# Copyright (C) 2015 Canonical Ltd. # # This file is part of cloud-init. See LICENSE file for license information. import copy class DictRegistry(object): """A simple registry for a mapping of objects.""" def __init__(self): self.reset() def reset(self): self._items = {} def register_item(self, key, item): """Add item to the registry.""" if key in self._items: raise ValueError( 'Item already registered with key {0}'.format(key)) self._items[key] = item def unregister_item(self, key, force=True): """Remove item from the registry.""" if key in self._items: del self._items[key] elif not force: raise KeyError("%s: key not present to unregister" % key) @property def registered_items(self): """All the items that have been registered. This cannot be used to modify the contents of the registry. """ return copy.copy(self._items) # vi: ts=4 expandtab