com.tinkerpop.gremlin.process.graph.step.map.match

Class MatchStep<S,E>

java.lang.Object

com.tinkerpop.gremlin.process.util.AbstractStep<S,java.util.Map<java.lang.String,E>>

com.tinkerpop.gremlin.process.graph.step.map.match.MatchStep<S,E>

All Implemented Interfaces:

TraversalHolder, Step<S,java.util.Map<java.lang.String,E>>, java.lang.Cloneable, java.util.Iterator<Traverser<java.util.Map<java.lang.String,E>>>

public final class MatchStep<S,E>
extends AbstractStep<S,java.util.Map<java.lang.String,E>>
implements TraversalHolder

Author:

Joshua Shinavier (http://fortytwo.net)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	MatchStep.TraversalUpdater<A,B> A helper object which wraps a traversal, submitting starts and counting results per start
static class	MatchStep.TraversalWrapper<A,B> A wrapper for a traversal in a query which maintains statistics about the traversal as it consumes inputs and produces outputs.

Nested classes/interfaces inherited from interface com.tinkerpop.gremlin.process.graph.marker.TraversalHolder

TraversalHolder.Child

Field Summary

Fields inherited from class com.tinkerpop.gremlin.process.util.AbstractStep

id, label, nextEnd, nextStep, previousStep, PROFILING_ENABLED, starts, traversal, traverserStepIdSetByChild

Constructor Summary

Constructors

Constructor and Description
MatchStep(Traversal traversal, java.lang.String startLabel, Traversal... traversals)

Method Summary

Modifier and Type	Method and Description
void	addTraversal(Traversal<S,S> traversal) Adds an individual traversal to an already-constructed MatchStep.
double	findCost(java.lang.String outLabel)
java.util.Set<TraverserRequirement>	getRequirements() Provide the necessary TraverserRequirement that must be met by the traverser in order for the step to function properly.
java.util.List<Traversal>	getTraversals()
void	optimize() Computes and applies a new query plan based on gathered statistics about traversal inputs and outputs.
protected Traverser<java.util.Map<java.lang.String,E>>	processNextStart()
void	setStartsPerOptimize(int startsPerOptimize)
Enumerator<S>	solveFor(java.util.Iterator<S> inputs) Directly applies this match query to a sequence of inputs
java.lang.String	summarize()
java.lang.String	toString()

Methods inherited from class com.tinkerpop.gremlin.process.util.AbstractStep

addStart, addStarts, clone, getId, getLabel, getNextStep, getPreviousStep, getTraversal, hasNext, next, reset, setId, setLabel, setNextStep, setPreviousStep, setTraversal

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.tinkerpop.gremlin.process.graph.marker.TraversalHolder

asStep, executeTraversalOperations, getChildStrategies, getTraversalRequirements, resetTraversals

Methods inherited from interface java.util.Iterator

forEachRemaining, remove

Constructor Detail

MatchStep

public MatchStep(Traversal traversal,
                 java.lang.String startLabel,
                 Traversal... traversals)

Method Detail

getRequirements

public java.util.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,java.util.Map<java.lang.String,E>>

Returns:

the set of requirements

toString

public java.lang.String toString()

Overrides:

toString in class AbstractStep<S,java.util.Map<java.lang.String,E>>

addTraversal

public void addTraversal(Traversal<S,S> traversal)

Adds an individual traversal to an already-constructed MatchStep. The query must be solvable after addition (i.e. should not require the addition of further traversals in order to be solvable) This method should be called before the query is first executed.

Parameters:

traversal - the traversal to add

setStartsPerOptimize

public void setStartsPerOptimize(int startsPerOptimize)

processNextStart

protected Traverser<java.util.Map<java.lang.String,E>> processNextStart()
                                                                 throws java.util.NoSuchElementException

Specified by:

processNextStart in class AbstractStep<S,java.util.Map<java.lang.String,E>>

Throws:

java.util.NoSuchElementException

summarize

public java.lang.String summarize()

Returns:

a description of the current state of this step, including the query plan and gathered statistics

solveFor

public Enumerator<S> solveFor(java.util.Iterator<S> inputs)

Directly applies this match query to a sequence of inputs

Parameters:

inputs - a sequence of inputs

Returns:

an enumerator over all solutions

optimize

public void optimize()

Computes and applies a new query plan based on gathered statistics about traversal inputs and outputs.

findCost

public double findCost(java.lang.String outLabel)

Parameters:

outLabel - the out-label of one or more traversals in the query

Returns:

the expected cost, in the current query plan, of applying the branch of the query plan at the given out-label to one start value

getTraversals

public java.util.List<Traversal> getTraversals()

Specified by:

getTraversals in interface TraversalHolder