In RDF, I can have an entity that is bound by a single property to multiple literal values. Those values can also be typed to add clarity.
:dumpTruck :weight "heavy"^^xsd:string .
:dumpTruck :weight "36000"^^xsd:integer .
In SPARQL, I can query for just they type I want
SELECT ?w
WHERE
{ :dumpTruck :weight ?w
FILTER ( datatype(?w) = xsd:integer )
}
Is there something like getStatement in RDF4J that can be constrained by datatype like that?
There's no a priori constraint possible, but you can post-process your result to filter on the datatype. For example you could use something along these lines (untested but you get the drift hopefully):
QueryResults.stream(conn.getStatements(dumptruck, weight, null))
.filter(s -> ((Literal)s.getObject()).getDatatype().equals(XMLSchema.INTEGER))
.collect(Collectors.toList());
Or alternatively, stick in a Model first and then filter:
Model m = QueryResults.asModel(conn.getStatements(dumptruck, weight, null));
List intValues = Models.objectLiterals(m).stream().filter(l -> l.getDatatype().equals(XMLSchema.INTEGER)).collect(Collectors.toList());
I'm sure there's a couple of other/handier shortcuts available that I haven't thought of. The RDF4J docs have tutorials and examples to spare, however.
