[rules-users] some pointers for solution

[Edson Tirelli]

   Why not use count() accumulate function? ;)

from accumulate( Criteria( this memberOf d, this memberOf q ),
                           count(1) )

   Edson

2009/11/8 Greg Barton <greg_barton at yahoo.com>

> In this case the accumulate clause is maintaining a counter (total) that's
> incremented whenever a Criteria is detected that is contained in both the
> Data and Query object matched in the rule.  So:
>
> # Find Criteria that are contained in both the Data and Query
> from accumulate( Criteria( this memberOf d, this memberOf q ),
> # Initialize the counter to 0
>  init( int total = 0; ),
> # Increment when the above condition is  matched
>  action( total ++; ),
> # Decrement if a matched Criteria now fails to match
>  reverse( total --; ),
> # return the total when all known Criteria are matched
>  result( total ) )
>
> --- On Sun, 11/8/09, Wishing Carebear <wishing.carebear at gmail.com> wrote:
>
> > From: Wishing Carebear <wishing.carebear at gmail.com>
> > Subject: Re: [rules-users] some pointers for solution
> > To: "Rules Users List" <rules-users at lists.jboss.org>
> > Date: Sunday, November 8, 2009, 11:39 AM
> > Hi Greg:
> > I'm trying to understand your first
> > solution.
> >
> > Ran the project and it works fine. If possible could
> > you explain me little bit on :
> >
> > from accumulate( Criteria( this memberOf d,
> > this memberOf q ),
> > init( int total = 0; ),
> > action( total ++; ),
> > reverse( total --; ),
> > result( total ) )
> >
> >
> > Thanks,
> > cabear
> >
> >
> > 2009/11/8 Greg Barton <greg_barton at yahoo.com>
> >
> > There are a couple of
> > ways to do this.  I'm sure there's a bit more clean
> > way than the example I'm providing, but this should get
> > you in the right direction.  It's not 100% rules,
> > because it involves a bit of java collections trickery. (See
> > attached project, collection_DroolsCriteriaMatch.tar.gz)
> >
> >
> > The heart of it is a single rule:
> >
> > rule "Match"
> >  when
> >    d : Data()
> >    q : Query( size <= d.size )
> >    Number( intValue == q.size )
> >    from accumulate(
> >      Criteria( this memberOf d, this memberOf q ),
> >
> >      init( int total = 0; ),
> >      action( total ++; ),
> >      reverse( total --; ),
> >      result( total )
> >    )
> >  then
> >    System.out.println("Match: " + d + "
> > and " + q) ;
> > end
> >
> > The Data object holds data to be queried, Query objects are
> > asserted to match the Data, and Criteria objects can be
> > contained in either. (With the aforementioned collections
> > trickery that if a Criteria is contained in a Query it can
> > be found in a Data object, but the reverse isn't true.
> >  See the Query.contains(Object) method for how that's
> > implemented.)
> >
> >
> > So the rule above basically says "There's a Data
> > object, and all of the Query objects Criteria are contained
> > in the Data object."
> >
> > There's an alternate way of doing this using eval and a
> > bit more java fu.  See the eval_DroolsCriteriaMatch.tar.gz
> > project attached.  This one's probably not optimal,
> > though, as it's basically a brute force check of all
> > Data objects against the asserted Query.
> >
> >
> > I tried for a while to get a solution working with
> > different criteria types from both Data and Query objects
> > being asserted into working memory, but I couldn't get
> > the accumulate syntax right.  Anyone know of a way to do
> > that? (I figure that would get a "pure rules"
> > solution.)
> >
> >
> > --- On Sat, 11/7/09, Wishing Carebear <wishing.carebear at gmail.com>
> > wrote:
> >
> > > From: Wishing Carebear <wishing.carebear at gmail.com>
> >
> > > Subject: [rules-users] some pointers for solution
> > > To: rules-users at lists.jboss.org
> > > Date: Saturday, November 7, 2009, 10:19 PM
> >
> >
> >
> > > Hello:
> > > There are n selection criteria from s1 .. sn for each
> > > item i1.. in. Each item can have a subset of criteria
> > which
> > > applies to them.
> > >
> > > The end user, can choose a subset of criteria like c1
> >
> > > and c5 and only the item that has c1 and c5 valid
> > should be
> > > returned. For example: if item i1 and i2 have
> > criterias
> > > valid for c1, c2, c5, c6, c8 since the request is only
> > for
> > > criteria c1 and c5, i1 and i2 must be returned.
> >
> > >
> > >
> > > Is it possible to write a rule using drools for this
> > > requirement.
> > >
> > > Thanks for your help and time,
> > > cabear
> > >
> > > -----Inline Attachment Follows-----
> >
> > >
> > > _______________________________________________
> > > rules-users mailing list
> > > rules-users at lists.jboss.org
> > > https://lists.jboss.org/mailman/listinfo/rules-users
> >
> > >
> >
> >
> >
> > _______________________________________________
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> > rules-users at lists.jboss.org
> > https://lists.jboss.org/mailman/listinfo/rules-users
> >
> >
> >
> >
> >
> > -----Inline Attachment Follows-----
> >
> > _______________________________________________
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> > rules-users at lists.jboss.org
> > https://lists.jboss.org/mailman/listinfo/rules-users
> >
>
>
>
>
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-- 
 Edson Tirelli
 JBoss Drools Core Development
 JBoss by Red Hat @ www.jboss.com
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