Package org.eclipse.rdf4j.query.algebra.evaluation.impl.evaluationsteps

Class StatementPatternQueryEvaluationStep

java.lang.Object

org.eclipse.rdf4j.query.algebra.evaluation.impl.evaluationsteps.StatementPatternQueryEvaluationStep

All Implemented Interfaces:

QueryEvaluationStep

public class StatementPatternQueryEvaluationStep
extends Object
implements QueryEvaluationStep

Evaluate the StatementPattern - taking care of graph/datasets - avoiding redoing work every call of evaluate if possible.

Nested Class Summary

Nested classes/interfaces inherited from interface org.eclipse.rdf4j.query.algebra.evaluation.QueryEvaluationStep

QueryEvaluationStep.DelayedEvaluationIteration

Field Summary

Fields

Modifier and Type	Field	Description
static Resource[]	ALL_CONTEXT
static Resource[]	DEFAULT_CONTEXT

Fields inherited from interface org.eclipse.rdf4j.query.algebra.evaluation.QueryEvaluationStep

EMPTY, EMPTY_ITERATION

Constructor Summary

Constructors

Constructor	Description
StatementPatternQueryEvaluationStep(StatementPattern statementPattern, QueryEvaluationContext context, TripleSource tripleSource)

Method Summary

Modifier and Type	Method	Description
CloseableIteration<BindingSet,QueryEvaluationException>	evaluate(BindingSet bindings)
protected static Function<Value,Resource[]>	extractContextsFromDatasets(Var contextVar, boolean emptyGraph, Set<IRI> graphs)
protected static Predicate<Statement>	filterContextOrEqualVariables(StatementPattern statementPattern, Value subjValue, Value predValue, Value objValue, Resource[] contexts)	Generate a predicate that tests for Named contexts are matched by retrieving all statements from the store and filtering out the statements that do not have a context.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_CONTEXT

public static final Resource[] DEFAULT_CONTEXT

ALL_CONTEXT

public static final Resource[] ALL_CONTEXT

Constructor Detail

StatementPatternQueryEvaluationStep

public StatementPatternQueryEvaluationStep(StatementPattern statementPattern,
                                           QueryEvaluationContext context,
                                           TripleSource tripleSource)

Method Detail

evaluate

public CloseableIteration<BindingSet,QueryEvaluationException> evaluate(BindingSet bindings)

Specified by:

evaluate in interface QueryEvaluationStep

filterContextOrEqualVariables

protected static Predicate<Statement> filterContextOrEqualVariables(StatementPattern statementPattern,
                                                                    Value subjValue,
                                                                    Value predValue,
                                                                    Value objValue,
                                                                    Resource[] contexts)

Generate a predicate that tests for Named contexts are matched by retrieving all statements from the store and filtering out the statements that do not have a context. Or the same variable might have been used multiple times in this StatementPattern, verify value equality in those cases.

extractContextsFromDatasets

protected static Function<Value,Resource[]> extractContextsFromDatasets(Var contextVar,
                                                                              boolean emptyGraph,
                                                                              Set<IRI> graphs)

Returns:

the contexts that are valid for this statement pattern or null