Question

I’ve got the following method of an public abstract class Model { //impl } (declared exactly like this):

 protected <T extends Model> HashMap<String, Model> resultsetMap(ResultSet res) {
     HashMap<String, Model> data = new HashMap<String, Model>();
     try {
         while(res.next()) {
            Model obj = T.getNew(res);
            data.put(obj.toString(), obj);
         }
     } catch(SQLException e) {
         return null;
     }
     return data;
 }

1. T is supposed to tell the caller the concrete class it should use. Is this possible?
2. How would I call this method from another method of a subclass of Model? I’ve tried with resultsetMap<Course>(res); but it looks like a syntactic error

Answer 1

Since the method is inherited, you can call it either as super.<ConcModel>resultsetMap(/* arg */); or this.<ConcModel>resultsetMap(/* arg */);. Second or first respectively based on whether the subclass is overriding it or not.

Tutorial on how to call a generic method.