[rules-users] Ensure all values in a list are unique?

[Wolfgang Laun]

Maybe I'm missing something but couldn't you simply create checkGroups as a
Set<String>and just compare its size() to $fact.Groups.size() ?


rule check
    when
        $fact : StrColl( $gr : groups, eval( $gr.size() != (new HashSet( $gr
)).size() ) )
    then
        System.out.println( "failed" );
end

-W

On Fri, Apr 17, 2009 at 8:22 AM, campbeln <nicholas.campbell at arc.gov.au>wrote:

>
> I have an ArrayList of strings that I need to ensure are all internally
> unique (ie: {"1","2","3"} = OK, {"1","2","1"} = Error). I've managed to
> cobble together the code below but I'm running into the "forall w/ an
> internal from" issue. I don't believe an upgrade is feasible at the moment,
> so are there any alternative solutions?
>
> NOTE: The collection of both $factGroups and $checkGroups is almost
> definitely redundant, so please keep any laughing to a minimum =)
>
>
> rule "BR033"
>   no-loop true
>     when
>                $fact : MyFact()
>
>                //# Get 2 copies of all the Groups associated with the $fact
>                $factGroups : ArrayList() from collect (
>                        Group() from $fact.Groups
>                )
>                $checkGroups : ArrayList() from collect (
>                        Group() from $fact.Groups
>                )
>
>                //# Traverse the $factGroups comparing each $currentGroup to
> the list
>                //# within $checkGroups, erroring out if something other
> then 1 is found
>                forall (
>                        $currentGroup : Group(this memberOf $factGroups)
>                        $test : ArrayList(size != 1) from collect(
>                                Group(this == $currentGroup) from
> $checkGroups
>                        )
>                )
>    then
>        System.out.println("Failed: BR033");
>    end
>
> I have found a number of postings that seem to be related, namely
>
> http://www.nabble.com/Best-practice-for-rules-against-multiple-objects-td5621720.html#a5621720
> but I've been unable to cobble together a solution thus far. All help is
> appreciated!
>
> Thanks!
> --
> View this message in context:
> http://www.nabble.com/Ensure-all-values-in-a-list-are-unique--tp23071079p23071079.html
> Sent from the drools - user mailing list archive at Nabble.com.
>
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