[eclipse-users] Predicates order

Dear users.

I use Java Interface to connect with ECLiPSe.
My program uses three main predicates: start, ask_prices and buy_goods.
The problem is dealt with order of predicates execution.
I would like first ask_prices predicate to be finished and only then
buy_goods predicate to start.
When I execute this in the following manner :
        eclipse.rpc("start");
        eclipse.rpc("ask_prices");
        eclipse.rpc("buy_goods");                           
they interlace each other.
Is there any way to force the order of predicate execution ?

Best regards,
Wojciech Pieprzyca