디자인 모델 - 생성과 관련된 모델

Singleton

개요

그 반에는 단지 하나의 실례가 있을 것이라고 보증한다
외부에서 직접 대상을 생성하는 것을 방지하고 관리 클래스 자체가 동시에 생성할 수 있는 대상의 수량

용도

항상 프로그램에서 같은 대상을 처리하기를 원합니다
DB 연결 수를 제한하려면

예제

require 'singleton'
class SingletonObject
  # instanceメソッドが定義され、newメソッドがprivateに設定される
  include Singleton
  attr_accessor :counter, :name
  def initialize
    @counter = 0
    @name = "Singleton"
  end
end

obj1 = SingletonObject.instance
obj1.counter += 1
p "--- #{obj1.name} ---"
p obj1.counter

obj2 = SingletonObject.instance
obj2.counter += 1
obj2.name = "UpdatedName"
p "--- #{obj1.name} ---"
p obj2.counter
p obj1.equal?(obj2)

# "--- Singleton ---"
# 1
# "--- UpdatedName ---"
# 2
# true

Builder

개요

다른 개체에 복잡한 인스턴스 생성 의뢰(Director)
Builder가 작업 담당
Director에서 작업 프로세스 담당

예제

# ConcreteBuilder
class SaltWater
  attr_accessor :water, :salt, :color
  def initialize(water, salt, color)
    @water = water
    @salt = salt
    @color = color
  end

  def add_material(salt_amount)
    @salt += salt_amount
  end

  def update_color
    @color = "blue"
  end
end

# ConcreteBuilder
class SugarWater
  attr_accessor :water, :sugar, :color
  def initialize(water, sugar, color)
    @water = water
    @sugar = sugar
    @color = color
  end

  def add_material(sugar_amount)
    @sugar += sugar_amount
  end

  def update_color
    @color = "red"
  end
end

# Builder
class WaterWithMaterialBuilder
  attr_reader :water_with_material
  def initialize(class_name)
    @water_with_material = class_name.new(0,0, "white")
  end

  def add_material(material_amount)
    @water_with_material.add_material(material_amount)
  end

  def add_water(water_amount)
    @water_with_material.water += water_amount
  end

  def update_color
    @water_with_material.update_color
  end

  def result
    @water_with_material
  end
end

# Director
class Director
  attr_reader :builder
  def initialize(builder)
    @builder = builder
  end

  def magic
    @builder.add_water(150)
    @builder.add_material(90)
    @builder.add_material(35)
    @builder.update_color()
  end
end

builder = WaterWithMaterialBuilder.new(SugarWater)
director = Director.new(builder)
director.magic
p builder.result
p director.builder.water_with_material.color
# #<SugarWater:0x007fed55824b10 @water=150, @sugar=125, @color="red">
# "red"

builder = WaterWithMaterialBuilder.new(SaltWater)
director = Director.new(builder)
director.magic
p builder.result
p director.builder.water_with_material.color
# #<SaltWater:0x007fed5582fe98 @water=150, @salt=125, @color="blue">
# "blue"

Abstract Factory

개요

연관된 객체의 컬렉션을 생성할 수 있습니다.
모순되지 않는 대상을 만들기 위해

예제

class DinnaerFactory
  def initialize
  end
  def createDinner
    return [createAppetizer,createMain]
  end
  def createMain
  end
  def createAppetizer
  end
end

class Soup
  def initialize
  end
end

class Rice
  def initialize
  end
end

class Salad
  def initialize
  end
end

class Pizza
  def initialize
  end
end

class JapaneseFactory < DinnaerFactory
  def createMain
    Rice.new
  end
  def createAppetizer
    Soup.new
  end
end

class ItalyFactory < DinnaerFactory
  def createMain
    Pizza.new
  end
  def createAppetizer
    Salad.new
  end
end

japanese = JapaneseFactory.new
puts japanese.createDinner

italy = ItalyFactory.new
puts italy.createDinner

Factory Method

개요

하위 클래스에 대한 인스턴스 생성
실례의 생성 부분을 끊으면 추가, 변경, 유지보수에 편리하도록 결합도를 낮출 수 있다

예제

class Saxophone
  def initialize(name)
    @name = name
  end
  def play
    puts "#{self.class} #{@name} is being played!"
  end
end

class Trumpet
  def initialize(name)
    @name = name
  end
  def play
    puts "#{self.class} #{@name} is being played!"
  end
end

class InstrumentFactory
  def initialize(number_instruments)
    @instruments = []
    number_instruments.times do |i|
      instrument = new_instrument("No.#{i + 1}")
      @instruments << instrument
    end
  end
  def ship_out
    @tmp = @instruments.dup
    @instruments = []
    @tmp
  end
end

class SaxophoneFactory < InstrumentFactory
  def new_instrument(name)
    Saxophone.new(name)
  end
end

class TrumpetFactory < InstrumentFactory
  def new_instrument(name)
    Trumpet.new(name)
  end
end

factory = SaxophoneFactory.new(3)
saxophones = factory.ship_out
saxophones.each { |saxophone| saxophone.play }

factory = TrumpetFactory.new(2)
trumpets = factory.ship_out
trumpets.each { |trumpet| trumpet.play }