[rules-dev] Question about Metadata for Rules

[Michael Neale]

not at the moment - there have been some thoughts along those lines
though - that it may be useful to have them.

personally I find the @ syntax in java horrible, but hey, thats just me ;)

The rule attributes in a sense are attributes already - it woudl be a
matter of extending that to be user defined values that you can use at
runtime or however you need to.


On Sun, May 18, 2008 at 7:41 PM, tservas <tservas at web.de> wrote:
>
> Hello everybody,
>
> I have a simple question about annotations for rules. Is it possible to add
> metadata
> to a rule in the following or in a similar way?
>
> ------------------------------------------------------------------------------------------------
> @CostumAnnotation(ruleType=RuleType.GOOD, otherInformation="This rule ist
> very important since ...")
> rule "A rule with metadata"
> when
>    eval(true)
> then
>
> System.out.println(drools.getRule().getAnnotation(CostumAnnotation.class).toString());
> end
> ------------------------------------------------------------------------------------------------
> The annotatons should also be accesible within my java program otherwise it
> wouldn't be very useful at all. So for example I should be able to do the
> following
>
> Package[] packages = ruleBase.getPackages();
> for (Package pack : packages) {
>    Rule[] rules = pack.getRules();
>    for (Rule rule : rules) {
>        rule.getAnnotation(CostumAnnotation.class).toString();
>    }
> }
>
> Why would I like to have such meta information along with my rules in one
> file? ... here it comes ...
>
> The result of firing all my rules is a list of all rules (whether they have
> been fired or not)
> with certain meta information.
> On the lhs of each rule I append an entry to that list with all the meta
> information. Depending
> on the inserted facts only a subset of all my rules fires and only a few
> rules will add entries to
> the list. My problem is that I want the rules that havn't been fired to
> appear in the list with all
> the meta information.
>
> A possible but not feasible solution would be to double all my rules. For
> each rule I could
> add second rule that fires if the original rule doesn't fire and this newly
> added rule inserts the
> entry in the list with all the meta information. Doubling the number of
> rules makes editing rules
> error prone and tedious.
>
> Another strategy could be to put all the meta information in a separate
> file. Via the rule name
> all meta information could be uniquely assigned to one rule. This strategy
> is also not very appealing
> since I have a lot of rules and editing rules again becomes error prone and
> tedious, since I have to
> keep the metadata file in sync.
>
> The by far best solution I can think of is to allow annotaions in the drl
> file as shown above.
>
> Any hints or suggestions about the stated problem are highly appreciated.
>
> Thanks in advance
>
> --
> View this message in context: http://www.nabble.com/Question-about-Metadata-for-Rules-tp17300617p17300617.html
> Sent from the drools - dev mailing list archive at Nabble.com.
>
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>



-- 
Michael D Neale
home: www.michaelneale.net
blog: michaelneale.blogspot.com