java - 策略模式和模板模式该怎么区分?

Question

看了这两个设计模式之后, 对于简单直接的例子可以判断, 策略模式就是定义算法族, 然后通过组合算法族和委托的办法来实现类, 模板方法则是父类定义算法的骨架，子类再来实现骨架中的部分步骤； 但是有两个例子我很...

迷茫 · Answer

Strategy, object behavior pattern ＝》Use combination method
Template method, behavioral class pattern => Use inheritance

There are instructions in the Q&A in Head First

Because the Strategy pattern uses object composition. In a way, you're right - we use array objects to sort our arrays, and this part is very similar to the Strategy pattern. But remember that in the Strategy pattern, the classes you compose implement the entire algorithm. The sorting algorithm implemented by the array is not complete, it requires a class to fill in the implementation of the compareTo() method. So we think this is more of a template approach.

There is another API in the Arrays class:

public static  void sort(T[] a,
            Comparator c)

If you look at Comparator as an algorithm, it feels like this API is more like a strategy model.

To put it bluntly, the object of the template method pattern only implements a certain step of the algorithm, and most of the specific algorithms are defined in the parent class. The object of the Strategy pattern implements the entire algorithm.

PHP中文网 · Answer

Design patterns are just the result of abstraction. The main function of abstraction is to increase the readability, reusability and scalability of the code. So you don’t have to worry about whether you are using a template or a strategy.