Comparing the values of two generic Numbers

Question

I want to compare to variables, both of type T extends Number. Now I want to know which of the two variables is greater than the other or equal. Unfortunately I

Answer 1

If your Number instances are never Atomic (ie AtomicInteger) then you can do something like:

private Integer compare(Number n1, Number n2) throws SecurityException, NoSuchMethodException, IllegalArgumentException, IllegalAccessException, InvocationTargetException {

 Class n1Class = n1.getClass();
 if (n1Class.isInstance(n2)) {
  Method compareTo = n1Class.getMethod("compareTo", n1Class);
  return (Integer) compareTo.invoke(n1, n2);
 }

 return -23;
}

This is since all non-Atomic Numbers implement Comparable

EDIT:

This is costly due to reflection: I know

EDIT 2:

This of course does not take of a case in which you want to compare decimals to ints or some such...

EDIT 3:

This assumes that there are no custom-defined descendants of Number that do not implement Comparable (thanks @DJClayworth)