Close or open the output for the source

Hello,

I have different sources which produce different objects, and each source is connected to a queue. My question is: How to send a message to the source to close or open the output for the source? (so that source produces when the queue is empty)
And my other question is : For example i want my source to produce a maximum content of 60 objects, how can i stop the source from producing once it has produced 60 objects?

Any suggestions?

Greetings.

Source producing only 60:
-Select "arrival sequence" as Arrival Style and set quantity column of first line on 60
-Select "arrival schedule" as Arrival Style and set quantity column of first line on 60

Source only producing when queue is empty:
-Make queue size 1, then it will only produce next one if this one is being removed from queue
- use batching and flush contents between batch, the it will only start producing when queue is empty
- use the onentry triggers and onexit triggers of the queue to determine when you want to close and open the output of the source and simply use closeoutput and openoutput

Thank you for your answers, that was very helpful.