org.apache.tinkerpop.gremlin.process.traversal

Interface TraversalStrategies

All Superinterfaces:

Cloneable, Serializable

All Known Implementing Classes:

DefaultTraversalStrategies, EmptyTraversalStrategies

public interface TraversalStrategies
extends Serializable, Cloneable

A Traversal maintains a set of TraversalStrategy instances within a TraversalStrategies object. TraversalStrategies are responsible for compiling a traversal prior to its execution.

Author:

Marko A. Rodriguez (http://markorodriguez.com), Matthias Broecheler (me@matthiasb.com)

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	TraversalStrategies.GlobalCache

Field Summary

Fields

Modifier and Type	Field and Description
static List<Class<? extends TraversalStrategy>>	STRATEGY_CATEGORIES

Method Summary

Modifier and Type	Method and Description
TraversalStrategies	addStrategies(TraversalStrategy<?>... strategies) Add all the provided TraversalStrategy instances to the current collection.
void	applyStrategies(Traversal.Admin<?,?> traversal) Apply all the TraversalStrategy optimizers to the Traversal.
TraversalStrategies	clone()
default <T extends TraversalStrategy> Optional<T>	getStrategy(Class<T> traversalStrategyClass) Return the TraversalStrategy instance associated with the provided class.
TraversalStrategies	removeStrategies(Class<? extends TraversalStrategy>... strategyClasses) Remove all the provided TraversalStrategy classes from the current collection.
static Set<TraversalStrategy<?>>	sortStrategies(Set<TraversalStrategy<?>> strategies) Sorts the list of provided strategies such that the TraversalStrategy.applyPost() and TraversalStrategy.applyPrior() dependencies are respected.
List<TraversalStrategy<?>>	toList() Return all the TraversalStrategy singleton instances associated with this TraversalStrategies.
static void	visit(Map<Class<? extends TraversalStrategy>,Set<Class<? extends TraversalStrategy>>> dependencyMap, List<Class<? extends TraversalStrategy>> sortedStrategyClasses, Set<Class<? extends TraversalStrategy>> seenStrategyClases, List<Class<? extends TraversalStrategy>> unprocessedStrategyClasses, Class<? extends TraversalStrategy> strategyClass)

Field Detail

STRATEGY_CATEGORIES

static final List<Class<? extends TraversalStrategy>> STRATEGY_CATEGORIES

Method Detail

toList

List<TraversalStrategy<?>> toList()

Return all the TraversalStrategy singleton instances associated with this TraversalStrategies.

getStrategy

default <T extends TraversalStrategy> Optional<T> getStrategy(Class<T> traversalStrategyClass)

Return the TraversalStrategy instance associated with the provided class.

Type Parameters:

T - the strategy class type

Parameters:

traversalStrategyClass - the class of the strategy to get

Returns:

an optional containing the strategy instance or not

applyStrategies

void applyStrategies(Traversal.Admin<?,?> traversal)

Apply all the TraversalStrategy optimizers to the Traversal. This method must ensure that the strategies are sorted prior to application.

Parameters:

traversal - the traversal to apply the strategies to

addStrategies

TraversalStrategies addStrategies(TraversalStrategy<?>... strategies)

Add all the provided TraversalStrategy instances to the current collection. When all the provided strategies have been added, the collection is resorted.

Parameters:

strategies - the traversal strategies to add

Returns:

the newly updated/sorted traversal strategies collection

removeStrategies

TraversalStrategies removeStrategies(Class<? extends TraversalStrategy>... strategyClasses)

Remove all the provided TraversalStrategy classes from the current collection. When all the provided strategies have been removed, the collection is resorted.

Parameters:

strategyClasses - the traversal strategies to remove by their class

Returns:

the newly updated/sorted traversal strategies collection

clone

TraversalStrategies clone()

sortStrategies

static Set<TraversalStrategy<?>> sortStrategies(Set<TraversalStrategy<?>> strategies)

Sorts the list of provided strategies such that the TraversalStrategy.applyPost() and TraversalStrategy.applyPrior() dependencies are respected.

Note, that the order may not be unique.

Parameters:

strategies - the traversal strategies to sort

visit

static void visit(Map<Class<? extends TraversalStrategy>,Set<Class<? extends TraversalStrategy>>> dependencyMap,
                  List<Class<? extends TraversalStrategy>> sortedStrategyClasses,
                  Set<Class<? extends TraversalStrategy>> seenStrategyClases,
                  List<Class<? extends TraversalStrategy>> unprocessedStrategyClasses,
                  Class<? extends TraversalStrategy> strategyClass)