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

Class GraphStep<S,E extends Element>

java.lang.Object

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

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

All Implemented Interfaces:

Serializable, AutoCloseable, Cloneable, Iterator<Traverser.Admin<E>>, Step<S,E>, Configuring, GraphComputing, GraphStepContract<S,E>, Parameterizing, PopContaining, ReadOnlyTraversalParent, TraversalParent

Direct Known Subclasses:

TinkerGraphStep

public class GraphStep<S,E extends Element>
extends AbstractStep<S,E>
implements GraphStepContract<S,E>, ReadOnlyTraversalParent

Author:

Marko A. Rodriguez (http://markorodriguez.com), Pieter Martin

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

Modifier and Type	Field	Description
protected boolean	done
protected Object[]	ids
protected boolean	isStart
protected Supplier<Iterator<E>>	iteratorSupplier
protected Parameters	parameters
protected final Class<E>	returnClass

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

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

Fields inherited from interface org.apache.tinkerpop.gremlin.process.traversal.step.map.GraphStepContract

CONCRETE_STEPS

Constructor Summary

Constructors

Constructor	Description
GraphStep(Traversal.Admin traversal, Class<E> returnClass, boolean isStart, Object... ids)
GraphStep(Traversal.Admin traversal, Class<E> returnClass, boolean isStart, Traversal.Admin<?,?> idTraversal)

Method Summary

Modifier and Type	Method	Description
void	addIds(Object... newIds)
void	clearIds()
GraphStep<S,E>	clone()	Cloning is used to duplicate steps for the purpose of traversal optimization and OLTP replication.
void	close()	Attempts to close an underlying iterator if it is of type CloseableIterator.
void	configure(Object... keyValues)	Accept a configuration to the Step.
void	convertElementsToIds()
Object[]	getIds()
Traversal.Admin<?,?>	getIdTraversal()	Returns the child traversal used to resolve element IDs, or null if literal IDs are used.
<S, E> List<Traversal.Admin<S,E>>	getLocalChildren()	Gets a list of all "local" child traversals for this step.
Parameters	getParameters()	Gets the parameters on the step.
Class<E>	getReturnClass()
int	hashCode()
boolean	isStartStep()
static boolean	isStartStep(Step<?,?> step)
void	onGraphComputer()	The step will be executing on a GraphComputer.
static boolean	processHasContainerIds(GraphStep<?,?> graphStep, HasContainer hasContainer)	Helper method for providers that want to "fold in" HasContainer's based on id checking into the ids of the GraphStep.
protected Traverser.Admin<E>	processNextStart()
void	reset()	Reset the state of the step such that it has no incoming starts.
boolean	returnsEdge()
boolean	returnsVertex()
void	setIdTraversal(Traversal.Admin<?,?> idTraversal)	Sets the child traversal used to resolve element IDs.
void	setIteratorSupplier(Supplier<Iterator<E>> iteratorSupplier)
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.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.GraphComputing

atMaster

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

getIdsAsGValues

Methods inherited from interface java.util.Iterator

forEachRemaining, hasNext, next, remove

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

addLabel, addStart, addStarts, clearLabels, equals, getId, getLabels, getNextStep, getPreviousStep, getRequirements, getTraversal, hasStarts, removeLabel, setId, setNextStep, setPreviousStep

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

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

Field Details

parameters

protected Parameters parameters

returnClass

protected final Class<E extends Element> returnClass

ids

protected Object[] ids

iteratorSupplier

protected transient Supplier<Iterator<E extends Element>> iteratorSupplier

isStart

protected boolean isStart

done

protected boolean done

Constructor Details

GraphStep

public GraphStep(Traversal.Admin traversal,
 Class<E> returnClass,
 boolean isStart,
 Object... ids)

GraphStep

public GraphStep(Traversal.Admin traversal,
 Class<E> returnClass,
 boolean isStart,
 Traversal.Admin<?,?> idTraversal)

Method Details

getIdTraversal

public Traversal.Admin<?,?> getIdTraversal()

Returns the child traversal used to resolve element IDs, or null if literal IDs are used.

setIdTraversal

public void setIdTraversal(Traversal.Admin<?,?> idTraversal)

Sets the child traversal used to resolve element IDs. Calls TraversalParent.integrateChild(Traversal.Admin) on the provided traversal.

toString

public String toString()

Overrides:

toString in class AbstractStep<S,E extends Element>

getParameters

public Parameters getParameters()

Description copied from interface: Parameterizing

Gets the parameters on the step.

Specified by:

getParameters in interface Parameterizing

configure

public void configure(Object... keyValues)

Description copied from interface: Configuring

Accept a configuration to the Step. Note that this interface extends Parameterizing and so there is an expectation that the Step implementation will have a Parameters instance that will house any values passed to this method. Storing these configurations in Parameters is not a requirement however, IF the configuration is an expected option for the step and can be stored on a member field that can be accessed on the step by more direct means (i.e. like a getter method).

Specified by:

configure in interface Configuring

getReturnClass

public Class<E> getReturnClass()

Specified by:

getReturnClass in interface GraphStepContract<S,E extends Element>

isStartStep

public boolean isStartStep()

Specified by:

isStartStep in interface GraphStepContract<S,E extends Element>

isStartStep

public static boolean isStartStep(Step<?,?> step)

returnsVertex

public boolean returnsVertex()

Specified by:

returnsVertex in interface GraphStepContract<S,E extends Element>

returnsEdge

public boolean returnsEdge()

Specified by:

returnsEdge in interface GraphStepContract<S,E extends Element>

setIteratorSupplier

public void setIteratorSupplier(Supplier<Iterator<E>> iteratorSupplier)

getIds

public Object[] getIds()

Specified by:

getIds in interface GraphStepContract<S,E extends Element>

addIds

public void addIds(Object... newIds)

clearIds

public void clearIds()

Specified by:

clearIds in interface GraphStepContract<S,E extends Element>

onGraphComputer

public void onGraphComputer()

Description copied from interface: GraphComputing

The step will be executing on a GraphComputer.

Specified by:

onGraphComputer in interface GraphComputing

convertElementsToIds

public void convertElementsToIds()

processNextStart

protected Traverser.Admin<E> processNextStart()

Specified by:

processNextStart in class AbstractStep<S,E extends Element>

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 extends Element>

Overrides:

reset in class AbstractStep<S,E extends Element>

hashCode

public int hashCode()

Overrides:

hashCode in class AbstractStep<S,E extends Element>

getLocalChildren

public <S,
E> 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

clone

public GraphStep<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 extends Element>

Overrides:

clone in class AbstractStep<S,E extends Element>

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 extends Element>

Overrides:

setTraversal in class AbstractStep<S,E extends Element>

Parameters:

parentTraversal - the new traversal for this step

close

public void close()

Attempts to close an underlying iterator if it is of type CloseableIterator. Graph providers may choose to return this interface containing their vertices and edges if there are expensive resources that might need to be released at some point.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface TraversalParent

processHasContainerIds

public static boolean processHasContainerIds(GraphStep<?,?> graphStep,
 HasContainer hasContainer)

Helper method for providers that want to "fold in" HasContainer's based on id checking into the ids of the GraphStep.

Parameters:

graphStep - the GraphStep to potentially addIds(Object...).

hasContainer - The HasContainer to check for id validation.

Returns:

true if the HasContainer updated ids and thus, was processed.