How can I restrict a method accepting certain user defined class objects using generics?

Question

I have 2 empty classes emp and reset . I have method in another class which will accept only these two classes these I need to achieve using generics . Both these classes are not related to each other in any manner.

package abstracta;

import generics.emp;
import generics.nonemp;
import generics.reset;

// A Simple Java program to show working of user defined
// Generic functions

class Test
{
    // A Generic method example
    static <T> void genericDisplay ( T element)
    {
        System.out.println(element.getClass().getName() +
                           " = " + element);
    }

    // Driver method
    public static void main(String[] args)
    {
         // Calling generic method with Integer argument
        genericDisplay(new emp());

        // Calling generic method with String argument
        genericDisplay(new reset());

        genericDisplay(new nonemp());// should not accept  . restrict this class
    }
}

i want genericDisplay not to accept nonemp class

Answer 1

You haven't shown us your code, but the common solution to this is to create a common interface.

Both classes then implement this interface and the Generic just applies to the the interface as the type of its input parameter.