Source Code for Module pypat.creational.pool

 1  from abc import ABCMeta 
 2  from copy import deepcopy 
 3  from pypat.behavioral.memento import Originator 
 4   
 5   
 6 -class Reusable(Originator, metaclass=ABCMeta): 
 7      """ 
 8      An abstract reusable class. 
 9   
10      - External Usage documentation: U{https://github.com/tylerlaberge/PyPatterns/wiki/Creational-Pattern-Usage} 
11      - External Object Pool Pattern documentation: U{https://en.wikipedia.org/wiki/Object_pool_pattern} 
12      """ 
13 -    def __init__(self): 
14          """ 
15          Initialize a new Reusable instance. 
16          """ 
17          self.memento = self.commit() 
18   
19 -    def reset(self): 
20          """ 
21          Reset this objects state to the state that it was created with. 
22          """ 
23          memento = self.memento 
24          self.rollback(deepcopy(memento)) 
25          self.memento = memento 
26   
27   
28 -class Pool(object): 
29      """ 
30      An Object Pool design pattern implementation. 
31   
32      - External Usage documentation: U{https://github.com/tylerlaberge/PyPatterns/wiki/Creational-Pattern-Usage} 
33      - External Object Pool Pattern documentation: U{https://en.wikipedia.org/wiki/Object_pool_pattern} 
34      """ 
35 -    def __init__(self, reusable_class, *args, **kwargs): 
36          """ 
37          Initialize a new object pool instance. 
38   
39          @param reusable_class: The reusable class this object pool is responsible for. 
40          @param args: args for reusable object creation. 
41          @param kwargs: kwargs for reusable object creation. 
42          """ 
43          self.reusables = list() 
44          self.reusable_class = reusable_class 
45          self.args = args 
46          self.kwargs = kwargs 
47          self.pool_size = 2 
48          self._expand(self.pool_size) 
49   
50 -    def acquire(self): 
51          """ 
52          Acquire an object from the pool. 
53   
54          @return: An object from the pool. 
55          """ 
56          try: 
57              reusable = self.reusables.pop() 
58          except IndexError: 
59              self._expand(self.pool_size) 
60              reusable = self.reusables.pop() 
61   
62          return reusable 
63   
64 -    def release(self, reusable): 
65          """ 
66          Release an object back into the pool. 
67   
68          @param reusable: The object to return to the pool. 
69          """ 
70          reusable.reset() 
71          self.reusables.append(reusable) 
72   
73 -    def _expand(self, size): 
74          for i in range(0, size): 
75              self.reusables.append(self.reusable_class(*self.args, **self.kwargs)) 
76