OWL API：遍历导入的本体

Question

我试图将一个本体导入到主本体，并遍历所有类：

     manager = OWLManager.createOWLOntologyManager();
            ontology = manager.loadOntologyFromOntologyDocument(new File("data/prim.owl"));
            factory = manager.getOWLDataFactory();
            OWLImportsDeclaration im = factory.getOWLImportsDeclaration(IRI.create("https://protege.stanford.edu/ontologies/pizza/pizza.owl"));
            manager.applyChange(new AddImport(ontology,im));
            reasoner = OpenlletReasonerFactory.getInstance().createReasoner(ontology);

我正在运行这段代码以获取所有类：

      //*********************
            Set<OWLClass> allCls = ontology.getClassesInSignature();
            allCls.forEach(System.out::println);

Answer 1

问题中的代码包含一个错误：它没有将所需的导入本体（pizza）加载到Manager中。

OWLImportsDeclaration im = factory.getOWLImportsDeclaration(IRI.create("https://protege.stanford.edu/ontologies/pizza/pizza.owl"));
manager.applyChange(new AddImport(ontology,im));

这些行只是将owl:imports声明添加到Pizza-IRI的本体头(_:x a owl:ontology)中。

为了使代码工作，您需要单独加载pizza-ontology：

OWLOntology pizza = manager.loadOntology(IRI.create("https://protege.stanford.edu/ontologies/pizza/pizza.owl"));
OWLImportsDeclaration im = factory.getOWLImportsDeclaration(pizza.getOntologyID().getOntologyIRI().orElseThrow(AssertionError::new));
manager.applyChange(new AddImport(ontology, im));

Assert.assertEquals(1, ontology.importsDeclarations().count());
Assert.assertEquals(1, ontology.imports().count());
Assert.assertEquals(2, manager.ontologies().count());

ontology.classesInSignature(Imports.INCLUDED).forEach(System.err::println);

还请注意：方法set getClassesInSignature（boolean includeImportsClosure） 不推荐使用（在OWL-API v5中）。