To Workflow or Not to Workflow?

Question

I am responsible for a team of developers who will are about to start development of a light weight insurance claims system. The system involves a lot of manual tasks and business workflows and we are looking at using Windows Workflow (.NET 4.0).

An example of the business domain is as follows: A policy holder calls the contact centre to lodge a claim. This “event” fires two sub tasks which are manually actioned in parallel and may take a lengthy time to complete;

1. Check customer for fraud – A manual process whereby an operator calls various credit companies to check and assess the potential of a fraudulent customer. From here the sub task can enter a number of sub-statuses (Check in progress, Failed Reference Check, Passed Reference Check, etc)
2. Send item to repairs centre – A manual process where the item for which the policy holder lodged the claim is sent the repairs centre to be fixed. From here the sub task can enter a number of sub-statuses (Awaiting Repair, In Progress, Repaired, Posted, etc). The claim can only proceed once the status of each sub task has reached a predefined status (based on the business rules).

On the surface it seems that Workflow is indeed the best technology choice; however I do have a few concerns in using WF 4.0.

1. Skill set – Looking at the average developer skill set I do not see many developers who understand or know Workflow.
2. Maintainability – There seems to be little support within the community for WF 4.0 projects and this coupled with the lack of skill set raise concerns around maintainability.
3. Barrier to entry – I have a feeling that Windows Workflow has a steep learning curve and it’s not always that easy to pick up.
4. New product – As Workflow has been completely rewritten for .NET 4.0 I see the product as a first generation product and may not have the necessary stability.
5. Reputation – Previous versions of Workflow were not well received, considered difficult to develop with and resulted in poor business uptake.

So my question is should we use Windows Workflow (WF) 4.0 for this situation or is there an alternative technology (e.g., Simple State Machine, etc) or even a better workflow engine to use?

Answer 1

I have done several WF4 projects so lets see if I can add any useful info to the other answers.

From the description of your business problem it sounds like WF4 is a good match, so no problems there.

Regarding your concerns you are right. Basically WF4 is a new product and is lacking some important features and has some rough edges. There is a learning curve, you do have to do some things differently. The main point is long running and serialization, which is something the average developer is not used to and requires some thought to get right as I hear far too often that people have problems serializing an entities framework data context.

Most of the time using workflow services hosted in IIS/WAS is the best route when doing these long running type of workflows. That makes solving the versioning problem not to hard either, just have the first message return the workflow version and make that a part of each subsequent message. Next put the WCF router in between that routes the message to the correct endpoint based on the version. The basic is never to change an existing workflow, always create a new one.

So what is my advise to you? Don't take a big gamble on a unknown, and for you unproven, piece of technology. Do a small, non critical, piece of the application using WF4. That way if it works you can expand on it but if it fails you can rip it out and replace it with more traditional .NET code. That way you get real experience with WF4 instead of having to base a decision on second hand information and you learn a new and powerful technology in the process. If possible take a course on WF4 as that will save you a lot of time in getting up to speed (shameless self plug here).

About the Simple State Machine. I have not used it but I was under the impression it was for short running, in memory, state machines. One of the main benefits of WF4 is the long running aspects.