bin/observator.py

   1 # -*- encoding: utf-8 -*-
   2 ##############################################################################
   3 #
   4 # Copyright (c) 2004-2008 Tiny SPRL (http://tiny.be) All Rights Reserved.
   5 #
   6 # $Id$
   7 #
   8 # WARNING: This program as such is intended to be used by professional
   9 # programmers who take the whole responsability of assessing all potential
  10 # consequences resulting from its eventual inadequacies and bugs
  11 # End users who are looking for a ready-to-use solution with commercial
  12 # garantees and support are strongly adviced to contract a Free Software
  13 # Service Company
  14 #
  15 # This program is Free Software; you can redistribute it and/or
  16 # modify it under the terms of the GNU General Public License
  17 # as published by the Free Software Foundation; either version 2
  18 # of the License, or (at your option) any later version.
  19 #
  20 # This program is distributed in the hope that it will be useful,
  21 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  22 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23 # GNU General Public License for more details.
  24 #
  25 # You should have received a copy of the GNU General Public License
  26 # along with this program; if not, write to the Free Software
  27 # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  28 ###############################################################################
  29 try:
  30     set()
  31 except NameError:
  32     from sets import Set as set
  33
  34
  35 class ObservatorRegistry(object):
  36     def __new__(cls):
  37         if not hasattr(cls, '_inst'):
  38             cls._inst = object.__new__(cls)
  39         return cls._inst
  40
  41     def __init__(self):
  42         self._observables = {}
  43         self._receivers = {}
  44
  45     def add_observable(self, oid, obj):
  46         self._observables[oid] = obj
  47
  48     def add_receiver(self, signal, callable):
  49         if signal not in self._receivers:
  50             self._receivers[signal] = []
  51         self._receivers[signal].append(callable)
  52
  53     def remove_receiver(self, signal, callable):
  54         self._receivers[signal].remove(callable)
  55
  56     def warn(self, *args):
  57         for receiver in self._receivers.get(args[0], []):
  58             receiver(*args[1:])
  59
  60 oregistry = ObservatorRegistry()
  61
  62
  63 class Observable(object):
  64     def __init__(self):
  65         oregistry.add_observable(id(self), self)
  66
  67     def warn(self, *args):
  68         oregistry.warn(args[0], self, *args[1:])
  69
  70 # vim:expandtab:smartindent:tabstop=4:softtabstop=4:shiftwidth=4:
  71