Files
deb-python-taskflow/taskflow/logbook.py
2013-05-15 17:59:26 -07:00

119 lines
3.5 KiB
Python

# -*- coding: utf-8 -*-
# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright (C) 2012 Yahoo! 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.
import abc
import weakref
from datetime import datetime
class Page(object):
"""A logbook page has the bare minimum of these fields."""
def __init__(self, name, metadata=None):
self.date_created = datetime.utcnow()
self.name = name
self.metadata = metadata
def __str__(self):
return "Page (%s, %s): %s" % (self.name, self.date_created,
self.metadata)
class Chapter(object):
"""Base class for what a chapter of a logbook should provide."""
__metaclass__ = abc.ABCMeta
def __init__(self, book, name):
self.book = weakref.proxy(book)
self.name = name
@abc.abstractmethod
def __iter__(self):
"""Iterates over all pages in the given chapter.
The order will be in the same order that they were added."""
raise NotImplementedError()
@abc.abstractmethod
def __contains__(self, page_name):
"""Determines if any page with the given name exists in this
chapter."""
raise NotImplementedError()
@abc.abstractmethod
def fetch_pages(self, page_name):
"""Fetch any pages that match the given page name."""
raise NotImplementedError()
@abc.abstractmethod
def add_page(self, page):
"""Adds a page to the underlying chapter."""
raise NotImplementedError()
@abc.abstractmethod
def __len__(self):
"""Returns how many pages the underlying chapter has."""
raise NotImplementedError()
def __str__(self):
return "Chapter (%s): %s pages" % (self.name, len(self))
class LogBook(object):
"""Base class for what a logbook should provide"""
__metaclass__ = abc.ABCMeta
@abc.abstractmethod
def add_chapter(self, chapter_name):
"""Atomically adds a new chapter to the given logbook
or raises an exception if that chapter (or a chapter with
that name) already exists.
"""
raise NotImplementedError()
@abc.abstractmethod
def fetch_chapter(self, chapter_name):
"""Fetches the given chapter or raises an exception if that chapter
does not exist."""
raise NotImplementedError()
@abc.abstractmethod
def __contains__(self, chapter_name):
"""Determines if a chapter with the given name exists in this
logbook."""
raise NotImplementedError()
@abc.abstractmethod
def __iter__(self):
"""Iterates over all the chapters.
The order will be in the same order that they were added."""
raise NotImplementedError()
@abc.abstractmethod
def __len__(self):
"""Returns how many pages the underlying chapter has."""
raise NotImplementedError()
def close(self):
"""Allows the logbook to free any resources that it has."""
pass