How do I evaluate null conditions in the following case for example? seller: ( seller.cheese != null && seller.active == true ) cheese: ( cheese.type == "chedder" ) from seller.cheese In the above example seller.cheese is null but seller is used in the second part of the rule since we can't evaluate facts for null for some reason how do you check for a null condition. -- View this message in context: http://www.nabble.com/null-checking-tp20015953p20015953.html Sent from the drools - user mailing list archive at Nabble.com. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users

samd wrote: > > How do I evaluate null conditions in the following case for example? > > seller: ( seller.cheese != null && seller.active == true ) > cheese: ( cheese.type == "chedder" ) from seller.cheese > > In the above example seller.cheese is null but seller is used in the > second part of the rule since we can't evaluate facts for null for some > reason how do you check for a null condition. > > should be cheese: ( type == "chedder" ) from seller.cheese anyways I tried doing this ( seller: ( seller.cheese != null && seller.active == true ) cheese: ( cheese.type == "chedder" ) from seller.cheese ) or ( seller: ( seller.cheese = null && seller.active == true ) ) Which throws an error I just need the correct syntax I guess heh -- View this message in context: http://www.nabble.com/null-checking-tp20015953p20016182.html Sent from the drools - user mailing list archive at Nabble.com. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users

I think it's not in the manual. Try this : seller: ( seller.cheese != null, seller.active == true ) cheese: ( this != null, cheese.type == "chedder" ) from seller.cheese I don't kown if it's fine but it works. dave sinclair wrote: > > read the manual > > http://downloads.jboss.com/drools/docs/4.0.7.19894.GA/html_single/index.html > > On Thu, Oct 16, 2008 at 3:03 PM, samd <sdoyle_2(a)yahoo.com&gt; wrote: > >> >> >> >> samd wrote: >> > >> > How do I evaluate null conditions in the following case for example? >> > >> > seller: ( seller.cheese != null && seller.active == true ) >> > cheese: ( cheese.type == "chedder" ) from seller.cheese >> > >> > In the above example seller.cheese is null but seller is used in the >> > second part of the rule since we can't evaluate facts for null for some >> > reason how do you check for a null condition. >> > >> > >> >> should be cheese: ( type == "chedder" ) from seller.cheese >> >> anyways I tried doing this >> >> ( >> seller: ( seller.cheese != null && seller.active == true ) >> cheese: ( cheese.type == "chedder" ) from seller.cheese >> ) >> or >> ( >> seller: ( seller.cheese = null && seller.active == true ) >> ) >> Which throws an error >> I just need the correct syntax I guess heh >> >> -- >> View this message in context: >> http://www.nabble.com/null-checking-tp20015953p20016182.html >> Sent from the drools - user mailing list archive at Nabble.com. >> >> _______________________________________________ >> rules-users mailing list >> rules-users(a)lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/rules-users >> > > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > >