game/util/changelistener.py

   1 # ###################################################
   2 # Copyright (C) 2008 The OpenAnno Team
   3 # team@openanno.org
   4 # This file is part of OpenAnno.
   5 #
   6 # OpenAnno is free software; you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation; either version 2 of the License, or
   9 # (at your option) any later version.
  10 #
  11 # This program is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with this program; if not, write to the
  18 # Free Software Foundation, Inc.,
  19 # 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  20 # ###################################################
  21
  22 #because of unclean inheritance, bad usage of parameters and bad use of super in most world object, i cant trust that the init constructor is called.
  23
  24 from weakmethod import WeakMethod
  25
  26 class Changelistener(object):
  27         def __init__(self, *args, **kwargs):
  28                 super(Changelistener, self).__init__(**kwargs)
  29                 self.__listeners = []
  30
  31         def addChangeListener(self, listener):
  32                 if not hasattr(self, '_Changelistener__listeners'):
  33                         self.__listeners = []
  34                 self.__listeners.append(WeakMethod(listener))
  35
  36         def removeChangeListener(self, listener):
  37                 if not hasattr(self, '_Changelistener__listeners'):
  38                         self.__listeners = []
  39                 self.__listeners.remove(WeakMethod(listener))
  40
  41         def hasChangeListener(self, listener):
  42                 if WeakMethod(listener) in self.__listeners:
  43                         return True
  44                 else:
  45                         return False
  46
  47         def _changed(self):
  48                 if not hasattr(self, '_Changelistener__listeners'):
  49                         self.__listeners = []
  50                 for listener in self.__listeners:
  51                         listener()