How to encapsulate .NET Stateless state machine

Question

I have a project where there is a mostly linear workflow. I\'m attempting to use the .NET Stateless library to act as workflow engine/state machine. The number of examples out

Answer 1

This is how I achieved it in my project.

Separated workflow logic to separate class. I had couple of workflows based on one of the flags present in the request object; below is one of the workflow classes:

public class NationalWorkflow : BaseWorkflow
{
    public NationalWorkflow(SwiftRequest request) : this(request, Objects.RBDb)
    { }

    public NationalWorkflow(SwiftRequest request, RBDbContext dbContext)
    {
        this.request = request;
        this.dbContext = dbContext;
        this.ConfigureWorkflow();
    }

    protected override void ConfigureWorkflow()
    {
        workflow = new StateMachine(
           () => request.SwiftRequestStatus, state => request.SwiftRequestStatus = state);

        workflow.OnTransitioned(Transitioned);

        workflow.Configure(SwiftRequestStatus.New)
            .OnEntry(NotifyRequestCreation)
            .Permit(SwiftRequestTriggers.ProcessRequest, SwiftRequestStatus.InProgress);

        workflow.Configure(SwiftRequestStatus.InProgress)
            .OnEntry(ValidateRequestEligibility)
            .Permit(SwiftRequestTriggers.AutoApprove, SwiftRequestStatus.Approved)
            .Permit(SwiftRequestTriggers.AdvancedServicesReview, SwiftRequestStatus.PendingAdvancedServices);

.....................
}

Which is triggered from the controller/any other layer:

private static void UpdateRequest(SwiftRequestDTO dtoRequest)
    {
            var workflow = WorkflowFactory.Get(request);
            workflow.UpdateRequest();
    }

As mentioned above, I had different workflow rules based on conditions in the request object and hence used a factory pattern WorkflowFactory.Get(request); you may create an instance of your workflow/inject it as desired

And inside the workflow class (BaseWorkflow class in my case), I have exposed the actions:

    public void UpdateRequest()
    {
        using (var trans = this.dbContext.Database.BeginTransaction())
        {
            this.actionComments = "Updating the request";
            this.TryFire(SwiftRequestTriggers.Update);

            SaveChanges();
            trans.Commit();
        }
    }

  protected void TryFire(SwiftRequestTriggers trigger)
    {
        if (!workflow.CanFire(trigger))
        {
            throw new Exception("Cannot fire " + trigger.ToString() + " from state- " + workflow.State);
        }
        workflow.Fire(trigger);
    }