Question: Possible to share common transitions / specialize different classes?

[paul42]

Hey all, love the project but just wondering if there a way to have state machines inherit base transitions so I'm not copy/pasting default 'error' transition states for my specialized machines - I'm possibly coming to state machines in the wrong way, but right now I have it like this:

GetTicketByIdMachine
NewUpdateToTicketMachine
NewTicketMachine

I was hoping to have each machine just inherit from a base class that has an abstract methods for ValidateIncomingRequest and RequestValidatedCallback since I want to have the 'CompletedSuccessfullyandInternalErrorStates` handle reporting the same way - but each machine has a different amount of states / actions for various work.

also is there a way to use classes for states, like in #234 ? There was no code posted so I am curious what your base-class looks like.

Thanks in advance!

[paul42]

Alternatively does anyone have any patterns for how they do items sequentially?

[mclift]

Typically when I need to apply a general-use transition such as an error handling state, I'd use substates and configure the Permitted trigger on the parent state. I expect I'm missing some details, but could this be a useful approach for you? If not, can you elaborate a little?

    public enum MyTrigger
    {
        Next,
        Error
    }
    public enum MyState
    {
        ParentState,
        State1,
        State2,
        HandleError
    }
    class Program
    {
        static void Main(string[] args)
        {
            var stateMachine = new StateMachine<MyState, MyTrigger>(MyState.State1);
            stateMachine.Configure(MyState.State1).SubstateOf(MyState.ParentState);
            stateMachine.Configure(MyState.State2).SubstateOf(MyState.ParentState);
            stateMachine.Configure(MyState.ParentState).Permit(MyTrigger.Error, MyState.HandleError);
        }
    }

[paul42]

I think I get it a bit more - so I'd make all my base states and then for my more specialized machines, I'd just have additional states and configurations, and in the methods in the more specialized machines, if I fire a permitted trigger it'll handle the transition based on the already configured machine? Do you have any other code laying around where you use this? I think I'm starting to get it, and really appreciate your help!

[mclift]

Good to hear I wasn’t too far off the track! I’m not at a machine with Visual Studio right now, but there are a handful of samples using substates in the unit tests, e.g. here: https://github.com/dotnet-state-machine/stateless/blob/07b92c56dbf2621abec9b90c55c42691fd8cd754/test/Stateless.Tests/StateMachineFixture.cs

[HenningNT]

@paul42 I think you are on the right track.
I did something similar on a project I worked on a few years ago. Since you can call .Configure() repeatedly you can add more trigger handlers in your specialized classes.

[HenningNT]

In case someone finds this question looking for starters on using objects for states and/or triggers, I've put together a small example here:
https://github.com/HenningNT/ObjectsAsStates/blob/master/ObjectsAsStates/ObjectsAsStates/Program.cs