[rules-users] checking for complex conditions

Hi, Suppose I have a class Foo with integers a, b and c ( methods getA getB and getC respectively ) and I Want to check if an object of Foo satisfies a - (b + c) > 0 Is this the best way I go about doing this ? rule "Foo check" when Foo( varA : a , varB:b, varC:c ) eval( varA - (varB + varC) > 0 ) then <do actions> end Writing this as rule "Foo check" when Foo( a - (b + c) > 0 ) then <do actions> end doesnt seem to work. Its not able to find the variables (a, b and c ) from the getA getB and get C methods. Thanks Jai