Example: Car simualtion
First, we need to define the possible car states that we are interested to simulate. This can differ from case to case.
public enum CarState { Off, On, Start, Drive, Stop }
Second, we need to define events that will trigger certain state transitions. For this case, we have chosen the following ones.
public enum CarStateEvent { TurnOn, TurnOff, Acceleerate, Break }
The CarSimulator class is the acutal simulator that can be used to wrap up the state machine and privide a way to control the class states in a simple way.
public class CarSimulator
{
private StateMachine<CarState, CarStateEvent> _stateMachine;
public CarSimulator()
{
_stateMachine = new StateMachine<CarState, CarStateEvent>(CarState.Off);
LoadTransitions();
}
private void LoadTransitions()
{
_stateMachine.AddTransition(CarState.Off, CarStateEvent.TurnOn, () => _stateMachine.CurrentState == CarState.Off, CarState.On, () => { });
_stateMachine.AddTransition(CarState.Off, CarStateEvent.Break, () => _stateMachine.CurrentState == CarState.Off, CarState.Off, () => { });
_stateMachine.AddTransition(CarState.On, CarStateEvent.Acceleerate, () => _stateMachine.CurrentState == CarState.On, CarState.Drive, () => { });
_stateMachine.AddTransition(CarState.Drive, CarStateEvent.Break, () => _stateMachine.CurrentState == CarState.Drive, CarState.Stop, () => { });
_stateMachine.AddTransition(CarState.On, CarStateEvent.TurnOff, () => _stateMachine.CurrentState == CarState.On, CarState.Off, () => { });
_stateMachine.AddTransition(CarState.Stop, CarStateEvent.TurnOff, () => true, CarState.Off, () => { });
}
public void TurnOn()
{
_stateMachine.HandleEvent(CarStateEvent.TurnOn);
}
public void TurnOff()
{
_stateMachine.HandleEvent(CarStateEvent.TurnOff);
}
public void Accelerate()
{
_stateMachine.HandleEvent(CarStateEvent.Acceleerate);
}
public void Break()
{
_stateMachine.HandleEvent(CarStateEvent.Break);
}
public void Stop()
{
_stateMachine.HandleEvent(CarStateEvent.Break);
}
}