How to process a series of values that occur over time

My first encounter with stream processing was StreamBase, which is now owned by Tibco. StreamBase is a Java application which you can program via a "coding by pictures" Eclipse plugin. Coding-by-pictures is never a good idea, it has been tried many times and text based languages always win. That said the StreamBase product did work well, especially when we wrote the core of the system as a Java StreamBase operator, basically using StreamBase for its input and output adapters.

Interestingly StreamBase was by Turing award winner Michael Stonebraker, who also created Ingres, Postgres and VoltDB.

Coming out of Microsoft was a great open source project called Reactive Extensions which enabled you to program the .NET platform to handle complex event. It has a functional design, basically LINQ but for events that occur over time.

Netflix has open-sourced a Java version of RX, which they use extensively with the Netflix platform.