Package com.complexible.stardog.plan.eval.service

Interface Service

public interface Service

Interface representing a Service that is capable of providing results due to the evaluation of a SPARQL query.

Since:

3.0

Author:

Michael Grove

Method Summary

Modifier and Type	Method	Description
default boolean	answersSparqlQueries()	Are queries against this service SPARQL queries? If so, we can perform reasoning, etc.
boolean	canEvaluate(IRI iri)	Return whether or not the Service can answer
default boolean	customTermReplacement()	If this returns true, the service is expected to override replaceQueryTerms(PlanNodeVarReplacer, ServicePlanNode) to implement custom logic of replacing query terms.
default java.util.function.BooleanSupplier	getAvailability(IRI serviceIri)	Return a BooleanSupplier that indicates whether the service is available (not closed) and therefore still valid for use in the cache The purpose of using a BooleanSupplier rather than just calling an availability method is to account for the possibility that a Service may delegate to different virtual graphs over time.
default boolean	isAccessibleFrom(java.lang.String database, IRI serviceIri)
default com.complexible.stardog.plan.PlanNode	replaceQueryTerms(com.complexible.stardog.plan.util.PlanNodeVarReplacer replacer, com.complexible.stardog.plan.ServicePlanNode serviceNode)	Replaces query terms in the given ServicePlanNode.
default boolean	respectsNamedGraphSecurity()	Is the service restricted to graphs accessible according to the named graph security constraints?
default boolean	supportsConstantReplacement()	Does this service create queries which support constant replacement? If so, caching with constant canonicalization is performed.
default com.complexible.stardog.plan.PlanNode	translate(com.complexible.stardog.plan.eval.ExecutionContext execCxt, IRI iri, com.complexible.stardog.plan.PlanNode body, com.complexible.stardog.plan.QueryTerm context, java.util.function.IntFunction<java.lang.String> varNames, java.util.function.Function<java.lang.String,java.lang.Integer> varAllocator, boolean silent)
com.complexible.stardog.plan.PlanNode	translate(com.complexible.stardog.plan.eval.ExecutionContext execCxt, IRI iri, com.complexible.stardog.plan.PlanNode body, java.util.function.IntFunction<java.lang.String> varNames, java.util.function.Function<java.lang.String,java.lang.Integer> varAllocator, boolean silent)	Translate a query fragment to a call to this service

Method Detail

canEvaluate

boolean canEvaluate(IRI iri)

Return whether or not the Service can answer

Parameters:

iri - the IRI of the service

Returns:

true if this service can evaluate the query, false otherwise

translate

com.complexible.stardog.plan.PlanNode translate(com.complexible.stardog.plan.eval.ExecutionContext execCxt,
                                                IRI iri,
                                                com.complexible.stardog.plan.PlanNode body,
                                                java.util.function.IntFunction<java.lang.String> varNames,
                                                java.util.function.Function<java.lang.String,java.lang.Integer> varAllocator,
                                                boolean silent)

Translate a query fragment to a call to this service

translate

default com.complexible.stardog.plan.PlanNode translate(com.complexible.stardog.plan.eval.ExecutionContext execCxt,
                                                        IRI iri,
                                                        com.complexible.stardog.plan.PlanNode body,
                                                        com.complexible.stardog.plan.QueryTerm context,
                                                        java.util.function.IntFunction<java.lang.String> varNames,
                                                        java.util.function.Function<java.lang.String,java.lang.Integer> varAllocator,
                                                        boolean silent)

respectsNamedGraphSecurity

default boolean respectsNamedGraphSecurity()

Is the service restricted to graphs accessible according to the named graph security constraints?

supportsConstantReplacement

default boolean supportsConstantReplacement()

Does this service create queries which support constant replacement? If so, caching with constant canonicalization is performed. If not, the service body will be added to the cache without canonicalization.

customTermReplacement

default boolean customTermReplacement()

If this returns true, the service is expected to override replaceQueryTerms(PlanNodeVarReplacer, ServicePlanNode) to implement custom logic of replacing query terms.

replaceQueryTerms

default com.complexible.stardog.plan.PlanNode replaceQueryTerms(com.complexible.stardog.plan.util.PlanNodeVarReplacer replacer,
                                                                com.complexible.stardog.plan.ServicePlanNode serviceNode)

Replaces query terms in the given ServicePlanNode. Most services would simply delegate to the PlanNodeVarReplacer but some may require custom logic for inlining constants etc.

answersSparqlQueries

default boolean answersSparqlQueries()

Are queries against this service SPARQL queries? If so, we can perform reasoning, etc.

getAvailability

default java.util.function.BooleanSupplier getAvailability(IRI serviceIri)

Return a BooleanSupplier that indicates whether the service is available (not closed) and therefore still valid for use in the cache The purpose of using a BooleanSupplier rather than just calling an availability method is to account for the possibility that a Service may delegate to different virtual graphs over time. The BooleanSupplier will return the availability of the virtual graph that handled this serviceIri at the time this method is called, not when BooleanSupplier.getAsBoolean() is called. Important for plan cache invalidation.

isAccessibleFrom

default boolean isAccessibleFrom(java.lang.String database,
                                 IRI serviceIri)