How can I extract code into its own class while still calling a protected method?

Question

I was hoping to extract a lot of logic into a separate class in the following code, but I am having trouble with that since it ends up calling a protected method.

This is my current code:

class ExcelSheet
  ...
  protected

  def save_stuff
    # do work
  end
end

class CustomSheet < ExcelSheet
  def custom_stuff
    # lots of logic
    save_stuff
    # more logic
  end
end

This was my attempted code:

class LogicManager
  def logic_valid?
    # lots of logic
    save_stuff
  end
end

class CustomSheet < ExcelSheet
  def custom_stuff
    manager = LogicManager.new(some_data)
    if manager.logic_valid?
      # more logic
    end
  end
end

Unfortunately in my LogicManager I can't call save_stuff because it's protected. I didn't write the original method, and I'm sure it's marked as protected for a reason, so I don't think I should change that.

What options do I have to still refactor nicely?

Answer 1

It seems that you have a bit of a misunderstanding of protected methods.

Protected methods can be invoked only by the class that defines it, or by it's subclasses. In your case, it means that if you would like to invoke the method save_stuff in the class LogicManager, that means that LogicManager must inherit from ExcelSheet.

Given the naming of the classes, I am not sure if you want to do that as it doesn't seem logical to me (no pun intended).