Read the section on the "Conditional Element eval" in the Expert manual (and more of the same manual, especially Chapter 4, Rule Language Reference). -W On 11/10/2013, merry0900 <m1e1r1r1y(a)163.com&gt; wrote: > > my drl file like this： > import ******** > function boolean isNotNull(String a){ > if(a!=null){ > return true;} > return false; > }. > rule a > when > isNotNull("aaaa"); > then > // mycode > end > > how i could use like this， thank you all > > > > -- > View this message in context: > http://drools.46999.n3.nabble.com/use-a-boolean-returned-type-function-in... > Sent from the Drools: User forum 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

Do you need to do eval( isNotNull("aaaa")) maybe? -- View this message in context: http://drools.46999.n3.nabble.com/use-a-boolean-returned-type-function-in... Sent from the Drools: User forum mailing list archive at Nabble.com. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users