///// <summary>
///// Provides a mechanism to stop the finite state machine.
///// It will cause the method <see cref="RunStateMachine()"/> to complete so that the thread in which it runs can stop too.
/////
///// Note that for finite state machine designs that raise events in the event handlers,
///// you must have a Stopping event handler as part of your state machine design.
///// The code in the Stopping event must not raise any events and Stop() should be called from within that handler.
///// </summary>
//public void Stop()
//{
// string methodName = System.Reflection.MethodBase.GetCurrentMethod().Name;
// if (log.IsDebugEnabled)
// log.Debug($"{methodName}: enter");
// stopRequested = true;
// lock (locker)
// {
// Monitor.Pulse(locker); // Wakes up the state machine thread if it is sleeping.
// }
// if (log.IsDebugEnabled)
// log.Debug($"{methodName}: exit");
//}
/// <summary>
/// Sets the current state of the finite state machine.
/// </summary>
/// <param name="toState">The finite state that we want to become the current state.</param>
/// <exception cref="ArgumentException">Thrown if the parameter toState is a finite state that has not been added by <see cref="AddState(FiniteState)"/></exception>
public void SetCurrentState(FiniteState toState)
{
string methodName = System.Reflection.MethodBase.GetCurrentMethod().Name;
if (log.IsDebugEnabled)
{
log.Debug($"{methodName}: enter");
}
if (!ManagedStates.TryGetValue(toState.Name, out FiniteState currentStateCandidate))
{
throw new ArgumentException($"Attempted to set current state to '{toState.Name}' but no state of that name is managed by this state machine.");
}
CurrentState = currentStateCandidate;
if (log.IsInfoEnabled)
{
log.Info($"{methodName}: changed to [{CurrentState.Name}]");
}
if (log.IsDebugEnabled)
{
log.Debug($"{methodName}: exit");
}
}
/// <summary>
/// Add a new FiniteState to the collection of states managed by this state machine.
/// </summary>
/// <param name="StateToAdd">The finite state to add.</param>
/// <returns>A reference to the finite state that was just added.</returns>
/// <exception cref="ArgumentException">Thrown if you try to add a finite state that has already been added.</exception>
public FiniteState AddState(FiniteState StateToAdd)
{
string methodName = System.Reflection.MethodBase.GetCurrentMethod().Name;
try
{
if (log.IsDebugEnabled)
{
log.Debug($"{methodName}: enter");
}
if (ManagedStates.ContainsKey(StateToAdd.Name))
{
throw new ArgumentException($"Attempt to add a duplicate state '{StateToAdd.Name}'.");
}
if (log.IsInfoEnabled)
{
log.Info($"{methodName}: [{StateToAdd.Name}]");
}
ManagedStates.Add(StateToAdd.Name, StateToAdd);
return(StateToAdd);
}
finally
{
if (log.IsDebugEnabled)
{
log.Debug($"{methodName}: exit");
}
}
}
/// <summary>
/// Starts the state machine.
///
/// Every state diagram has a start state with a single transition to some initial state in the diagram via a start event.
/// This method performs the following actions:
/// * creates the start state
/// * creates the start event
/// * adds a transition from the start state, via the start event to InitialState, the finite state passed as a parameter
/// * sets the current state to be the start state
/// * raises the start event
/// The OnEntry event handler for InitialState will be executed.
/// The state machine is now sitting in it's initial state and waiting for an event to occur.
/// </summary>
/// <param name="InitialState">The finite state in which this state machine starts.</param>
public void Start(FiniteState InitialState)
{
string methodName = System.Reflection.MethodBase.GetCurrentMethod().Name;
if (log.IsDebugEnabled)
{
log.Debug($"{methodName}: enter");
}
engine.Start(InitialState);
if (log.IsDebugEnabled)
{
log.Debug($"{methodName}: exit");
}
}
/// <summary>
/// Create and add a new FiniteState to the collection of states managed by this state machine.
