Python Callback

gistfile1.py

class CallbackBase:
  def __init__(self):
    self.__callbackMap = {}
    for k in (getattr(self, x) for x in dir(self)):
      if hasattr(k, "bind_to_event"):
        self.__callbackMap.setdefault(k.bind_to_event, []).append(k)
      elif hasattr(k, "bind_to_event_list"):
        for j in k.bind_to_event_list:
      self.__callbackMap.setdefault(j, []).append(k)
    ## staticmethod is only used to create a namespace
  @staticmethod
  def callback(event):
    def f(g, ev = event):
      g.bind_to_event = ev
      return g
    return f
  @staticmethod
  def callbacklist(eventlist):
    def f(g, evl = eventlist):
      g.bind_to_event_list = evl
      return g
    return f
  def dispatch(self, event):
    l = self.__callbackMap[event]
    f = lambda *args, **kargs: \
      map(lambda x: x(*args, **kargs), l)
    return f

## Sample
class MyClass(CallbackBase):
  EVENT1 = 1
  EVENT2 = 2
 
  @CallbackBase.callback(EVENT1)
  def handler1(self, param = None):
    print "handler1 with param: %s" % str(param)
    return None
 
  @CallbackBase.callbacklist([EVENT1, EVENT2])
  def handler2(self, param = None):
    print "handler2 with param: %s" % str(param)
    return None
 
  def run(self, event, param = None):
    self.dispatch(event)(param)
 
 
if __name__ == "__main__":
  a = MyClass()
  a.run(MyClass.EVENT1, 'mandarina')
  a.run(MyClass.EVENT2, 'naranja')