Is this a threading question? ?If not, then I would just call a method from tick price that does the calculation but it can also just be done in tickPrice. ?The only reason not to is for cleaner code.
ie. in tickPrice you check the tickerId and set the appropriate securities value. ?Note that field is important here, 4 means last price. ?Then check it's difference from the other security. ?Place order as needed.
If you're worried about threading, it's true this will all be done on the EReader thread. ?However such a small calculation is no reason to use another thread.
