I have diagramm
When I call task3 in Event SubProcess and completed task my process instance is closed, but EndEvent does not call. Why? (((
a) Are you sure you want to be using terminating end events everywhere?
https://docs.camunda.org/manual/latest/reference/bpmn20/events/terminate-event/
and
https://docs.camunda.org/manual/latest/reference/bpmn20/events/none-events/
Since there is no parallel activity, is see no need for a terminating end event. in general I discourage the use of terminating end events. There are usually better ways to achieve the desired outcome.
b) The event sub process uses an interrupting start event.
https://docs.camunda.org/manual/latest/reference/bpmn20/subprocesses/event-subprocess/
An event subprocess may be interrupting or non-interrupting. An
interrupting subprocess cancels any executions in the current scope. A
non-interrupting event subprocess spawns a new concurrent execution.
While an interrupting event subprocess can only be triggered once for
each activation of the scope hosting it, a non-interrupting event
subprocess can be triggered multiple times. Whether the subprocess is
interrupting or non-interrupting is configured using the start event
which triggers the event subprocess.
Your parent process' execution is canceled by the interrupting start event of the event sub process. Next, only the sub process is executed.
My new diagramm. Now called EndEvent on both processes
Related
How to model running multiple tasks/branches in parallel, and wait for just the first one to finish. Then the other (running) branches should be cancelled. To illustrate what I'm asking (what to use instead of the X gateway):
As far as I know, the exclusive gateway's join function is to immediately proceed. It neither stops/cancels the other branches, nor does it stop further executions of the output (so multiple tokens can pass through it).
Is this the answer?
Or perhaps this is even better?
I would do the following:
Starting off from your third diagramme, wrap the tasks ‘a’ and ‘b’ inside your subprocess into another transaction subprocess (but still inside the bigger subprocess that you had already used.
At the boundary of this new sub process as well as the boundary of the task ‘c’, you should add interrupting boundary signal events that lead to a None end event.
After task ‘b’ and ‘c’, add a signal end event. Each of these two signal end events should be caught by the interrupting boundary signal events of the other subprocess or task that you want to stop. So, if task ‘c’ is completed, the signal that is thrown right after that should be caught by the boundary on the transaction subprocess of tasks ‘a’ and ‘b’. The signal end event after ‘b’ should be caught by the boundary event on task ‘c’.
After the bigger subprocess, which contains tasks ‘c’ as well the inner subprocess for ‘a’ and ‘b’, you continue just like in your third diagramme with a merging exclusive gateway and the “Do once” task. I would keep the timer boundary event on the bigger subprocess like you did in your third diagramme.
Here is how this would look like:
However, you could also draw a simpler diagramme with an additional exclusive gateway before the "Do only once" activity that filters out all remaining process instances if that activity has already been carried out. You diagramme would be easier to understand but the process would be slightly different from your requirements: You would allow a situation where activity b will be carried out even though activity c has already been completed. So, instead of cancelling one process instance you would ignore it. Depending on your business context, this might have certain implications.
A third option would be to use a terminate end event instead of a none end event. That way, all remaining process instances will be deleted as soon as the first one reaches the end. However, semantically, that might not be the most elegant solution because a termination is intended to signal that your process has finished abnormally.
I'm new to threading, so there are a few things I'm trying to grasp correctly.
I have a windows form application that uses threading to keep my UI responsive while some server shenanigans are going on.
My question is: when I quit my application, what happens to ongoing threads? Will they run to completion or will the abruptly be interrupted?
If they are interrupted, what can I do to make sure they at least don't get interrupted in such a way that would corrupt data on my server (force them to run to a safe place in the code where I know it's ok to interrupt the execution)
You will want to keep a reference of said threads, and call .Abort() on them when you want to terminate. Then you put your thread's code in a try/catch block and handle ThreadAbortException's. This will let you clean up what you are doing and terminate the thread cleanly at your own pace. In the main thread, after you called .Abort(), you just wait until the thread is no longer running (by polling the .IsAlive property of the Thread object) and close your application afterwards.
A thread needs a process to run in. The process won't be able to terminate if you don't terminate all the non-background threads you have started. Threads marked as background thread will be aborted.
So, the behavior is entirely up to your implementation. If you want to close the application, you could wait for all threads to terminate by themself, you could set an event to ask them to terminate and wait or you could just kill the threads.
