pysize/core/observable.py

   1 # This program is free software; you can redistribute it and/or modify
   2 # it under the terms of the GNU General Public License as published by
   3 # the Free Software Foundation; either version 2 of the License, or
   4 # (at your option) any later version.
   5 #
   6 # This program is distributed in the hope that it will be useful,
   7 # but WITHOUT ANY WARRANTY; without even the implied warranty of
   8 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9 # GNU Library General Public License for more details.
  10 #
  11 # You should have received a copy of the GNU General Public License
  12 # along with this program; if not, write to the Free Software
  13 # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  14 #
  15 # See the COPYING file for license information.
  16 #
  17 # Copyright (c) 2006 Guillaume Chazarain <guichaz@yahoo.fr>
  18
  19 class observable(object):
  20     """The Observer/Observable pattern"""
  21
  22     def __init__(self):
  23         self.callbacks = []
  24
  25     def add_observer(self, callback):
  26         self.callbacks.append(callback)
  27
  28     def del_observer(self, callback):
  29         self.callbacks.remove(callback)
  30
  31     def fire_observers(self, *args, **kwargs):
  32         # Copy in case the list is modified by an observer
  33         for cb in self.callbacks[:]:
  34             cb(*args, **kwargs)