[rules-users] correlating two collects

[Yuri de Wit]

Hi Edson,

A follow up question just came up:

I not only need to collect Items that share common properties
(grouping) but I also want to further filter the collect by selecting
only the ones that dont have a related fact.

Just to exemplify, here is what my rule would look like if I were
trying to group two Items:

i : Item()
not ItemEvent( item == i )

i2: Item( a == i.a, b == i.b, ... )
not ItemEvent( item == i2 )

Is that possible to use collect? It seems that I should resort to
accumulate, right?

thanks,

-- yuri



On 8/2/07, Edson Tirelli <tirelli at post.com> wrote:
>
>     Yury,
>
>     Correlation can happen in many ways, but I would say your general
> approach is correct. Answering your questions:
>
> 1. Both collect and accumulate work (as it is today) on single patterns.
> This means whenever you are using collect, you could be using accumulate.
> Just have in mind that accumulate is more powerful and flexible that
> collect, but it is also heavier. So, if collect does what you need, go with
> collect, otherwise fall back to accumulate.
>
> 3. Collect is incremental (on 4.0 GA) for all working memory operations:
> insert/update/retract. Accumulate is always incremental for insert, but for
> modify and retract it is incremental only if you provide the "reverse"
> action in case you are using adhoc operations. If you are using accumulate
> functions, modify and retract are incremental if the function supports
> reverse calculation.
>
>     []s
>     Edson
>
> 2007/8/1, Yuri de Wit <ydewit at gmail.com>:
> >
> > I am finally having some time to use collects. What I basically need
> > to do is to collect items from a list using a specific criteria, then
> > collect items from a diff list using another criteria, and finally
> > compare the groups collected using a 3rd criteria
> >
> > Here is what I am thinking:
> >
> > i : Item(type==A)
> > ig : ItemGroup(size>1)
> >          collect Item(a==i.a, b==i.b, ... n==i.n)
> >
> > i2: Item(type==B)
> > ig2 : ItemGroup( size>1,
> >                          ga== ig.ga, gb==i.gb, .... )
> >          collect Item(a==i.a, b==i.b, ... n==i.n)
> >
> > 1) It is quite nice that any implementation of java.util.Collection
> > can be the resut of collect. ItemGroup here not only keeps hold of all
> > Items returned but has some aggregate properties (afaik, I cannot use
> > the aggregate functions with accumulate since I have multiple column
> > aggregation).
> >
> > 2) Am I on the right track? Or is there a better way?
> >
> > 3) Is the collect recomputed from scratch or incrementally every time
> > a new fact is asserted or updated?
> >
> > thanks
> > _______________________________________________
> > rules-users mailing list
> > rules-users at lists.jboss.org
> > https://lists.jboss.org/mailman/listinfo/rules-users
> >
>
>
>
> --
>   Edson Tirelli
>   Software Engineer - JBoss Rules Core Developer
>   Office: +55 11 3529-6000
>   Mobile: +55 11 9287-5646
>   JBoss, a division of Red Hat @ www.jboss.com
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