上拉重构，Objective-C [英] Pull-up refactoring, Objective-C

问题描述

我有两个相似的类， MultiSlotBlock 和 SingleSlotBlock 。他们已经开始共享许多通用代码，因此我决定进行一些重构，并将一些方法提升到新的超类中，我们将其称为 Block 。

现在，我举起来的一种方法（为示例简化）看起来像这样：

  //（Block.mm）
 
-（void）doACommonBehaviour 
 {
 // ..做一些事情
 
 [self doAUniqueBehaviour]; 
} 
  

这里的问题是 [self doAUniqueBehaviour] 正在显示警告，因为我的超类当然没有在任何地方实现此方法。

我认为这两个解决方案听起来并不好我。一种是像这样使用协议（我目前正在使用的方式）：

  //（Block.mm）
 
-（void）doACommonBehaviour 
 {
 // ..如果（[selfconformsToProtocol：@protocol（UniqueBehaviourProtocol）]）有东西
 
 b $ b {
 id< UniqueBehaviourProtocol>块=（id< UniqueBehaviourProtocol>）自身; 
 [block doAUniqueBehaviour]; 
} 
} 
  

另一种方法是在我的方法主体中留空超类（在这种情况下会很多），只返回 doesNotRespondToSelector 。

后面有些东西刺痛我的想法是我应该使用策略模式，但我可能还遥遥无期，而且我还没有考虑过如何实现该策略。

有什么想法吗？谢谢。

编辑：我知道 doAUniqueBehaviour 将在所有子类中实现的事实，实施会有所不同。

解决方案

超类不应该知道其子类。您应该在每个子类中实现
-（void）doACommonBehaviour 方法：

 -（void）doACommonBehaviour 
 {
 [super doACommonBehaviour]; 
 [self doAUniqueBehaviour]; 
} 
  

编辑-澄清：

如果所有子类都将实现 -doAUniqueBehaviour ，则应在超类中实现（甚至为空），并且每个子类都会根据需要覆盖它。

如果subclass1实现 -doAUniqueBehaviour1 ，subclass2实现 -doAUniqueBehaviour2 等然后按照我上面的建议做；例如。在子类1中：

 -（void）doACommonBehaviour 
 {
 [super doACommonBehaviour]; 
 [self doAUniqueBehaviour1]; 
} 
  

I have two similar classes, MultiSlotBlock and SingleSlotBlock. They have started to share a lot of common code so I have decided to do some refactoring and pull some of the methods up to a new superclass, let's call it Block.

Now one of the methods that I pull up, simplified for the example, looks like this:

// (Block.mm)

- (void)doACommonBehaviour
{       
      // .. does some stuff

      [self doAUniqueBehaviour];
}

The problem here is that [self doAUniqueBehaviour] is showing a warning because of course my superclass doesn't implement this method anywhere.

The two solutions I thought of don't sound great to me. One is to use a protocol (the way I am currently doing it) like so:

// (Block.mm)

- (void)doACommonBehaviour
{       
      // .. does some stuff

      if ([self conformsToProtocol:@protocol(UniqueBehaviourProtocol)])
      {
           id<UniqueBehaviourProtocol> block = (id<UniqueBehaviourProtocol>)self;
           [block doAUniqueBehaviour];
      }
}

The other is to have a blank method body in my superclass (in this case there would be a lot) and just return doesNotRespondToSelector.

Something is tingling at the back of my mind that I should be using the Strategy Pattern, but I might be way off, and I haven't thought through how that would be implemented.

Any ideas? Thanks.

EDIT: I know for a fact that doAUniqueBehaviour will be implemented in all subclasses, it is just the implementation that will differ.

解决方案

The superclass should not know about its subclasses. You should implement the - (void)doACommonBehaviour method in every subclass and there:

- (void)doACommonBehaviour
{     
      [super doACommonBehaviour];
      [self doAUniqueBehaviour];
}

EDIT - clarification:

If all the subclasses are going to implement -doAUniqueBehaviour then it should be implemented in the superclass (even empty) and each subclass will override it to its needs.

If subclass1 implements -doAUniqueBehaviour1, subclass2 implements -doAUniqueBehaviour2 etc then do what I propose above; eg. in subclass1:

- (void)doACommonBehaviour
{     
      [super doACommonBehaviour];
      [self doAUniqueBehaviour1];
}

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