Re: Private class?

[Kent Johnson]

codecraig wrote:
class EventListener:
    def eventOccurred(self, eventType): pass
The EventListener class is not needed in Python; you can include it for its documentation value if 
you like but Python does not require interfaces the way Java does.

class EventBus:
    EVENT_GROW_LEAVES = 0
    __listeners = {}
    def register(listener, eventType):
        if __listeners.has_key(eventType):
            curListeners = __listeners.get(eventType)
            curListeners.append(listener)
        else:
            __listeners[eventType] = [listener]
    def fire(eventType):
        if __listeners.has_key(eventType):
            x = __listeners.get(eventType)
            for l in x:
                l.eventOccurred(eventType)
...so that is what I am thinking.  However, i guess my issue is how to
make EventBus a singleton or prevent it from being instaniated and
making it's methods statically accessible.
One way to do this is to make an EventBus module and make __listeners, register() and fire() be 
module attributes. Your client code would look like
import EventBus
...
EventBus.register(...)
EventBus.fire(...)

Kent
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