OCL (Object Constraint Language) select, use sum for attribute

Asked Oct 30 '15 at 14:18

Active Oct 30 '15 at 15:03

Viewed 1,422 times

I'm trying to find an OCL excpression (calculator), but I'm not sure how to get the sum of the attributes of a collection.

I have a class Customer and a class Orders. I want to have the sum of all orders of a particular year saved in the Customer class, attribute revenue. Orders has attributes 'date_order' and 'amount'. Given is that year(Date) gives the year of a specific date and Date.now() gives the current date.

I found this solution:

context Customer::revenue

derive: self.orders -> select(year(datum_order) = (year(Date.now()) – 1)) -> collect(amount) -> sum()

I would like to not use collect, but I really don't know how to do this with only the select statement. I assume leaving out collect(amount) and change sum to amount.sum() is also not right?

I hope someone can help me with this expression.

edited Oct 30 '15 at 15:03

bofredo

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asked Oct 30 '15 at 14:18

Maaike

What is the reason for wanting to avoid `select`? – qwerty_so Oct 30 '15 at 15:33
Because it should not be in my vocabulary yet ;). But never mind, I can just use it of course. – Maaike Nov 08 '15 at 16:06
Thank you for the solution you found (perhaps for the same assignment? ;), I just needed this! – Marcel Korpel Apr 21 '17 at 16:44

OCL (Object Constraint Language) select, use sum for attribute

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