[rules-dev] declare LocalEvent @role( event ) end

[Michael Neale]

those sorts of market objects used to be pretty common. Adding in a dummy
field is probably acceptable for now though.

On Thu, Nov 11, 2010 at 3:12 AM, Edson Tirelli <tirelli at post.com> wrote:

>    Wolfgang,
>
>    I am not sure how useful such a no-field control fact is, but
> anyway, feel free to open a JIRA and propose a way to support that
> from a syntax perspective. I.e., we will probably need to use a new
> annotation to allow users to explicitly tell the engine to generate
> the no-field bean, what could be more cumbersome than simply use a
> dummy field in these specific cases.
>
>    Open for suggestions,
>     Edson
>
>
> 2010/11/10 Wolfgang Laun <wolfgang.laun at gmail.com>:
> > I can declare a useful event type which doesn't have any fields
> > except the implicit timestamp and duration. As you've described,
> > the compiler assumes that this is an extension of an imported
> > fact, and complains if this cannot be found.
> >
> > Here is a complete, not too contrived use case.
> >
> > declare Trigger
> >  @role( event )
> >  @expires( 1s )
> >  void: Void         ## required due to compiler's insistence of
> > Trigger being defined elsewhere
> > end
> >
> > rule "1m ticker"
> >    timer(int: 1m 1m)
> > when
> > then
> >    insert( new Trigger() );
> > end
> >
> > rule "count jobs 30 minutes before Trigger"
> > when
> >    $t: Trigger()
> >    Number( $i: intValue > 3 ) from accumulate(
> >       Job( this before[0,30m] $t )
> >       count( 1 ) )
> > then
> >    retract( $t );
> >    System.out.println( "Too many jobs (" + $i + ") at " + clockAsString()
> );
> > end
> >
> > Cheers
> > Wolfgang
> >
> > On 10 November 2010 16:03, Edson Tirelli <tirelli at post.com> wrote:
> >>   Hi Wolfgang,
> >>
> >>   Not sure what is the intent with that?
> >>
> >>   Just to explain the design, the compiler differentiates two use
> >> cases: (1) if a declare has no fields in it, it understands the user
> >> is annotating an existing class. (2) If a declare has at least one
> >> field, then the compiler tries to generate a new class and annotate
> >> it.
> >>
> >>   In case (1) above, if the compiler does not find an existing class,
> >> it (correctly, IMO) raises an error.
> >>
> >>   Can you please clarify?
> >>
> >>   Thanks,
> >>       Edson
> >>
> >> 2010/11/10 Wolfgang Laun <wolfgang.laun at gmail.com>:
> >>> This simple declare for a new (not imported) class isn't permitted by
> >>> the compiler, although it makes sense.
> >>>
> >>> Of course, it's possible to work around by adding a dummy field.
> >>>
> >>> But is this restriction intentional by design, to alert users when
> >>> they misspell a class name, or forget to import a class?
> >>>
> >>> If not, I'll make a request to permit this.
> >>>
> >>> -W
> >>> _______________________________________________
> >>> rules-dev mailing list
> >>> rules-dev at lists.jboss.org
> >>> https://lists.jboss.org/mailman/listinfo/rules-dev
> >>>
> >>
> >>
> >>
> >> --
> >>   Edson Tirelli
> >>   JBoss Drools Core Development
> >>   JBoss by Red Hat @ www.jboss.com
> >>
> >> _______________________________________________
> >> rules-dev mailing list
> >> rules-dev at lists.jboss.org
> >> https://lists.jboss.org/mailman/listinfo/rules-dev
> >>
> >
> > _______________________________________________
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> > rules-dev at lists.jboss.org
> > https://lists.jboss.org/mailman/listinfo/rules-dev
> >
>
>
>
> --
>   Edson Tirelli
>   JBoss Drools Core Development
>   JBoss by Red Hat @ www.jboss.com
>
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>



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