Re: [rules-dev] declare LocalEvent @role( event ) end
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(a)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(a)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
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>
--
Edson Tirelli
JBoss Drools Core Development
JBoss by Red Hat @ www.jboss.com
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