root/trunk/RBFoundation/RBFoundation/Aspects/Pointcut.py

#!/usr/bin/env python
##~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
##~ License 
##~ 
##- The RuneBlade Foundation library is intended to ease some 
##- aspects of writing intricate Jabber, XML, and User Interface (wxPython, etc.) 
##- applications, while providing the flexibility to modularly change the 
##- architecture. Enjoy.
##~ 
##~ Copyright (C) 2002  TechGame Networks, LLC.
##~ 
##~ This library is free software; you can redistribute it and/or
##~ modify it under the terms of the BSD style License as found in the 
##~ LICENSE file included with this distribution.
##~ 
##~ TechGame Networks, LLC can be reached at:
##~ 3578 E. Hartsel Drive #211
##~ Colorado Springs, Colorado, USA, 80920
##~
##~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#~ Imports 
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

from RBFoundation import ContextApply

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#~ Definitions 
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

class Pointcut(object):
    #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    #~ Constants / Variables / Etc. 
    #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    class Pass(Exception): pass

    #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    #~ Special 
    #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    def __init__(self, name, *args, **kw):
        self.__name__ = name
        self.__doc__ = kw.get('doc', '')

        if args:
            self.PointcutAdvice = PointcutAdviceCollection()
            map(self.PointcutAdvice.AddAdvice, args)

    def __get__(self, obj, klass):
        if obj:
            method = ContextApply.ContextApply_s_p(obj._AspectedOperation, getattr)
            return self.PointcutAdvice('get', method, obj, self.__name__) 
        else: return self

    def __set__(self, obj, value):
        method = ContextApply.ContextApply_s_p(obj._AspectedOperation, setattr)
        return self.PointcutAdvice('set', method, obj, self.__name__, value) 

    def __delete__(self, obj):
        method = ContextApply.ContextApply_s_p(obj._AspectedOperation, delattr)
        return self.PointcutAdvice('delete', method, obj, self.__name__)

    #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    #~ Public Methods 
    #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    def PointcutAdvice(self, AdviceType, method, *args, **kw):
        return method(*args, **kw)

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

class PointcutAdviceCollection(object):
    #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    #~ Special 
    #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    def __init__(self):
        self.Advise = {}

    def __call__(self, AdviceType, method, obj, name, *args, **kw):
        try:
            # Advise the 'Before', AdviceType pointcuts
            for Advise in self.Advise.get(('before', AdviceType), []):
                AdviseResult = Advise.AdviseBefore(obj, name, *args, **kw)
                if AdviseResult is not None: args = (AdviseResult,) + args[1:]

            # Apply the method
            result = method(obj, name, *args, **kw)

            # Advise the 'After', AdviceType pointcuts
            for Advise in self.Advise.get(('after', AdviceType), []):
                result = Advise.AdviseAfter(obj, name, result, *args, **kw)

            return result
        except Pointcut.Pass, PassResult: 
            return PassResult

    #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    #~ Public Methods 
    #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    def AddAdvice(self, Advice):
        AdviseType = Advice.AdviseType
        for AdviseTime in Advice.AdviseTimes:
            self.AddAdviceEx(Advice, AdviseTime, AdviseType)

    def AddAdviceEx(self, Advice, AdviseTime=None, AdviseType=None):
        self.Advise.setdefault((AdviseTime, AdviseType), []).append(Advice)