/// </summary>
/// <param name="Name">The name finite state to create and add.</param>
/// <returns>A reference to the finite state that was just created and added.</returns>
/// <exception cref="ArgumentException">Thrown if you try to add a finite state that has already been added.</exception>
public FiniteState AddState(string Name)
{
string methodName = System.Reflection.MethodBase.GetCurrentMethod().Name;
try
{
if (log.IsDebugEnabled)
{
log.Debug($"{methodName}: enter");
}
FiniteState stateToAdd = new FiniteState(Name);
return(engine.AddState(stateToAdd));
}
finally
{
if (log.IsDebugEnabled)
{
log.Debug($"{methodName}: exit");
}
}
}
/// <summary>
/// Starts the state machine.
///
/// Every state diagram has a start state with a single transition to some initial state in the diagram via a start event.
/// This method performs the following actions:
/// * creates the start state
/// * creates the start event
/// * adds a transition from the start state, via the start event to InitialState, the finite state passed as a parameter
/// * sets the current state to be the start state
/// * raises the start event
/// The OnEntry event handler for InitialState will be executed.
/// The state machine is now sitting in it's initial state and waiting for an event to occur.
///
/// On a technical note, the underlying Thread, in which the event handlers are run, is also created and started here.
/// </summary>
/// <param name="InitialState">The finite state in which this state machine starts.</param>
/// <exception cref="ArgumentException">Thrown if the parameter InitialState is a finite state that has not been added by <see cref="AddState(FiniteState)"/></exception>
public void Start(FiniteState InitialState)
{
string methodName = System.Reflection.MethodBase.GetCurrentMethod().Name;
if (log.IsDebugEnabled)
{
log.Debug($"{methodName}: enter");
}
//if (OnExceptionAction == null)
//{
// throw new ArgumentException($"The state machine must have an OnExceptionAction before you can start it.");
//}
//
// Perform sanity checks
//
foreach (KeyValuePair <string, FiniteState> kvp in ManagedStates)
{
//
// 1. Make sure each finite state has an OnEnterAction
//
FiniteState finiteState = kvp.Value;
if (finiteState.OnEnterAction == null)
{
throw new Exception($"The finite state, '{finiteState.Name}' does not have an OnEnterAction.");
}
//
// 2. Make sure the target state in every transition has been added to the state machine.
//
foreach (KeyValuePair <string, FiniteStateTransition> transitionKvp in finiteState.Transitions)
{
FiniteStateTransition fst = transitionKvp.Value;
string stateName = fst.ToState.Name;
if (!ManagedStates.ContainsKey(stateName))
{
throw new Exception($"The finite state, '{stateName}' has not been added to the state machine.");
}
}
}
FiniteState startState = new FiniteState(START_STATE_NAME);
FiniteStateEvent startEvent = new FiniteStateEvent(START_EVENT_NAME);
startState.OnEnterAction = () => { }; // needs an empty handler
AddState(startState);
startState.AddTransition(startEvent, InitialState);
SetCurrentState(startState);
RaiseEvent(startEvent);
//Thread runner = new Thread(RunStateMachine)
//{
// Name = Name
//};
//runner.Start();
if (log.IsDebugEnabled)
{
log.Debug($"{methodName}: exit");
}
}
/// <summary>
/// Add a new transition to the collection of transitions from this state that is created from an event and a state.
/// </summary>
/// <param name="ViaEvent">The event that will trigger this transition.</param>
/// <param name="ToState">The state that is the destination of the transition.</param>
/// <exception cref="ArgumentException">Thrown if the event in TransitionToAdd has already been used in a transition from this state.</exception>
public void AddTransition(FiniteStateEvent ViaEvent, FiniteState ToState)
{
AddTransition(new FiniteStateTransition(ViaEvent, ToState));
}
public void start(FiniteState startState)
{
engine.Start(startState);
}
