passing generic type to some method

[B Nirvan]

Hi,
I have a class that looks this

    
public class PagedDataModel<E> extends LazyDataModel<E> {
}

I want to call a Generic method of another class, passing it the type information of the above class. I tried E.class, but compiler doesn't allow that(and shouldn't allow because E doesn't exist at runtime. How do I pass E type to a generic method then.

regards,
Nirvan.

[Henry Wong]

Do you happen to have an instance of type E? If you do, you can call the getClass() method. Otherwise, no, it's not possible.

Henry

[B Nirvan]

I don't have an instance of E. I will have to force the client of this generic class to pass a dummy instance of E in the constructor. Thanks very much for reply.

regards,
Nirvan.

[Rob Spoor]

I'd require a Class<E> instead. That allows you to use Integer.class etc - so you won't need to initialize the class for every call.

[Yuriy Fuksenko]

you can try something like this:
http://gafter.blogspot.com/2006/12/super-type-tokens.html

here is the small example

  
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

public class GenericTest{
	public static void main(String...args){
		MyType<Integer> x = new MyType<Integer>(){};
		System.out.println(x.getManagedClass().toString());
	}

}

abstract class MyType<T>{

	public Class<T> getManagedClass()
    {
		ParameterizedType superclass = (ParameterizedType) getClass().getGenericSuperclass();
		Type[] actualTypeArguments = superclass.getActualTypeArguments();
		Type type = actualTypeArguments[0];
		return (Class<T>) type;
    }
}