#!/usr/bin/python2.5
#
# Copyright 2009 the Melange authors.
#
# 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.
"""Functions that are useful when dealing with timelines.
"""
__authors__ = [
'"Lennard de Rijk" <ljvderijk@gmail.com>',
]
import datetime
def isBeforePeriod(entity, period):
"""Returns true iff the current DateTime is before the given period_start.
Args:
entity: Instance of a timeline model.
period: The name of a period (without start or end).
"""
return isBeforeEvent(entity, '%s_start' % period)
def isBeforeEvent(entity, event):
"""Returns true iff the current DateTime is before the given event.
Args:
entity: Instance of a timeline model.
event: The name of property in the timeline model.
"""
event_time = getDateTimeByName(entity, event)
if event_time:
return datetime.datetime.utcnow() < event_time
else:
return False
def isActivePeriod(entity, period):
"""Returns true iff the current DateTime is between period_start
and period_end.
Args:
entity: Instance of a timeline model.
period: The name of a period (without start or end).
"""
period_start = '%s_start' % period
period_end = '%s_end' % period
period_started = isAfterEvent(entity, period_start)
period_not_ended = isBeforeEvent(entity, period_end)
return period_started and period_not_ended
def isAfterPeriod(entity, period):
"""Returns true iff the current DateTime is after the given period_end.
Args:
entity: Instance of a timeline model.
period: The name of a period (without start or end).
"""
return isAfterEvent(entity, '%s_end' % period)
def isAfterEvent(entity, event):
"""Returns true iff the current DateTime is after the given event.
Args:
entity: Instance of a timeline model.
event: The name of property in the timeline model.
"""
event_time = getDateTimeByName(entity, event)
if event_time:
return event_time < datetime.datetime.utcnow()
else:
return False
def getDateTimeByName(entity, name):
"""Returns the DateTime property with the given name.
Args:
entity: Instance of a timeline model.
name: The name of a specific property in the given timeline model.
Returns:
The requested DateTime property, or None if there is no such property set.
"""
if hasattr(entity, name):
return getattr(entity, name)
else:
return None