[rules-users] Collecting / sorting by the number of matches

[David Sinclair]

Take a look at the *AgendaEventListener*. It allows you to get callbacks for
when a rule has fired. This would allow you to keep track of which rules
fire along with the objects that caused it to fire.

On Wed, Aug 19, 2009 at 4:27 AM, KDR <dr.soprano at neverbox.com> wrote:

>
> Hi, ta very much everyone for the help so far.
>
> Another question - how to sort by number of matches please?
>
> Say I have objects A, B, C and D and rules 1 to 5. Each object can match
> each rule independently e.g. A can match rule 1 and 2, B might match all
> rules 1 to 5, C might match none, D rules 3 and 4 etc.
>
> I need to rank them and then print out info about them in order of number
> of
> matches, with an indication of which rules matched, i.e. print info on B
> before A but nothing at all on C, etc.
>
> In Java I'd probably do it by having, as a global variable, a map where the
> key is the name or ID field of the object and the value is an arraylist
> which gets added to in the consequence (with a string about what kind of
> match it was i.e. which rule was matched) whenever there's a match on a
> rule
> for that object. Then sort it by descending length of the arraylists.
>
> There has to be a better and more elegant way of doing it in Drools,
> probably involving collecting info on the matches and then sorting them,
> but
> I can't think what or how.
>
> Does anyone have any thoughts or suggestions please?
>
> Many thanks in advance.
>
> --
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> http://www.nabble.com/Collecting---sorting-by-the-number-of-matches-tp25039921p25039921.html
> Sent from the drools - user mailing list archive at Nabble.com.
>
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