# -*- coding: utf-8 -*-
'''
:Author: Juti Noppornpitak
:Version: 1.5
:Usage: Internal
The module contains the classes used for interceptable actions/methods of any
instance of :class:`imagination.entity.Entity`.
.. note::
Copyright (c) 2012 Juti Noppornpitak
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
of the Software, and to permit persons to whom the Software is furnished to do
so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
'''
from imagination.decorator.validator import restrict_type, SpecialType
from imagination.meta.interception import Interception
from imagination.meta.package import Parameter
[docs]class EventType(object):
'''
Type of intercepting events
'''
pre_action = 'before'
''' Event before the execution that doesn't care about the input given to the action. '''
pre_condition = 'pre'
''' Event before the execution that only concerns about the input given to the action. '''
post_condition = 'post'
''' Event after the execution that only concerns about the returned value from the action. '''
post_action = 'after'
''' Event after the execution that doesn't care about the returned value from the action. '''
[docs]class Action(object):
'''
Method wrapper for intercepting actions
'''
@restrict_type(SpecialType.function)
def __init__(self, f):
self.__doc__ = f.__doc__
self.__name__ = f.__name__
self._reference = f
self.__pre_actions = []
self.__post_actions = []
def __call__(self, *args, **kwargs):
parameters = Parameter(args, kwargs)
self.__run_pre_events(parameters)
feedback = self.reference(*parameters.largs, **parameters.kwargs)
feedback = self.__run_post_events(feedback)
return feedback
@property
def name(self):
''' Name of the action '''
return self.__name__
@property
def reference(self):
''' Reference of the action '''
return self._reference
@restrict_type(Interception)
def register(self, interception):
event = str(interception.event)
if event in [EventType.pre_action, EventType.pre_condition]:
self.__pre_actions.append(interception)
return
if event in [EventType.post_action, EventType.post_condition]:
self.__post_actions.append(interception)
return
raise ValueError('The event "%s" is not recognized.' % event)
@restrict_type(Interception)
def __retrieve_callback(self, interception):
callback = interception.handler.interface
# cache callback?
if not callable(callback):
raise NonCallableError('%s.%s is not callable' % (
interception.handler.id,
interception.handler.method_name
))
return callback
@restrict_type(Parameter)
def __run_pre_events(self, parameters):
for interception in self.__pre_actions:
callback = self.__retrieve_callback(interception)
if interception.event == EventType.pre_action:
interception.handler.engage()
continue
if interception.event == EventType.pre_condition:
callback(*parameters.largs, **parameters.kwargs)
continue
raise ValueError('The event "%s" is not recognized.' % interception.event)
def __run_post_events(self, feedback):
for interception in self.__post_actions:
callback = self.__retrieve_callback(interception)
if interception.event == EventType.post_action:
interception.handler.engage()
continue
if interception.event == EventType.post_condition:
feedback = callback(feedback)
continue
raise ValueError('The event "%s" is not recognized.' % interception.event)
return feedback