[Pellet-users] KnowledgeBase changes do not appear in OWLOntology

[Evren Sirin]

Sorry, for the late reply. It is a busy time of the year for us. Some 
comments below.

On 3/8/07 6:22 AM, Martin Kolb wrote:
> Hi,
>
> here you can download the TestClass I prepared:
> http://87.230.1.132/TestClass.java (it's only about 20 Lines of code).
>   
Ok, now I understand the problem. I thought you were trying the 
reasoner.getClasses() function which should contain the newly added 
function. But you are using ontology.getClasses() which is not modified 
by the reasoner. That's expected behavior.
> Meanwhile, I tried the same thing with Jena Reasoner, and when I try to
> list all Classes of the model (model.listClasses()) it throws the Exception:
>
> "Cannot convert node DUMMY to OntClass: it does not have rdf:type
> owl:Class or equivalent" Where DUMMY is the new Class, added by the Same
> Method as in the Code in TestClass.java.
>   
Situation for Jena should be different because all the queries you ask a 
Jena model is combined with the answers form the reasoner. And when I 
modify your code as below it works for me:

        String ont_file = "http://87.230.1.132/computer_final.owl";
        OntModel model = ModelFactory.createOntologyModel( 
PelletReasonerFactory.THE_SPEC );
        model.read( ont_file );
        model.prepare();
       
        KnowledgeBase kb = ((PelletInfGraph) model.getGraph()).getKB();

        //Adding a new Class with complete Namespace (Domain 
partialmatch.org does not exist yet)
        ATermAppl newClass = 
ATermUtils.makeTermAppl("http://partialmatch.org/computer#NewClass");
        kb.addClass(newClass);
        kb.prepare();
       
        //In the Class Tree, the new Class appears obviously
        kb.printClassTree();
       
        //In this Set, the new Class will appear now
        Iterator allClasses = model.listClasses();
        while (allClasses.hasNext()) {
            System.out.println(allClasses.next());
        }

There is still an issue with model.getOntClass returning null for the 
new URI. I might be able to solve this but as I said earlier this use 
case is not really something supported so you might get weird behavior 
somewhere else.
> Further, I am testing consistency of a term, added by
> kb.addEquivalentClass(...) to a class added by the method mentioned
> above. Maybe that is connected with the errors I listed above, the
> reasoner always gets out of Memory if I even try to print the class
> tree. (Irrespective of which API I use, the Pellet-OWL-Api, or the
> Jena-Framework). Are there any other known performance issues with
> qualified number restrictions (that's the thing I am working on...)
>   
No, not anything that does not also affect unqualified number 
restrictions, e.g. a cardinality restriction with values greater than 
100 are likely to cause problem.

Regards,
Evren
> Thank you in advance,
>
> Martin Kolb
>
> Evren Sirin schrieb:
>   
>> On 3/7/07 9:38 AM, Martin Kolb wrote:
>>     
>>> Hello everybody,
>>>
>>> I am using Pellet with the OWL Api. I am usually loading an ontology
>>> into a OWLOntology Object, and the
>>> org.mindswap.pellet.owlapi.Reasoner.
>>>
>>> During my program, changes are made via the ATerm-Library directly on
>>> the KnowledgeBase Object, retrieved with reasoner.getKB().
>>> But, if I add Classes to the KnowledgeBase and call prepare(), they do
>>> not appear in the set of all Classes which I can retrieve through
>>> reasoner.getClasses() later.
>>> Maybe that even is not supposed to be?
>>>   
>>>       
>> This is not really a use case I have considered but I would think it
>> should work because all the Reasoner class does is to call functions
>> from the underlying KB and translate results to OWLAPI structures. If
>> you have a complete minimal code example showing the problem I could
>> take a look.
>>
>> Cheers,
>> Evren
>>     
>>> Thank you in advance for any hints,
>>> Regards,
>>>
>>> Martin Kolb
>>>
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>>