private void runWithSeparateFiles() {
    if (owlFile == null) {
      throw new NullPointerException("You have to specify an ontology file!");
    }

    OWLOntologyManager manager = OWLManager.createOWLOntologyManager();
    OWLOntology ontology = null;
    OBDADataFactory obdaDataFactory = OBDADataFactoryImpl.getInstance();
    try {
      ontology = manager.loadOntologyFromOntologyDocument((new File(owlFile)));

      if (disableReasoning) {
        /*
         * when reasoning is disabled, we extract only the declaration assertions for the vocabulary
         */
        ontology = extractDeclarations(manager, ontology);
      }

      Collection<Predicate> predicates = new ArrayList<>();

      for (OWLClass owlClass : ontology.getClassesInSignature()) {
        Predicate predicate = obdaDataFactory.getClassPredicate(owlClass.getIRI().toString());
        predicates.add(predicate);
      }
      for (OWLDataProperty owlDataProperty : ontology.getDataPropertiesInSignature()) {
        Predicate predicate =
            obdaDataFactory.getDataPropertyPredicate(owlDataProperty.getIRI().toString());
        predicates.add(predicate);
      }
      for (OWLObjectProperty owlObjectProperty : ontology.getObjectPropertiesInSignature()) {
        Predicate predicate =
            obdaDataFactory.getObjectPropertyPredicate(owlObjectProperty.getIRI().toString());
        predicates.add(predicate);
      }

      OBDAModel obdaModel = loadMappingFile(mappingFile);

      Ontology inputOntology = OWLAPI3TranslatorUtility.translate(ontology);

      obdaModel.declareAll(inputOntology.getVocabulary());

      int numPredicates = predicates.size();

      int i = 1;
      for (Predicate predicate : predicates) {
        System.err.println(String.format("Materializing %s (%d/%d)", predicate, i, numPredicates));
        serializePredicate(ontology, inputOntology, obdaModel, predicate, outputFile, format);
        i++;
      }

    } catch (OWLOntologyCreationException e) {
      e.printStackTrace();
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
  private static Predicate getPredicate(OWLEntity entity) {
    Predicate p = null;
    if (entity instanceof OWLClass) {
      /* We ignore TOP and BOTTOM (Thing and Nothing) */
      if (((OWLClass) entity).isOWLThing() || ((OWLClass) entity).isOWLNothing()) {
        return null;
      }
      String uri = entity.getIRI().toString();

      p = dfac.getClassPredicate(uri);
    } else if (entity instanceof OWLObjectProperty) {
      String uri = entity.getIRI().toString();

      p = dfac.getObjectPropertyPredicate(uri);
    } else if (entity instanceof OWLDataProperty) {
      String uri = entity.getIRI().toString();

      p = dfac.getDataPropertyPredicate(uri);
    }
    return p;
  }