[rules-users] some pointers for solution
Greg Barton
greg_barton at yahoo.com
Sun Nov 8 20:45:50 EST 2009
Because I keep forgetting the convenience functions exist. :P
--- On Sun, 11/8/09, Edson Tirelli <ed.tirelli at gmail.com> wrote:
> From: Edson Tirelli <ed.tirelli 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, 4:41 PM
>
> 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
>
> >
>
> > >
>
> >
>
> >
>
> >
>
> > _______________________________________________
>
> > rules-users mailing list
>
> > rules-users at lists.jboss.org
>
> > https://lists.jboss.org/mailman/listinfo/rules-users
>
> >
>
> >
>
> >
>
> >
>
> >
>
> > -----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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>
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>
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>
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>
>
>
>
> --
> Edson Tirelli
> JBoss Drools Core Development
> JBoss by Red Hat @ www.jboss.com
>
>
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>
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