shinken/singleton.py

   1 #!/usr/bin/env python
   2 #Copyright (C) 2009-2010 :
   3 #    Gabes Jean, naparuba@gmail.com
   4 #    Gerhard Lausser, Gerhard.Lausser@consol.de
   5 #    Gregory Starck, g.starck@gmail.com
   6 #    Hartmut Goebel, h.goebel@goebel-consult.de
   7 #
   8 #This file is part of Shinken.
   9 #
  10 #Shinken is free software: you can redistribute it and/or modify
  11 #it under the terms of the GNU Affero General Public License as published by
  12 #the Free Software Foundation, either version 3 of the License, or
  13 #(at your option) any later version.
  14 #
  15 #Shinken is distributed in the hope that it will be useful,
  16 #but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 #MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 #GNU Affero General Public License for more details.
  19 #
  20 #You should have received a copy of the GNU Affero General Public License
  21 #along with Shinken.  If not, see <http://www.gnu.org/licenses/>.
  22
  23
  24 #The classic Singleton class. So all instance of this class will be the same
  25 #instance in fact.
  26
  27 class Singleton(type):
  28     def __init__(cls, name, bases, dict):
  29         print "Init de singleton"
  30         super(Singleton, cls).__init__(name, bases, dict)
  31         cls.instance = None
  32
  33     def __call__(cls, *args, **kw):
  34         if cls.instance is None:
  35             cls.instance = super(Singleton, cls).__call__(*args, **kw)
  36             return cls.instance