This application will fire events on arbitrary conditions set by the users.

It will have to support reading the conditions from somewhere and updating those conditions (when a condition is added, deleted or modified by a user) while the application is running.

The events could take the form of:

• Notifications via the web interface;
• HTTP posts to a specified address;
• Sending emails;

The conditions will operate on object data. They could be something like for example: when a vessel with MMSI = 23093290 has a SOG of 20 then fire a notification; or, when a vessel enters a predetermined polygon issue an http post somewhere.

To have the notifications delivered to the user it's probably best to do it via websockets. Maybe the transmitter application could do that since it already has that infrastructure setup - in this case, the evaluator would communicate to the transmitter via the message broker what should be notified to the user.

It would be nice to maybe have some sort of templating engine to form the notification event text that the user would receive when a rule is triggered.