Real world example of the Builder pattern

src/builder/real_world/main.rb

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+# EN: Pizza is the product that the builder class is going to be building
+#
+# RU: Pizza - это продукт, который будет строить класс строителей
+#
+class Pizza
+  attr_accessor :toppings
+
+  def initialize(crust)
+    @crust = crust
+    @toppings = []
+  end
+
+  def present
+    puts 'This pizza is a'
+    puts "#{@crust} pizza"
+    puts 'with:'
+    puts @toppings.join("\n")
+    puts '-*-*--*--*--*--*--*-'
+  end
+end
+
+# EN: PizzaBuilder is an abstract interface that allows us to add toppings to
+# the pizza.
+#
+# RU: PizzaBuilder - это абстрактный интерфейс, который позволяет нам добавлять
+# начинки в пиццу.
+#
+class PizzaBuilder
+  attr_reader :pizza
+
+  def add_tomato_sauce
+    @pizza.toppings << 'Tomato sauce'
+    self
+  end
+
+  def add_cheese
+    @pizza.toppings << 'Cheese'
+    self
+  end
+
+  def add_basil
+    @pizza.toppings << 'Basil'
+    self
+  end
+
+  def add_pepperoni
+    @pizza.toppings << 'Pepperoni'
+    self
+  end
+end
+
+# EN: ThinCrustPizzaBuilder and StuffedCrustPizzaBuilder are the concrete
+# builder classes used to build pizzas with specific crust types.
+#
+# RU: ThinCrustpizzabuilder и FackedCrustpizzabuilder - это бетонные классы,
+# используемые для строительства пиццы с определенными типами коров.
+#
+class ThinCrustPizzaBuilder < PizzaBuilder
+  def initialize
+    @pizza = Pizza.new('Thin crust')
+  end
+end
+
+class StuffedCrustPizzaBuilder < PizzaBuilder
+  def initialize
+    @pizza = Pizza.new('Stuffed crust')
+  end
+end
+
+# EN: The Chef class act as the Director using the builder provided to make the
+# pizzas that are requested.
+#
+# RU: Класс Chef -повара действует в качестве директора, использующего
+# застройщика, предоставленного для изготовления запрашиваемой пиццы.
+#
+class Chef
+  attr_accessor :builder
+
+  def make_margherita_pizza
+    @builder.add_tomato_sauce
+            .add_cheese
+            .add_basil
+  end
+
+  def make_pepperoni_pizza
+    @builder.add_tomato_sauce
+            .add_cheese
+            .add_pepperoni
+  end
+end
+
+# EN: This is an example in the real world
+#
+# RU: Это пример в реальном мире
+#
+chef = Chef.new
+
+thin_crust_builder = ThinCrustPizzaBuilder.new
+chef.builder = thin_crust_builder
+chef.make_margherita_pizza
+thin_crust_builder.pizza.present
+
+stuffed_crust_builder = StuffedCrustPizzaBuilder.new
+chef.builder = stuffed_crust_builder
+chef.make_pepperoni_pizza
+stuffed_crust_builder.pizza.present

src/builder/real_world/output.txt

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+This pizza is a
+Thin crust pizza
+with:
+Tomato sauce
+Cheese
+Basil
+-*-*--*--*--*--*--*-
+This pizza is a
+Stuffed crust pizza
+with:
+Tomato sauce
+Cheese
+Pepperoni
+-*-*--*--*--*--*--*-