[rules-users] Checking whether an element exists as well doesnt exists in several lists

[Wolfgang Laun]

On 08/01/2013, devan.vanreenen at gmail.com <devan.vanreenen at gmail.com> wrote:

> I use the following rule to be able to do this logic and expect a single
> HighPriority intance in working memory but there are several, am I doing it
> wrong,

Do you need just a single HighPriority() irrespective of the number of
cases where there is 4/5/6 but no 7/8? Or do you need one for each
caseNumber?

> rule 'Determine if High priority'
> dialect 'java'
> when
> 	    $a1 : Alert( alertNo == 4 || == 5 || == 6 )
> 	    $a2 : Alert( alertNo == 7 || == 8 )
> 	    $m : CaseList( value contains $a1 && not contains $a2 )

This logic is wrong. It detects (repeatedly) a CaseList where there is
4, 5, or 6 which does not contain an Alert with *any* caseNumber with
an alertNo of 7 or 8.

The following rule creates a *single* HighPriority fact, no matter how
many matching cases there are.

rule find456no78
when
    not HighPriority()
    Alert( $c: caseNumber, alertNo == 4 || == 5 || == 6 )
    not Alert( caseNumber == $c, alertNo == 7 || == 8 )
then
    insert( new HighPriority( true ) );
    System.out.println( "high prio for "  + $c );
end

If you need one HighPriority for each case, store the caseNumber in
the HighPriority fact and constrain accordingly.

-W

> 		
> then
> 		HighPriority hp = new HighPriority();
> 		hp.setValue(true);
> 		insertLogical(hp);
> end
>
>
>
> --
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