[rules-users] Help with syntax for detecting when an object exists, none of whose children match a pattern

As a newbie to Drools (using v4.0.7), I'm struggling a bit with the right way to express the following concept I have a ParentFactObject with an array of ChildFactObjects. The ChildFactObjects have a boolean attribute "TestMe" I want to pattern match all ParentFactObjects for whom all ChildFactObjects have false for TestMe Here's what I've tried: rule "NoTestChildren" when $parentFactObject : ParentFactObject // parent exists ( ) not ChildFactObject // no child exists that has TestMe true ( TestMe == true ) from $parentFactObject.childFactObjects then log("Rule NoTestChildren fired."); end I get the following: org.drools.rule.InvalidRulePackage: [66,4]: unknown:66:4 mismatched token: [@1085,4469:4472='from',<38>,66:4]; expecting type THEN Also tried this: rule " NoTestChildren " when $parentFactObject : Borrower // parent exists ( ) forall ($childFactObject : ChildFactObject // no child exists that has TestMe true ( TestMe == true ) )from $parentFactObject. childFactObjects then log("Rule NoTestChildren fired."); end I've tried a series of variations with similar results. Can anyone provide any guidance on how to do this? Thanks in advance. Tom Murphy This message may contain confidential and/or privileged information. If you are not the addressee or authorized to receive this for the addressee, you must not use, copy, disclose, or take any action based on this message or any information herein. If you have received this message in error, please advise the sender immediately by reply e-mail and delete this message. Thank you for your cooperation.