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package uk.ac.ox.cs.pagoda.approx;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Map;
import java.util.Set;
import org.semanticweb.owlapi.model.IRI;
import org.semanticweb.owlapi.model.OWLAxiom;
import org.semanticweb.owlapi.model.OWLClass;
import org.semanticweb.owlapi.model.OWLClassExpression;
import org.semanticweb.owlapi.model.OWLIndividual;
import org.semanticweb.owlapi.model.OWLObjectAllValuesFrom;
import org.semanticweb.owlapi.model.OWLObjectHasSelf;
import org.semanticweb.owlapi.model.OWLObjectOneOf;
import org.semanticweb.owlapi.model.OWLObjectProperty;
import org.semanticweb.owlapi.model.OWLSubClassOfAxiom;
import uk.ac.ox.cs.pagoda.owl.OWLHelper;
import uk.ac.ox.cs.pagoda.util.Utility;
public class RLOntology extends RLPlusOntology {
@Override
public void transform() {
super.transform();
eliminateSelf();
eliminateNominals();
eliminateOWLThing();
save();
if (aBox.getAxiomCount() != 0)
save(aBox);
}
private void eliminateSelf() {
Collection<OWLAxiom> axioms = new LinkedList<OWLAxiom>(outputOntology.getAxioms());
OWLClassExpression subExp, superExp, newSubExp, newSuperExp;
for (OWLAxiom axiom: axioms)
if (axiom instanceof OWLSubClassOfAxiom) {
subExp = ((OWLSubClassOfAxiom) axiom).getSubClass();
superExp = ((OWLSubClassOfAxiom) axiom).getSuperClass();
newSubExp = approximateSelf4Sub(subExp);
newSuperExp = approximateSelf4Super(superExp);
if (newSubExp != subExp || newSuperExp != superExp)
replaceAxiom4output(axiom, factory.getOWLSubClassOfAxiom(newSubExp, newSuperExp));
}
}
private void replaceAxiom4output(OWLAxiom oldAxiom, OWLAxiom newAxiom) {
manager.removeAxiom(outputOntology, oldAxiom);
manager.addAxiom(outputOntology, newAxiom);
correspondence.put(newAxiom, correspondence.remove(oldAxiom));
}
private boolean hasSelf(OWLClassExpression conjunction) {
for (OWLClassExpression conjunct: conjunction.asConjunctSet())
if (conjunct instanceof OWLObjectHasSelf)
return true;
return false;
}
private OWLClassExpression approximateSelf4Sub(OWLClassExpression exp) {
if (!hasSelf(exp)) return exp;
Set<OWLClassExpression> newConjuncts = new HashSet<OWLClassExpression>();
for (OWLClassExpression conjunct: exp.asConjunctSet())
if (conjunct instanceof OWLObjectHasSelf)
newConjuncts.add(factory.getOWLObjectSomeValuesFrom(((OWLObjectHasSelf) exp).getProperty(), factory.getOWLThing()));
else
newConjuncts.add(conjunct);
return OWLHelper.getSimplifiedConjunction(factory, newConjuncts);
}
private OWLClassExpression approximateSelf4Super(OWLClassExpression exp) {
if (!hasSelf(exp)) return exp;
Set<OWLClassExpression> newConjuncts = new HashSet<OWLClassExpression>();
for (OWLClassExpression conjunct: exp.asConjunctSet())
if (conjunct instanceof OWLObjectHasSelf) {
OWLIndividual freshNominal = getNewIndividual(outputOntology, rlCounter++);
newConjuncts.add(factory.getOWLObjectOneOf(freshNominal));
newConjuncts.add(factory.getOWLObjectHasValue(((OWLObjectHasSelf) exp).getProperty(), freshNominal));
}
else
newConjuncts.add(conjunct);
return OWLHelper.getSimplifiedConjunction(factory, newConjuncts);
}
private void eliminateNominals() {
Collection<OWLAxiom> axioms = new LinkedList<OWLAxiom>(outputOntology.getAxioms());
OWLClassExpression superExp, newSuperExp;
for (OWLAxiom axiom: axioms)
if (axiom instanceof OWLSubClassOfAxiom) {
superExp = ((OWLSubClassOfAxiom) axiom).getSuperClass();
newSuperExp = approximateNominals(superExp);
if (newSuperExp != superExp)
