Hi! I'm new here and a have a doubt about rules and functions in Drools.

I have this rule:

rule "ProductDescription validation"
    when
        $listing : Listing( $description:productDescription != null )
        eval( $description.getTitle() != null )
        eval( hasForbiddenWordsSet( wordsSet, $description.getTitle() ) )
    then
        System.out.println("ERROR!");
end

And this function:

function boolean hasForbiddenWordsSet(Set wordsSet, String value) {
#do something useful here
}


And everything works fine. But now I want that function "hasForbiddenWordsSet" return a String. For example to print at "then".
I tried something like this:

rule "ProductDescription validation"
    when
        $listing : Listing( $description:productDescription != null )
        eval( $description.getTitle() != null )
        $word : hasForbiddenWordsSet( wordsSet, $description.getTitle() )
    then
        System.out.println("ERROR: " + word);
end

function String hasForbiddenWordsSet(Set wordsSet, String value) {
#do something useful here
}

But it doesn't work, tried some other things and still no success.

Could someone help me?

Thanks in advance.

--
Leandro Carvalho