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

Class CountStrategy

java.lang.Object

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

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

All Implemented Interfaces:

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

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

This strategy optimizes any occurrence of CountGlobalStep followed by an IsStep. The idea is to limit the number of incoming elements in a way that it's enough for the IsStep to decide whether it evaluates true or false. If the traversal already contains a user supplied limit, the strategy won't modify it.

Author:

Daniel Kuppitz (http://gremlin.guru)

See Also:

Serialized Form

Example:

 __.outE().count().is(0)      // is replaced by __.not(outE())
 __.outE().count().is(lt(3))  // is replaced by __.outE().limit(3).count().is(lt(3))
 __.outE().count().is(gt(3))  // is replaced by __.outE().limit(4).count().is(gt(3))
 

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

Field Summary

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

STRATEGY

Method Summary

Modifier and Type	Method and Description
void	apply(Traversal.Admin<?,?> traversal)
static CountStrategy	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.OptimizationStrategy

compareTo, getTraversalCategory

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

applyPost, applyPrior, getConfiguration

Method Detail

instance

public static CountStrategy instance()

apply

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

Specified by:

apply in interface TraversalStrategy<TraversalStrategy.OptimizationStrategy>