org.eclipse.rdf4j.query.algebra.evaluation.federation

Class TupleFunctionFederatedService

java.lang.Object

org.eclipse.rdf4j.query.algebra.evaluation.federation.TupleFunctionFederatedService

All Implemented Interfaces:

FederatedService

public class TupleFunctionFederatedService
extends Object
implements FederatedService

A federated service that can evaluate TupleFunctions.

Constructor Summary

Constructors

Constructor and Description
TupleFunctionFederatedService(TupleFunctionRegistry tupleFunctionRegistry, ValueFactory vf)

Method Summary

Modifier and Type	Method and Description
boolean	ask(Service service, BindingSet bindings, String baseUri) Evaluate the provided SPARQL ASK query at this federated service.
CloseableIteration<BindingSet,QueryEvaluationException>	evaluate(Service service, CloseableIteration<BindingSet,QueryEvaluationException> bindings, String baseUri) Evaluate the provided SPARQL query at this federated service, possibilities for vectored evaluation.
void	initialize() Method to perform any initializations, invoked after construction.
boolean	isInitialized() Method to check if FederatedService.initialize() had been called.
CloseableIteration<BindingSet,QueryEvaluationException>	select(Service service, Set<String> projectionVars, BindingSet bindings, String baseUri) Evaluate the provided SPARQL query at this federated service.
void	shutdown() Method to perform any shutDown code, invoked at unregistering.

Methods inherited from class java.lang.Object

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

Constructor Detail

TupleFunctionFederatedService

public TupleFunctionFederatedService(TupleFunctionRegistry tupleFunctionRegistry,
                                     ValueFactory vf)

Method Detail

isInitialized

public boolean isInitialized()

Description copied from interface: FederatedService

Method to check if FederatedService.initialize() had been called.

Specified by:

isInitialized in interface FederatedService

initialize

public void initialize()

Description copied from interface: FederatedService

Method to perform any initializations, invoked after construction.

Specified by:

initialize in interface FederatedService

shutdown

public void shutdown()

Description copied from interface: FederatedService

Method to perform any shutDown code, invoked at unregistering.

Specified by:

shutdown in interface FederatedService

ask

public boolean ask(Service service,
                   BindingSet bindings,
                   String baseUri)
            throws QueryEvaluationException

Description copied from interface: FederatedService

Evaluate the provided SPARQL ASK query at this federated service.

 Expected behavior: evaluate boolean query using the bindings as constraints
 

Specified by:

ask in interface FederatedService

Parameters:

service - the reference to the service node, contains additional meta information (vars, prefixes)

bindings - the bindings serving as additional constraints

Returns:

true if at least one result exists

Throws:

QueryEvaluationException - If there was an exception generated while evaluating the query.

select

public CloseableIteration<BindingSet,QueryEvaluationException> select(Service service,
                                                                      Set<String> projectionVars,
                                                                      BindingSet bindings,
                                                                      String baseUri)
                                                               throws QueryEvaluationException

Description copied from interface: FederatedService

Evaluate the provided SPARQL query at this federated service.

Important: The original bindings need to be inserted into the result.

 Expected behavior: evaluate the given SPARQL query using the bindings as constraints
 

Specified by:

select in interface FederatedService

Parameters:

service - the reference to the service node, contains additional meta information (vars, prefixes)

projectionVars - The variables with unknown value that should be projected from this evaluation

bindings - the bindings serving as additional constraints

Returns:

an iteration over the results of the query

Throws:

QueryEvaluationException - If there was an exception generated while evaluating the query.

evaluate

public final CloseableIteration<BindingSet,QueryEvaluationException> evaluate(Service service,
                                                                              CloseableIteration<BindingSet,QueryEvaluationException> bindings,
                                                                              String baseUri)
                                                                       throws QueryEvaluationException

Description copied from interface: FederatedService

Evaluate the provided SPARQL query at this federated service, possibilities for vectored evaluation.

Contracts:

• The original bindings need to be inserted into the result
• SILENT service must be dealt with in the method

Compare SPARQLFederatedService for a reference implementation

Specified by:

evaluate in interface FederatedService

Parameters:

service - the reference to the service node, contains information to construct the query

bindings - the bindings serving as additional constraints (for vectored evaluation)

baseUri - the baseUri

Returns:

the result of evaluating the query using bindings as constraints, the original bindings need to be inserted into the results!

Throws:

QueryEvaluationException - If there was an exception generated while evaluating the query.