public Process(Environment environment, IEnumerable<Event> generator)
: base(environment)
{
this.generator = generator.GetEnumerator();
IsOk = true;
target = new Initialize(environment, this);
}
protected virtual void CollectValues(Event @event) {
if (@event.IsOk) {
var value = new OrderedDictionary();
foreach (var v in GetValues())
value.Add(v.Key, v.Value);
Value = value;
}
}
protected virtual void TriggerRequest(Event @event = null) {
while (RequestQueue.Count > 0) {
var request = RequestQueue.Peek();
DoRequest(request);
if (request.IsTriggered) {
RequestQueue.Dequeue();
} else break;
}
}
protected virtual void TriggerGet(Event @event = null) {
while (GetQueue.Count > 0) {
var get = GetQueue.Peek();
DoGet(get);
if (get.IsTriggered) {
GetQueue.Dequeue();
} else break;
}
}
protected virtual void TriggerPut(Event @event = null) {
while (PutQueue.Count > 0) {
var put = PutQueue.Peek();
DoPut(put);
if (put.IsTriggered) {
PutQueue.Dequeue();
} else break;
}
}
protected virtual void TriggerRequest(Event @event = null) {
while (RequestQueue.Count > 0) {
var request = RequestQueue.First.Value;
DoRequest(request);
if (request.IsTriggered) {
RequestQueue.RemoveFirst();
} else break;
}
}
/// <summary>
/// This interrupts a process and causes the IsOk flag to be set to false.
/// If a process is interrupted the iterator method needs to call HandleFault()
/// before continuing to yield further events.
/// </summary>
/// <exception cref="InvalidOperationException">This is thrown in three conditions:
/// - If the process has already been triggered.
/// - If the process attempts to interrupt itself.
/// - If the process continues to yield events despite being faulted.</exception>
/// <param name="cause">The cause of the interrupt.</param>
public virtual void Interrupt(object cause = null) {
if (IsTriggered) throw new InvalidOperationException("The process has terminated and cannot be interrupted.");
if (Environment.ActiveProcess == this) throw new InvalidOperationException("A process is not allowed to interrupt itself.");
var interruptEvent = new Event(Environment);
interruptEvent.AddCallback(Resume);
interruptEvent.Fail(cause);
if (Target != null)
Target.RemoveCallback(Resume);
}
protected virtual void TriggerRequest(Event @event = null) {
var current = RequestQueue.First;
while (current != null) {
var request = current.Value;
DoRequest(request);
if (request.IsTriggered) {
var next = current.Next;
RequestQueue.Remove(current);
current = next;
}
if (Resources.Count == 0) break;
}
}
protected void Check(Event @event) {
if (IsTriggered || IsProcessed) {
if ([email protected]) throw new InvalidOperationException(
@"Errors that happen after the condition has been triggered will not be
handled by the condition and cause the simulation to crash.");
return;
}
FiredEvents.Add(@event);
if ([email protected])
Fail(@event.Value);
else if (Evaluate()) {
Succeed();
}
}
protected virtual void TriggerRequest(Event @event = null) {
foreach (var entry in RequestQueue) {
var cascade = false;
var requests = entry.Value;
while (requests.Count > 0) {
var req = requests.Peek();
DoRequest(req);
if (req.IsTriggered) {
requests.Dequeue();
} else {
cascade = true;
break;
}
}
if (cascade) break;
}
}
protected virtual void Resume(Event @event) {
Environment.ActiveProcess = this;
while (true) {
if (@event.IsOk) {
if (generator.MoveNext()) {
if (IsTriggered) {
// the generator called e.g. Environment.ActiveProcess.Fail
Environment.ActiveProcess = null;
return;
}
if (ProceedToEvent()) break;
} else if (!IsTriggered) {
Succeed(@event.Value);
break;
} else break;
} else {
/* Fault handling differs from SimPy as in .NET it is not possible to inject an
* exception into an enumerator and it is impossible to put a yield return inside
* a try-catch block. In SimSharp the Process will set IsOk and will then move to
* the next yield in the generator. However, if after this move IsOk is still false
* we know that the error was not handled. It is assumed the error is handled if
* HandleFault() is called on the environment's ActiveProcess which will reset the
* flag. */
IsOk = false;
Value = @event.Value;
if (generator.MoveNext()) {
if (IsTriggered) {
// the generator called e.g. Environment.ActiveProcess.Fail
Environment.ActiveProcess = null;
return;
}
// if we move next, but IsOk is still false
if (!IsOk) throw new InvalidOperationException("The process did not react to being faulted.");
