title: Using a compact URI in Jena
body: <p>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 <code>setNSPrefix(String prefix, String uri)</code> 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 <code>http://www.w3.org/2001/XMLSchema#</code></p>
  
  <p>For example, I'm using the uri <code>http://www.example.com#</code>, I've defined my prefix mapping as <code>ex</code>, and my Statement is <code>http://www.example.com#father http://www.example.com#parentOf http://www.example.com#child</code> where father is the subject, parentOf is the predicate, and child is the object. If I try to retrieve it using <code>ex:father</code> 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 <code>model.write(OutputStream)</code>, 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?</p>