3.7. Notification

Notification listeners are used to notify the state of the MCO to external listeners, including the data that is obtained by the MCO as it performs the evaluation. Communication to databases (for writing) and CSV/HDF5 writers are notification listeners.

Each notification listener is defined by an implementation of BaseNotificationListenerFactory, which contributes both BaseNotificationListenerModel and BaseNotificationListener subclasses. It therefore requires implementation of the following additional abstract methods alongside the standard get_identifier, get_name, and get_description methods

def get_model_class(self):
    Returns a BaseNotificationListenerModel subclass

def get_listener_class(self):
    Returns a BaseNotificationListener subclass

The BaseNotificationListener class must reimplement the following methods, that are invoked in specific lifetime events of the BDSS

def initialize(self):
    Called once, when the BDSS is initialized. For example, to setup the
    connection to a database, or open a file.

def finalize(self):
    Called once, when the BDSS is finalized. For example, to close the
    connection to a database, or close a file.

def deliver(self, event):
    Called every time the MCO generates an event. The event will be passed
    as an argument. Depending on the argument, the listener implements
    appropriate action. The available events are in the api module.