Class NegationFOQueryEvaluator<QD extends QueryableData>

java.lang.Object

fr.inria.rules.integraal.query_evaluation.negation.NegationFOQueryEvaluator<QD>

Type Parameters:

QD - the queryable data type handled by this evaluator

All Implemented Interfaces:

FOQueryEvaluator<FOFormulaNegation, QD>, QueryEvaluator<FOQuery<? extends FOFormulaNegation>, QD>

public class NegationFOQueryEvaluator<QD extends QueryableData>
extends Object
implements FOQueryEvaluator<FOFormulaNegation, QD>

Evaluator for ¬φ. It delegates the evaluation of the inner formula φ to another evaluator and returns the logical negation of its existence :

• if φ has at least one homomorphism compatible with the current pre-mapping, the result stream is empty ;
• otherwise the stream contains a single empty Substitution.

Author:

Guillaume Perution-Kihli

Constructor Summary

Constructors

Constructor	Description
NegationFOQueryEvaluator(FOQueryEvaluator<FOFormula, QD> innerEvaluator)	Creates a negation evaluator delegating positive subqueries to the supplied evaluator.

Method Summary

Modifier and Type	Method	Description
Stream<Substitution>	evaluate(FOQuery<? extends FOFormulaNegation> query, QD data, Collection<Variable> mustBeGround, Substitution preHomomorphism)	Evaluates a first-order query against a data source.
PreparedFOQuery<? extends FOFormulaNegation, QD>	prepareQuery(FOQuery<? extends FOFormulaNegation> query, QD data, Collection<Variable> mustBeGround)	Creates a prepared first-order query bound to a data source and ground-term policy.
String	toString()

Methods inherited from class Object

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

Methods inherited from interface FOQueryEvaluator

prepareQuery

Methods inherited from interface QueryEvaluator

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

Constructor Details

NegationFOQueryEvaluator

public NegationFOQueryEvaluator(FOQueryEvaluator<FOFormula, QD> innerEvaluator)

Creates a negation evaluator delegating positive subqueries to the supplied evaluator.

Parameters:

innerEvaluator - the evaluator used for the inner positive formula

Method Details

toString

public String toString()

Overrides:

toString in class Object

prepareQuery

public PreparedFOQuery<? extends FOFormulaNegation, QD> prepareQuery(FOQuery<? extends FOFormulaNegation> query,
 QD data,
 Collection<Variable> mustBeGround)

Description copied from interface: FOQueryEvaluator

Creates a prepared first-order query bound to a data source and ground-term policy.

Specified by:

prepareQuery in interface FOQueryEvaluator<FOFormulaNegation, QD extends QueryableData>

Specified by:

prepareQuery in interface QueryEvaluator<FOQuery<? extends FOFormulaNegation>, QD extends QueryableData>

Parameters:

query - the query to prepare

data - the data source against which the query will run

mustBeGround - variables constrained to ground answers

Returns:

a prepared query wrapper

evaluate

public Stream<Substitution> evaluate(FOQuery<? extends FOFormulaNegation> query,
 QD data,
 Collection<Variable> mustBeGround,
 Substitution preHomomorphism)
                              throws EvaluationException

Description copied from interface: FOQueryEvaluator

Evaluates a first-order query against a data source.

Specified by:

evaluate in interface FOQueryEvaluator<FOFormulaNegation, QD extends QueryableData>

Specified by:

evaluate in interface QueryEvaluator<FOQuery<? extends FOFormulaNegation>, QD extends QueryableData>

Parameters:

query - the query to evaluate

data - the data source against which the query is evaluated

mustBeGround - 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