameters:
    
    traversalStrategies - the strategies to use on this traversal
  - addStep
```
public <S2,E2> Traversal.Admin<S2,E2> addStep(int index,
                                                          Step<?,?> step)
                                                   throws IllegalStateException
```
    Description copied from interface: Traversal.Admin
    
    Add a Step to an arbitrary point in the traversal.
    
    Specified by:
    
    addStep in interface Traversal.Admin<S,E>
    
    Type Parameters:
    
    S2 - the new start type of the traversal (if the added step was a start step)
    
    E2 - the new end type of the traversal (if the added step was an end step)
    
    Parameters:
    
    index - the location in the traversal to insert the step
    
    step - the step to add
    
    Returns:
    
    the newly modulated traversal
    
    Throws:
    
    IllegalStateException - if the TraversalStrategies have already been applied
  - removeStep
```
public <S2,E2> Traversal.Admin<S2,E2> removeStep(int index)
                                                      throws IllegalStateException
```
    Description copied from interface: Traversal.Admin
    
    Remove a Step from the traversal.
    
    Specified by:
    
    removeStep in interface Traversal.Admin<S,E>
    
    Type Parameters:
    
    S2 - the new start type of the traversal (if the removed step was a start step)
    
    E2 - the new end type of the traversal (if the removed step was an end step)
    
    Parameters:
    
    index - the location in the traversal of the step to be evicted
    
    Returns:
    
    the newly modulated traversal
    
    Throws:
    
    IllegalStateException - if the TraversalStrategies have already been applied
  - equals
```
public boolean equals(Object object)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - getTraverserRequirements
```
public Set<TraverserRequirement> getTraverserRequirements()
```
    Description copied from interface: Traversal.Admin
    
    Get the set of all TraverserRequirements for this traversal.
    
    Specified by:
    
    getTraverserRequirements in interface Traversal.Admin<S,E>
    
    Returns:
    
    the features of a traverser that are required to execute properly in this traversal
  - getGraph
```
public Optional<Graph> getGraph()
```
    Description copied from interface: Traversal.Admin
    
    Gets the Graph instance associated directly to this Traversal or through its parent.
    
    Specified by:
    
    getGraph in interface Traversal.Admin<S,E>
  - setGraph
```
public void setGraph(Graph graph)
```
    Specified by:
    
    setGraph in interface Traversal.Admin<S,E>

Class EmptyTraversal<S,​E>

Nested Class Summary

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

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Iterator

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

Methods inherited from interface org.apache.tinkerpop.gremlin.process.traversal.Traversal.Admin

Constructor Detail

EmptyTraversal

Method Detail

instance

getBytecode

asAdmin

hasNext

next

getSideEffects

applyStrategies

addStarts

addStart

addStep

getSteps

clone

isLocked

lock

getTraverserGenerator

setSideEffects

getStrategies

setParent

getParent

setStrategies

addStep

removeStep

equals

hashCode

getTraverserRequirements

getGraph

setGraph

Class EmptyTraversal<S,E>