Question

I have a String which can either be of Double or Integer type or some other type. I first need to create a Double or Integer object and then send it over to a overloaded method. Here’s my code so far;

public void doStuff1(object obj, String dataType){

 if ("Double".equalsIgnoreCase(dataType)) {
        doStuff2(Double.valueOf(obj.toString()));
    } else if ("Integer".equalsIgnoreCase(dataType)) {
        doStuff2(Integer.valueOf(obj.toString()));
    }

 }

 public void doStuff2(double d1){
   //do some double related stuff here
 }

 public void doStuff2(int d1){
   //do some int related stuff here
 }

I’d like to do this without if/else, with something like this;

Class<?> theClass = Class.forName(dataType);

The problem is ‘theClass’ still can’t be cast to either double or int. I would be gratefull for any ideas.
Thanks.

Found a related thread; Overloading in Java and multiple dispatch

Answer 1

This is not just a problem of dealing with primitive types.

Which method to call is decided in compile time, that is, if you want to be able to call different methods depending on the type of the arguments, you’ll need several calls (i.e. you need the if-construct).

In other words, it wouldn’t work even if doStuff2 took Integer and Double as arguments (your code is basically as good as it gets).

(In fancy words, this is due to the fact that Java has single dispatch. To emulate multiple dispatch you either need to use conditional statements or a visitor pattern.)