// otherwise HandleFault was called and the fault was handled
if (ProceedToEvent()) break;
} else if (!IsTriggered) {
if (!IsOk) Fail(@event.Value);
else Succeed(@event.Value);
break;
} else break;
}
}
Environment.ActiveProcess = null;
}
public virtual void ScheduleD(double delay, Event @event) {
Schedule(TimeSpan.FromSeconds(DefaultTimeStepSeconds * delay), @event);
}
protected virtual void StopSimulation(Event @event) {
throw new StopSimulationException(@event.Value);
}
public virtual object Run(Event stopEvent = null) {
if (stopEvent != null) {
if (stopEvent.IsProcessed) return stopEvent.Value;
stopEvent.AddCallback(StopSimulation);
}
try {
var stop = Queue.Count == 0 && ScheduleQ.Count == 0;
while (!stop) {
Step();
ProcessedEvents++;
lock (locker) {
stop = Queue.Count == 0 && ScheduleQ.Count == 0;
}
}
} catch (StopSimulationException e) { return e.Value; }
if (stopEvent == null) return null;
if (!stopEvent.IsTriggered) throw new InvalidOperationException("No scheduled events left but \"until\" event was not triggered.");
return stopEvent.Value;
}
protected virtual void TriggerRelease(Event @event = null) {
while (ReleaseQueue.Count > 0) {
var release = ReleaseQueue.Peek();
DoRelease(release);
if (release.IsTriggered) {
ReleaseQueue.Dequeue();
} else break;
}
}
protected virtual bool ProceedToEvent()
{
target = generator.Current;
Value = target.Value;
if (target.IsProcessed) return false;
target.AddCallback(Resume);
return true;
}
/// <summary>
/// This method schedules the event right now. It takes the IsOk state
/// and uses the <see cref="Value"/> of the given <paramref name="@event"/>.
/// Thus if the given event fails, this event will also be triggered as
/// failing.
/// </summary>
/// <exception cref="InvalidOperationException">
/// Thrown when the event has already been triggered.
/// </exception>
/// <remarks>
/// The signature of this method allows it to be used as a callback.
/// </remarks>
/// <param name="event">The event that triggers this event.</param>
public virtual void Trigger(Event @event) {
if (IsTriggered)
throw new InvalidOperationException("Event has already been triggered.");
IsOk = @event.IsOk;
Value = @event.Value;
IsTriggered = true;
Environment.Schedule(this);
}
protected virtual void TriggerGet(Event @event = null) {
var current = GetQueue.First;
while (current != null) {
var get = current.Value;
DoGet(get);
if (get.IsTriggered) {
var next = current.Next;
GetQueue.Remove(current);
current = next;
} else current = current.Next;
if (Items.Count == 0) break;
}
}
public virtual void Schedule(Event @event) {
lock (locker) {
Queue.Enqueue(@event);
}
}
protected virtual void DisposeCallback(Event @event) {
var request = @event as Request;
if (request != null) Release(request);
}
public virtual void Schedule(TimeSpan delay, Event @event) {
if (delay < TimeSpan.Zero)
throw new ArgumentException("Negative delays are not allowed in Schedule(TimeSpan, Event).");
lock (locker) {
if (delay == TimeSpan.Zero) {
Queue.Enqueue(@event);
return;
}
var eventTime = Now + delay;
DoSchedule(eventTime, @event);
}
}
protected virtual void TriggerRequest(Event @event = null) {
foreach (var entry in RequestQueue) {
var requests = entry.Value;
var current = requests.First;
while (current != null) {
var request = current.Value;
DoRequest(request);
if (request.IsTriggered) {
var next = current.Next;
requests.Remove(current);
current = next;
} else current = current.Next;
}
}
}
protected virtual EventQueueNode DoSchedule(DateTime date, Event @event) {
if (ScheduleQ.MaxSize == ScheduleQ.Count) {
// the capacity has to be adjusted, there are more events in the queue than anticipated
var oldSchedule = ScheduleQ;
ScheduleQ = new EventQueue(ScheduleQ.MaxSize * 2);
foreach (var e in oldSchedule) ScheduleQ.Enqueue(e.Priority, e.Event);
}
return ScheduleQ.Enqueue(date, @event);
}
protected void DisposeCallback(Event @event) {
var request = @event as PreemptiveRequest;
if (request != null) Release(request);
}
public virtual object Run(DateTime until) {
if (until <= Now) throw new InvalidOperationException("Simulation end date must lie in the future.");
var stopEvent = new Event(this);
var node = DoSchedule(until, stopEvent);
// stop event is always the first to execute at the given time
node.InsertionIndex = -1;
ScheduleQ.OnNodeUpdated(node);
return Run(stopEvent);
}