How do I use interfaces with "fallback" parameters in the methods?

Question

I am writing some code in java, and am struggling with deciding if this is Ok code since I've never had any real education. I want to force use save(ConfigurationSection) in my classes, but if not available allow for using save(String). I realize I could just do this conversion before I'd call this method. Is that what I am supposed to be doing?

public interface Serializable {

    default void save(String path){
        save(Claims.getDataManager().getData().createSection(path));
    }
    void save(ConfigurationSection section);

}

I'd like to know if I am allowed to do this. Also any good resources that are relatively comprehendable for someone without any real knowledge of jargon.

Answer 1

I want to force use save(ConfigurationSection) in my classes

It's difficult to force the user to use one overloaded method over another. If I have two options, I choose the simplest one and let the API do all the dirty work for me. I will not be constructing a ConfigurationSection on my own if there is an enticing String option unless the former offers me a more flexible/fine-grained/performant way.

You may document these methods well, though. Stating clearly which method is preferable, and why.

if not available allow for using save(String)

I didn't get it. There is either one method or two methods. If the user can't build a ConfigurationSection , it doesn't mean save(ConfigurationSection) magically disappears, and save(String) appears. Your interface is still these two methods.

I'd like to know if I am allowed to do this.

Yes, you are. Your code looks absolutely fine to me.

Claims.getDataManager().getData().createSection(path)

is OK as a default way to turn a String into a ConfigurationSection as long as it doesn't bring any side-effects, and is transparent to the caller. It's like a shortcut that the user is (or can get) familiar with.

I like your question, by the way. It looks simple and humble.

Answer 2

Instead of providing such default method it seems to be better to create a fromString adapter method inside your ConfigurationSection class

public static ConfigurationSection fromString(String s) {
    // ...
}

or event better, in case you have some additional logic to be applied to create builder class

public class ConfigurationSectionBuilder {
    // dependencies and constructors
    private DataManagerData dataManagerData;

    public ConfigurationSection fromString(String s) {
        return dataManagerData.createSection(s);
    }
}

Interface should be as simple as that. What od you want to add new way of creating ConfigurationSection (let say from Long ), and you will need some additional service dependency for this? It's obvious violetion of SRP

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Also don't create 'chains' like this

Claims.getDataManager().getData().createSection(path)

It's violetion of Law of Demeter