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

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

Constructor Details

StatementPatternQueryEvaluationStep

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

Method Details

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)

Parameters:

statementPattern -

contextValue -

Returns:

the contexts that are valid for this statement pattern or null