[rules-users] calls to 'Helper' classes in LHS - are they allowed?

[Steven Williams]

I believe there is a caveat on functions and helper methods called from the
LHS that they need to be constant over time (or at least over the life of
the working memory) which then allows matches to be computed as per normal.

Steve

On 2/13/07, Michael Suzio <msuzio at gmail.com> wrote:
>
> The JBoss guys can correct me if I'm wrong, but although I think that
> works, what you've just done is eliminate any chance to precompute matches
> and trim down the checks that need to happen to find a rule match.  Since
> the engine can't know that Helper.transform("value") returns a constant
> value, it has to re-run that every time and it has to reject for matches to
> the rule constraint every time.
>
> I'm sure this would really sink performance, in other words.  You can
> easily see the effect -- write the rule this way and time it, and then write
> it with the return value of Helper.transform being inlined, and I'm sure
> there's a big difference.  It's the same as any other eval(...) situation in
> Drools; possible, but not good for performance.
>
> On 2/12/07, Olenin, Vladimir (MOH) <Vladimir.Olenin at moh.gov.on.ca> wrote:
> >
> > Hi,
> >
> > I was wondering if calls to a Helper class are allowed in LHS of the
> > rule?
> > Eg:
> >
> > Rule myRule
> > When
> >         MyObject(objField == Helper.transform("value"))
> > Then
> >        // smth
> > End
> >
> >
> > Thanks,
> >
> > Vlad
> > _______________________________________________
> > rules-users mailing list
> > rules-users at lists.jboss.org
> > https://lists.jboss.org/mailman/listinfo/rules-users
> >
>
>
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>


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Steven Williams

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