root/trunk/RBSkinning/RBSkinning/wxTools/wxSubObsEvtHandler.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
##~
##~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

"""A subject/observer implementation of a wxEvtHandler"""

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

from wxPython import wx

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

class wxEventSubject(object):
    __slots__ = ['observers']

    def __init__(self):
        self.observers = []

    def Connect(self, function, *args):
        self.observers.insert(0, (function, args))

    def Disconnect(self, function, *args):
        self.observers = [x for x in self.observers if x[0] != function]

    def Notify(self, evt, *args):
        result = NotImplemented
        for observer, obsargs in self.observers:
            if evt.GetSkipped():
                # Restore it to not skipped
                evt.Skip(False)
            result = observer(evt, *(args+obsargs))

        if result is NotImplemented:
            evt.Skip()

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

class wxSubObsEvtHandler(wx.wxEvtHandler):
    __slots__ = ['_subject_map']

    def ReplaceEvtHandlerOf(self, eventhandler):
        eventhandler.Connect = self.Connect
        eventhandler.Disconnect = self.Disconnect
        try:
            # Push the event handler
            eventhandler.PushEventHandler(self)
        except AttributeError:
            # Replace the event handler
            next = eventhandler.GetNextHandler()
            if next is not None:
                next.SetPreviousHandler(self)
            self.SetNextHandler(next)

            eventhandler.SetNextHandler(self)
            self.SetPreviousHandler(eventhandler)

    def Connect(self, id, lastid, eventType, function, *args, **kw):
        if lastid < 0: wxidrange = (id,)
        else: wxidrange = range(id, lastid)

        # Iterate through the id range manually
        for wxid in wxidrange:
            key = (wxid, -1, eventType)
            try: subject = self.SubjectMap[key]
            except KeyError:
                subject = wxEventSubject()
                self.SubjectMap[key] = subject
                # Connect the subject to the event
                subjectargs = key + (subject.Notify,)
                wx.wxEvtHandler.Connect(self, *subjectargs)

            #connect the function to the subject
            subject.Connect(function, *args, **kw)

    def Disconnect(self, id, lastid, eventType, function, *args):
        if lastid < 0: wxidrange = (id,)
        else: wxidrange = range(id, lastid)

        # Iterate through the id range manually
        for wxid in wxidrange:
            key = (wxid, -1, eventType)
            try: subject = self.SubjectMap[key]
            except KeyError: pass
            else: subject.Disconnect(function, *args)

    def _GetSubjectMap(self):
        try: 
            return self._subject_map
        except AttributeError:
            self._subject_map = {}
            return self._subject_map
    SubjectMap = property(_GetSubjectMap)