public T ExecuteScalar <T>(QueryModel queryModel)
{
Type t = typeof(T);
if (t == typeof(bool))
{
// Generate and execute ASK query.
SparqlQueryModelVisitor <T> visitor = new SparqlQueryModelVisitor <T>(new AskQueryGenerator());
visitor.VisitQueryModel(queryModel);
ISparqlQuery query = visitor.GetQuery();
ISparqlQueryResult result = Model.ExecuteQuery(query, _inferenceEnabled);
return(new object[] { result.GetAnwser() }.OfType <T>().First());
}
else if (queryModel.ResultOperators.Any(o => o is CountResultOperator))
{
SparqlQueryModelVisitor <T> visitor = new SparqlQueryModelVisitor <T>(new SelectBindingsQueryGenerator());
visitor.VisitQueryModel(queryModel);
ISparqlQuery query = visitor.GetQuery();
ISparqlQueryResult result = Model.ExecuteQuery(query, _inferenceEnabled);
BindingSet b = result.GetBindings().FirstOrDefault();
if (b != null && b.Any())
{
return(new object[] { b.First().Value }.OfType <T>().First());
}
else
{
return(new object[] { 0 }.OfType <T>().First());
}
}
else
{
// Unknown scalar type.
throw new NotImplementedException();
}
}
public IEnumerable <T> ExecuteCollection <T>(QueryModel queryModel)
{
Type t = queryModel.SelectClause.Selector.Type;
if (typeof(Resource).IsAssignableFrom(t))
{
// Handle queries which return instances of resources.
SparqlQueryModelVisitor <T> visitor = new SparqlQueryModelVisitor <T>(new SelectTriplesQueryGenerator());
visitor.VisitQueryModel(queryModel);
MethodInfo getResources = _getResourceMethod.MakeGenericMethod(typeof(T));
object[] args = new object[] { visitor.GetQuery(), _inferenceEnabled, null };
foreach (T value in getResources.Invoke(Model, args) as IEnumerable <T> )
{
yield return(value);
}
}
else
{
// Handle queries which return value type objects.
SparqlQueryModelVisitor <T> visitor = new SparqlQueryModelVisitor <T>(new SelectBindingsQueryGenerator());
visitor.VisitQueryModel(queryModel);
ISparqlQuery query = visitor.GetQuery();
ISparqlQueryResult result = Model.ExecuteQuery(query, _inferenceEnabled);
// TODO: This works correctly for single bindings, check with multiple bindings.
foreach (BindingSet bindings in result.GetBindings())
{
foreach (var value in bindings.Values.OfType <T>())
{
yield return(value);
}
}
}
}
