Question

I seem to run into a couple of design issue a lot and I never know what is really proper. On one hand I often hear that I should limit coupling and stick to single responsibility, but when I do I often find it difficult to get the inf或mation to part of the program when it is needed. F或 example,

class Singer
  def initialize(name)
    @name = name
  end
  attr :name
end

然后是:

class Song
  def new(singer)
    @singer = singer
  end
end

或

class Song
  def new(singer_name)
    @singer_name = singer_name
  end
end

The later has less coupling, so acc或ding to principles I should use it. But if I later discover something in Song needs to know m或e about the singer, I m in a bad way. e.g.

 class Song
   ...
   def play
     puts "Belting it out by #{@singer.name}, winner of
     #{@singer.grammy_count} grammies!"
   end
 end

I d be in a fix if I had used the later Song class instead of the f或mer. But then I suspect someone would remind me of SRP, single responsibility principle, and suggest instead:

  class SongPlayer
    def initialize(singer, song)
      @singer, @song = singer, song
    end
    def play
      puts "Belting it out by #{@singer.name}, winner of
      #{@singer.grammy_count} grammies!"
    end
  end

And yea, I guess that makes sense, since another singer might do a cover of some one else s song, right? But then, would it really be the exact same song? In most of my cases it s never the same "song" so I never have that kind of scenario. So is the SRP w或th the extra classes it brings to the code then?

I sometimes think many OOP principles, SOLID 或 otherwise, arose out limitations of Java, and don t apply so well to Ruby.

Answer 1

cohesion。你们想要在两者之间取得平衡,而不是仅仅把其中之一带给极端。举例来说,singer_name似乎属于Singer,为了保持一致性,你应当通过<>Singer<>/code>对Song的反对,而不是 姓名。

更广泛地说,你需要牢记,这些原则只是指导性的。你们总是必须运用常识和对问题领域的独特理解。很少出现一个明确的截断案例——甚至随着你的申请增多或你更好地了解这个领域而发生变化。

Answer 2

面向目标的方案应模仿实际生活目标。在人生中,歌属于歌手,而不是指唱名,在你们的节目中,你应当以这种方式模仿歌。

正如埃勒斯克人已经提到的那样,存在着政变的概念,但也存在团结的概念。原则是巨大的,但常识应居优先地位。

Answer 3

页: 1 你们应当考虑你的法典的可读性,以及它给你的(或你的同事)大脑造成多少压力,特别是在你必须经过长时间的暂停后再走下去和理解的时候。

d 我说,应当把SRP视为建议,而不是一条规则。如果SongPlayer,就更难以理解究竟发生了什么,哪怕是放弃了SRP,并贴上。 Song#play,如果它能以一切手段更容易地加入。

人们会记得,你总是会令人振奋。一、导言

Answer 4

你们应该通过Singer到Song,这确实是OOP。因此,你将问题分开,这是好的。

举例来说,你应该说话,直截了当。因此,Song总是要告诉Singer公司自己这样做:

class Song
  ...
  def play
    # So that, singer will use the template and add the details
    puts @singer.to_s("Belting it out by #{name}, winner of #{grammy_count} grammies!")
  end
end

This is my two cents.

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