How can I fire a Traits static event notification on an array change?

Question

I'm trying to setup a static notification if a value in an array gets changed, but so far I've had no success... I found an earlier question about notifications on changes to a List that used the _items_changed wording that looked like it might work, but alas, it didn't :(

Anyone have a suggestion how I should go about setting up a static notification handler whenever an element of an array gets changed?

BTW, I'm using Enthought Canopy V1.4.1.1975

Answer 1

Have you taken a look at how most event driven applications work? You can make a custom list class for yourself, then override the __setitem__ method to notify all listeners that the list has been modified.

class eventList(list):
    def __init__(self, ...):
        self.listeners = []
        ...
    def __setitem__(self, i, val):
        ret = super.__setitem__(self, i, val)
        for l in listeners:
            if isinstance(l, eventListListener):
                l.actionPerformed(self)
        return ret

Where objects that will be notified of this event have to inherit from the eventListListener class and have implemented a method called actionPerformed.

... means incomplete

Note this should be done in a multithreaded environment for it to yield any real benefits