class CachedUUIDObjectJSON(ObjectJSON):
def __init__(self, unit_system=None):
super(CachedUUIDObjectJSON, self).__init__(unit_system)
self.excluded_keys = ['json']
self.uuid_cache = WeakValueCache()
def simplify(self, obj, base_type=''):
if obj.__class__.__module__ != '__builtin__':
if hasattr(obj, 'to_dict') and hasattr(obj, '__uuid__'):
# the object knows how to dismantle itself into a json string
if obj.__uuid__ not in self.uuid_cache:
self.uuid_cache[obj.__uuid__] = obj
return {
'_cls': obj.__class__.__name__,
'_obj_uuid': str(obj.__uuid__),
'_dict': self.simplify(obj.to_dict(), base_type)}
else:
return {
'_obj_uuid': str(obj.__uuid__)}
return super(CachedUUIDObjectJSON, self).simplify(obj, base_type)
def build(self, jsn):
if type(jsn) is dict:
if '_obj_uuid' in jsn:
uuid = UUID(jsn['_obj_uuid'])
if uuid in self.uuid_cache:
return self.uuid_cache[uuid]
elif '_cls' in jsn and '_dict' in jsn:
if jsn['_cls'] not in self.class_list:
self.update_class_list()
if jsn['_cls'] not in self.class_list:
raise ValueError((
'Cannot create jsn of class `%s`.\n' +
'Class is not registered as creatable! '
'You might have to define\n' +
'the class locally and call '
'`update_storable_classes()` on your storage.') %
jsn['_cls'])
attributes = self.build(jsn['_dict'])
obj = self.class_list[jsn['_cls']].from_dict(attributes)
obj.__uuid__ = uuid
self.uuid_cache[uuid] = obj
return obj
else:
# this should not happen!
raise ('What happend here. JSN `%s`' % jsn)
pass
return super(CachedUUIDObjectJSON, self).build(jsn)
def to_json(self, obj, base_type=''):
# we need to clear the cache, since we have no idea, what the other end
# still knows. We can only cache stuff we are sending this time
self.uuid_cache.clear()
return super(CachedUUIDObjectJSON, self).to_json(obj, base_type)
def __init__(self, unit_system=None):
super(CachedUUIDObjectJSON, self).__init__(unit_system)
self.excluded_keys = ['json']
self.uuid_cache = WeakValueCache()