Re: [rules-users] About for and inheritance
On 15 January 2011 11:32, Evert Penninckx <evert.penninckx(a)gmail.com> wrote:
I thought I had an error from the drools plugin when using instanceof even
in eval, but I'll try that again, I think I tried eval(this instanceof
...).
You cannot use this in an eval. The eval is "moved out" from the containing
pattern,
and there this has no meaning.
Overloading getLikes() would be more elegant. Still, for me these are
workarounds.
Would it be that strange or unconventional to have the from only match on
the required subclass?
Given that getLikes() is *your *choice of method producing the data, and
that
FrenchCheese is *your *choice of type for the receiver: would it be that
strange
or unconventional to expect you to employ matching types? ;-)
Type checking should not result in the silent elimination of data at
runtime. What
I would expect Drools to tell me is the incompatibility of the from and the
receiving
pattern, at compile time.
-W
Grtz
Evert
Wolfgang Laun-2 wrote:
>
> If smell is a property of Cheese and not just of FrenchCheese you could
> use
>
>
> when
> $person : Person ()
> $c: Cheese( eval( $c instanceof FrenchCheese), smell == "good" )
> from
> $person.getLikes()
> then
>
> Also, I think that a selective retrieval with an overloaded version of
> getLikes():
> getLikes( Class clazz )
> might be useful, avoiding useless elements in the returned collection.
>
> -W
>
>
--
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