DBQuery query = db.createQuery(q);
query.setEntity("anIdentity", identity);
query.setString("resName", subscriptionContext.getResName());
query.setLong("resId", subscriptionContext.getResId().longValue());
query.setString("subidentifier", subscriptionContext.getSubidentifier());
List res = query.list();
// must return one result or null
if (res.isEmpty()) return false;
long cnt = ( (Long)res.get(0) ).longValue();
if (cnt == 0) return false;
else if (cnt == 1) return true;