How to call a different constructor conditionally in Java?

Question

Let's say someone gives you a class, Super, with the following constructors:

public class Super
{
    public Super();
    public Super(int arg);
    public Super(String arg);
    public Super(int[] arg);
}

And let's say you want to create a subclass Derived. How do you conditionally call a constructor in Super?

In other words, what is the "proper" way to make something like this work?

public class Derived extends Super
{
    public Derived(int arg)
    {
        if (some_condition_1)
            super();
        else if (some_condition_2)
            super("Hi!");
        else if (some_condition_3)
            super(new int[] { 5 });
        else
            super(arg);
    }
}

Answer 1

Use static factories, and four private constructors.

class Foo {
 public static Foo makeFoo(arguments) {
    if (whatever) {
      return new Foo(args1);
    } else if (something else) {
      return new Foo(args2);
    }
    etc...
  }
  private Foo(constructor1) { 
    ...
  }
  ...
}

Answer 2

Yeah, what @Johan Sjöberg said.

Also looks like your example is highly contrived. There's no magical answer which would clear this mess :)

Usually, if you have such a bunch of constructors it would be a good idea to refactor them as four separate classes (a class should be only responsible for one type of thing).