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package rsacomb
import org.semanticweb.owlapi.model.{OWLAxiom, OWLSubClassOfAxiom, OWLEquivalentClassesAxiom, OWLObjectPropertyExpression}
import org.semanticweb.owlapi.model.OWLAxiomVisitorEx
import tech.oxfordsemantic.jrdfox.logic.{Rule, BodyFormula}
import tech.oxfordsemantic.jrdfox.logic.{Atom, Term, Variable, Literal}
import tech.oxfordsemantic.jrdfox.logic.{TupleTableName}
import scala.collection.JavaConverters._
import rsacomb.SkolemStrategy
import rsacomb.RDFoxRuleShards
import org.semanticweb.owlapi.model.OWLSubObjectPropertyOfAxiom
import org.semanticweb.owlapi.model.OWLObjectProperty
object RDFoxAxiomConverter {
def apply(
term : Term = Variable.create("x"),
skolem : SkolemStrategy = SkolemStrategy.None,
unsafe : List[OWLObjectPropertyExpression] = List()
) : RDFoxAxiomConverter =
new RDFoxAxiomConverter(term, skolem, unsafe)
} // object RDFoxAxiomConverter
class RDFoxAxiomConverter(term : Term, skolem : SkolemStrategy, unsafe : List[OWLObjectPropertyExpression])
extends OWLAxiomVisitorEx[List[Rule]]
{
override
def visit(axiom : OWLSubClassOfAxiom) : List[Rule] = {
// Skolemization is needed only for the head of an axiom
val subVisitor = new RDFoxClassExprConverter(term,SkolemStrategy.None, unsafe)
val superVisitor = new RDFoxClassExprConverter(term, skolem, unsafe)
// Each visitor returns a `RDFoxRuleShards`, a tuple (res,ext):
// - the `res` List is a list of atoms resulting from the conversion
// of the axiom.
// - for some Class Expressions appearing in the head of an Axiom,
// the conversion might produce atoms that need to appear in the
// body (and not in the head) of the rule. This is what the `ext`
// List is for.
val sub = axiom.getSubClass.accept(subVisitor)
val sup = axiom.getSuperClass.accept(superVisitor)
val head = sup.res.asJava
val body = (sub.res ++ sup.ext).asJava
List(Rule.create(head,body))
}
override
def visit(axiom : OWLEquivalentClassesAxiom) : List[Rule] = {
for {
axiom1 <- axiom.asPairwiseAxioms.asScala.toList
axiom2 <- axiom1.asOWLSubClassOfAxioms.asScala.toList
rule <- axiom2.accept(this)
} yield rule
}
override
def visit(axiom : OWLSubObjectPropertyOfAxiom) : List[Rule] = {
// TODO: variables needs to be handled at visitor level. Hardcoding
// the name of the varibles might lead to errors for complex cases.
val term1 = Variable.create("y")
val subVisitor = new RDFoxPropertyExprConverter(term,term1,SkolemStrategy.None)
val superVisitor = new RDFoxPropertyExprConverter(term,term1,skolem)
val body: List[BodyFormula] = axiom.getSubProperty.accept(subVisitor)
val head: List[Atom] = axiom.getSuperProperty.accept(superVisitor)
List(Rule.create(head.asJava,body.asJava))
}
def doDefault(axiom : OWLAxiom) : List[Rule] = List()
} // class RDFoxAxiomConverter
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