Can I do arithmetic operations on the Number baseclass?

Question

I am trying to create a generic class in Java that will perform operations on numbers. In the following example, addition, as follows:

public class Example <T extends Number> {      public T add(T a, T b){         return a + b;     }  } 

Forgive my naivety as I am relatively new to Java Generics. This code fails to compile with the error:

The operator + is undefined for the argument type(s) T, T

I thought that with the addition of "extends Number" the code would compile. Is it possible to do this Java or will I have to create overridden methods for each Number type?

Answer 1

Number does not have a + operator associated with it, nor can it since there is no operator overloading.

It would be nice though.

Basically, you are asking java to autobox a descedant of Number which happens to include Integer, Float and Double, that could be autoboxed and have a plus operator applied, however, there could be any number of other unknown descendants of Number that cannot be autoboxed, and this cannot be known until runtime. (Damn erasure)