Hourra ! La version française est enfin sortie ! Laissez-nous un message svp, si vous voulez nous faire part de vos commentaires ou signaler une erreur.
Monteur

Monteur en Ruby

Le Monteur est un patron de conception de création qui permet de construire des objets complexes étape par étape.

Le monteur n’est pas comme les autres patrons de création : les produits n’ont pas besoin d’avoir une interface commune. Il est ainsi possible de créer différents produits en utilisant le même procédé de fabrication.

Utilisation du patron de conception en Ruby

Complexité :

Popularité :

Exemples d’utilisation : Le monteur est bien connu dans le monde du Ruby. Il se montre très utile lorsque vous devez créer un objet possédant de nombreuses configurations possibles.

Identification : Le monteur peut être identifié à l’intérieur d’une classe qui n’a qu’une seule méthode de création et plusieurs méthodes permettant de configurer l’objet en résultant. Les méthodes du monteur prennent souvent en charge le chaînage (par exemple, someBuilder->setValueA(1)->setValueB(2)->create()).

Exemple conceptuel

Dans cet exemple, nous allons voir la structure du patron de conception Monteur. Nous allons répondre aux questions suivantes :

  • Que contiennent les classes ?
  • Quels rôles jouent-elles ?
  • Comment les éléments du patron sont-ils reliés ?

main.rb: Exemple conceptuel

# The Builder interface specifies methods for creating the different parts of
# the Product objects.
class Builder
  # @abstract
  def produce_part_a
    raise NotImplementedError, "#{self.class} has not implemented method '#{__method__}'"
  end

  # @abstract
  def produce_part_b
    raise NotImplementedError, "#{self.class} has not implemented method '#{__method__}'"
  end

  # @abstract
  def produce_part_c
    raise NotImplementedError, "#{self.class} has not implemented method '#{__method__}'"
  end
end

# The Concrete Builder classes follow the Builder interface and provide specific
# implementations of the building steps. Your program may have several
# variations of Builders, implemented differently.
class ConcreteBuilder1 < Builder
  # A fresh builder instance should contain a blank product object, which is
  # used in further assembly.
  def initialize
    reset
  end

  def reset
    @product = Product1.new
  end

  # Concrete Builders are supposed to provide their own methods for retrieving
  # results. That's because various types of builders may create entirely
  # different products that don't follow the same interface. Therefore, such
  # methods cannot be declared in the base Builder interface (at least in a
  # statically typed programming language).
  #
  # Usually, after returning the end result to the client, a builder instance is
  # expected to be ready to start producing another product. That's why it's a
  # usual practice to call the reset method at the end of the `getProduct`
  # method body. However, this behavior is not mandatory, and you can make your
  # builders wait for an explicit reset call from the client code before
  # disposing of the previous result.
  def product
    product = @product
    reset
    product
  end

  def produce_part_a
    @product.add('PartA1')
  end

  def produce_part_b
    @product.add('PartB1')
  end

  def produce_part_c
    @product.add('PartC1')
  end
end

# It makes sense to use the Builder pattern only when your products are quite
# complex and require extensive configuration.
#
# Unlike in other creational patterns, different concrete builders can produce
# unrelated products. In other words, results of various builders may not always
# follow the same interface.
class Product1
  def initialize
    @parts = []
  end

  # @param [String] part
  def add(part)
    @parts << part
  end

  def list_parts
    print "Product parts: #{@parts.join(', ')}"
  end
end

# The Director is only responsible for executing the building steps in a
# particular sequence. It is helpful when producing products according to a
# specific order or configuration. Strictly speaking, the Director class is
# optional, since the client can control builders directly.
class Director
  # @return [Builder]
  attr_accessor :builder

  def initialize
    @builder = nil
  end

  # The Director works with any builder instance that the client code passes to
  # it. This way, the client code may alter the final type of the newly
  # assembled product.
  def builder=(builder)
    @builder = builder
  end

  # The Director can construct several product variations using the same
  # building steps.

  def build_minimal_viable_product
    @builder.produce_part_a
  end

  def build_full_featured_product
    @builder.produce_part_a
    @builder.produce_part_b
    @builder.produce_part_c
  end
end

# The client code creates a builder object, passes it to the director and then
# initiates the construction process. The end result is retrieved from the
# builder object.

director = Director.new
builder = ConcreteBuilder1.new
director.builder = builder

puts 'Standard basic product: '
director.build_minimal_viable_product
builder.product.list_parts

puts "\n\n"

puts 'Standard full featured product: '
director.build_full_featured_product
builder.product.list_parts

puts "\n\n"

# Remember, the Builder pattern can be used without a Director class.
puts 'Custom product: '
builder.produce_part_a
builder.produce_part_b
builder.product.list_parts

output.txt: Résultat de l’exécution

Standard basic product: 
Product parts: PartA1

Standard full featured product: 
Product parts: PartA1, PartB1, PartC1

Custom product: 
Product parts: PartA1, PartB1

Monteur dans les autres langues

Patrons de conception : Monteur en Java Patrons de conception : Monteur en C# Patrons de conception : Monteur en C++ Patrons de conception : Monteur en PHP Patrons de conception : Monteur en Python Patrons de conception : Monteur en Swift Patrons de conception : Monteur en TypeScript Patrons de conception : Monteur en Go