Jena dbpedia how to use (STR(?foo) AS ?foo2)? - sparql

Question

i want to avoid using substring to eliminate by example #en in my
ontology:abstract or ontology:label, it work with sparql explorer but when i use http query in jena it dont give any result... i tried this query in android project with jena library (androjena)
SELECT ?type (STR(?l) AS ?label) {
?type a owl:Class;
rdfs:label ?l .
FILTER (LANG(?l) = "en")
}
once i put this in my Jena httpquery (STR(?l) AS ?label)it dont give any result anymore. someone can help me?
here is the part of the code that i try to manage to change to avoid use of substrings :
private String entityQuery(String entity, String keyWord, String language) {
return addPrefix("rdfs: <http://www.w3.org/2000/01/rdf-schema#>") +
addPrefix("ontology: <http://dbpedia.org/ontology/>") +
addQuery("SELECT ?name ?desc ?thumb WHERE {\n"
+"?author a ontology:" + entity + ";\n"
+"rdfs:label ?name;\n"
+"ontology:abstract ?desc.\n"
+"FILTER(<bif:contains>(?desc,\"'"+keyWord+"'\") && langMatches(lang(?desc), \""+language+"\") " +
"&& langMatches( lang(?name), \""+language+"\"))\n"
+"OPTIONAL { ?author ontology:thumbnail ?thumb }.\n"
+"}ORDER BY ?name\n");
}
private LinkedList<Entity> collectEntities(ResultSet results) {
LinkedList<Entity> temp = new LinkedList<>();
/* do stuff with the results */
while (results.hasNext()) {
Entity a = new Entity();
QuerySolution row = results.next();
if (row.getResource("thumb") != null)
a.setPictureURL(row.get("thumb").toString());
a.setTitle(row.get("name").toString().substring(0, row.get("name").toString().indexOf("#")));
a.setSummary(row.get("desc").toString().substring(0, row.get("desc").toString().indexOf("#")));
temp.add(a);
}
return temp;
}
private String addPrefix(String prefix) {
return "PREFIX " + prefix + "\n";
}
private String addQuery(String query) {
return query;
}
i use substring here :
a.setTitle(row.get("name").toString().substring(0, row.get("name").toString().indexOf("#")));
a.setSummary(row.get("desc").toString().substring(0, row.get("desc").toString().indexOf("#")));