[rules-users] Newbie question on accessing predecessor and successor in a list

Hi everyone! I'm relatively new to Drools and rule languages. I'm wondering if it is possible to access the predecessor and successor in a match using from operator on an (Array)List. I have something like this (simplified): ... $segment : Segment( countries contains Country.Switzerland && ... ) from $journey.segmentList $preSegment : Segment ( indexOf(this) == indexOf($segment) - 1, countries not contains Country.Switzerland && ... ) from $journey.segmentList I need something like indexOf() for the exact predecessor of the matched segment. If the matched business object was an element of a double linked list it would be easy. Unfortunately I don't have the luxury to change the business object into knowing it's predecessor or successor. I have to prove that we could write our java coded business rules in Drools rule language without changing the business object model. Thanks in advance, Chris -- View this message in context: http://www.nabble.com/Newbie-question-on-accessing-predecessor-and-succes... Sent from the drools - user mailing list archive at Nabble.com.