如何使用OWL API获取对象属性声明的注释

Question

Assume the following example (see image below): an individual "bmw-x5" has the object property assertion "has-type car". This object property has an annotation property "wheels" with value "4".

Using OWL API, I managed to get the individual "bmw-x5", the object property assertion "hastype car". I am now stuck with the annotation property "wheels". How can I get its value from the OWL API?

    <ObjectPropertyAssertion>
        <Annotation>
            <AnnotationProperty IRI="#wheels"/>
            <Literal datatypeIRI="&rdf;PlainLiteral">4</Literal>
        </Annotation>
        <ObjectProperty IRI="#has-type"/>
        <NamedIndividual IRI="#bmw-x5"/>
        <NamedIndividual IRI="#car"/>
    </ObjectPropertyAssertion>

Answer 1

If you have got hold of an object property assertion axiom, then the annotations are available as follows:

OWLObjectAssertionAxiom axiom = ...
for(OWLAnnotation a: axiom.getAnnotations()) {
    // this cycle will go over all annotations, with annotation property and annotation value
}

In order to access all object property assertion axioms for a certain individual, you can use:

Set<OWLObjectAssertionAxiom> set = ontology.getObjectPropertyAssertionAxioms(individual);