What is it ?

Pyjon.Events is an easy-to-use event dispatcher metaclass for your objects : Just add it to any of your class, and you can add event listeners and dispatch events.

You can define arguments passed to your listener when you add it. You can also define argument passed to the listener when emiting an event.


For our example, we will define a person class. Just import the module, and add it to your class (Python2 example):

from import EventDispatcher

class Person(object):
    __metaclass__ = EventDispatcher

    def __init__(self, name):
        # just a sample initialization, you can do whatever you want, of course. = name

    def run(self, meters=1):
        print "I'm running for %d meters !" % meters
        self.emit_event('ran', meters)
        self.emit_event('moved', meters=meters)

    def walk(self, meters=1):
        print "I'm walking for %d meters !" % meters
        self.emit_event('walked', meters)
        self.emit_event('moved', meters=meters)

    def sleep(self):
        print "sleeping..."
        print "Wow... had a good night !"

For Python3, just replace this:

class Person(object):
    __metaclass__ = EventDispatcher

with this:

class Person(metaclass = EventDispatcher):

Now, let's instanciate our class and subscribe to events:

>>> henry = Person('henry')

>>> def handle_movement(meters=None):
...     print "he moved for %d meters" % meters

>>> def handle_person_movement(who, meters=None):
...     print "%s moved for %d meters" % (who, meters)

>>> henry.add_listener('moved', handle_movement)

>>> henry.add_listener('moved', handle_person_movement, "henry")

>>> henry.walk(5)
I'm walking for 5 meters !
he moved for 5 meters
henry moved for 5 meters

>>> def handle_advanced_movement(meters, who, movement_type):
...     print "%s %s for %d meters" % (who, movement_type, meters)

>>> henry.add_listener('walked', handle_advanced_movement, "henry", "walked")

>>> henry.add_listener('ran', handle_advanced_movement, "henry", "ran")

>>> henry.walk(5)
I'm walking for 5 meters !
henry walked for 5 meters
he moved for 5 meters
henry moved for 5 meters

I'm running for 5 meters !
henry ran for 5 meters
he moved for 5 meters
henry moved for 5 meters

That's simple isn't it ?