We have a system at my work that is basically a message-driven state machine. It takes in a variety of types of messages, looks up some context/state based on the message, then decides what to do, based on the message and the current state. Normally the result is a message being sent out of the system.
Are there any good open-source frameworks for implementing a state machine in .NET? I've looked into the latest release of Windows Workflow, and it seems like it would be a good option; however, I have some concerns about the default persistence mechanisms (we need to report off the state transition data), testability, and the fact that the WF team is re-architecting the framework as we speak (supposedly).
Instead of WF, I'm thinking of trying to implement a plain-old GoF "State" pattern, and using Spring.NET to wire everything together. Is there anything out there that already does this, or something similar?
Depending on your exact requirements you might find the State Machine Compiler is sufficient for implementing the GoF "State" pattern. It can generate C# as well as dot which can be transformed into several image formats using Graphviz. I've used it on a previous project and found it sufficient for generating a 'simple' state machine. I hope this helps.