Question

I have a class Range, the declaration of which reads:

public abstract class Range<T extends Comparable<T>>

I’d like to create a class RangeSet that takes one generic type — a Range. In the body of the RangeSet class, however, I’d like to be able to refer to two generic types

1. The Range the RangeSet was typed with, and
2. The T extends Comparable<T> the Range was typed with

Is this possible?

Answer 1

No, you would have to make your RangeSet have two type parameters. For example:

public class RangeSet<T extends Comparable<T>, R extends Range<T>> {
    // ...
}

However, are you sure that you really need the type R of the Range? Couldn’t you just make the methods in RangeSet accept a Range<T> instead of R?