//purpose: Show an interface with a livelock

interface BlindLoop
{
    in void start();
    behaviour
    {
        enum States { InitialState, Started, InBusiness };
        States state = States.InitialState;
        [state.InitialState]
        {
            // first step
            on start: state = States.Started;
        }
        [state.Started]
        {
            // change of state caused by an internal (i.e. externally not visible) action.
            // the components which use this interface are not informed about this state change.
            on inevitable: state = States.InBusiness;
            on start:      illegal;
        }
        [state.InBusiness]
        {
            // change of state caused by an internal (i.e. externally not visible) action.
            // the components which use this interface are not informed about this state change.
            // in fact this is a return to a previous state (see State Diagram).
            on inevitable: state = States.Started;
            on start:      illegal;
        }
    }
}
// this is a simple component which implements the BlindLoop interface
component InterfaceLivelock
{
    provides BlindLoop LoopingInterface;
    behaviour
    {
        on LoopingInterface.start(): {  }
    }
}