Refactoring the Code (If else )

Question

I was trying to refactor the code and I came across this piece of code. Can you suggest any refactoring in it and please name what refracting you used.

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Answer 1

You are actually violating SRP (Single Responsibility Principle) therefore you need to touch this code base whenever a new language is being added.

In order to avoid huge list of if else statements, you need a loosely coupled design in which addLetters() behaviour should be implemented in a separate LanguageImpl class (like English, etc..) as shown in the below code, which uses state pattern:

Step (1): Define Language interface

    public interface Language {
      addLetters();
    }

Step (2): Define Language Implementations

    public English implements Language {
      //implement addLetters() for English
    }

    //Implement other Language Classes as well in separate classes

Step (3): Modify setUpBag method which takes Language object

    public void setUpBag(Language language){
        language.addLetters();
    }

Each Language class follows SRP here which is key in designing OOP applications i.e., Each Language class handles only a specific behaviour.

You can look here for more details.