Coverage for src/susi/utils/annotators/singleton.py: 73%

1""" 

2Python annotator to create singletons 

3 

4Usage: 

5<pre> 

6@singleton 

7class MyCass: 

8 pass 

9</pre> 

10 

11@author hoelken 

12""" 

13 

14 

15def singleton(clazz): 

16 """Singleton annotator ensures the annotated class is a singleton""" 

17 

18 class ClassW(clazz): 

19 """Creates a new sealed class from the object to create.""" 

20 _instance = None 

21 

22 def __new__(cls, *args, **kwargs): 

23 if ClassW._instance is None: 

24 ClassW._instance = super(ClassW, cls).__new__(clazz, *args, **kwargs) 

25 ClassW._instance._sealed = False 

26 

27 return ClassW._instance 

28 

29 def __init__(self, *args, **kwargs): 

30 if self._sealed: 

31 return 

32 

33 super(ClassW, self).__init__(*args, **kwargs) 

34 self._sealed = True 

35 

36 ClassW.__name__ = clazz.__name__ 

37 return ClassW