| 1 | class Delegator: |
| 2 | |
| 3 | def __init__(self, delegate=None): |
| 4 | self.delegate = delegate |
| 5 | self.__cache = set() |
| 6 | # Cache is used to only remove added attributes |
| 7 | # when changing the delegate. |
| 8 | |
| 9 | def __getattr__(self, name): |
| 10 | attr = getattr(self.delegate, name) # May raise AttributeError |
| 11 | setattr(self, name, attr) |
| 12 | self.__cache.add(name) |
| 13 | return attr |
| 14 | |
| 15 | def resetcache(self): |
| 16 | "Removes added attributes while leaving original attributes." |
| 17 | # Function is really about resetting delegator dict |
| 18 | # to original state. Cache is just a means |
| 19 | for key in self.__cache: |
| 20 | try: |
| 21 | delattr(self, key) |
| 22 | except AttributeError: |
| 23 | pass |
| 24 | self.__cache.clear() |
| 25 | |
| 26 | def setdelegate(self, delegate): |
| 27 | "Reset attributes and change delegate." |
| 28 | self.resetcache() |
| 29 | self.delegate = delegate |
| 30 | |
| 31 | |
| 32 | if __name__ == '__main__': |
no outgoing calls
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