Esper

Events are everywhere, in massive amounts , containing information you never imagined and in real time. But can you handle them all?
You are not alone, Esper allows you to process streams of events. A continous flow of events you can query and detect patterns.
The patterns are the real power of Esper, you can make use of sequencial and time patterns.

For example: If after the ocurrence of a Stock with more than 5 dollars, arrives a new Stock with less than 4 dollars, notify me!

Esper only notifies you, and leaves the rest to you.

Esper is an incredibly powerful application ready to tackle the most mind bending problems right out of the box. My team tackled some extremely difficult problems using Esper where we had repeatedly failed with other rules/CEP engines.

In addition to being a fantastic code base, the open source project is run very well and the code is rock solid.