| import random |
| |
| from .cache import Cache |
| |
| |
| class RRCache(Cache): |
| """Random Replacement (RR) cache implementation.""" |
| |
| def __init__(self, maxsize, choice=random.choice, missing=None, |
| getsizeof=None): |
| Cache.__init__(self, maxsize, missing, getsizeof) |
| self.__choice = choice |
| |
| @property |
| def choice(self): |
| """The `choice` function used by the cache.""" |
| return self.__choice |
| |
| def popitem(self): |
| """Remove and return a random `(key, value)` pair.""" |
| try: |
| key = self.__choice(list(self)) |
| except IndexError: |
| raise KeyError('%s is empty' % self.__class__.__name__) |
| else: |
| return (key, self.pop(key)) |