replaceAxiom4output(axiom, factory.getOWLSubClassOfAxiom(((OWLSubClassOfAxiom) axiom).getSubClass(), newSuperExp));
}
}
private OWLClassExpression approximateNominals(OWLClassExpression exp) {
if (!hasIllegalNominals(exp)) return exp;
Set<OWLIndividual> nominals;
Set<OWLClassExpression> newConjuncts = new HashSet<OWLClassExpression>();
for (OWLClassExpression conjunct: exp.asConjunctSet()) {
if (conjunct instanceof OWLObjectOneOf) {
nominals = ((OWLObjectOneOf) conjunct).getIndividuals();
newConjuncts.add(approximateNominal(nominals));
}
else if (conjunct instanceof OWLObjectAllValuesFrom) {
OWLObjectAllValuesFrom allValuesFrom = ((OWLObjectAllValuesFrom) conjunct);
if (allValuesFrom.getFiller() instanceof OWLObjectOneOf) {
nominals = ((OWLObjectOneOf) allValuesFrom.getFiller()).getIndividuals();
newConjuncts.add(factory.getOWLObjectAllValuesFrom(allValuesFrom.getProperty(),
approximateNominal(nominals)));
}
}
}
return OWLHelper.getSimplifiedConjunction(factory, newConjuncts);
}
private OWLClassExpression approximateNominal(Set<OWLIndividual> nominals) {
if (nominals.size() > 1) {
Utility.logError("Error: more than one nominal appearing in OWLObjectOneOf");
return null;
}
OWLIndividual nominal = nominals.iterator().next();
OWLObjectProperty freshProperty = getNewRole4Nominal(nominal);
addAxiom2output(factory.getOWLInverseFunctionalObjectPropertyAxiom(freshProperty), null);
manager.addAxiom(aBox, factory.getOWLObjectPropertyAssertionAxiom(freshProperty, nominal, nominal));
return factory.getOWLObjectHasValue(freshProperty, nominal);
}
Map<OWLIndividual, OWLObjectProperty> role4nominal = new HashMap<OWLIndividual, OWLObjectProperty>();
private OWLObjectProperty getNewRole4Nominal(OWLIndividual nominal) {
OWLObjectProperty property;
if ((property = role4nominal.get(nominal)) == null)
role4nominal.put(nominal, property = getNewRole(outputOntology, rlCounter++));
return property;
}
private boolean hasIllegalNominals(OWLClassExpression exp) {
for (OWLClassExpression conjunct: exp.asConjunctSet()) {
if (conjunct instanceof OWLObjectOneOf) return true;
if (conjunct instanceof OWLObjectAllValuesFrom) {
OWLObjectAllValuesFrom allValuesFrom = ((OWLObjectAllValuesFrom) conjunct);
if (allValuesFrom.getFiller() instanceof OWLObjectOneOf)
return true;
}
}
return false;
}
private void eliminateOWLThing() {
OWLClassExpression subExp;
boolean mark = false;
for (Clause clause: clauses) {
subExp = OWLHelper.getSimplifiedConjunction(factory, clause.getSubClasses());
if (subExp.equals(factory.getOWLThing())) {
mark = true;
}
}
if (mark) {
Utility.logDebug("Top appears in the left of an axiom.");
OWLSubClassOfAxiom subClassAxiom;
OWLClass TOP = factory.getOWLClass(IRI.create(ontologyIRI + "#TOP"));
for (OWLAxiom axiom: new HashSet<OWLAxiom>(outputOntology.getAxioms()))
if (axiom instanceof OWLSubClassOfAxiom && (subClassAxiom = (OWLSubClassOfAxiom) axiom).getSubClass().equals(factory.getOWLThing()))
replaceAxiom4output(axiom, factory.getOWLSubClassOfAxiom(TOP, subClassAxiom.getSuperClass()));
for (OWLClass c: outputOntology.getClassesInSignature(true)) {
if (!c.equals(factory.getOWLThing()))
addAxiom2output(factory.getOWLSubClassOfAxiom(c, TOP), null);
else
addAxiom2output(factory.getOWLSubClassOfAxiom(TOP, c), null);
}
for (OWLObjectProperty p: outputOntology.getObjectPropertiesInSignature(true)) {
addAxiom2output(factory.getOWLObjectPropertyDomainAxiom(p, TOP), null);
addAxiom2output(factory.getOWLObjectPropertyRangeAxiom(p, TOP), null);
}
}
}
}
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