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

Class MergeStep<S,E,C>

java.lang.Object

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

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

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

All Implemented Interfaces:

Serializable, AutoCloseable, Cloneable, Iterator<Traverser.Admin<E>>, Step<S,E>, Configuring, Deleting<Event>, Mutating<Event>, Parameterizing, TraversalOptionParent<Merge,S,C>, TraversalParent, Writing<Event>

Direct Known Subclasses:

MergeEdgeStep, MergeVertexStep

public abstract class MergeStep<S,E,C>
extends FlatMapStep<S,E>
implements Writing<Event>, Deleting<Event>, TraversalOptionParent<Merge,S,C>

Abstract base class for the mergeV/E() implementations.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	MergeStep.GuardRailStep<S,E>	Guard rail to ensure that the incoming object is not an Element.

Field Summary

Fields

Modifier and Type	Field	Description
protected CallbackRegistry<Event>	callbackRegistry
protected boolean	first
protected boolean	isStart
protected Traversal.Admin<S,Map>	mergeTraversal
protected Traversal.Admin<S,Map>	onCreateTraversal
protected Traversal.Admin<S,Map<String,?>>	onMatchTraversal
protected boolean	usesPartitionStrategy

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
MergeStep(Traversal.Admin traversal, boolean isStart)
MergeStep(Traversal.Admin traversal, boolean isStart, Map mergeMap)
MergeStep(Traversal.Admin traversal, boolean isStart, Traversal.Admin mergeTraversal)

Method Summary

Modifier and Type	Method	Description
void	addChildOption(Merge token, Traversal.Admin<S,C> traversalOption)	The child as defined by the token it takes, like Pick or Merge.
MergeStep<S,E,C>	clone()	Cloning is used to duplicate steps for the purpose of traversal optimization and OLTP replication.
void	configure(Object... keyValues)	This implementation should only be used as a mechanism for supporting PartitionStrategy.
protected abstract Iterator<E>	flatMap(Traverser.Admin<S> traverser)
protected abstract Set	getAllowedTokens()
CallbackRegistry<Event>	getCallbackRegistry()
protected Graph	getGraph()
<S,C> List<Traversal.Admin<S,C>>	getLocalChildren()
Traversal.Admin<S,Map>	getMergeTraversal()	Gets the traversal that will be used to provide the Map that will be used to search for elements.
CallbackRegistry<Event>	getMutatingCallbackRegistry()	Gets the callback registry for events that the step raises.
Traversal.Admin<S,Map>	getOnCreateTraversal()	Gets the traversal that will be used to provide the Map that will be used to create elements that do not match the search criteria of getMergeTraversal().
Traversal.Admin<S,Map<String,?>>	getOnMatchTraversal()	Gets the traversal that will be used to provide the Map that will be used to modify elements that match the search criteria of getMergeTraversal().
Parameters	getParameters()	Gets the parameters on the step.
Set<TraverserRequirement>	getRequirements()	Provide the necessary TraverserRequirement that must be met by the traverser in order for the step to function properly.
int	hashCode()
boolean	isFirst()	Determine if this is the first pass through processNextStart().
boolean	isStart()	Determines if this is a start step.
boolean	isUsingPartitionStrategy()
protected Map	materializeMap(Traverser.Admin<S> traverser, Traversal.Admin<S,?> mapTraversal)	null Map == empty Map
protected Traverser.Admin<E>	processNextStart()
void	reset()	Reset the state of the step such that it has no incoming starts.
protected CloseableIterator<Vertex>	searchVertices(Map search)	Translate the Map into a g.V() traversal against the supplied graph.
protected GraphTraversal	searchVerticesLabelConstraint(GraphTraversal t, String label)
protected GraphTraversal	searchVerticesPropertyConstraints(GraphTraversal t, Map search)
protected GraphTraversal	searchVerticesTraversal(Graph graph, Object id)
void	setTraversal(Traversal.Admin<?,?> parentTraversal)	Set the Traversal that this step is contained within.
String	toString()
protected void	validate(Map map, boolean ignoreTokens)
protected static void	validate(Map map, boolean ignoreTokens, Set allowedTokens, String op)
protected void	validateNoOverrides(Map<?,?> mergeMap, Map<?,?> onCreateMap)	Prohibit overrides to the existence criteria (id/label/from/to) in onCreate.

