Source Code for Module pypat.behavioral.null

 1 -class Null(object): 
 2      """ 
 3      A Null object class as part of the Null object design pattern. 
 4   
 5      - External Usage documentation: U{https://github.com/tylerlaberge/PyPatterns/wiki/Behavioral-Pattern-Usage} 
 6      - External Null Object Pattern documentation: U{https://en.wikipedia.org/wiki/Null_Object_pattern} 
 7      """ 
 8 -    def __init__(self, *args, **kwargs): 
 9          """ 
10          Do nothing. 
11          """ 
12          pass 
13   
14 -    def __call__(self, *args, **kwargs): 
15          """ 
16          Do nothing. 
17   
18          @return: This object instance. 
19          @rtype: Null 
20          """ 
21          return self 
22   
23 -    def __getattr__(self, name): 
24          """ 
25          Do nothing. 
26   
27          @return: This object instance. 
28          @rtype: Null 
29          """ 
30          return self 
31   
32 -    def __setattr__(self, name, value): 
33          """ 
34          Do nothing. 
35   
36          @return: This object instance. 
37          @rtype: Null 
38          """ 
39          return self 
40   
41 -    def __delattr__(self, name): 
42          """ 
43          Do nothing. 
44   
45          @return: This object instance. 
46          @rtype: Null 
47          """ 
48          return self 
49   
50 -    def __repr__(self): 
51          """ 
52          Null object string representation is the empty string. 
53   
54          @return: An empty string. 
55          @rtype: String 
56          """ 
57          return '' 
58   
59 -    def __str__(self): 
60          """ 
61          Null object string representation is the empty string. 
62   
63          @return: An empty string. 
64          @rtype: String 
65          """ 
66          return '' 
67   
68 -    def __bool__(self): 
69          """ 
70          Null object evaluates to False. 
71   
72          @return: False. 
73          @rtype: Boolean 
74          """ 
75          return False 
76