NotificationFramework

The NotificationFramework is a python implementation of the "Observer" Design Pattern, allowing one-to-many dependency between objects even when they have no idea of who and where the other objects live.

It is distributed under a 3-clause BSD-style license; see the LICENSE file for details.

>>> from NotificationFramework import NotificationCenter as NC

>>> SUBJECT_CHANGED='Subject changed' # string identifying the notification

>>> class Subject:
...   value=0
...   def __init__(self, name):
...     self.name=name
...   def change_and_notify(self, value):
...     self.value=value
...     NC.postNotification(SUBJECT_CHANGED, self, info=value)
...   def __str__(self):
...     return self.name

>>> class Observer:
...   def __init__(self, name):
...     self.name=name
...
...   def handle_notification(self, notification):
...     print self.name, 'received notification:', str(notification)
...     print '                    with info:', notification.userInfo()
...
>>> s1=Subject('s1')
>>> s2=Subject('s2')
>>> observ1, observ2 = Observer('observ1'), Observer('observ2')
>>> generic = Observer('generic')

>>> # observ1 listens to SUBJECT_CHANGED posted by s1
... NC.addObserver(observ1, Observer.handle_notification, SUBJECT_CHANGED, s1)
>>> # observ2 listens to SUBJECT_CHANGED posted by s2
... NC.addObserver(observ2, Observer.handle_notification, SUBJECT_CHANGED, s2)
>>> # generic listens to all SUBJECT_CHANGED notifications
... NC.addObserver(generic, Observer.handle_notification, SUBJECT_CHANGED)

>>> s1.change_and_notify(value='hop')
observ1 received notification: <Notification name:'Subject changed' object:'s1'>
                    with info: hop
generic received notification: <Notification name:'Subject changed' object:'s1'>
                    with info: hop

>>> s2.change_and_notify(value=3)
observ2 received notification: <Notification name:'Subject changed' object:'s2'>
                    with info: 3
generic received notification: <Notification name:'Subject changed' object:'s2'>
                    with info: 3

Package NotificationFramework