/// <summary>
/// Execute a process transaction
/// Warning: you need to execute this method inside a Transaction (TransactionScope)
/// this is how you control if the changes will be saved to the db.
/// @param persMode - persistence mode
///
/// assume we have all process tasks in a single record
/// so when performing modification, we need to limit our scope to that record (this process instance)
/// and all messages leaving the process will be handled async
/// so we divide our messages between in-process and inter-process
/// inter-process are always async
/// in-process are sync when they're task control messages
/// async when they are from send/receive message tasks (hmmm, this doesn't really matter when in proc)
///
/// what about transactions?
/// - we assume we're already inside a system transaction
/// - we can get an external db connection. If we don't get it, we need to open it.
/// - process session
/// - other components should have an option to be notified about commit - use system.transactions api...
/// </summary>
public void RunProcessTransaction(TaskPersistenceMode persMode, Action <ProcessSession> act)
{
if (ProcessSession.Current != null)
{
act(ProcessSession.Current);
return;
}
Queue <ProcessMessage> outgoing = null;
InSystemTransaction(() =>
{
InDbTransaction(SessionFactory, dbs =>
{
var pess = TaskPersister.OpenSession(dbs);
pess.PersistenceMode = persMode;
var ps = new ProcessSession(pess, MessageBus, ServiceResolver);
try
{
ProcessSession.Current = ps;
ps.MessageBus = MessageBus;
ps.TaskPersister = pess;
act(ps);
PumpMessages(ps);
outgoing = ps.AsyncQueue;
}
finally
{
ProcessSession.Current = null;
ps.Dispose();
}
pess.SaveChanges();
pess.Dispose();
});
});
if (outgoing != null)
{
foreach (var pm in outgoing)
{
SendLocalAsyncMessage(pm);
}
}
}
protected void PumpMessages(ProcessSession ps)
{
var queue = ps.SyncQueue;
while (queue.Count > 0)
{
var m = queue.Dequeue();
if (m is TaskExecEvent)
{
var te = m as TaskExecEvent;
if (te.FromTaskInstanceId == te.FromProcessInstanceId || InstanceId.IsSameProcessInstance(te.ParentTaskInstanceId, te.FromProcessInstanceId))
{
DeliverTaskExecEvent(te);
}
else
{
MessageBus.Notify(te);
}
}
else if (m is TaskControlCommand)
{
var tc = m as TaskControlCommand;
if (InstanceId.IsSameProcessInstance(tc.FromProcessInstanceId, tc.ToTaskInstanceId))
{
DeliverTaskControlMessage(tc);
}
else
{
MessageBus.Notify(tc);
}
}
else
{
throw new Exception("Unexpected message in queue");
}
}
}
