I am working on a project where there is a continuous stream of events. There are many concurrent users who can create/update/delete rules and get alerts when the stream matches those rules.

I used Esper for this where I am generating EPL statements from rules dynamically and registering them. This is very error prone as the rules at times are complex and cannot be dynamically converted to EPL. This is also not scalable.

What would be the correct approach to handle this? Is there a standard way/ library for this kind of use cases.