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

Class RepeatUnrollStrategy

java.lang.Object

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

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

All Implemented Interfaces:

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

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

RepeatUnrollStrategy is an OLTP-only strategy that unrolls any RepeatStep if it uses a constant number of loops (times(x)) and doesn't emit intermittent elements. The strategy only applies to repeat traversals that contain exclusively safe, stateless steps from the allowed set:

• VertexStepContract
• EdgeVertexStep
• EdgeOtherVertexStep
• HasStep
• RepeatStep and RepeatStep.RepeatEndStep

Steps that are not in this allowed set will prevent the strategy from being applied. This allowed set of steps is intentionally conservative as there have been unintentional traversal semantics changes in the past when allowing a large variety of steps (especially barriers). Only steps that can be safely executed outside the repeat (and not modify semantics of the traversal) should be included. The allowed set can be expanded in future versions as additional steps are verified to be safe.

Author:

Marko A. Rodriguez (http://markorodriguez.com)

See Also:

• Serialized Form

Example:

     __.repeat(out()).times(2)   // is replaced by __.out().barrier(2500).out().barrier(2500)
 

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.
static RepeatUnrollStrategy	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

applyPrior, getConfiguration

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

applyPost, compareTo, getTraversalCategory

Method Details

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>

instance

public static RepeatUnrollStrategy instance()