The document provides an introduction to object-oriented programming (OOP) principles and design patterns. It discusses the four pillars of OOP - abstraction, encapsulation, modularity, and hierarchy. It then defines what an object is in terms of its properties of state, behavior, and identity. The document outlines several OOP principles like least astonishment, command query separation, tell don't ask, and the law of Demeter. It concludes by briefly introducing some common design patterns like decorator, strategy, chain of responsibility, composite, template method, and facade.

1. Orientação a Objetos
Princípios e Padrões

2. Quem sou eu?
‣ Programador no Glio
‣ Trabalhei na Dafiti, Emprego Ligado e Tripda
‣ Não mexo com PHP faz exatamente 1 ano
‣ Ruby
‣ @nelson_senna

3. Agenda
‣ Uma breve introdução a OOP
‣ Os primos pobres do S.O.L.I.D
‣ Padrões de projeto (GoF)

5. O que é Orientação a
Objetos?

7. O método é apoiado por
quatro pilares

8. Abstração

10. Abstração
Onde podemos errar?

11. “If a precondition is violated, this means
that a client has not satisfied its part of
the bargain, and hence the server
cannot proceed reliably. Similarly, if a
postcondition is violated, this means
that a server has not carried out its part
of the contract, and so its clients can no
longer trust the behavior of the server.”
Grady Booch

12. Encapsulamento

14. Encapsulamento
Onde podemos errar?

15. “No part of a complex system should
depend on the internal details of any
other part”
Ingalls, D.

16. Modularidade

18. Modularidade
Onde podemos errar?

19. “The overall goal of the decomposition
into modules is the reduction of
software cost by allowing modules to be
designed and revised independently....
Each module's structure should be
simple enough that it can be
understood fully;”
Britton and Parnas

20. Hierarquia

22. Hierarquia
Onde podemos errar?

23. “Inheritance makes it possible to define
new software in the same way we
introduce any concept to a newcomer,
by comparing it with something that is
already familiar”
Cox, B.

24. O que é um objeto?

26. Propriedades de um
objeto
‣ Estado
‣ Comportamento
‣ Identidade

27. “The state of an object encompasses all
of the (usually static) properties of the
object plus the current (usually dynamic)
values of each of these properties.”
Grady Booch

28. “The state of an object represents the
cumulative results of its behavior.”
Grady Booch

29. “Assim como átomos podem existir
repetidas vezes, a identidade possibilita
que múltiplas instâncias possam
coexistir.”
Um troxa aí

30. Objetos não são sacos
de dados!

31. Princípios

32. Least Astonishment

33. Command Query
Separation

34. Tell don’t ask

35. Law of Demeter

36. Padrões

37. Decorator

38. Strategy

39. Chain of Responsibility

40. Composite

41. Template Method

42. Facade

43. Dúvidas?

44. Avalie a palestra!

45. Lista de imagens
‣ Builders: https://flic.kr/p/mjweU
‣ Ikebana: https://flic.kr/p/6P7McX
‣ Boundary: https://flic.kr/p/3QrzLy
‣ Modularity: https://flic.kr/p/9sdBqQ
‣ Hierarchy: https://flic.kr/p/fgGtcP
‣ Objects: https://flic.kr/p/AD4FMh

46. Referências
‣ Tell don’t ask: https://pragprog.com/articles/tell-dont-ask
‣ OOP: Object-Oriented Analysis and Design with Applications - Grady Booch et
al
‣ Law of Demeter: http://www.ccs.neu.edu/research/demeter/demeter-
method/LawOfDemeter/paper-boy/demeter.pdf
‣ CQS: http://martinfowler.com/bliki/CommandQuerySeparation.html
‣ Least Astonishment: http://c2.com/cgi/wiki?PrincipleOfLeastAstonishment
‣ Design Patterns: Design Patterns: Elements of Reusable Object-Oriented
Software - Gamma et al
‣ Decorator: https://8thlight.com/blog/doug-bradbury/2016/07/18/not-a-
decorator-ruby.html
‣ Template Method: https://medium.com/ruby-on-rails/what-i-learned-from-
sandi-metz-9d0c94347b7f#.2y8u1prb4