Plataformatec Hack Evening: SOLID Series - Interface Segregation Principle

In this presentation, we will understand how the Interface Segregation Principle can be used to reduce the interface fatness.

Transcript

1. HACKEVENING Lucas Santos Plataformatec
2. S.O.L.I.D.
3. S.O.L.I.D.
4. S.O.L.I.D. Interface Segregation Principle
5. Interface Segregation Principle is all about…
6. Interface Segregation Principle is all about… INTERFACES
7. • "Clients should not be forced to depend on methods that they don’t use” 
 -Robert C. Martin; Prentice Hall, 2003
8. An use case…
9. Consider a printer software…
13. There’s a problem…
14. The interface is getting too fat…
15. Solution:
16. Solution: Segregate!
18. Ruby + interface = ?
19. We can follow (or break) the ISP using the methods signatures in Ruby
20. An example…
22. class UserRepository def get_all_by_ids(ids) @entity.where(id: ids) end private def entity User end end class UserController def index UserRepository.new.get_all_by_ids(params[ids]) end end
24. class UserRepository def get_all_by_ids(ids, sort) users = @entity.where(ids: ids) if sort users.order(created_at: :asc) end users end private def entity User end end class UserController def index UserRepository.new.get_all_by_ids(params[ids]) end end
25. Yes, we are breaking the ISP even with Ruby…
26. To solve this problem we can segregate the ordering functionality in another method.
28. class UserRepository def get_all_by_ids(ids) @entity.where(ids: ids) end def get_all_by_ids_sorted(ids) get_all_by_ids.order(created_at: :asc) end private def entity User end end class UserController def index UserRepository.new.get_all_by_id_sorted(params[ids]) end end
29. Let’s debate…
30. Thank you!