Add two numbers without knowing exact type in Java

Question

I have two Numbers they maybe integer float or double, how to add them in java, Number object cannot add each other.

I can only test there type(class) and convert one by one, it's ugly (lots of if else) and obscure， any better idea?

score 2 · Accepted Answer · answered Oct 07 '16 at 13:36

2

You can invoke Number.doubleValue() and add:

Number n1 = new Double(10.3d);
Number n2 = new Integer(12);
System.out.println(n1.doubleValue() + n2.doubleValue());

answered Oct 07 '16 at 13:36

olsli

score 0 · Answer 2 · answered Oct 07 '16 at 13:40

If precision loss is acceptable, you can add their double (or even BigDecimal) values:

double result = a.doubleValue() + b.doubleValue();

Otherwise, you will have implement all cases (which you can do only do for common types, as Number is an abstract class).

To be honest, this is very likely to be a sign of bad conception.

2 Answers2