# Copyright (c) 2004 Divmod.
# See LICENSE for details.
DEBUG = False
class EventNotification:
def __init__(self):
self._subscribers = {}
self._currentId = 0
def subscribe(self, identifier, subscriber):
"""Subscribe to events sent to the given identifier.
Returns a token which should be passed to unsubscribe when done.
"""
if DEBUG:
print "SUBSCRIBE", self, identifier, subscriber
self._subscribers.setdefault(identifier, []).append(subscriber)
return identifier, subscriber
def unsubscribe(self, token):
"""Unsubscribe the given token from events.
"""
if DEBUG:
print "UNSUBSCRIBE", token
identifier, reference = token
self._subscribers[identifier].remove(reference)
def publish(self, identifier, *args):
"""Notify the listeners on a given identifier that an event has occurred.
"""
if DEBUG:
print "PUBLISH", self, identifier,
subscribers = self._subscribers.get(identifier, [])
for sub in subscribers:
sub(*args)
if DEBUG:
print "NOTIFY SUBSCRIBER", sub
if DEBUG:
print "done"
def nextId(self):
self._currentId += 1
return str(self._currentId)
def __getstate__(self):
d = self.__dict__.copy()
d['_subscribers'] = {}
d['_currentId'] = 0
return d
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