What is for you the "value of a resource"? The URI? There is only one good source for developers, and that's Javadoc [1] - that's why we always refer to if people have questions.
asResource() converts the RDFNode object to a resource [1] https://jena.apache.org/documentation/javadoc/jena/org/apache/jena/rdf/model/RDFNode.html > Hello Lorenz, this was the question I was expected to ask? I mean values of > BestCategory are resources. > Kindly if you can guide me how to get the value, I searched it on the web > but could not found any related resources. > > Kind regards > > On Wed, Jan 18, 2017 at 10:57 AM, Lorenz B. < > [email protected]> wrote: > >>> OntModel model2=ModelFactory.createOntologyModel( >> OntModelSpec.OWL_DL_MEM); >>> InputStream in =FileManager.get().open("F://20-8.owl"); >>> if (in==null) { >>> throw new IllegalArgumentException( "File: " + " not >>> found"); >>> } model2.read(in,""); >>> >>> String ns=" >>> http://www.semanticweb.org/t/ontologies/2016/7/myOWL#";; >>> >>> OntProperty favcat=model2.getOntProperty(ns+ "BestCategory"); >>> String name=jTextField1.getText(); >>> Individual indiv = user1.createIndividual(ns + name); >>> RDFNode phFav=indiv.getPropertyValue(favcat); >>> if (phFav!=null){ >>> Literal l1=phFav.asLiteral(); >> If BestCategory is an object property, why do you cast the value as >> literal?! >>> s1=l1.toString(); } >>> } >>> if (s1=="CatPhysics"){ >>> JOptionPane.showMessageDialog(null, "Physics"); >>> } >>> >>> The rule itself is >>> >>> String rule ="[rule1: ( ?x http://www.semanticweb.org/ >>> t/ontologies/2016/7/myOWL#Physics_Preferred_Category ?cat1 )" + >>> "( ?x http://www.semanticweb.org/t/ontologies/2016/7/myOWL# >>> Chem_Preferred_Category ?cat2 )" + >>> "( ?x http://www.semanticweb.org/t/ontologies/2016/7/myOWL#Geo_ >>> Preferred_Category ?cat3 )" + >>> "greaterThan(?cat1,?cat2), greaterThan(?cat1,?cat3)" >>> + " -> (?x http://www.semanticweb.org/t/ >>> ontologies/2016/7/myOWL#BestCategory http://www.semanticweb.org/t/ >>> ontologies/2016/7/myOWL#BestCategory#Physics )]"; >>> >>> >>> The BestCategory is object property. >>> >>> Regards >>> >>> >>> On Tue, Jan 17, 2017 at 8:16 PM, Andy Seaborne <[email protected]> wrote: >>> >>>> A Complete, Minimal Example please. >>>> >>>> >>>> Partial code, no data is not complete. >>>> It must compile and run to be complete. >>>> >>>> Minimal means only what is necessary to ask the question not the whole >>>> data or whole application. >>>> >>>> Andy >>>> >>>> On 17/01/17 17:14, Sidra shah wrote: >>>> >>>>> I am surprise that when there is no value in BestCategory, it gives me >> no >>>>> error and when the rule executes and value comes in BestCategory, it >> gives >>>>> me now *"RequiredLiteralException*" >>>>> >>>>> The code I used here is >>>>> >>>>> OntProperty favcat=model2.getOntProperty(ns+ "BestCategory"); >>>>> >>>>> RDFNode phFav=indiv.getPropertyValue(favcat); >>>>> if (phFav!=null){ >>>>> Literal l1=phFav.asLiteral(); >>>>> >>>>> s1=l1.toString();} >>>>> >>>>> if (s1=="CatPhysics"){ >>>>> JOptionPane.showMessageDialog(null, "Physics"); >>>>> } >>>>> >>>>> Best regards >>>>> >>>>> On Tue, Jan 17, 2017 at 5:53 PM, Sidra shah <[email protected]> >>>>> wrote: >>>>> >>>>> Hello Chris, thanks a lot for your suggestion. >>>>>> Best regards. >>>>>> >>>>>> On Tue, Jan 17, 2017 at 5:37 PM, Chris Dollin < >>>>>> [email protected]> wrote: >>>>>> >>>>>> >>>>>>> On 17/01/17 13:30, Sidra shah wrote: >>>>>>> >>>>>>> Hi Lorenz, I am sorry but with much regards, you discussed here the >>>>>>>> problem, not the solution :) :) >>>>>>>> >>>>>>>> I know this if there is no value, there must be Null exception, >>>>>>>> >>>>>>>> >>>>>>> This is not true. >>>>>>> >>>>>>> but can you suggest me a way where we dodge the compiler >>>>>>> >>>>>>> No "dodging" of the compiler is required. Instead, just write >>>>>>> perfectly ordinary code that tests to see if the result of >>>>>>> getPropertyValue is null, and take one action if it isn't and >>>>>>> a different one if it is. >>>>>>> >>>>>>> There's nothing special about this. You don't need to use >>>>>>> break (which is for escaping from loops); just an if >>>>>>> with suitable then and else parts. >>>>>>> >>>>>>> I know this is more a Java problem, but any help I will appreciate. >>>>>>> >>>>>>> Find someone /local/ doing the same or similar course and talk to >>>>>>> them (and have them talk to you) about programming and this >>>>>>> problem. I don't mean copy each other's work; I mean use each >>>>>>> other to understand what the problem is about and how the code >>>>>>> works. Each of you will know things that the other doesn't; share. >>>>>>> >>>>>>> Chris >>>>>>> >>>>>>> -- >>>>>>> "He could not weigh up which was worse and so tried not to think >> about >>>>>>> either." >>>>>>> /The Spellgrinder's >>>>>>> Apprentice/ >>>>>>> >>>>>>> Epimorphics Ltd, http://www.epimorphics.com >>>>>>> Registered address: Court Lodge, 105 High Street, Portishead, Bristol >>>>>>> BS20 6PT >>>>>>> Epimorphics Ltd. is a limited company registered in England (number >>>>>>> 7016688) >>>>>>> >>>>>>> >> -- >> Lorenz Bühmann >> AKSW group, University of Leipzig >> Group: http://aksw.org - semantic web research center >> >> -- Lorenz Bühmann AKSW group, University of Leipzig Group: http://aksw.org - semantic web research center
