Actor Framework Discussions
Auto Self destructing actors
Solved!
Hi Mani,
So depending on your use case, I'd suggest the following options might help you :
0 - you can simply end and relaunch Actors as needed, if you have some information about when you need them. They're pretty lightweight to start and so this can be considered, but doesn't answer your question (hence 0 not 1).
1 - as you suggested, create a helper loop in Actor Core and have it send a stop message on timeout from an Event Structure. Create a user event in Pre Launch Init and send the event each time you want to refresh the timeout. Register for the user event in AC. Be careful not to have other Events in the event structure. This can be reused via inheritance either with a Refresh message sent to self and handled by your parent class (this class) or by making the event reference available via protected accessor. You could perhaps use something akin to composition by launching this as a nested Actor for any other Actor, then having it stop the caller, but you'd have to prevent passing the message upwards.
2 - have a counter in the private data and override Receive Message to reset it to the max timeout if a certain subset of messages (or place a SubVI doing that in each chosen message). Send a time delayed message every however many seconds (E.g. 1 second, to have the counter be in seconds) to decrement the counter. If it reaches zero, have the time delayed message send a stop message.
It seems like the easiest answer would be to override Receive Message.vi and keep track of the timestamp of the last received message in the Actors private data that you update there. Then have a time-delayed message that checks to see if the time has elapsed( just make sure that doesn't reset the timestamp)
I attached a demo that does what you want. You could just create a parent class similar to the one in the demo and then have any actor where you want a timeout, just inherit from that. You could make it even more generic by adding some sort of strategy pattern to determine what happens when the timer expires (ie. shutdown, throw an error, perhaps something else?)
As far as the initialization, simply grabbing the actor from the last ack should be enough. You'll have prelaunch init running everytime, but you should only be using that for things that get initialized everytime it launches (for example refnums). For everything else just set it once before you launch it.
Hope that helps.
@manig wrote:
Powell, In my application, there will be >10 actors launched (apart from other actors) to acquire from the camera and it will have a helper loop for the acquisition to stream images at a faster rate. Since not all the cameras are needed to run every time, planning to launch the actor on-demand with a pre-initialized Actor Object. Let me know your thoughts.
I'd stand by my previous answers, but I do wonder if (given this topic may become a little longer than simply "how can I do X?") if this is necessary/the best approach.
If you'd like, perhaps you can describe a bit more of your application and forum readers could give some feedback or suggestions?
Of course, if you're happy with what you've already gotten and don't wish further discussion, that's also fine.
I agree with Christian and Dr Powell. Just because you can doesn't necessarily mean it is a good idea or in this case necessary.
