Question

I wondered if it was possible to create a “templatized” getter, such as :

class TestGet
{
    private static Map<String,Object> theMap.....

    public static getObject<T>(String key).....

And somewhere in the code, something like :

JButton myButton = TestGet.getObject<JButton>("theButton");

Beware : this is just an “idle” question, I’m trying to avoid “dirty” casts in my code since they make my eyes bleed each time I look at them.

I know there are more elegant ways to do that, but I really would do it with a map of to avoid linking with other classes.

I tried out some configurations, but nothing seems to fit what I want to do… Is a templating like that just possible ?

Answer 1

You can write

 public static <T> T getObject(String key) {
     return (T) theMap.get(key); // produces a warning.
 }

and

 JButton myButton = TestGet.<JButton>getObject("theButton");

or just

 JButton myButton = TestGet.getObject("theButton");

---

For a more complicated example 😉

class A<T> {
    class B<S> {
        public <U extends S> U tsu() {
            return null;
        }
    }
}

List<String> list = new A<Integer>().new B<List>().<List<String>>tsu();