[rules-dev] An odd couple of patterns

[Wolfgang Laun]

On 24 March 2011 20:03, Joe White <Joe.White at recondotech.com> wrote:

> Wolfgang I use patterns like that for a data filtering problem and also for
> a preferential selection problem. Any time I have two sources of the same
> data and I prefer one over the other that pattern allows you to pick the
> secondary source when the preferred data doesn’t exist. Also used in cases
> where we want to execute a different action in the absence of the second
> source.
>
>
>
> It also occurs for us when dealing with a list of objects where we have two
> sources for the same type of data and we prefer one data source over the
> other, but we don’t always get data for the preferred source.. We use your
> pattern to make sure the preferred source doesn’t exist before using the
> secondary source
>
>
>

So you distinguish "source" by ranges of a numeric property? This is
unusual. For your use case I'd expect something like

   not Data( source == Source.PRIM )
   Data( source == Source.SEC, ... )

To clarify, here is the rule logic I posted, written with a redundant
constraint in the first pattern.

   Fact( field >= 10 && field <= 20 )  // if > 20, LHS fails due to "not"
   not Fact( field > 20 )


Thanks
Wolfgang


>
>
> Joe
>
>
>
> Here is an example from our code. $ebs is a List<Map>. Mapping to your
> example the Map is the fact and the combination of BnftInfoCdoe and
> BnftCvgeLevelCode would be the field.:
>
>
>
>   Map(*this*[BenefitsConsts.BenefitResponseEligibility.BnftInfoCode] ==
> 'C',
>
>       *this*[BenefitsConsts.BenefitResponseEligibility.BnftCvgeLevelCode]
> == 'IND',
>
>       *this*[BenefitsConsts.BenefitResponseEligibility.SvcTypeCode] ==
> "30",
>
> *this*[BenefitsConsts.BenefitResponseEligibility.CvgePeriodQlfr] == '25',
>
>       *this*[BenefitsConsts.BenefitResponseEligibility.BnftAmt] *matches*
> "0.*") *from* $ebs
>
>
>
> *not* (Map(*this*[BenefitsConsts.BenefitResponseEligibility.BnftInfoCode]
> == 'C',
>
>           *this*[BenefitsConsts.BenefitResponseEligibility.BnftCvgeLevelCode]
> == 'FAM') *from* $ebs)
>
>
>
> *From:* rules-dev-bounces at lists.jboss.org [mailto:
> rules-dev-bounces at lists.jboss.org] *On Behalf Of *Wolfgang Laun
> *Sent:* Thursday, March 24, 2011 11:07 AM
> *To:* Rules Dev List
>
> *Subject:* [rules-dev] An odd couple of patterns
>
>
>
> Has anybody ever seen a situation where a couple of patterns such as
>
>
>    Fact( field >= 10 )
>    not Fact( field > 20 )
>
> was appropriate? This does not match Facts where field isn't between 10 and
> 20, and so it would seem to be the same as
>
>    Fact( field >= 10 && <= 20 )
>
> but actually it doesn't match any such Fact whenever any *other* Fact with
> field > 20 is around.
>
> Cheers
> Wolfgang
>
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