Whats the most elegant way to add two numbers that are Optional

Question

I need to perform an add operation on two big decimals that are wrapped optionals:

Optional ordersTotal;
Optional newOrder;
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Answer 1

I know this is an old thread, but how about this?

orderTotal = !newOrder.isPresent()? 
             orderTotal : 
             newOrder.flatMap(v -> Optional.of(v.add(orderTotal.orElse(BigDecimal.ZERO));

My thinking behind this approach is like this:

• Behind all the shinny Optional etc. the basic logic here is still
  orderTotal += newOrder

• Before the first newOrder exists orderTotal does not exist, which is represented by an empty Optional in the code.

• If a newOrder does not exist yet (another empty Optional), no operation is necessary at all, i.e. there is no need to modify orderTotal
• If there is a newOrder, invoke its flatMap(..) as presented in maxTrialfire's original post.