| class Delegator: |
| |
| def __init__(self, delegate=None): |
| self.delegate = delegate |
| self.__cache = set() |
| # Cache is used to only remove added attributes |
| # when changing the delegate. |
| |
| def __getattr__(self, name): |
| attr = getattr(self.delegate, name) # May raise AttributeError |
| setattr(self, name, attr) |
| self.__cache.add(name) |
| return attr |
| |
| def resetcache(self): |
| "Removes added attributes while leaving original attributes." |
| # Function is really about resetting delagator dict |
| # to original state. Cache is just a means |
| for key in self.__cache: |
| try: |
| delattr(self, key) |
| except AttributeError: |
| pass |
| self.__cache.clear() |
| |
| def setdelegate(self, delegate): |
| "Reset attributes and change delegate." |
| self.resetcache() |
| self.delegate = delegate |
| |
| if __name__ == '__main__': |
| from unittest import main |
| main('idlelib.idle_test.test_delegator', verbosity=2) |