Question

I have an application that reads a barcode, extracts a part and checks if it is valid.
I use C#, Autofac and Nunit and I am undecided on which is the best implementation:

Solution A:
(Facade Pattern?)

public class Checker {
   public Checker(IBarcodeReader reader, IBarcodeParser parser) {
      ...
   }
   public bool Check() {
     string barcode = reader.Read();
     string id = parser.Parse(barcode);
     // check if id is valid

   }
}

Solution B:
(Strategy Pattern?)

public class Checker {
   public Checker(IBarcodeReader reader) {
      ...
   }
   public bool Check() {
     string id = reader.Read();
     // check if id is valid

   }
}

public class BarcodeReader: IBarcodeReader {
   public BarcodeReader(IBarcodeParser parser) {
      ...
   }
   public string Read() {
     string barcode = ... // read barcode from device
     return parser.Parse(barcode);
   }
}

Answer 1

Aren’t you overengineering a bit? At least that’s how it looks from the example.
I would drop the Strategy pattern idea. Are you going to ever have more then one strategy?

I like the first solution (good testability and DI), but I wouldn’t call 3 line code a Facade, really.