1. @vagnerzampieri
vgzampieri@gmail.com

2. Contando uma história com Orientação a Objeto

3. - Ruby, Python, C++, C#, VB.NET, Java, Object Pascal,
Objective-C e Smalltalk são exemplos de linguagens de
programação orientadas a objetos.
- ActionScript, ColdFusion, Javascript, PHP (a partir da versão 4.0),
Perl (a partir da versão 5) e Visual Basic (a partir da versão 4)
são exemplos de linguagens de programação com suporte
a orientação a objetos.

4. Conceitos básicos de O.O.
- Classe
- Objeto/instância
- Atributo
- Método
- Mensagem
- Herança
- Associação
- Encapsulamento

5. Vou falar dos 3 porquinhos

6. Objeto
Um objeto é capaz de armazenar estados através de seus atributos
e reagir a mensagens enviadas a ele, assim como se relacionar e
enviar mensagens a outros objetos. Um objeto está associado com
classe.
Ex.: Cícero, Heitor e Prático.

7. Atributos
São as características do objeto, basicamente a estrutura de
dados que vai representar a classe.
Ex.: Nome, peso, altura, idade

8. Classes
É um conjunto de objetos, a classe define o comportamento
dos objetos através de seus métodos.
Ex.: Animal, Pig, Wolf, House, TypeHouse

9. Vamos ver um pouco de código :)

10. Animal
name
weight
height
age
Pig < Animal
house_id
Wolf < Animal
House
type_house_id
color
length
width
height
TypeHouse
name

11. 1.9.3p194 :002 > p1 = Pig.create(name: 'Cícero')
=> #<Pig id: 1, name: "Cícero", type: "Pig", weight: nil, height: nil, age: nil,
created_at: "2012-12-12 21:55:14", updated_at: "2012-12-12 21:55:14", house_id: nil>
1.9.3p194 :012 > p2 = Pig.create(name: 'Heitor')
=> #<Pig id: 3, name: "Heitor", type: "Pig", weight: nil, height: nil, age: nil,
created_at: "2012-12-12 22:29:21", updated_at: "2012-12-12 22:29:21", house_id: nil>
1.9.3p194 :016 > p3 = Pig.create(name: 'Prático')
=> #<Pig id: 4, name: "Prático", type: "Pig", weight: nil, height: nil, age: nil,
created_at: "2012-12-12 22:35:09", updated_at: "2012-12-12 22:35:09", house_id: nil>

12. 1.9.3p194 :005 > w = Wolf.create(name: "Lobo Mau")
=> #<Wolf id: 2, name: "Lobo Mau", type: "Wolf", weight: nil, height: nil, age: nil,
created_at: "2012-12-12 21:57:46", updated_at: "2012-12-12 21:57:46", house_id: nil>
1.9.3p194 :006 > w.speak
=> "Aaauuuuuuu"

13. type_house = TypeHouse.find 1
=> #<TypeHouse id: 1, name: "Palha", created_at: "2012-12-12 21:54:14",
updated_at: "2012-12-12 21:54:14">
1.9.3p194 :003 > p1.create_house(type_house_id: type_house.id, color: 'Amarela')
=> #<House id: 1, type_house_id: 1, color: "Amarelo", length: nil, width: nil, height: nil,
created_at: "2012-12-12 21:55:19", updated_at: "2012-12-12 21:55:19">
1.9.3p194 :004 > p1.save
=> true
class TypeHouse < ActiveRecord:Base
has_many :houses
end
class House < ActiveRecorBase
belongs_to :type_house
has_many :pigs, dependent: :nullify
end
class Animal < ActiveRecord:Base
end
class Pig < Animal
belongs_to :house
end

14. 1.9.3p194 :011 > type_house = TypeHouse.find 2
=> #<TypeHouse id: 2, name: "Madeira", created_at: "2012-12-12 21:54:14",
updated_at: "2012-12-12 21:54:14">
1.9.3p194 :013 > p2.create_house(type_house_id: type_house.id, color: 'Marrom')
=> #<House id: 2, type_house_id: 2, color: "Marrom", length: nil, width: nil, height: nil,
created_at: "2012-12-12 22:29:54", updated_at: "2012-12-12 22:29:54">
1.9.3p194 :014 > p2.save
=> true

15. 1.9.3p194 :015 > type_house = TypeHouse.find 3
=> #<TypeHouse id: 3, name: "Tijolo", created_at: "2012-12-12 21:54:14",
updated_at: "2012-12-12 21:54:14">
1.9.3p194 :017 > p3.create_house(type_house_id: type_house.id, color: 'Vermelha')
=> #<House id: 3, type_house_id: 3, color: "Vermelha", length: nil, width: nil, height: nil,
created_at: "2012-12-12 22:35:22", updated_at: "2012-12-12 22:35:22">
1.9.3p194 :018 > p3.save
=> true

