Load Ontology serialized in Turtle using OWL API

Question

I am trying to load an ontology from a Jena model using OWL API, but most of the axioms are appearing as annotations.

The ontology in Turtle is shown below. I use a Jena model to store it. NB: The ontology below is not correct, as mentioned in answers down

@prefix owl:   <http://www.w3.org/2002/07/owl#> .
@prefix rdf:   <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix xsd:   <http://www.w3.org/2001/XMLSchema#> .
@prefix rdfs:  <http://www.w3.org/2000/01/rdf-schema#> .

<http://example.com/minimalDecoupling>
        a           "http://www.w3.org/2002/07/owl#DatatypeProperty" ;
        rdfs:label  "minimal decoupling" .

<http://example.com/frequency>
        a           "http://www.w3.org/2002/07/owl#DatatypeProperty" ;
        rdfs:label  "frequency" .

<http://example.com/voltage>
        a           "http://www.w3.org/2002/07/owl#DatatypeProperty" ;
        rdfs:label  "Voltage" .

<http://example.com/powerConsumed>
        a           "http://www.w3.org/2002/07/owl#DatatypeProperty" ;
        rdfs:label  "power consumed" .

<http://example.com/installation>
        a           "http://www.w3.org/2002/07/owl#DatatypeProperty" ;
        rdfs:label  "installation" .

<http://example.com/Device>
        a           "http://www.w3.org/2002/07/owl#Class" ;
        rdfs:label  "device" .

<http://example.com/dimension>
        a           "http://www.w3.org/2002/07/owl#DatatypeProperty" ;
        rdfs:label  "dimension" .

<http://example.com/>
        a       "http://www.w3.org/2002/07/owl#Ontology" .

Suppose that the above ontology is stored in the Jena model ontologyGraph, I am using the code below to load the Jena model as an OWL ontology.

OWLOntology ontology = ontologyManager.
                loadOntologyFromOntologyDocument
                        (new ByteArrayInputStream(Ontology.toTurtle(ontologyGraph).getBytes()));

The toTurtle method is shown below:

public static String toTurtle(Model ontologyGraph){
        StringWriter out = new StringWriter();
        ontologyGraph.write(out,"TTL");
        return out.toString();
    }

However, as we see in the output below, the axioms from the ontology are appearing annotation axiom:

Ontology(OntologyID(Anonymous-2)) [Axioms: 15 Logical Axioms: 0] First 20 axioms: {AnnotationAssertion(rdfs:label http://example.com/powerConsumed "power consumed") AnnotationAssertion(rdfs:label http://example.com/minimalDecoupling "minimal decoupling") AnnotationAssertion(rdf:type http://example.com/ "http://www.w3.org/2002/07/owl#Ontology") AnnotationAssertion(rdfs:label http://example.com/dimension "dimension") AnnotationAssertion(rdf:type http://example.com/dimension "http://www.w3.org/2002/07/owl#DatatypeProperty") AnnotationAssertion(rdf:type http://example.com/voltage "http://www.w3.org/2002/07/owl#DatatypeProperty") AnnotationAssertion(rdf:type http://example.com/Device "http://www.w3.org/2002/07/owl#Class") AnnotationAssertion(rdfs:label http://example.com/installation "installation") AnnotationAssertion(rdfs:label http://example.com/voltage "Voltage") AnnotationAssertion(rdf:type http://example.com/minimalDecoupling "http://www.w3.org/2002/07/owl#DatatypeProperty") AnnotationAssertion(rdf:type http://example.com/frequency "http://www.w3.org/2002/07/owl#DatatypeProperty") AnnotationAssertion(rdfs:label http://example.com/Device "device") AnnotationAssertion(rdf:type http://example.com/powerConsumed "http://www.w3.org/2002/07/owl#DatatypeProperty") AnnotationAssertion(rdfs:label http://example.com/frequency "frequency") AnnotationAssertion(rdf:type http://example.com/installation "http://www.w3.org/2002/07/owl#DatatypeProperty") }

My questions are:

why are all the axioms appearing as annotations ?
Is it possible to directly load a Jena model as an OWL ontology using OWL API without having to pass through Turtle ?

cygri · Accepted Answer · 2019-04-02T10:44:25.260

2

Why are all the axioms appearing as annotations?

