Package org.apache.tinkerpop.gremlin.process.traversal.strategy.optimization

Class IncidentToAdjacentStrategy

java.lang.Object

org.apache.tinkerpop.gremlin.process.traversal.strategy.AbstractTraversalStrategy<TraversalStrategy.OptimizationStrategy>

org.apache.tinkerpop.gremlin.process.traversal.strategy.optimization.IncidentToAdjacentStrategy

All Implemented Interfaces:

Serializable, Comparable<Class<? extends TraversalStrategy>>, TraversalStrategy<TraversalStrategy.OptimizationStrategy>, TraversalStrategy.OptimizationStrategy

public final class IncidentToAdjacentStrategy
extends AbstractTraversalStrategy<TraversalStrategy.OptimizationStrategy>
implements TraversalStrategy.OptimizationStrategy

This strategy looks for .outE().inV(), .inE().outV() and .bothE().otherV() and replaces these step sequences with .out(), .in() or .both() respectively. The strategy won't modify the traversal if:

• the edge step is labeled
• the traversal contains a path step
• the traversal contains a lambda step

By re-writing the traversal in this fashion, the traversal eliminates unnecessary steps and becomes more normalized.

Author:

Daniel Kuppitz (http://gremlin.guru)

See Also:

• Serialized Form

Example:

 __.outE().inV()         // is replaced by __.out()
 __.inE().outV()         // is replaced by __.in()
 __.bothE().otherV()     // is replaced by __.both()
 __.bothE().bothV()      // will not be modified
 __.outE().inV().path()  // will not be modified
 __.outE().inV().tree()  // will not be modified
 

Nested Class Summary

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

TraversalStrategy.DecorationStrategy, TraversalStrategy.FinalizationStrategy, TraversalStrategy.OptimizationStrategy, TraversalStrategy.ProviderOptimizationStrategy, TraversalStrategy.VerificationStrategy

Method Summary

Modifier and Type	Method	Description
void	apply(Traversal.Admin<?,?> traversal)	The transformation the strategy applies to the traversal.
Set<Class<? extends TraversalStrategy.OptimizationStrategy>>	applyPost()	The GValueReductionStrategy should be the last TinkerPop optimnization strategy applied.
Set<Class<? extends TraversalStrategy.OptimizationStrategy>>	applyPrior()	The set of strategies that must be executed before this strategy is executed.
static IncidentToAdjacentStrategy	instance()

Methods inherited from class org.apache.tinkerpop.gremlin.process.traversal.strategy.AbstractTraversalStrategy

equals, hashCode, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

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

getConfiguration

Methods inherited from interface org.apache.tinkerpop.gremlin.process.traversal.TraversalStrategy.OptimizationStrategy

compareTo, getTraversalCategory

Method Details

instance

public static IncidentToAdjacentStrategy instance()

apply

public void apply(Traversal.Admin<?,?> traversal)

Description copied from interface: TraversalStrategy

The transformation the strategy applies to the traversal.

Specified by:

apply in interface TraversalStrategy<TraversalStrategy.OptimizationStrategy>

applyPrior

public Set<Class<? extends TraversalStrategy.OptimizationStrategy>> applyPrior()

Description copied from interface: TraversalStrategy

The set of strategies that must be executed before this strategy is executed. If there are no ordering requirements, the default implementation returns an empty set.

Specified by:

applyPrior in interface TraversalStrategy<TraversalStrategy.OptimizationStrategy>

Returns:

the set of strategies that must be executed prior to this one.

applyPost

public Set<Class<? extends TraversalStrategy.OptimizationStrategy>> applyPost()

Description copied from interface: TraversalStrategy.OptimizationStrategy

The GValueReductionStrategy should be the last TinkerPop optimnization strategy applied. Adding it here ensures will help to enforce that more globally. Implementations overriding this method should have a good reason to ignore this.

Specified by:

applyPost in interface TraversalStrategy<TraversalStrategy.OptimizationStrategy>

Specified by:

applyPost in interface TraversalStrategy.OptimizationStrategy

Returns:

the set of strategies that must be executed post this one