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

Modifier and Type	Class	Description
private static final class	StatementPatternQueryEvaluationStep.ConvertStatementToBindingSetIterator	Converts statements into the required bindingsets.
private static final class	StatementPatternQueryEvaluationStep.JoinStatementWithBindingSetIterator

Nested classes/interfaces inherited from interface QueryEvaluationStep

QueryEvaluationStep.DelayedEvaluationIteration

Field Summary

Fields

Modifier and Type	Field	Description
static final Resource[]	ALL_CONTEXT
private final QueryEvaluationContext	context
private final Function<Value, Resource[]>	contextSup
private final BiConsumer<MutableBindingSet, Statement>	converter
static final Resource[]	DEFAULT_CONTEXT
private final boolean	emptyGraph
private final Function<BindingSet, Value>	getContextVar
private final Function<BindingSet, Value>	getObjectVar
private final Function<BindingSet, Value>	getPredicateVar
private final Function<BindingSet, Value>	getSubjectVar
private static final Function<Value, Resource[]>	RETURN_NULL_VALUE_RESOURCE_ARRAY
private final StatementPattern	statementPattern
private final TripleSource	tripleSource
private final Predicate<BindingSet>	unboundTest

Fields inherited from interface QueryEvaluationStep

EMPTY, EMPTY_ITERATION

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
private static Predicate<Statement>	andThen(Predicate<Statement> pred, Predicate<Statement> and)
private static Resource[]	contextsGivenContextVal(Value contextValue)
CloseableIteration<BindingSet, QueryEvaluationException>	evaluate(BindingSet bindings)
protected static Function<Value, Resource[]>	extractContextsFromDatasets(Var contextVar, boolean emptyGraph, Set<IRI> graphs)
private static Resource[]	fillContextsFromDatasSetGraphs(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.
private static Predicate<Statement>	filterSameVariable(StatementPattern statementPattern, Value subjValue, Value predValue, Value objValue, Predicate<Statement> filter)	Build one predicate that filters the statements for ?s ?p ?s cases.
private StatementPatternQueryEvaluationStep.ConvertStatementToBindingSetIterator	getIteration()
private StatementPatternQueryEvaluationStep.JoinStatementWithBindingSetIterator	getIteration(BindingSet bindings)
private static Predicate<BindingSet>	getUnboundTest(QueryEvaluationContext context, Var s, Var p, Var o, Var c)
private CloseableIteration<? extends Statement, QueryEvaluationException>	handleFilter(Resource[] contexts, Resource subject, IRI predicate, Value object, CloseableIteration<? extends Statement, QueryEvaluationException> iteration)
private static BiConsumer<MutableBindingSet, Statement>	makeConverter(QueryEvaluationContext context, Var s, Var p, Var o, Var c)	We need to test every binding with hasBinding etc.
private static Function<BindingSet, Value>	makeGetVarValue(Var var, QueryEvaluationContext context)
private static Predicate<Statement>	predicateVariableHasEquals(boolean predEqObjVar, boolean predEqConVar)
private static Predicate<Statement>	subjectVariableHasEquals(boolean subEqPredVar, boolean subEqObjVar, boolean subEqConVar)

Methods inherited from class Object

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

Field Details

DEFAULT_CONTEXT

public static final Resource[] DEFAULT_CONTEXT

ALL_CONTEXT

public static final Resource[] ALL_CONTEXT

RETURN_NULL_VALUE_RESOURCE_ARRAY

private static final Function<Value, Resource[]> RETURN_NULL_VALUE_RESOURCE_ARRAY

statementPattern

private final StatementPattern statementPattern

tripleSource

private final TripleSource tripleSource

emptyGraph

private final boolean emptyGraph

contextSup

private final Function<Value, Resource[]> contextSup

converter

private final BiConsumer<MutableBindingSet, Statement> converter

context

private final QueryEvaluationContext context

unboundTest

private final Predicate<BindingSet> unboundTest

getContextVar

private final Function<BindingSet, Value> getContextVar

getSubjectVar

private final Function<BindingSet, Value> getSubjectVar

getPredicateVar

private final Function<BindingSet, Value> getPredicateVar

getObjectVar

private final Function<BindingSet, Value> getObjectVar

Constructor Details

StatementPatternQueryEvaluationStep

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

Method Details

getUnboundTest

private static Predicate<BindingSet> getUnboundTest(QueryEvaluationContext context,
 Var s,
 Var p,
 Var o,
 Var c)

makeGetVarValue

private static Function<BindingSet, Value> makeGetVarValue(Var var,
 QueryEvaluationContext context)

evaluate

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

Specified by:

evaluate in interface QueryEvaluationStep

getIteration

private StatementPatternQueryEvaluationStep.JoinStatementWithBindingSetIterator getIteration(BindingSet bindings)

getIteration

private StatementPatternQueryEvaluationStep.ConvertStatementToBindingSetIterator getIteration()

handleFilter

private CloseableIteration<? extends Statement, QueryEvaluationException> handleFilter(Resource[] contexts,
 Resource subject,
 IRI predicate,
 Value object,
 CloseableIteration<? extends Statement, QueryEvaluationException> iteration)

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.

filterSameVariable

private static Predicate<Statement> filterSameVariable(StatementPattern statementPattern,
 Value subjValue,
 Value predValue,
 Value objValue,
 Predicate<Statement> filter)

Build one predicate that filters the statements for ?s ?p ?s cases. But only generates code that is actually needed else returns null.

predicateVariableHasEquals

private static Predicate<Statement> predicateVariableHasEquals(boolean predEqObjVar,
 boolean predEqConVar)

subjectVariableHasEquals

private static Predicate<Statement> subjectVariableHasEquals(boolean subEqPredVar,
 boolean subEqObjVar,
 boolean subEqConVar)

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

contextsGivenContextVal

private static Resource[] contextsGivenContextVal(Value contextValue)

fillContextsFromDatasSetGraphs

private static Resource[] fillContextsFromDatasSetGraphs(Set<IRI> graphs)

makeConverter

private static BiConsumer<MutableBindingSet, Statement> makeConverter(QueryEvaluationContext context,
 Var s,
 Var p,
 Var o,
 Var c)

We need to test every binding with hasBinding etc. as these are not guaranteed to be equivalent between calls of evaluate(bs). Each conversion kind is special cased in with a specific method.

Returns:

a converter from statement into MutableBindingSet

andThen

private static Predicate<Statement> andThen(Predicate<Statement> pred,
 Predicate<Statement> and)