Source Code for Module pypat.creational.singleton

 1 -class Singleton(type): 
 2      """ 
 3      Singleton Metaclass. 
 4   
 5      Enforces any object using this metaclass to only create a single instance. 
 6   
 7      - External Usage documentation: U{https://github.com/tylerlaberge/PyPatterns/wiki/Creational-Pattern-Usage} 
 8      - External Singleton Pattern documentation: U{https://en.wikipedia.org/wiki/Singleton_pattern} 
 9      """ 
10      __instance = None 
11   
12 -    def __call__(cls, *args, **kwargs): 
13          """ 
14          Override the __call__ method to make sure only one instance is created. 
15          """ 
16          if cls.__instance is None: 
17              cls.__instance = type.__call__(cls, *args, **kwargs) 
18   
19          return cls.__instance 
20