Question

public Subclass(String[] parameters) throws IllegalArgumentException {
    super("Rectangle",
        Double.parseDouble(parameters[0]),
    Double.parseDouble(parameters[1]),
    90,
    Double.parseDouble(parameters[2]),
    Double.parseDouble(parameters[3]));
            if(parameters.length != 4) throw new IllegalArgumentException("bla, bla");
    if(parameters == null) throw new IllegalArgumentException("bla, bla");
}

I would like to put these 2 if statements before calling super-constructor. I know that I can’t do that, so what’s the painless way to do that kind of parsing of parameters (throwing Exception) before calling super()?

Answer 1

Declare a validation method taking String[] and returning it:

private static String[] validate(String[] param) {
    // do validation here
    return param;
}

And call it when using param first time

super("Rectangle", Double.parseDouble(validate(param).parameters[0]),

This trick solves problem quickly, but, as another poster noted, sometimes it’s better to refactor your API (like creating a factory method).