Source Code for Module pypat.creational.builder

 1  from abc import ABCMeta, abstractmethod 
 2   
 3   
 4 -class Director(object, metaclass=ABCMeta): 
 5      """ 
 6      Abstract director class, responsible for using a builder to fully construct an object. 
 7   
 8      - External Usage documentation: U{https://github.com/tylerlaberge/PyPatterns/wiki/Creational-Pattern-Usage} 
 9      - External Builder Pattern documentation: U{https://en.wikipedia.org/wiki/Builder_pattern} 
10      """ 
11   
12 -    def __init__(self): 
13          """ 
14          Initialize a new Director. 
15          """ 
16          self.builder = None 
17   
18      @abstractmethod 
19 -    def construct(self): 
20          """ 
21          Abstract method for fully constructing an object. 
22   
23          Concrete implementations should override this and use a builder to construct the object. 
24   
25          @raise NotImplementedError: If this method is not overridden. 
26          """ 
27          pass 
28   
29 -    def get_constructed_object(self): 
30          """ 
31          Get the object this director is responsible for constructing. 
32   
33          @return: The object that this director is responsible for constructing. 
34          """ 
35          return self.builder.constructed_object 
36   
37   
38 -class Builder(object, metaclass=ABCMeta): 
39      """ 
40      Abstract builder class, responsible for constructing various pieces of an object. 
41   
42      - External Usage documentation: U{https://github.com/tylerlaberge/PyPatterns/wiki/Creational-Pattern-Usage} 
43      - External Builder Pattern documentation: U{https://en.wikipedia.org/wiki/Builder_pattern} 
44      """ 
45   
46 -    def __init__(self, constructed_object): 
47          """ 
48          Initialize a new Builder. 
49   
50          Concrete Builders should call this method from within their own __init__ method. 
51          The concrete __init__ method should also register all build options to build methods, 
52          by using the _register method. 
53   
54          @param constructed_object: An instance of an object this builder is responsible for. 
55          """ 
56          self.constructed_object = constructed_object 
57          self.build_methods = dict() 
58   
59 -    def build(self, build_option, **kwargs): 
60          """ 
61          Build a piece of the constructed object. 
62   
63          @param build_option: The part of the object to build. All build options should have been registered in __init__. 
64          @type build_option: str 
65          @param kwargs: Additional arguments for building. 
66          """ 
67          self.build_methods[build_option](**kwargs) 
68   
69 -    def _register(self, build_option, build_method): 
70          """ 
71          Register a build option to a build method. 
72   
73          All concrete builders should call this method in their constructor at least once. 
74   
75          @param build_option: A string representing the part of the object to build. 
76          @type build_option: str 
77          @param build_method: The method to call when given build option is selected. 
78          """ 
79          self.build_methods[build_option] = build_method 
80