| #!/usr/bin/env python |
| # -*- encoding: utf-8 -*- |
| |
| # Licensed to the Apache Software Foundation (ASF) under one |
| # or more contributor license agreements. See the NOTICE file |
| # distributed with this work for additional information |
| # regarding copyright ownership. The ASF licenses this file |
| # to you 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. |
| |
| '''state.py''' |
| from abc import abstractmethod |
| |
| class State(object): |
| """State represents the state interface as seen by stateful bolts and spouts. |
| In Heron, state gives a notional Key/Value interface along with the |
| ability to iterate over the key/values |
| """ |
| @abstractmethod |
| def put(self, key, value): |
| """Puts {key, value} pair into the state |
| :param key: The key to get back the value |
| :param value: The value associated with the key |
| """ |
| pass |
| |
| @abstractmethod |
| def get(self, key): |
| """Gets the value corresponding to a key |
| :param key: The key whose value we want back |
| :return: The value associated with the key |
| """ |
| pass |
| |
| @abstractmethod |
| def enumerate(self): |
| """Allows one to enumerate over the state. |
| :return: The enumerate object |
| """ |
| pass |
| |
| @abstractmethod |
| def clear(self): |
| """Clears the state to empty state |
| """ |
| pass |
| |
| class HashMapState(State): |
| """HashMapState represents default implementation of the State interface |
| """ |
| def __init__(self): |
| self._dict = {} |
| |
| def put(self, k, v): |
| self._dict[k] = v |
| |
| def get(self, k): |
| if k in self._dict: |
| return self._dict[k] |
| else: |
| return None |
| |
| def enumerate(self): |
| return enumerate(self._dict) |
| |
| def clear(self): |
| self._dict.clear() |
| |
| def __str__(self): |
| return str(self._dict) |