Source Code for Module pypat.behavioral.memento

 1  from copy import deepcopy 
 2   
 3   
 4 -class Memento(object): 
 5      """ 
 6      Memento class as part of the Memento design pattern. 
 7   
 8      - External Usage documentation: U{https://github.com/tylerlaberge/PyPatterns/wiki/Behavioral-Pattern-Usage} 
 9      - External Memento Pattern documentation: U{https://en.wikipedia.org/wiki/Memento_pattern} 
10      """ 
11 -    def __init__(self, state): 
12          """ 
13          Initialize a new Memento instance. 
14   
15          @param state: The state to save in this Memento. 
16          @type state: dict 
17          """ 
18          self.__state = state 
19   
20      @property 
21 -    def state(self): 
22          return self.__state 
23   
24   
25 -class Originator(object): 
26      """ 
27      Originator base class as part of the Memento design pattern. 
28   
29      - External Usage documentation: U{https://github.com/tylerlaberge/PyPatterns/wiki/Behavioral-Pattern-Usage} 
30      - External Mediator Pattern documentation: U{https://en.wikipedia.org/wiki/Memento_pattern} 
31      """ 
32 -    def commit(self): 
33          """ 
34          Commit this objects state to a memento. 
35   
36          @return: A memento instance with this objects state. 
37          """ 
38          return Memento(deepcopy(self.__dict__)) 
39   
40 -    def rollback(self, memento): 
41          """ 
42          Rollback this objects state to a previous state. 
43   
44          @param memento: The memento object holding the state to rollback to. 
45          @type memento: Memento 
46          """ 
47          self.__dict__ = memento.state 
48