As an aside if there is an issue with the end point you could try emailing
Chris Gutteridge as it's likely he will have had something to do with it...
Dick
-------- Original message --------
From: "Carlo.Allocca" <[email protected]>
Date: 01/03/2016 3:54 pm (GMT+00:00)
To: [email protected]
Subject: querying a SPARQL endpoint
Dear All,
I am using Jena to query a SPARQL endpoint but I got "==== No variables ===="
as result. But, when I run the same query over the SPARQL endpoint, I get the
expected results. Below, I reported the details of the query, sparql endpoint
and jena code.
I tried to check other endpoints, but I got the same experience.
What am I doing wrong? Any help to make it right?
Many Thanks,
Best Regards,
Carlo
=== Query Southampton SPARQL endpoint
1) SPARQL EndPoint:
String sparqlEndPoint = "http://sparql.data.southampton.ac.uk/";;
2) SPARQL Query:
String qString3 = "prefix rdfs:<http://www.w3.org/2000/01/rdf-schema#> "
+ "prefix rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#> "
+ " SELECT DISTINCT ?o where "
+ "{ "
+ " ?s ?prop ?o . "
+ " FILTER (isLiteral(?o)) "
+ "} LIMIT 1000";
3) Jena code:
QueryExecution qexec =
QueryExecutionFactory.sparqlService(sparqlEndPoint, qString3, "");
qexec.setTimeout(10 * 60 * 1000); //10 min
ResultSet results = qexec.execSelect();
ResultSetFormatter.out(out, results);
4) Jena Result:
==== No variables ====
----
| |
====
5) SPARQL endpoint Results:
http://www.w3.org/2000/01/rdf-schema#label
http://www.w3.org/2004/02/skos/core#prefLabel
http://www.w3.org/2000/01/rdf-schema#label
http://www.w3.org/2004/02/skos/core#prefLabel
http://www.w3.org/2000/01/rdf-schema#comment
http://www.w3.org/2000/01/rdf-schema#label
http://www.w3.org/2004/02/skos/core#prefLabel
http://www.w3.org/2000/01/rdf-schema#comment
http://www.w3.org/2000/01/rdf-schema#label
http://www.w3.org/2004/02/skos/core#prefLabel