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

closeIterator

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 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, getSelfAndChildRequirements, integrateChild, removeGlobalChild, removeLocalChild, replaceLocalChild

Field Detail

isStart

protected final boolean isStart

first

protected boolean first

mergeTraversal

protected Traversal.Admin<S,Map> mergeTraversal

onCreateTraversal

protected Traversal.Admin<S,Map> onCreateTraversal

onMatchTraversal

protected Traversal.Admin<S,Map<String,?>> onMatchTraversal

callbackRegistry

protected CallbackRegistry<Event> callbackRegistry

usesPartitionStrategy

protected boolean usesPartitionStrategy

Constructor Detail

MergeStep

public MergeStep(Traversal.Admin traversal,
                 boolean isStart)

MergeStep

public MergeStep(Traversal.Admin traversal,
                 boolean isStart,
                 Map mergeMap)

MergeStep

public MergeStep(Traversal.Admin traversal,
                 boolean isStart,
                 Traversal.Admin mergeTraversal)

Method Detail

getMergeTraversal

public Traversal.Admin<S,Map> getMergeTraversal()

Gets the traversal that will be used to provide the Map that will be used to search for elements. This Map also will be used as the default data set to be used to create the element if the search is not successful.

getOnCreateTraversal

public Traversal.Admin<S,Map> getOnCreateTraversal()

Gets the traversal that will be used to provide the Map that will be used to create elements that do not match the search criteria of getMergeTraversal().

getOnMatchTraversal

public Traversal.Admin<S,Map<String,?>> getOnMatchTraversal()

Gets the traversal that will be used to provide the Map that will be used to modify elements that match the search criteria of getMergeTraversal().

isStart

public boolean isStart()

Determines if this is a start step.

isFirst

public boolean isFirst()

Determine if this is the first pass through processNextStart().

getCallbackRegistry

public CallbackRegistry<Event> getCallbackRegistry()

addChildOption

public void addChildOption(Merge token,
                           Traversal.Admin<S,C> traversalOption)

Description copied from interface: TraversalOptionParent

The child as defined by the token it takes, like Pick or Merge. This traversal may be of local or global scope depending on the step implementation that works with option().

Specified by:

addChildOption in interface TraversalOptionParent<S,E,C>

getLocalChildren

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

Specified by:

getLocalChildren in interface TraversalParent

configure

public void configure(Object... keyValues)

This implementation should only be used as a mechanism for supporting PartitionStrategy. Using this with GraphTraversal.with(String,Object) will have an ill effect of simply acting like a call to GraphTraversal.property(Object, Object, Object...). No mutating steps currently support use of GraphTraversal.with(String,Object) so perhaps it's best to not start with that now.

Specified by:

configure in interface Configuring

getParameters

public Parameters getParameters()

Description copied from interface: Parameterizing

Gets the parameters on the step.

Specified by:

getParameters in interface Parameterizing

isUsingPartitionStrategy

public boolean isUsingPartitionStrategy()

processNextStart

protected Traverser.Admin<E> processNextStart()

Overrides:

processNextStart in class FlatMapStep<S,E>

getGraph

protected Graph getGraph()

getMutatingCallbackRegistry

public CallbackRegistry<Event> getMutatingCallbackRegistry()

Description copied from interface: Mutating

Gets the callback registry for events that the step raises.

Specified by:

getMutatingCallbackRegistry in interface Mutating<S>

hashCode

public int hashCode()

Overrides:

hashCode in class AbstractStep<S,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 FlatMapStep<S,E>

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

toString

public String toString()

Overrides:

toString in class AbstractStep<S,E>

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,E>

Parameters:

parentTraversal - the new traversal for this step

clone

public MergeStep<S,E,C> 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,E>

Returns:

The cloned step

validate

protected void validate(Map map,
                        boolean ignoreTokens)

validate

protected static void validate(Map map,
                               boolean ignoreTokens,
                               Set allowedTokens,
                               String op)

validateNoOverrides

protected void validateNoOverrides(Map<?,?> mergeMap,
                                   Map<?,?> onCreateMap)

Prohibit overrides to the existence criteria (id/label/from/to) in onCreate.

materializeMap

protected Map materializeMap(Traverser.Admin<S> traverser,
                             Traversal.Admin<S,?> mapTraversal)

null Map == empty Map

searchVertices

protected CloseableIterator<Vertex> searchVertices(Map search)

Translate the Map into a g.V() traversal against the supplied graph. Graph providers will presumably optimize this traversal to use whatever indices are present and appropriate for efficiency. Callers are responsible for closing this iterator when finished.

searchVerticesTraversal

protected GraphTraversal searchVerticesTraversal(Graph graph,
                                                 Object id)

searchVerticesLabelConstraint

protected GraphTraversal searchVerticesLabelConstraint(GraphTraversal t,
                                                       String label)

searchVerticesPropertyConstraints

protected GraphTraversal searchVerticesPropertyConstraints(GraphTraversal t,
                                                           Map search)

flatMap

protected abstract Iterator<E> flatMap(Traverser.Admin<S> traverser)

Specified by:

flatMap in class FlatMapStep<S,E>

getAllowedTokens

protected abstract Set getAllowedTokens()