python设计模式4：适配器模式

使用适配器模式使用两个或是多个不兼容的接口兼容。在不修改不兼容代码的情况下使用适配器模式实现接口一致性。通过Adapter 类实现。

例子： 一个俱乐部类Club，艺术加被请到俱乐部在表演节目： organize_performance（）

Musician类 play()  方法  Dancer 类主要是dance() 方法执行  （external.py） 

外部模块导入（adapter.py）创建一个通用的  Adapter类调整不兼容的对象。

 __init__() 方法的obj 参数是需要修改的对象，adapted_methods 是一个字典，包含与客户端调用的方法和应该调用方法匹配的键值对。

chapter04/external.py

class Musician: def __init__(self, name): self.name = namedef __str__(self): return f'the musician {self.name}' def play(self): return 'plays music' class Dancer: def __init__(self, name): self.name = name def __str__(self): return f'the dancer {self.name}' def dance(self): return 'does a dance performance' 

chapter04/adapter.py

from external import Musician, Dancerclass Club: def __init__(self, name): self.name = name def __str__(self): return f'the club {self.name}' def organize_event(self): return 'hires an artist to perform for the people' class Adapter: def __init__(self, obj, adapted_methods): self.obj = obj self.__dict__.update(adapted_methods) def __str__(self): return str(self.obj) def main(): objects = [Club('Jazz Cafe'), Musician('Roy Ayers'), Dancer('Shane Sparks')]for obj in objects:if hasattr(obj, 'play') or hasattr(obj, 'dance'):if hasattr(obj, 'play'):adapted_methods = dict(organize_event=obj.play)   # 设置调用方法统一organize_eventelif hasattr(obj, 'dance'):            adapted_methods = dict(organize_event=obj.dance)    # 设置调用方法统一organize_event# referencing the adapted object hereobj = Adapter(obj, adapted_methods)print(f' 输出 {obj} {obj.organize_event()}')  # 调用统一方法if __name__ == "__main__": main()

 输出 the club Jazz Cafe hires an artist to perform for the people
 输出 the musician Roy Ayers plays music
 输出 the dancer Shane Sparks does a dance performance