@Override
public DataByteArray exec(Tuple input) throws IOException {
Object measureKey = input.get(0);
Measure m = measureKey == null ? null : cube.getMeasures().get(measureName);
Validate.notNull(m, "no measure passed/found");
Object d = m.compiler2Fact(input.get(1));
// we don't measures to evaluate to nulls to simplify null issues .
if (d == null)
return null;
Aggregation.Builder aggrb = Aggregation.newBuilder();