The UI thread will terminate by itself because it runs a messageloop that stops when requested by the operating system, also see wikipedia and this answer.
This is my code, it works only on form load or click.
But I need to show this msgbox when process close while my app running.
Dim p() As Process
p = Process.GetProcessesByName("notepad")
If p.Count > 0 Then
' Process is running
MsgBox("Running!")
Else
' Process is not running
MsgBox("Not running!")
End If
So, you want to monitor the status->Running or status->NotRunning of a process,
while your Application is executing.
This requires a method that continuously updates the Status of a monitored foreign process.
How this method works, depends on you application functionality:
Is invisible and becomes visible/operable when the monitored process
starts?
Operates indipendently from this foreign process, but takes special
actions when this other process becomes active?
Executes visible and its only purpose is to monitor the foreign
process?
Other
First take a look to:
Check if process is done in VB.Net
application closes itself when another program closes?
Wait for a specefic program to open before continue VB.NET
I suggest you learn how to instantiate a BackgroundWorker.
It's a very straightforward and helpful tool to use if you don't want to manually control an Asynchronous task.
A BackgroundWorker can be instructed to notify your main process (application) that a defined condition has changed.
When this condition is met, the BW raises an Event, letting you know what happend or changed.
Then you decide how to proceed, or - if it is the case - you can terminate the activity of the BackgroundWorker.
Give it a try.
I have the following sub in my program:
public sub RunThis()
Me.Hide()
NEWFORM.Show()
Dim t = New Thread(Sub() Me.printToPowerPoint(saveLocation, printlist))
t.SetApartmentState(ApartmentState.STA)
t.IsBackground = True
t.Start()
While t.isAlive
end while
NEWFORM.close()
Me.Close()
end sub
Running this my program hangs. Does anyone have a solution for this problem.
I am new to threading.
As you probably know, in WinForm projects, the UI can only be dealt with from a single thread. This is affectionately known as the UI thread. That's why, any time you need to access or modify a UI element, you must call the control or form's Invoke method. The Invoke method causes the given delegate to be run on the UI thread. However, doing so will not interrupt any processing that is already being performed by the UI thread. If the UI thread is currently busy, when you call Invoke, it will hang until the UI thread is no longer busy, then it will execute the given delegate.
So, in your code, you are starting a new thread which inside it is trying to invoke a method back on the UI thread. However, immediately after starting the new thread, you then enter a loop which keeps the UI thread busy until the other thread is done. So, when your new thread invokes back to the UI thread, the UI thread is busy and both threads are effectively hung forever.
DoEvents is a keyword you can call from within a lengthy process or loop in the UI thread to signal that you want to, essentially, pause your current processing thereby freeing up the UI thread to process any waiting window messages (painting events, click events, invoke requests, etc.). As soon as all those pending window messages are processed, it will return to doing whatever the next statement is after you called DoEvents. Therefore, if calling DoEvents inside the loop causes it to work properly, that means that your new thread must be invoking back onto the UI thread, or waiting for some other window message to be processed before continuing.
Calling DoEvents is dangerous and widely panned as being bad practice. Typically, if you need to call DoEvents, it's a sign that you need to rethink your design. Usually there is a better way to do what you are doing.
In your case, it looks like starting the new thread is utterly pointless. Unless you have abbreviated you code, it appears that as soon as you start the new thread, you simply put the UI thread on hold waiting for the other thread to finish. If that's the case, it would make much more sense to simply do the work on the UI thread itself rather than starting a new one. In the code you provided, no two threads will ever be effectively be doing processing at the same time, so it's no better than a single thread.
How can I make my thread sleep first before it runs? I know how to get sleep to work, however, whenever my program is run, the thread immediately runs. I want it to WAIT once it is first created to start running. (I am using handlers)
You cannot control when threads are scheduled. If you want it to go to sleep, have the first statement in the thread subroutine do a wait on a condition or something like that and when you are ready you can broadcast to that condition. In pseudo-code:
get-lock
if (we-are-still-supposed-to-sleep)
pthread_cond_wait()
release-lock
I suppose you could have the parent hold the lock while creating the children and then all they have to do is:
get-lock
release-lock
and avoid the condition thing.
What OS? Windoze allows you to create threads in a suspended state. When you have loaded up the thread fields in the ctor, you can resume the thread. Failing that, pass some synchro object in the thread start parameter for the new thread to wait on.
Rgds,
Martin.