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

Class ProjectStep<S,E>

java.lang.Object

org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep<S,E>

org.apache.tinkerpop.gremlin.process.traversal.step.map.MapStep<S,E>

org.apache.tinkerpop.gremlin.process.traversal.step.map.ScalarMapStep<S,Map<String,E>>

org.apache.tinkerpop.gremlin.process.traversal.step.map.ProjectStep<S,E>

All Implemented Interfaces:

Serializable, AutoCloseable, Cloneable, Iterator<Traverser.Admin<Map<String,E>>>, Step<S,Map<String,E>>, ByModulating, PopContaining, TraversalParent

public class ProjectStep<S,E>
extends ScalarMapStep<S,Map<String,E>>
implements TraversalParent, ByModulating

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.step.PopContaining

PopContaining.PopInstruction

Field Summary

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

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

Constructor Summary

Constructors

Constructor	Description
ProjectStep(Traversal.Admin traversal, String... projectKeys)
ProjectStep(Traversal.Admin traversal, TraversalRing<S,E> traversalRing, String... projectKeys)

Method Summary

Modifier and Type	Method	Description
ProjectStep<S,E>	clone()	Cloning is used to duplicate steps for the purpose of traversal optimization and OLTP replication.
List<Traversal.Admin<S,E>>	getLocalChildren()	Gets a list of all "local" child traversals for this step.
List<String>	getProjectKeys()
Set<TraverserRequirement>	getRequirements()	Provide the necessary TraverserRequirement that must be met by the traverser in order for the step to function properly.
TraversalRing<S,E>	getTraversalRing()
int	hashCode()
protected Map<String,E>	map(Traverser.Admin<S> traverser)
void	modulateBy(Traversal.Admin<?,?> selectTraversal)
void	replaceLocalChild(Traversal.Admin<?,?> oldTraversal, Traversal.Admin<?,?> newTraversal)
void	reset()	Reset the state of the step such that it has no incoming starts.
void	setTraversal(Traversal.Admin<?,?> parentTraversal)	Set the Traversal that this step is contained within.
String	toString()

Methods inherited from class org.apache.tinkerpop.gremlin.process.traversal.step.map.ScalarMapStep

processNextStart

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

addLabel, addStart, addStarts, clearLabels, equals, getId, getLabels, getNextStep, getPreviousStep, getStarts, getTraversal, hasNext, hasStarts, isTraverserStepIdAndLabelsSetByChild, next, prepareTraversalForNextStep, removeLabel, setId, setNextStep, setPreviousStep

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.ByModulating

modulateBy, modulateBy, modulateBy, modulateBy, modulateBy, modulateBy, modulateBy, modulateBy, modulateBy, modulateBy, modulateBy

Methods inherited from interface java.util.Iterator

forEachRemaining, remove

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

equals

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

addGlobalChild, addLocalChild, asStep, close, getGlobalChildren, getPopInstructions, getSelfAndChildRequirements, integrateChild, removeGlobalChild, removeLocalChild

Constructor Detail

ProjectStep

public ProjectStep(Traversal.Admin traversal,
                   String... projectKeys)

ProjectStep

public ProjectStep(Traversal.Admin traversal,
                   TraversalRing<S,E> traversalRing,
                   String... projectKeys)

Method Detail

map

protected Map<String,E> map(Traverser.Admin<S> traverser)

Specified by:

map in class ScalarMapStep<S,Map<String,E>>

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>

Overrides:

reset in class AbstractStep<S,Map<String,E>>

toString

public String toString()

Overrides:

toString in class AbstractStep<S,Map<String,E>>

clone

public ProjectStep<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 AbstractStep<S,Map<String,E>>

Returns:

The cloned step

setTraversal

public void setTraversal(Traversal.Admin<?,?> parentTraversal)

Description copied from interface: Step

Set the Traversal that this step is contained within.

Specified by:

setTraversal in interface Step<S,E>

Overrides:

setTraversal in class AbstractStep<S,Map<String,E>>

Parameters:

parentTraversal - the new traversal for this step

hashCode

public int hashCode()

Overrides:

hashCode in class AbstractStep<S,Map<String,E>>

getLocalChildren

public List<Traversal.Admin<S,E>> getLocalChildren()

Description copied from interface: TraversalParent

Gets a list of all "local" child traversals for this step. A "local" traversal is one which is evaluated independently for each incoming traverser to the parent step. This is typically used in cases where the child is used to process or augment each traverser individually. See LocalStep or ByModulating as examples.

Specified by:

getLocalChildren in interface TraversalParent

modulateBy

public void modulateBy(Traversal.Admin<?,?> selectTraversal)

Specified by:

modulateBy in interface ByModulating

replaceLocalChild

public void replaceLocalChild(Traversal.Admin<?,?> oldTraversal,
                              Traversal.Admin<?,?> newTraversal)

Specified by:

replaceLocalChild in interface TraversalParent

getProjectKeys

public List<String> getProjectKeys()

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

getTraversalRing

public TraversalRing<S,E> getTraversalRing()