[rules-users] Re: About for and inheritance

[Chris Woodrow]

Thanks.
I was supposing so...
Do you think test 3 should throw a ClassCastException or just not match?
Chris

2007/9/27, Edson Tirelli <tirelli at post.com >:
>
>
>    Yes, drools is deferring the type verification until it is needed (in
> your example, to check the constraint). May I ask you please to open a
> JIRA... I will fix that.
>
>   []s
>   Edson
>
> 2007/9/27, Chris Woodrow <woodrow.chris at gmail.com>:
>
> >  I am sorry I didn't mean 'for' but 'from'.
> > :D
> >
> > 2007/9/27, Chris Woodrow < woodrow.chris at gmail.com>:
> > >
> > > Hi,
> > > I recently find out a few issues using for, and I wanted to share it
> > > with you. I made a simple exemple to illustrate my purpose.
> > >
> > > My classes are (I did not represent accessors & constructors):
> > >
> > > public class Cheese {
> > >     protected String name;
> > > }
> > >
> > > public class FrenchCheese extends Cheese{
> > >     private String smell;
> > > }
> > >
> > > public class Person {
> > >     private Cheese likes;
> > > }
> > >
> > > Here is my rule set :
> > >
> > > package rules
> > >
> > > rule "likes cheese"
> > >     when
> > >         $person : Person ()
> > >         Cheese(  ) from $person.getLikes()
> > >     then
> > >         System.out.println ("likes cheese");
> > > end
> > >
> > >
> > > rule "likes french cheese"
> > >     when
> > >         $person : Person ()
> > >         FrenchCheese(  ) from $person.getLikes()
> > >     then
> > >         System.out.println ("likes french cheese");
> > > end
> > >
> > > First test :
> > >         Cheese cheese = new FrenchCheese("good", "camembert");
> > >         Person person = new Person();
> > >         person.setLikes(cheese);
> > >
> > > Output :
> > > likes french cheese
> > > likes cheese
> > >
> > > Wich is expected...
> > >
> > > Second test :
> > >         Cheese cheese = new Cheese();
> > >         Person person = new Person();
> > >         person.setLikes(cheese);
> > >
> > > Output :
> > > likes french cheese
> > > likes cheese
> > >
> > > That's the first strange thing. As far as I am concerned, rule "likes
> > > french cheese" should not match (since a Cheese is not a FrenchCheese).
> > >
> > > I made a change to the second rule :
> > > rule "likes french cheese"
> > >     when
> > >         $person : Person ()
> > >         FrenchCheese( smell == "good" ) from $person.getLikes()
> > >     then
> > >         System.out.println("likes french cheese");
> > > end
> > >
> > > Third test :
> > >         Cheese cheese = new Cheese();
> > >         Person person = new Person();
> > >         person.setLikes(cheese);
> > >
> > > output :
> > > It throwed an exception : Exception in thread "main"
> > > java.lang.ClassCastException: rules.Cheese
> > > I am not saying the ClassCastException is not to expect in such a case
> > > but I think I would simply expect it not to match (as far as a Cheese is not
> > > a FrenchCheese).
> > >
> > > Chris
> > >
> >
> >
> > _______________________________________________
> > rules-users mailing list
> > rules-users at lists.jboss.org
> > https://lists.jboss.org/mailman/listinfo/rules-users
> >
> >
>
>
> --
>   Edson Tirelli
>   Software Engineer - JBoss Rules Core Developer
>   Office: +55 11 3529-6000
>   Mobile: +55 11 9287-5646
>   JBoss, a division of Red Hat @ www.jboss.com
> _______________________________________________
> rules-users mailing list
> rules-users at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.jboss.org/pipermail/rules-users/attachments/20070927/8d07097f/attachment.html