Event Handling

The BaseDriverEvent class is the main object used to relay messages internally between components of the BDSSApplication. It can also be serialized in order to be passed between external programs (i.e. the force_wfmanager) as a JSON.

Any events that are created during runtime are propagated through the Workflow object hierarchy, up to the BaseOperation class that is being performed by the BDSSApplication, before finally being broadcast to all BaseNotificationListener classes present. Consequently, the BaseModel class contains an event attribute, as well as a notify method that is used to set it. Listeners can then detect changes in any BaseModel.event subclass, and process the new event accordingly.

Any actions that are required to be performed upon notification of a specific BaseDriverEvent subclass are handled by the BaseNotificationListener.deliver method.

In this way, we can also use BaseDriverEvents to control the progress of an MCO run, since after every broadcast, the OptimizeOperation checks its run time status to see whether the event has triggered a MCO ‘pause’ or ‘stop’ signal.

Additionally, the BaseDataSource._run method shadows the BaseDataSource.run method in order to signal the beginning and end of a data source execution. By doing so, we are able to pause and stop and MCO run between each run method invocation, which represents a black box operation.