[rules-users] doubt regarding FORALL and contains operator...

[Edson Tirelli]

   Sudhir,

   As I said in my previous e-mail, in case 1, it is the expected behavior.

http://en.wikipedia.org/wiki/First-order_logic

   If you want to ensure that there is at least one Vehicle AND for all
Vehicles the model is bmw, write your rule as:

when
    exists( Vehicle() )
    forall( Vehicle( model == "bmw" ) )
then
    // do something...
end

   []s
   Edson

2009/2/3 Sudhir M <sudhir.cse at gmail.com>

> Hi Edson,
>
> Thanks for a quick reply.
> Regarding the second second point I will open an issue in JIRA.
>
> Regarding  the first one is that a bug as well? since I haven't assert any
> of the vehicle instances  I suppose the rule shouldn't fire right? But the
> rule is firing always.
>
> Thanks,
> sudhir.
>
>
> On Tue, Feb 3, 2009 at 6:49 PM, Edson Tirelli <tirelli at post.com> wrote:
>
>>
>>     Regarding 1, it is the expected behavior, since there is no vehicle in
>> the wm whose model is not "bmw".
>>
>>     Regarding 2, probably a bug. Can you please open a JIRA with a test
>> case?
>>
>>     []s
>>     Edson
>>
>> 2009/2/3 Sudhir M <sudhir.cse at gmail.com>
>>
>>>  Hi ALL,
>>> We are using drools 4.0.7  for one of our projects. We encountered some
>>> issues which I thought are strange.
>>>
>>> 1. When using FORALL on an entity for which we haven't asserted any of
>>> the instances in the working memory the rule always fires. I thought this
>>> rule should be evaluted to true only if all the asserted instances satisfy
>>> the condition and if we don't insert any of the instances in the working
>>> memory it should no fire the rule. Is this the expected behaviour or am I
>>> wrong?
>>>
>>>   ex: rule "rule1"
>>>  when
>>> forall (
>>>  Vehicle( model == "bmw" )
>>>  )
>>>
>>>  then
>>>                 System.out.println("in forall");end
>>>
>>> 2. When using 'contains' operator on array or collection of strings its
>>> working fine. But when we use it for an array of primitive type double it
>>> gives a classcastexception . Is auto boxing not supported? May be this is
>>> fine as it mentioned in the documentation that it works only on Objects. I
>>> tried using the array of Double objects, here it doesn't throw an excpetion
>>> but the rule wasn't firing. The behaviour was same even if I use a
>>> collection of Double objects. Is this a bug or am I missing something?
>>>
>>>  ex:
>>> using Array
>>>
>>>      rule "OrderArray"
>>>  when
>>>
>>>  Order(valueArray contains 0)
>>>
>>>  then
>>>              System.out.println("OrderArray");
>>> end.
>>>
>>> using Collection
>>>
>>>
>>>  rule "OrderList"
>>>  when
>>>
>>>  Order(valueList contains 0)
>>>
>>>  then
>>>              System.out.println("OrderList");
>>> end.
>>>
>>> May be for collections I can write it as below
>>>
>>>
>>> rule "OrderList"
>>>  when
>>>
>>> $order : Order( $val:valueList)
>>>               Double(doubleValue   ==0) from $val
>>>
>>>  then
>>>        System.out.println("OrderList");
>>> end.   but this working but not intuitive as these rules were maintained
>>> later by a business user it will be easy for him if we contains and also if
>>> we can directly use array instead of collections it would be a great as
>>> current BOM uses arrays everywhere.
>>>
>>> Thanks,
>>> sudhir.
>>>
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> rules-users mailing list
>>> rules-users at lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/rules-users
>>>
>>>
>>
>>
>> --
>>  Edson Tirelli
>>  JBoss Drools Core Development
>>  JBoss, a division of Red Hat @ www.jboss.com
>>
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>>
>>
>
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-- 
 Edson Tirelli
 JBoss Drools Core Development
 JBoss, a division of Red Hat @ www.jboss.com
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