I tried to search all over the web for a Java Faces component, which will do a simple thing: totals and subtotals. And I failed. It seems that whole web is about how much more AJAX you could put everywhere, not how more useful your product could be for average user.

It could be done through a facet tag, which is obvious.

I think about that as competitive advantage for myself. If nobody done it – I should do it and be recognised for it!