Ruby策略模式优化：避免无关方法继承的DRY实现问询

Great question—this is a classic case where overusing inheritance can lead to bloated base classes and unnecessary method exposure, which is definitely a code smell we want to avoid. Let’s walk through a few clean, Ruby-idiomatic solutions tailored to your scenario:

方案1：使用模块（Module）实现组合式复用 #

Ruby’s modules are perfect for extracting shared behavior that only applies to a subset of your strategy classes. Instead of polluting the base class with add_hot_sauce, we’ll wrap this method in a module and "mix it in" only where it’s needed.

# 提取共享的加辣酱行为到模块
module HotSauceable
  def add_hot_sauce
    # 这里是你的具体实现逻辑
    puts "Drizzling spicy hot sauce!"
  end
end

# 基类只保留所有策略共有的核心方法
class FoodStrategy
  def prepare_food
    raise NotImplementedError, "Subclasses must implement #prepare_food"
  end
end

# 需要加辣酱的策略混入模块
class FoodStrategies::Taco < FoodStrategy
  include HotSauceable

  def prepare_food
    add_hot_sauce
    # 其他制作taco的逻辑
    puts "Assembling crunchy taco!"
  end
end

class FoodStrategies::Burrito < FoodStrategy
  include HotSauceable

  def prepare_food
    add_hot_sauce
    # 其他制作burrito的逻辑
    puts "Wrapping hearty burrito!"
  end
end

# 不需要辣酱的策略直接继承基类，无多余方法
class FoodStrategies::Cereal < FoodStrategy
  def prepare_food
    # 制作麦片的逻辑
    puts "Pouring milk over cereal!"
  end
end

优点:

• 遵循组合优于继承的原则，避免了不必要的继承层次
• 每个策略类只包含它实际需要的行为，符合单一职责原则
• 模块可以轻松复用在其他需要加辣酱的类中，扩展性强

方案2：拆分基类形成层次结构 #

If add_hot_sauce is part of a larger set of shared behaviors for your spicy food strategies, you can split your base class into a two-level hierarchy:

# 最基础的基类，包含所有策略通用的方法
class BaseFoodStrategy
  def prepare_food
    raise NotImplementedError, "Subclasses must implement #prepare_food"
  end
end

# 专门为需要加辣酱的策略创建子类
class SpicyFoodStrategy < BaseFoodStrategy
  def add_hot_sauce
    puts "Drizzling spicy hot sauce!"
  end
end

# 辣味策略继承自SpicyFoodStrategy
class FoodStrategies::Taco < SpicyFoodStrategy
  def prepare_food
    add_hot_sauce
    puts "Assembling crunchy taco!"
  end
end

class FoodStrategies::Burrito < SpicyFoodStrategy
  def prepare_food
    add_hot_sauce
    puts "Wrapping hearty burrito!"
  end
end

# 非辣味策略直接继承BaseFoodStrategy
class FoodStrategies::Cereal < BaseFoodStrategy
  def prepare_food
    puts "Pouring milk over cereal!"
  end
end

优点:

• 清晰划分了策略的层次，适合有多个共享行为的场景
• 保留了继承的语义，让代码意图更明确
• 避免了无用方法的跨类继承

注意: 这个方案更适合当你有一组相关的共享方法（不止add_hot_sauce），否则模块方案会更轻量灵活。

为什么不把add_hot_sauce放在基类？ #

Putting add_hot_sauce in the base class would force FoodStrategies::Cereal to inherit a method it never uses. This violates the Interface Segregation Principle (clients shouldn’t depend on interfaces they don’t need) and creates a "fat base class" that becomes harder to maintain as your strategy set grows.

内容的提问来源于stack exchange，提问作者Argus9