Scott Weinstein on .Net

A few months ago, playing with CTP 2 of StreamInsight, I created a small VWAP demo on a sliding window. Now that a proper CTP of the RX is available, I wanted to see how much effort the same demo would be without the CEP infrastructure of StreamInsight. I’ll admit that this was a little bit harder to write then I expected – and there’s still at least one bug remaining (updated) , but the code for actually computing the VWAPS feels much cleaner in the RX version then it did in the StreamInsight version. The debugability (which is really about transparency) of RX is a welcome difference to most CEP systems.

Downloads of the Reactive Framework (RX) can now be found at MS DevLabs. Versions for 3.5 SP1, 4.0 Beta, and Silverlight 3 are available. Interestingly, the API size appears to be substantially larger than the preview which was leaked as part of the Silverlight 3 Toolkit. That DLL was all of 84KB, the current release is weighs in at 283KB.

In my last post I showed how to send StreamInsight output streams to a UI via the ReactiveFramework. Here’s we’ll do the reverse, by sending an RX stream into a CEP stream. Instead of a partial example, I’ll use an end to end example showing simulated stock ticks, computing the 5 min rolling VWAP, and showing the results on a UI.

One compelling feature of StreamInsight is it’s in-process hosting model. In addition to reducing the complexity of server side installs, it’s now possible to have a  CEP engine in the client UI.

This morning I was hoping to take a few minutes to modify one of the examples in the StreamInsight CTP and send an output stream to a UI, rather than the text files used in the examples. I thought this would be easy, as the readme states that there’s

Talk around the water cooler is that it might be possible to use the Reactive Framework for some lightweight CEP.

A few days ago, intentionally or not, a version of the Reactive Framework was released into the wild. Let’s see how we can use the RX for computations on a stream of data. As an example we’ll take a stream of ints and produce the averages in groups of five.

Via Jafar Husain - it appears that there’s a early release of the Live Labs Reactive Framework (& with Brian Beckman and Erik Meijer) in the latest Silverlight Toolkit