observer.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# $Id$
#
#    Copyright (c) 2006 Juan Manuel Gimeno Illa
#    Copyright (C) 2007 Alberto Montañola Lacort
#    See the file AUTHORS for more info
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
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#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
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#    You should have received a copy of the GNU General Public License
#    along with this program; if not, write to the Free Software
#    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
#    USA.
#
#    Please see the file COPYING for the full license.
#
# -----------------------------------------------------------------------------
# ORIGINAL LICENSE FOR tkSudoku.py - Revision 11 and Revision 12
#
# Only the pieces of code submitted under Revisions 11 and 12
# are under the next License. The revision numbers may change when the
# code is moved from the MPL private repository to the projects public
# one. (Current Address of this file $HeadURL$)
#
# Copyright (c) 2006 Juan Manuel Gimeno Illa
# 
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"""Observer --> Subject Model"""

# Util classes 

class Observer(object):
    def __init__(self):
        self._subject = None
	
    def setSubject(self,subject):
        self._subject = subject

    def getSubject(self):
        return self._subject
    
class Subject(object):
    def __init__(self):
        self._observers = []

    def attach(self, observer):
        observer.setSubject(self)
        self._observers.append(observer)

    def notify(self):
        for observer in self._observers:
            observer.update()