/**
  * Insert Triple/Statement into graph
  *
  * @param s subject uriref
  * @param p predicate uriref
  * @param o value object (URIref or Literal)
  */
 public void add(URI s, URI p, Value o) {
   try {
     RepositoryConnection con = therepository.getConnection();
     try {
       ValueFactory myFactory = con.getValueFactory();
       Statement st = myFactory.createStatement(s, p, o);
       con.add(st);
     } finally {
       con.close();
     }
   } catch (Exception e) {
     // handle exception
   }
 }