The types in the input model are string literals, but they need to be IRIs. For example this one:

<http://example.com/Device>
    a "http://www.w3.org/2002/07/owl#Class" ;

It should be:

<http://example.com/Device>
    a <http://www.w3.org/2002/07/owl#Class> ;

Which would then be abbreviated automatically as:

<http://example.com/Device>
    a owl:Class ;

Is the ontology in the input Jena model created using the Jena API? In that case, the code needs to be changed to create IRIs (also known as “Resources” or “URIResources” in Jena) instead of string literals.

Is it possible to directly load a Jena model as an OWL ontology using OWL API without having to pass through Turtle?

There is no way to directly load a Jena model into OWL-API, but there certainly are options that avoid the round-trip through Turtle, like ONT-API.

edited Apr 02 '19 at 10:44

answered Apr 02 '19 at 09:39

cygri

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you are probably know about [ONT-D2RQ](https://github.com/avicomp/ont-d2rq) which is a workable fork of your project (d2rq), updated to use modern Jena. This project supports OWL2 and contains [ONT-API](https://github.com/avicomp/ont-api) in dependencies. So, the question is why you don't think so? Have you some arguments to prove it or it is about just feelings? – ssz Apr 02 '19 at 09:55
I focused on the “directly” part of the question. I edited the answer to clarify. – cygri Apr 02 '19 at 10:11
ONT-API supports also direct passing Graph as it is: see `OntologyManager#addOntology(...)` – ssz Apr 02 '19 at 10:13
@ssz I've edited again. I should have worded that better the first time. The D2RQ discussion would be more appropriate over at GitHub. – cygri Apr 02 '19 at 10:45

ssz · Answer 2 · 2020-01-04T11:45:06.830

1) as stated in the other answer - the provided ontology is not correct, instead of URIs there are literals.
2) ONT-API - a Jena based impl of OWL-API-api.

You can load turtle into a manager, having some changes due to transformers, or pass Graph as it is (with or without transformers). In the last case for the given RDF there would be only AnnotationAssertion axioms. If you fix manually your RDF, replacing literals with URIs, the following axioms are expected:

    Declaration(Class(<http://example.com/Device>))
    Declaration(DataProperty(<http://example.com/dimension>))
    Declaration(DataProperty(<http://example.com/installation>))
    Declaration(DataProperty(<http://example.com/powerConsumed>))
    Declaration(DataProperty(<http://example.com/voltage>))
    Declaration(DataProperty(<http://example.com/frequency>))
    Declaration(DataProperty(<http://example.com/minimalDecoupling>))
    AnnotationAssertion(rdfs:label <http://example.com/minimalDecoupling> "minimal decoupling"^^xsd:string)
    AnnotationAssertion(rdfs:label <http://example.com/frequency> "frequency"^^xsd:string)
    AnnotationAssertion(rdfs:label <http://example.com/voltage> "Voltage"^^xsd:string)
    AnnotationAssertion(rdfs:label <http://example.com/powerConsumed> "power consumed"^^xsd:string)
    AnnotationAssertion(rdfs:label <http://example.com/installation> "installation"^^xsd:string)
    AnnotationAssertion(rdfs:label <http://example.com/Device> "device"^^xsd:string)
    AnnotationAssertion(rdfs:label <http://example.com/dimension> "dimension"^^xsd:string)

Also note: there is one more RDF data view: com.github.owlcs.ontapi.jena.model.OntModel, it is recommended to use it instead of org.apache.jena.ontology.OntModel, since the last one does not support OWL2

So foolish of me, I'm sorry, I really didn't notice that the ontology isn't correct !! I'll fix this and i believe it will work !! — Noor, Apr 02 '19 at 10:32

Load Ontology serialized in Turtle using OWL API

2 Answers2