ok, after a little tryout and searching in the api doc's i get the information that i whant.
OrderMgr orderMgr = kkAppEng.getOrderMgr();
OrderIf order = orderMgr.getCheckoutOrder();
OrderTotalIf[] totals = order.getOrderTotals();totals contains the information as strings.
an my solution for "not continue the checkout process" i returned with :
return mapping.findForward("ShowCartItems"); if the total price is not zero ,is this a good one?

but now i have another problem.
if the user is logged in and gets to the "Order Confirmation" after he confirmed the "What's In My Cart? " (sry i don't know the names of the pages, so i write the headlines ..

) the coupon code has to be retyped.
1. how do i get the coupon code shipped to the "Order Confirmation" page from "What's In My Cart? "?
2. if this is to complex for a simple answer , what java classfile corresponds to that page?!
the "What's In My Cart?" corresponds to the "CheckoutDeliveryAction.java" file as julie mentioned.
but i can't figure out which file correspondes to the "Order Confirmation" page.
in this case i could do the same changes as in "CheckoutDeliveryAction.java" to solve this problem.
best regards