Travelling in ontology by using gate.creole.ontology package

Dears, I'm working with GATE && JAPE rules to walk around in my ontology,

I run the following code:

OURI uri = ontology.createOURI(cURI);
    OClass nClass = ontology.getOClass(uri);
    byte closure = 0;
    Set<OClass> superClass = nClass.getSuperClasses(closure);// direct_closure

    for (OClass temp : superClass) 
        { 
        Set<OClass> disClass = temp.getDisjointClasses();
        }

I get : Error: The method getDisjointClasses() is undefined for the type OClass.

would you help please to correct this, and get the disjoint class ?!