How to convert OWL API Objects to Java objects?

Question

I'm using the OWL API for manipulating ontologies. I want to create my own Java objects corresponding to OWLObjects (e.g., OWLEntity, OWLClass, etc.). How can I do this?

To achieve this, I think I need to know how to get a name (String) of an OWLEntity object. But how? I've searched OWL API Javadoc and tutorials but can't find out how.

public class Arg {
    private String name;
    private String defaultValue;
    private boolean isEssential = false;
    private Set<String> preArgNames;

    public Arg(String name, String defaultValue, boolean isEssential,
            Set<String> preArgNames) {
        this.name = name;
        this.defaultValue = defaultValue;
        this.isEssential = isEssential;
        this.preArgNames = preArgNames;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public boolean isEssential() {
        return isEssential;
    }

    public void setEssential(boolean isEssential) {
        this.isEssential = isEssential;
    }

    public Set<String> getPreArgNames() {
        return preArgNames;
    }

    public void setPreArgNames(Set<String> preArgNames) {
        this.preArgNames = preArgNames;
    }

    public String getDefaultValue() {
        return defaultValue;
    }

    public void setDefaultValue(String defaultValue) {
        this.defaultValue = defaultValue;
    }
}

I have a data structure for my application. And data is stored in the ontology. I've added my code example above.

That member variables of Arg object must be filled by ontology data. e.g. Class SomeArg1, SomeArg2,... and it have children classes and restrictions in the ontology and I want to get the entity name, and associated restrictions, etc. to fill the appropriate variables of Arg object.

Answer 1

In this example in line 1093, the method printNode(Node<OWLClass> node) shows how to get the name of an entity. In brief you can define your prefix manager and use that to print the name of the entity you want.

Otherwise you can use the following method:

public void printEntity(OWLEntity e){
    String namespace = e.getIRI().getNamespace();
    String fragment = e.getIRI().getFragment();
    System.out.println("Namespace: " + namespace);
    System.out.println("Fragment: " + fragment);
}

So if you have an entity which name is http://www.co-ode.org/ontologies/pizza/pizza.owl#Pizza, then the previous code will print:

Namespace: http://www.co-ode.org/ontologies/pizza/pizza.owl# Fragment: Pizza

Answer 2

OWLEntity has a method getIRI() that will provide you with the IRI for the object; IRI is both a CharSequence and can be turned into a String with the classic toString() method.

In the latest OWL API you can also access the namespace and fragment of the IRI (which is just an extension of URI, i.e., something like http://example.com or urn:testuri), as mikrohelen mentions above.

This is valid for all OWLEntity subinterfaces, i.e., OWLClass, OWLDataProperty, OWLObjectProperty, OWLDatatype, OWLNamedIndividual and OWLAnnotationProperty.

I cannot answer Anthony's comment yet but I'm quoting here:

Blockquote Not all owl entities (classes, individuals...) have names. I'm guessing that by name you mean the URI used as rdf:id. Protege has a feature that automatically generates Java wrapper classes for owl classes in your ontology, it might be helpful for you. – Anthony Sep 5 at 15:04

That's not correct, strictly speaking: all OWLEntity instances have IRIs. Classes and individuals without IRIs are not entities: classes are OWLClassExpression instances, such as qualified restrictions, and individuals without IRIs are OWLAnonymousIndividual instances. The same applies for properties: the anonymous ones are only expressions, e.g., property chains, but they are not OWLEntity instances.