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
