It works, thanks for your help Dave!
On 5 April 2013 04:33, Dave Reynolds <[email protected]> wrote: > Hi Christian, > > > On 04/04/13 18:23, Christian Jauvin wrote: >> >> Hi, >> >> I'm currently following the Jena API inferencing tutorial: >> >> https://jena.apache.org/documentation/inference/ >> >> and as an exercise to test my understanding, I'd like to rewrite the >> first example, which demonstrates a trivial RDFS reasoning from a >> programmatically built model: >> >> import com.hp.hpl.jena.rdf.model.*; >> import com.hp.hpl.jena.vocabulary.*; >> >> public class Test1 { >> static public void main(String...argv) { >> String NS = "foo:"; >> Model m = ModelFactory.createDefaultModel(); >> Property p = m.createProperty(NS, "p"); >> Property q = m.createProperty(NS, "q"); >> m.add(p, RDFS.subPropertyOf, q); >> m.createResource(NS + "x").addProperty(p, "bar"); >> InfModel im = ModelFactory.createRDFSModel(m); >> Resource x = im.getResource(NS + "x"); >> // verify that property q of x is "bar" (which follows >> // from x having property p, and p being a subproperty of q) >> System.out.println("Statement: " + x.getProperty(q)); >> } >> } >> >> to something which does the same, but with the model read from this >> Turtle file instead (which is my own translation of the above, and >> thus might be buggy): >> >> @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>. >> @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>. >> @prefix foo: <http://example.org/foo#>. >> >> foo:p a rdf:Property. >> foo:q a rdf:Property. >> foo:p rdfs:subPropertyOf foo:q. >> foo:x foo:p "bar". >> >> with this code: >> >> public class Test2 { >> static public void main(String...argv) { >> String NS = "foo:"; > > > You want to make that: > String NS = "http://example.org/foo#";; > > >> Model m = ModelFactory.createDefaultModel(); >> m.read("foo.ttl"); >> InfModel im = ModelFactory.createRDFSModel(m); >> Property q = im.getProperty(NS + "q"); >> Resource x = im.getResource(NS + "x"); >> System.out.println("Statement: " + x.getProperty(q)); >> } >> } >> >> which doesn't seem to be the right approach (I suspect in particular >> that my extraction of the qproperty is somehow not right). What am I >> doing wrong? > > > The calls like getProperty need a full URI, not a prefixed name. The easy > fix is what I suggested above. > > Alternatively you can use the prefixes read in from your file to reconstruct > the URIs. E.g. > > Property q = im.getProperty( m.expandPrefix("foo:q") ) > > Dave > >
