I am new to drools and have been struggling with this rule. $subject: RqTargetType contains a list of RqAttrib objects $resource: RqTargetType also contains its own list of RqAttrib objects $subject in a certain role has to be selected based on (attribType == "subject", designator == "subject.role", attribValue == "patient") $subjectId is to be extracted from another attribute (attribType == "subject", designator == "subject.id", $subjectId: attribValue) We then need to select a resource that has an attribute to match this $subjectId (attribType == "resource", designator == "resource.patient", attribValue == $subjectId ) Here is the rule I wrote: rule "Patient Access Rule" #conditions RqTargetType( $subjectAttribs : rqAttribs ) RqAttrib (attribType == "subject", designator == "subject.role", attribValue == "patient") from $subjectAttribs RqAttrib (attribType == "subject", designator == "subject.id", $subjectId: attribValue) from $subjectAttribs $resource: RqTargetType( ) RqAttrib (attribType == "resource", designator == "resource.patient", attribValue == $subjectId ) from $resource.getRqAttribs() RqAttribute (attribType == "resource", designator == "resource.id", $resourceId: attribValue ) from $resource.getRqAttribs then #actions System.out.println( "resource: " + $resourceId ); System.out.println( "subject: " + $subjectId ); System.out.println( "Patient Access rule decision: Permit" ); decisions.add("Permit"); retract($subject); end I keep on getting "no viable alternative at input" error. Tried stripping the code so that only the following was left and still got the error: RqTargetType( $subjectAttribs : rqAttribs ) RqAttrib (attribType == "subject", designator == "subject.role", attribValue == "patient") from $subjectAttribs [ERR 101] Line 25:2 no viable alternative at input 'RqTargetType' in rule "Patient Access Rule" Then tried this with similar results. $subject: RqTargetType() $subjectAttrib: RqAttrib (attribType == "subject", designator == "subject.role", attribValue == "patient") from $subject.getRqAttribs() no viable alternative at input '$subject' in rule "Patient Access Rule" Any help will be much appreciated. Thank you and have a great day. -- View this message in context: http://drools-java-rules-engine.46999.n3.nabble.com/Matching-items-based-... 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

Thanks very much Wolfgang - that was clumsy of me! I corrected a couple of other errors, my code now runs, but does not work.

Am I approaching this correctly?

rule "Patient Access Rule"        when                #conditions                RqTargetType( $subjectAttribs : rqAttribs )                RqAttrib (attribType == "subject", designator == "subject.role",                        attribValue == "patient") from $subjectAttribs                RqAttrib (attribType == "subject", designator == "subject.id",                        $subjectId: attribValue) from $subjectAttribs                $resource: RqTargetType( )                RqAttrib (attribType == "resource", designator == "resource.patient",                        attribValue == $subjectId ) from $resource.getRqAttribs()                RqAttrib (attribType == "resource", designator == "resource.id",                        $resourceId: attribValue ) from $resource.getRqAttribs        then                #actions                System.out.println( "resource: " + $resourceId );                System.out.println( "subject: " + $subjectId );                System.out.println( "Patient Access rule decision: Permit" );                decisions.add("Permit"); end -- View this message in context: http://drools-java-rules-engine.46999.n3.nabble.com/Matching-items-based-... 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