Re: [rules-users] some pointers for solution

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(a)gmail.com&gt; wrote: > From: Wishing Carebear <wishing.carebear(a)gmail.com&gt; > Subject: Re: [rules-users] some pointers for solution > To: "Rules Users List" <rules-users(a)lists.jboss.org&gt; > 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(a)yahoo.com&gt; > > 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(a)gmail.com&gt; > wrote: > > > From: Wishing Carebear <wishing.carebear(a)gmail.com&gt; > > > Subject: [rules-users] some pointers for solution > > To: rules-users(a)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(a)lists.jboss.org > > https://lists.jboss.org/mailman/listinfo/rules-users > > > > > > > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > > > > > > -----Inline Attachment Follows----- > > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users