Class FOQueryEvaluatorWithDBMSDelegation

java.lang.Object

fr.inria.rules.integraal.query_evaluation.generic.FOQueryEvaluatorWithDBMSDelegation

All Implemented Interfaces:

FOQueryEvaluator<FOFormula, QueryableData>, QueryEvaluator<FOQuery<? extends FOFormula>, QueryableData>

public class FOQueryEvaluatorWithDBMSDelegation
extends Object
implements FOQueryEvaluator<FOFormula, QueryableData>

Evaluates a FOQuery by using the an (external) data management system, if this is one is present.

Constructor Summary

Constructors

Constructor	Description
FOQueryEvaluatorWithDBMSDelegation()	Creates the delegating FO-query evaluator.

Method Summary

Modifier and Type	Method	Description
long	countAnswers(FOQuery<? extends FOFormula> query, QueryableData queryableData)	If using a DBMS, we ask the DBMS storage to evaluate the whole query If anything throws an exception, we use the GenericFOQueryEvaluator as a fallback
static FOQueryEvaluator<FOFormula, QueryableData>	defaultInstance()	Returns the shared default configuration.
Stream<Substitution>	evaluate(FOQuery<? extends FOFormula> query, QueryableData queryableData, Collection<Variable> variablesThatMustBeMappedToConstants, Substitution preHomomorphism)	If using a DBMS, we ask the DBMS storage to evaluate the whole query If anything throws an exception, we use the GenericFOQueryEvaluator as a fallback

Methods inherited from class Object

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

Methods inherited from interface FOQueryEvaluator

prepareQuery, prepareQuery

Methods inherited from interface QueryEvaluator

countHomomorphism, evaluate, evaluate, existAnswer, existAnswer, existHomomorphism, existHomomorphism, homomorphism, homomorphism, postprocessResult, postprocessResult

Constructor Details

FOQueryEvaluatorWithDBMSDelegation

public FOQueryEvaluatorWithDBMSDelegation()

Creates the delegating FO-query evaluator.

Method Details

defaultInstance

public static FOQueryEvaluator<FOFormula, QueryableData> defaultInstance()

Returns the shared default configuration.

Returns:

the default configuration

evaluate

public Stream<Substitution> evaluate(FOQuery<? extends FOFormula> query,
 QueryableData queryableData,
 Collection<Variable> variablesThatMustBeMappedToConstants,
 Substitution preHomomorphism)
                              throws EvaluationException

If using a DBMS, we ask the DBMS storage to evaluate the whole query If anything throws an exception, we use the GenericFOQueryEvaluator as a fallback

Specified by:

evaluate in interface FOQueryEvaluator<FOFormula, QueryableData>

Specified by:

evaluate in interface QueryEvaluator<FOQuery<? extends FOFormula>, QueryableData>

Parameters:

query - the query to evaluate

queryableData - the data source against which the query is evaluated

variablesThatMustBeMappedToConstants - variables constrained to constant answers

preHomomorphism - a partial substitution to extend

Returns:

a stream of substitutions answering the query

Throws:

EvaluationException - if the evaluation cannot be completed

countAnswers

public long countAnswers(FOQuery<? extends FOFormula> query,
 QueryableData queryableData)

If using a DBMS, we ask the DBMS storage to evaluate the whole query If anything throws an exception, we use the GenericFOQueryEvaluator as a fallback

Specified by:

countAnswers in interface QueryEvaluator<FOQuery<? extends FOFormula>, QueryableData>

Parameters:

query - query to evaluate

queryableData - queryable data source in which atoms are stored

Returns:

the number of answers to the query