Eval's are indeed less performatic than any other type of constraints. "inline-evals" are not as bad, but are also heavier than regular constraints. The recommendation is to avoid when possible, but for some cases it is not possible. If you are using MR3 or later, you can use MVELs syntax in your constraints: when MyClass( aMapAttribute['aKey'] == "some Value" ) then ... end The above will transparently be translated to an inline-eval, but that is the best you can do when working with maps. []s Edson 2007/7/2, Rajesh_Kumar <Rajesh_Kumar(a)rsystems.com&gt;: > Hi all, > > I want to use "eval" in my rules, but in rule writing guidelines Mark > has > Written that "Eval is Evil". > > I want to compare the values of Hash Map in my when (conditions) part. > > 1) Will anyone suggest something so that I can compare Hash Map keys in > when part? > > 2) Does is there any performance related issue related to "eval"; > > Regards > > Rajesh > > -- > This message has been scanned for viruses and > dangerous content by MailScanner, and is > believed to be clean. > > > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users