Do I need to create separate service class for one function in java

Question

I have person class and then class like

Countries 
Languages

I have separate classes for countries and langauages. I need to display all counries in drop down and all languagaes. So do I need to create a CountryService class and a languagaeService class? With functions like getLanguages and getCountries in there?

Looking for a good solution.

Answer 1

The answer depends on the growth path you expect for this code base.

If you don't see much else being added to a CountryService or LanguageService class besides the functions you mention, then adding 2 new classes may be over-engineering the solution. In this case it may be better to do something more along the lines of adding a static method getLanguages to the Language class, and getCountries to the Country class

If you see your self expanding the role and functionality a CountryService and a LanguageService class then this approach would be fine.

Answer 2

Your solution isn't wrong, but generally methods like getAvailableCountries() and getAvailableLanguages() are declared as static methods in their respective classes. That way, you can use them like this:

List<Country> lc = Country.getAvailableCountries();
List<Language> ll = Language.getAvailableLanguages();

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Are you saving these objects in a database? In that case, I would use either of the following designs:

• The object is responsible for saving itself:

  new Country("United States").save();
  new Language("English").save();
  

• The class is responsible for saving the object:

  Country.save(new Country("United States"));
  Language.save(new Language("English"));