哪种模拟Java中的可选参数更好？

Question

I have a Java method that takes 3 parameters, and I'd like it to also have a 4th "optional" parameter. I know that Java doesn't support optional parameters directly, so I coded in a 4th parameter and when I don't want to pass it I pass null . (And then the method checks for null before using it.) I know this is kind of clunky... but the other way is to overload the method which will result in quite a bit of duplication.

Which is the better way to implement optional method parameters in Java: using a nullable parameter, or overloading? And why?

Answer 1

Write a separate 3-parameter method that forwards to the 4-parameter version. Don't kludge it.

With so many parameters, you might want to consider a builder or similar.

Answer 2

Use something like this:

public class ParametersDemo {

    public ParametersDemo(Object mandatoryParam1, Object mandatoryParam2, Object mandatoryParam3) {
    this(mandatoryParam1,mandatoryParam2,mandatoryParam3,null);
    }


    public ParametersDemo(Object mandatoryParam1, Object mandatoryParam2, Object mandatoryParam3, Object optionalParameter) {
    //create your object here, using four parameters
    }

}