Is it possible to write a Java generics expression that allows a subtype of a type and the type itself?

Given the following situation it's only possible to write a model handler which works on Specifi开发者_如何学CcModel, it's not possible to have a model handler which handles only models. But when we remove the T extends Model expression, it would be much to easy to create something illegal.

public interface Model {} 

public class SpecificModel implements Model {}

public interface ModelHandler<T extends Model> 
{
   void handleModel(T model);
}

Is it possible to write a construct like T extends Model || Model ? So T must either extend Model or must be a Model itself if the handler doesn't know a subtype of Model?

Thank you!

Quote from Effective Java, by Joshua Bloch about the <? extends E> notation:

The use of the keyword extends is slightly misleading: recall [from Item 26] that subtype is defined so that every type is a subtype of itself, even though it does not extend itself.

Therefore writing <T extends Model> is equivalent to what you expect: <T extends Model || Model>.

T extends Model matches Model. So, you can create a ModelHandler<Model> here.

The terminology is, admittedly, slightly misleading.

(Or is your goal to write a ModelHandler<any subtype of Model but not Model itself>?)

If T extends Model then T is a Model. I'm really not sure what you want to write here... Also -- in generics the extends also stands for implements meaningwise.