All right, let's hope that "business user" is up to write the rules, even without null checks ;-) Seriously now: are they up to handling monetary units represented as floating point numbers? A recent thread has emphasized the problems arising from tests such as floatVal <= floatConst, and I've been preaching about possible inconsistencies due to the inherent nature of FP arithmetic, even for doing sums. BigDecimal is one solution, but I guess your BUs will go ballistic if you tell them about the consequences...
But here's my last proposal for circumnavigating the NPE issue: At the point of fact insertion, wrap all "dangerous" bean objects into a container fact with a single field and insert the container. Write rules matching the container, testing the wrapped object for field == null and whatever; if so, change and log; and now insert the wrapped object as a fact proper. (If necessary, you could even write a single rule for all fact types, using inspection to determine all dangerous fields.) -W 2009/5/14 Shabbir Dhari <sdh...@hotmail.com> > Thanks to all. > > The problem we have is that rules will be code by business user. As a > developer I don’t mind putting null check on every rule. But for business > user its unacceptable for checking null for the same attribute in around 50 > rules. > > Shannon, can you please elaborate more about your solution or if possible > post some simple code?** > > Date: Wed, 13 May 2009 08:28:53 -0700 > > From: greg_bar...@yahoo.com > > Subject: RE: [rules-users] NullPointerException with Wrapper objects > > To: rules-users@lists.jboss.org > > > > > > Well, like Wolfgang said, good luck with that. :) The only rules engine I > know that does this is Tibco BusinessEvents, and it's accomplished by making > a copy of your objects before inserting them into working memory. > > > > >From this forum post I'm guessing JRules doesn't do it: > http://forums.ilog.com/brms/index.php?topic=1439.0 > > > > And probably Blaze Advisor doesn't do it either: > > > http://discuss.fico.com/blaze/board/message?board.id=Blaze_Advisor_Users_Forum&message.id=591 > > > > So, I'm thinking you're stuck with having to do null checks. > > > > > ------------------------------ > Click Here View photos of singles in your > area<http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Fdating%2Eninemsn%2Ecom%2Eau%2Fsearch%2Fsearch%2Easpx%3Fexec%3Dgo%26tp%3Dq%26gc%3D2%26tr%3D1%26lage%3D18%26uage%3D55%26cl%3D14%26sl%3D0%26dist%3D50%26po%3D1%26do%3D2%26trackingid%3D1046138%26r2s%3D1&_t=773166090&_r=Hotmail_Endtext&_m=EXT> > > _______________________________________________ > rules-users mailing list > rules-users@lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > >
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