Source Code for Module sparked.events

 1  # Copyright (c) 2010 Arjan Scherpenisse 
 2  # See LICENSE for details. 
 3  # -*- test-case-name: sparked.test.test_events -*- 
 4   
 5  """ 
 6  Classes which define a generic event system. 
 7  """ 
 8   
 9  from twisted.words.xish import utility 
10   
11 -class EventDispatcher(utility.EventDispatcher): 
12      """ 
13      The sparked event dispatcher is simpler than the twisted version: 
14      it does not use XPath arguments and its event prefix is always 
15      empty. 
16   
17      This class exists to simplify the implementation of event 
18      dispatchers in sparked without the syntactic sugar of xish' 
19      EventDispatcher class. 
20      """ 
21 -    def __init__(self, eventprefix=""): 
22          utility.EventDispatcher.__init__(self, eventprefix) 
23   
24   
25 -    def dispatch(self, event, *arg, **kwarg): 
26          """ 
27          Dispatch the named event to all the callbacks. 
28          """ 
29          foundTarget = False 
30   
31          self._dispatchDepth += 1 
32   
33          observers = self._eventObservers 
34   
35          priorities = observers.keys() 
36          priorities.sort() 
37          priorities.reverse() 
38   
39          emptyLists = [] 
40          for priority in priorities: 
41              for query, callbacklist in observers[priority].iteritems(): 
42                  if query == event: 
43                      callbacklist.callback(*arg, **kwarg) 
44                      foundTarget = True 
45                      if callbacklist.isEmpty(): 
46                          emptyLists.append((priority, query)) 
47   
48          for priority, query in emptyLists: 
49              del observers[priority][query] 
50   
51          self._dispatchDepth -= 1 
52   
53          # If this is a dispatch within a dispatch, don't 
54          # do anything with the updateQueue -- it needs to 
55          # wait until we've back all the way out of the stack 
56          if self._dispatchDepth == 0: 
57              # Deal with pending update operations 
58              for f in self._updateQueue: 
59                  f() 
60              self._updateQueue = [] 
61   
62          return foundTarget 
63