def publish(self, event):
"""
Publishes an event to subscribers.
"""
if not IEvent.providedBy(event):
raise BusError('Invalid dispatching, event should provide IEvent')
# Dispatches event to subscribers
if self.subscribers.has_key(type(event)):
for subscriber in self.subscribers[type(event)]:
subscriber(event)
# Publishes event on connected buses
for follower in self.followers:
follower.publish(event)
def subscribe(self, klass, callback):
"""
Subscribe a callable to an event type (class).
An already subscribed callback is ignored.
@param klass The event type to subscribe to
@param callback The callable object to pass event when an event is
dispatched.
"""
if not IEvent.implementedBy(klass):
raise BusError('Invalid unsubscription, klass should implenent IEvent')
if not self.subscribers.has_key(klass):
self.subscribers[klass] = []
if not callback in self.subscribers[klass]:
self.subscribers[klass].append(callback)
def unsubscribe(self, klass, callback):
"""
Unsubscribe a callable from an event type (class).
An already subscribed callback is ignored.
@param klass The event type to subscribe to
@param callback The callable object to pass event when an event is
dispatched.
"""
if not IEvent.implementedBy(klass):
raise BusError('Invalid unsubscription, klass should implenent IEvent')
if self.subscribers.has_key(klass):
# Removes subscriber callback
if callback in self.subscribers[klass]:
self.subscribers[klass].remove(callback)
# Cleans subscriber disctionnary
if not len(self.subscribers[klass]):
del self.subscribers[klass]
