|  | # Copyright 2014 Google Inc. All Rights Reserved. | 
|  | # | 
|  | # Licensed under the Apache License, Version 2.0 (the "License"); | 
|  | # you may not use this file except in compliance with the License. | 
|  | # You may obtain a copy of the License at | 
|  | # | 
|  | #      http://www.apache.org/licenses/LICENSE-2.0 | 
|  | # | 
|  | # Unless required by applicable law or agreed to in writing, software | 
|  | # distributed under the License is distributed on an "AS IS" BASIS, | 
|  | # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | 
|  | # See the License for the specific language governing permissions and | 
|  | # limitations under the License. | 
|  |  | 
|  | """An abstract class for caching the discovery document.""" | 
|  |  | 
|  | import abc | 
|  |  | 
|  |  | 
|  | class Cache(object): | 
|  | """A base abstract cache class.""" | 
|  |  | 
|  | __metaclass__ = abc.ABCMeta | 
|  |  | 
|  | @abc.abstractmethod | 
|  | def get(self, url): | 
|  | """Gets the content from the memcache with a given key. | 
|  |  | 
|  | Args: | 
|  | url: string, the key for the cache. | 
|  |  | 
|  | Returns: | 
|  | object, the value in the cache for the given key, or None if the key is | 
|  | not in the cache. | 
|  | """ | 
|  | raise NotImplementedError() | 
|  |  | 
|  | @abc.abstractmethod | 
|  | def set(self, url, content): | 
|  | """Sets the given key and content in the cache. | 
|  |  | 
|  | Args: | 
|  | url: string, the key for the cache. | 
|  | content: string, the discovery document. | 
|  | """ | 
|  | raise NotImplementedError() |