[rules-users] java.lang.ClassCastException: java.lang.String cannot be cast to com.sample.DroolsTest$Message

[Wolfgang Laun]

You cannot cast an object of type java.lang.String (i.e.
$a as it is bound to "add") to Message.

Apparently you have not understood how "from" works.
(Its various forms are described in the "Expert" manual.)
Most frequently, it is used to "pull" one or more objects,
one at a time, from a fact, in order to permit them to
match a pattern although they have not been inserted
in Working Memory.

What I see in this rule doesn't indicate what you might
have intended to do - so I cannot propose an improved
version.

-W


On 19/01/2012, Veera <veera.se at gmail.com> wrote:
> Hi All,
>
> Can anybody tell me what is the problem here ..
> i have a 2 classes:
>                          person(i have a field in this :java.lang.String
> add)
>                          Message(i have a filed in this :java.lang.String
> name)
> rule "H"
>     when
>           person( $a : add )
>           Message ( name == "tree" ) from $a
>
>     then
>         # System.out.println("in H rule");
>
> when i compile this rule i am getting below exception...
>
> java.lang.ClassCastException: java.lang.String cannot be cast to
> com.sample.DroolsTest$Message
>
> Thanks in Advance....
> Veeras
>
>
>
> --
> View this message in context:
> http://drools.46999.n3.nabble.com/java-lang-ClassCastException-java-lang-String-cannot-be-cast-to-com-sample-DroolsTest-Message-tp3671568p3671568.html
> Sent from the Drools: User forum mailing list archive at Nabble.com.
> _______________________________________________
> rules-users mailing list
> rules-users at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users
>