Question

I have a generic class which takes two type parameters:

public class MyGenericClass<T, S> {
    private List<T> myList;
    private List<S> mySecondList;

    //...

    public void addToFirstList(T e) {
        myList.add(e);
    }

    //...
}

I want to be able to specify concrete types for these two parameters upon creating an instance of the class within a factory and then to be able to derive these types from within the rest of my code.

For instance, if I have the code:

public class AccessFactory {        
    public static MyGenericClass<Integer, Float> getInst() {
        return new MyGenericClass<Integer, Float>();;
    }
}

public class UsingFactoryClass {
    private MyGenericClass access;

    ...

    public foo() {
        access = AccessFactory.getInst();
    }
}

I’d like to be able to derive that the MyGenericClass instance access in the UsingFactoryClass class uses the parameters Integer and Float.

Is it possible to do this without having to contend with type safety warnings everywhere?

Answer 1

Declare it as:

private MyGenericClass<Integer, Float> access;