javajenan-triples

Using a compact URI in Jena

I'm using Jena to read an ontology and it's working really well so far. Unfortunately I haven't been able to figure out how to use compact uris that I've defined in the model. I've defined the prefixes using the model's setNSPrefix(String prefix, String uri) method. When I try to retrieve statements using the prefix, I get nothing. Also, when I do successfully retrieve a Statement, it contains the full uri instead of the compact one that I defined. It will even do it for the xsd uri http://www.w3.org/2001/XMLSchema#

For example, I'm using the uri http://www.example.com#, I've defined my prefix mapping as ex, and my Statement is http://www.example.com#father http://www.example.com#parentOf http://www.example.com#child where father is the subject, parentOf is the predicate, and child is the object. If I try to retrieve it using ex:father I get no results, and when I do get the Statement back the full uri is there for the subject, predicate, and object. I've seen it use the prefix instead of the uri when I do model.write(OutputStream), but that isn't particularly helpful for me. Am I able to use the prefix as a substitute for the uri like I've been trying to do, or is that not something Jena will provide for me?

Solution

  • When I try to retrieve statements using the prefix, I get nothing.

    You can't do, e.g., 

    model.getResource("ex:foo")`

    You have to do 

    model.getResource("http://example.org/foo");

    You can make that simpler, of course, by 

    String EX = "http://example.org/";
model.getResource(EX+"foo");

    The prefixes are really just for making the serializations nicer to read and write.