16. 1.9.3p194 :001 > w = Wolf.last
Wolf Load (2.1ms) SELECT "animals".* FROM "animals" WHERE "animals"."type" IN ('Wolf')
ORDER BY "animals"."id" DESC LIMIT 1
=> #<Wolf id: 4, name: "Lobo Mau", type: "Wolf", weight: nil, height: nil, age: nil,
created_at: "2012-12-12 23:55:38", updated_at: "2012-12-12 23:55:38", house_id: nil>
1.9.3p194 :002 > w.blow_the_straw_house
Vou soprar, vou soprar e sua casa vou derrubar
TypeHouse Load (15.3ms) SELECT "type_houses".* FROM "type_houses" WHERE "type_hous
House Load (1.9ms) SELECT "houses".* FROM "houses" WHERE "houses"."type_house_id" =
(1.1ms) BEGIN
Pig Load (1.0ms) SELECT "animals".* FROM "animals" WHERE "animals"."type" IN ('Pig') AND
SQL (1.6ms) UPDATE "animals" SET "house_id" = NULL WHERE "animals"."type" IN ('Pig') AN
SQL (1.6ms) DELETE FROM "houses" WHERE "houses"."id" = $1 [["id", 1]]
(20.1ms) COMMIT
=> [#<House id: 1, type_house_id: 1, color: "Marrom", length: nil, width: nil, height: nil, created_at

17. # encoding: UTF-8
class Wolf < Animal
def speak
"Aaauuuuuuu"
end
def blow_the_straw_house
puts sentence_of_intimidation
TypeHouse.destroy_houses_with 1
end
def blowing_wooden_house
puts sentence_of_intimidation
TypeHouse.destroy_houses_with 2
end
def blowing_brick_house
puts sentence_of_intimidation
puts "Porcos - Lobo tolo, minha casa é de tijolo"
end
private
def sentence_of_intimidation
"Lobo - Vou soprar, vou soprar e sua casa vou derrubar"
end
end

18. class TypeHouse < ActiveRecord::Base
attr_accessible :name
has_many :houses
validates :name, presence: true, uniqueness: true
def self.destroy_houses_with id
type_house = TypeHouse.find id
type_house.houses.each do |house|
house.destroy
end
end
end

19. 1.9.3p194 :003 > w.blowing_wooden_house
Vou soprar, vou soprar e sua casa vou derrubar
TypeHouse Load (0.7ms) SELECT "type_houses".* FROM "type_houses"
WHERE "type_houses"."id" = $1 LIMIT 1 [["id", 2]]
House Load (0.8ms) SELECT "houses".* FROM "houses"
WHERE "houses"."type_house_id" = 2
(0.2ms) BEGIN
Pig Load (0.7ms) SELECT "animals".* FROM "animals" WHERE "animals"."type"
IN ('Pig') AND "animals"."house_id" = 2
SQL (0.7ms) UPDATE "animals" SET "house_id" = NULL WHERE "animals"."type"
IN ('Pig') AND "animals"."house_id" = 2 AND "animals"."id" IN (2)
SQL (0.4ms) DELETE FROM "houses" WHERE "houses"."id" = $1 [["id", 2]]
(17.3ms) COMMIT
=> [#<House id: 2, type_house_id: 2, color: "Vermelha", length: nil, width: nil, height: nil,
created_at: "2012-12-12 23:55:37", updated_at: "2012-12-12 23:55:37">]

20. 1.9.3p194 :002 > w.blowing_brick_house
Lobo - Vou soprar, vou soprar e sua casa vou derrubar
Porcos - Lobo tolo, minha casa é de tijolo
=> nil

21. 1.9.3p194 :005 > w.chimney_climb
Lobo - vou comer esses porquinhos
=> nil
1.9.3p194 :006 > w.entering_the_chimney
ploft!!. O lobo caiu na panela de água fervente
(0.3ms) BEGIN
SQL (10.8ms) DELETE FROM "animals" WHERE "animals"."type" IN ('Wolf')
AND "animals"."id" = $1 [["id", 4]]
(21.6ms) COMMIT
=> #<Wolf id: 4, name: "Lobo Mau", type: "Wolf", weight: nil, height: nil, age: nil,
created_at: "2012-12-14 19:56:59", updated_at: "2012-12-14 19:56:59", house_id: nil>

22. 1.9.3p194 :001 > Pig.singing
Quem tem medo do lobo mau, lobo mau, lobo mau ...
=> nil