Ah right, the String matching will also fail because of the wrong operator - but remember, IN ADDITION to the problem that the property is an object property and therefore the value is a resource which is identified by a URI
> You need to learn the difference between == and .equals(). > > Please read up on basic Java skills! These questions should be asked on the > Jena user group... > > > On 18 Jan 2017 1:14 pm, "Sidra shah" <[email protected]> wrote: > > Hello Lorenz, its not giving me the exception now but it does not display > the message JOption,. It does not read the * if (s1=="CatPhysics")* > > > RDFNode phFav=indiv.getPropertyValue(favcat); > if (phFav!=null){ > RDFNode l1=phFav.asResource(); > > > String s1=l1.toString(); > } > > if (s1=="CatPhysics"){ > JOptionPane.showMessageDialog(null, "Phyics category"); > } > > > > On Wed, Jan 18, 2017 at 2:12 PM, Sidra shah <[email protected]> wrote: > >> Thank you Lorenz, let me read the document you mention here. I will come >> back after reading and applying. >> >> Best regards >> >> On Wed, Jan 18, 2017 at 1:46 PM, Lorenz B. <[email protected] >> leipzig.de> wrote: >> >>> 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/o >>> ntologies/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 >>> >>> -- Lorenz Bühmann AKSW group, University of Leipzig Group: http://aksw.org - semantic web research center
