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跨两个Ruby模块继承/共享代码

dry module class ruby ruby-on-rails

TheNovice · 技术社区 · 7 年前

我是Noob,正在找人帮忙把这个弄干。假设我有 module DoAThing 看起来是这样的:

module DoAThing
  class ExportNames
    def initialize(names, limit = 1000)
      @names = names
      @limit = limit
    end

    def perform
      awesome = ::ClassAwesome.sort_names(names, per_page: @limit)
      awesome.generate_export(::ClassAwesome::EXPORT_DEFAULTS)
    end
  end
end

然后我想添加一个模块,该模块的功能完全相同,只是在生成报告时,我想传递一个不同的常量,如下所示:

module DoASlightDifferentThing
  class ExportNames
    def initialize(names, limit = 1000)
      @names = names
      @limit = limit
    end

    def perform
      awesome = ::ClassAwesome.sort_names(names, per_page: @limit)
      awesome.generate_export(::ClassAwesome::DIFFERENT_EXPORT_DEFAULTS)
    end
  end
end

我怎样才能优雅地擦干这个?实际上,我所需要做的就是传入一个不同的常量,即我想交换 EXPORT_DEFAULTS 对于 DIFFERENT_EXPORT_DEFAULTS

3 回复 | 直到 7 年前

Aleksei Matiushkin 7 年前

这通常被称为依赖注入,互联网上有很多关于这个主题的文章。主要方法是在调用中接受一个参数 #perform 方法:

module DoManyDifferentThings
  class ExportNames
    def initialize(names, limit = 1000)
      @names = names
      @limit = limit
    end

    def perform(report)
      awesome = ::ClassAwesome.sort_names(names, per_page: @limit)
      awesome.generate_export(report)
    end
  end
end

可以这样称呼:

DoManyDifferentThings::ExportNames.perform(
  ::ClassAwesome::EXPORT_DEFAULTS
)

无论report方法是否应该具有预定义的签名,都可以使用类继承:

module DoManyDifferentThings
  class ExportNames
    def initialize(names, limit = 1000)
      @names = names
      @limit = limit
    end

    def perform
      awesome = ::ClassAwesome.sort_names(names, per_page: @limit)
      awesome.generate_export(self.class.constant_get('REPORT'))
    end
  end

  class ExportNames1 < ExportNames
    REPORT = ::ClassAwesome::EXPORT_DEFAULTS_1
  end

  class ExportNames1 < ExportNames
    REPORT = ::ClassAwesome::EXPORT_DEFAULTS_2
  end
end

或者,也可以声明要在子体中覆盖的方法:

module DoManyDifferentThings
  class ExportNames
    def initialize(names, limit = 1000)
      @names = names
      @limit = limit
    end

    def perform
      awesome = ::ClassAwesome.sort_names(names, per_page: @limit)
      awesome.generate_export(report)
    end

    protected

    def report
      raise "DO NOT CALL ME DIRECTLY"
    end
  end

  class ExportNames1 < ExportNames
    def report
      ::ClassAwesome::EXPORT_DEFAULTS_1
    end
  end

  class ExportNames2 < ExportNames
    def report
      ::ClassAwesome::EXPORT_DEFAULTS_2
    end
  end
end

Alexis 7 年前

可以将此常量作为参数移动,也可以使用ihneritance。

提供默认值作为参数

module DoAThing
  class ExportNames
    def initialize(names, limit = 1000, defaults = ::ClassAwesome::EXPORT_DEFAULTS)
      @names = names
      @limit = limit
      @defaults = defaults
    end

    def perform
      awesome = ::ClassAwesome.sort_names(names, per_page: @limit)
      awesome.generate_export(@defaults)
    end
  end
end

您可以执行以下操作,而不是调用DoaSlingDifferentThing::ExportNames:

DoAThing::ExportNames.perform_now(names, 1000, ::ClassAwesome::DIFFERENT_EXPORT_DEFAULTS)

Ihneritance公司

或者,您可以使用ihneritance,其中我们添加了一个将被覆盖的默认方法:

module DoAThing
  class ExportNames
    def initialize(names, limit = 1000)
      @names = names
      @limit = limit
    end

    def perform
      awesome = ::ClassAwesome.sort_names(names, per_page: @limit)
      awesome.generate_export(defaults)
    end

    def defaults
      ::ClassAwesome::EXPORT_DEFAULTS
    end
  end
end

module DoASlightDifferentThing
  class ExportNames < DoAThing::ExportNames
    def defaults
      ::ClassAwesome::DIFFERENT_EXPORT_DEFAULTS
    end
  end
end

Nimish Gupta 7 年前

如果这两个类的名称空间可以相同,那么我将通过如下方式重写代码来清理代码

module DoAThing
  class ExportNames
    def initialize(names, limit = 1000)
      @names = names
      @limit = limit
    end

    def perform(value)
      awesome = ::ClassAwesome.sort_names(names, per_page: @limit)
      awesome.generate_export(value)
    end
  end
end

现在我要打电话

DoAThing::ExportNames.new('your names').perform(::ClassAwesome::EXPORT_DEFAULTS)
DoAThing::ExportNames.new('your names').perform(::ClassAwesome::DIFFERENT_EXPORT_DEFAULTS)