[rules-users] Inserting elements of a list into a session from a rule consequence

[David Sinclair]

If you need to reason over the contents of the list, I would probably write
a generic rule that will insert each element from a list into Working Memory

rule "Assert List Contents"
   when
          $list : List(size > 0)
          $obj : Object() from $list
   then
       insert($obj);
end

Then write the other rules specific to the items in the list

rule "Validate ONFI final action - code 666"
when
RuleFlag(value == "Validate ONFI final action")
a: PackageMovementInfo(actionCode == "666")
b: ONFIAssignmentInfo(reviewType == "ES", subId == a.subId)
ONFIReviewerInfo(notId == b.notId, revStatus == "CLO", reviewerRole == "PR")

then
result.addMessage(a, "You can't do action code 666..." );
end

On Mon, Dec 14, 2009 at 9:21 AM, Warren, David [USA]
<warren_david at bah.com>wrote:

> I am trying to write a rule whose consequence loads several lists into the
> session.  Each list contains a different type of class.  What I would like
> to do (need to do as far as I can tell) is loop through the list and insert
> each element individually, rather than inserting the list as a whole.  Is
> ther a way to do this in DRL?
>
> Here is my example rule:
> rule "Do we need to validate ONFI final action"
> when
>  a : PackageMovementInfo( finalActionInd == "*", packageId == "AA")
>  b : SubmissionsInfoForRules(subId == a.subId, amendment == false,
> onfiAssignmentId != null)
> then
>  insert( new RuleFlag("Validate ONFI final action") );
>  insert( onfiService.getONFIAssignment(b.getSubId()) );
>  insert( onfiService.getONFIReviewers(b.getOnfiAssignmentId()) );
>  insert( onfiService.getONFIAttachments(b.getOnfiAssignmentId()) );
> end
>
> The last two insert statements insert lists.  A problem occurs in
> subsequent rules if I try to evaluate the contents of the lists.  I've been
> getting a ClassCastException when lists are present for both the reviewers
> and attachments, because they are not the same class.   Here is an example
> rule that causes a ClassCastException:
>
> rule "Validate ONFI final action - code 666"
> when
> RuleFlag(value == "Validate ONFI final action")
> a: PackageMovementInfo(actionCode == "666")
> b: ONFIAssignmentInfo(reviewType == "ES", subId == a.subId)
> $list : List( size > 0 )
> ONFIReviewerInfo(notId == b.notId, revStatus == "CLO", reviewerRole ==
> "PR") from $list
> then
> result.addMessage(a, "You can't do action code 666..." );
> end
>
> What I need to do is either (1) load each element of the lists
> individually, or (2) rewrite "$list : List (size > 0)" to only pick up lists
> of a particular class.
> Is there a way to do either of these things from DRL?  Or do I need to
> handle the loading outside of my rules (in the Java class that calls the
> rules).
>
> Thank you,
> David Warren
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> rules-users at lists.jboss.org
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>
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