BPM process for manufacturing company-PBL code.

Question

I am very new to Oracle BPM and I'm currently using Oracle BPM 10g. I have done the expense report tutorial once.
And now I'm designing a process in a manufacturing company. I have a group,'items' with attributes name, pricePerItem, Quantity and Total. here Total is the product of pricePerItem and Quantity. the PBL program i wrote for it is :
amt as Decimal(3)
for each item in items do
amt = item.pricePerItem * item.quantity
     end     
     return amt
I have another attribute grossamt which is the sum of the every item's total value. the PBL program for this is:
amount as Decimal(3)
amount = 0
for each item in items do
amount = amount + item.total
end
return amount
However after I run the project, the 'total' field doesnt get calculated or populated which in turn leaves the grossamt field empty. Without this my process cannot proceed.
Please let me know if there is any error in the code i wrote above.
Or if there is any other work around for the same.
Thanks a lot in advance.

Answer 1

There's a trick you can employ that should make this easy. When you open an attribute, notice that you have a "Virtual" checkbox. After checking this, you'll notice that under the attribute in the Project Navigator tab that there will be "read" and "write" method.
For your line item total attribute inside the group add this logic to the read() method associated with the virtual attribute:
// this sets the line item “itemTotal” attribute of a Group.
//   (defined as Virtual). This code is in the Read Access
//    method for the itemTotal attribute and
//    “pricePerItem” and “quantity” are attributes in the group
return pricePerItem * quantityFor the overall total of the order that is based on the sum of the indiviidual order item lines in the group, add this logic in the virtual "grossAmount" attribute's read() method. The logic shown below assumes that your group's name is "items" and your order line item attribute inside the group is called "total".
// this is in a Virtual attribute’s Read Access code (the sum
// of all the order line items in a group is the order’s total)
return items[ ].total.sum( )Dan