Ruby设计模式编程中使用Builder建造者模式的实例例子解析

代码示例：

以下是使用 Ruby 实现 Builder 模式的一个详细示例：

定义产品类

首先定义一个复杂对象 Computer，它有多个属性，如 CPU、内存、存储、显卡和电源。

class Computer
  attr_accessor :cpu, :ram, :storage, :graphics_card, :power_supply

  def initialize(cpu, ram, storage, graphics_card, power_supply)
    @cpu = cpu
    @ram = ram
    @storage = storage
    @graphics_card = graphics_card
    @power_supply = power_supply
  end

  def specifications
    "CPU: #{@cpu}, RAM: #{@ram}, Storage: #{@storage}, Graphics Card: #{@graphics_card}, Power Supply: #{@power_supply}"
  end
end

创建构建器接口

定义一个构建器接口 ComputerBuilder，它规定了构建 Computer 各部分的方法。

class ComputerBuilder
  def build_cpu; end
  def build_ram; end
  def build_storage; end
  def build_graphics_card; end
  def build_power_supply; end
  def get_computer; end
end

实现具体构建器

实现两个具体构建器，分别用于构建游戏电脑和办公电脑。

游戏电脑构建器

class GamingComputerBuilder < ComputerBuilder
  def initialize
    @computer = Computer.new(nil, nil, nil, nil, nil)
  end

  def build_cpu
    @computer.cpu = 'i9-13900K'
  end

  def build_ram
    @computer.ram = '64GB'
  end

  def build_storage
    @computer.storage = '2TB SSD'
  end

  def build_graphics_card
    @computer.graphics_card = 'RTX 4090'
  end

  def build_power_supply
    @computer.power_supply = '1200W'
  end

  def get_computer
    @computer
  end
end

办公电脑构建器

class OfficeComputerBuilder < ComputerBuilder
  def initialize
    @computer = Computer.new(nil, nil, nil, nil, nil)
  end

  def build_cpu
    @computer.cpu = 'i5-12400'
  end

  def build_ram
    @computer.ram = '16GB'
  end

  def build_storage
    @computer.storage = '512GB SSD'
  end

  def build_graphics_card
    @computer.graphics_card = 'Integrated'
  end

  def build_power_supply
    @computer.power_supply = '500W'
  end

  def get_computer
    @computer
  end
end

创建指挥者类

指挥者类 ComputerDirector 负责控制构建过程，调用构建器的方法来逐步构建对象。

class ComputerDirector
  attr_accessor :builder

  def initialize(builder)
    @builder = builder
  end

  def construct_gaming_computer
    @builder.build_cpu
    @builder.build_ram
    @builder.build_storage
    @builder.build_graphics_card
    @builder.build_power_supply
    @builder.get_computer
  end

  def construct_office_computer
    @builder.build_cpu
    @builder.build_ram
    @builder.build_storage
    @builder.build_graphics_card
    @builder.build_power_supply
    @builder.get_computer
  end
end

客户端代码

客户端代码使用指挥者类和具体构建器来构建不同类型的电脑。

gaming_builder = GamingComputerBuilder.new
office_builder = OfficeComputerBuilder.new

gaming_director = ComputerDirector.new(gaming_builder)
office_director = ComputerDirector.new(office_builder)

gaming_computer = gaming_director.construct_gaming_computer
office_computer = office_director.construct_office_computer

puts "Gaming Computer Specifications: #{gaming_computer.specifications}"
puts "Office Computer Specifications: #{office_computer.specifications}"

输出结果

运行上述代码后，输出如下：

Gaming Computer Specifications: CPU: i9-13900K, RAM: 64GB, Storage: 2TB SSD, Graphics Card: RTX 4090, Power Supply: 1200W
Office Computer Specifications: CPU: i5-12400, RAM: 16GB, Storage: 512GB SSD, Graphics Card: Integrated, Power Supply: 500W

这个示例展示了如何使用 Builder 模式在 Ruby 中构建复杂对象。通过将构建过程与对象的表示分离，可以灵活地创建不同类型的电脑，同时保持代码的可读性和可维护性。
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