Event Centric: finding key business value by leveraging domain events and reactive extensions
Reactive Extensions (Rx) is one of the coolest additions to .NET ever. However, they have been largely ignored by the mainstream, in a significant part because (IMO) it’s seen as a UI technique, with samples that show how to handle mouse moves, drag & drop and so on. Its focus on asynchronous programming too makes it look like a niche technique that might even be worth skipping over as we wait for C# 5.0 async keyword (see Mike’s blog entry on a possible clarification of where it might fit in the async world).
There is, however, one mainstream application of reactive extensions that seems to have been missed by most: business intelligence. Here’s one concrete example: pretty soon, hospitals will face penalties for patient readmission, so you need a way to get an alert whenever patients are readmitted before a certain elapsed time (say 5 days or whatever). Another one: you want to preventively block a user’s account after 5 consecutive login failures within a minute (looks like an automated attack), or shoot an sms to the support team when failure rates for your app go above 5 crashes a day, or keep a report of top trending products in a store, and so on. ...