[rules-users] FW: Basic rules question

Mon May 9 06:22:05 EDT 2011

Abhay,

Do you need a list?

You can assign RAM to COMPUTERS with this:-

when
    $c : Computer( $type : type )
    $r : RAM( compatibleWith == $type )
then
   $c.addRAM( $r );
end

This would add all RAM (in Working Memory) compatible with COMPUTER to
computer.

You could use a list of RAM as a Fact in WM and change your rule to use
that:-

when
    $l : MyList( )
    $c : Computer( $type : type )
    $r : RAM( compatibleWith == $type ) from $l
then
    $c.addRAM( $r );
end

Or you can define a rule to construct the list too:-

when
    $l : MyList( $t : typeRAM )
    RAM( $c : $t )
then
    $l.add( $r )
end

I assume you'd need to differentiate different lists for different types; so
I have shown use of "MyList" which could subclass ArrayList and have a "Type
of RAM" attribute. Drools doesn't "do" generics.

With kind regards,

Mike

2011/5/9 Abhay B. Chaware <Abhay.Chaware at kpitcummins.com>

>
>
> Wendy,
>
>
>
> Thanks for helping me out so far.
>
>
>
> I have another question. What if I have all my “RAM” objects inserted into
> working memory.   How should I write my rule’s “when” portion to get a
> collection of all the RAM objects matching type “DDR” ?  In other words, can
> I get collection of facts assigned to a variable and use it in the “then”
> part ?
>
>
>
> Thanks
>
> Abhay
>
>
>
> ==================================
>
> *From:* rules-users-bounces at lists.jboss.org [mailto:
> rules-users-bounces at lists.jboss.org] *On Behalf Of *Wendy Mungovan
> *Sent:* Friday, May 06, 2011 5:47 PM
> *To:* Rules Users List
> *Subject:* Re: [rules-users] Basic rules question
>
>
>
>
>
> Q2:
>   So the rule would be something like:
>
> rule "RAM type"
>   when
>      $product: Product(type == "laptop");
>  then
>      //you are looking for the best way to set valid RAM types in the then
> part of the rule?
>     $product.setRamType("DDR");
>     //or
>    $product.setValidRamOptions( getValidRamOptions("DDR"));
>  end
>
> where getValidRamOptions would be a custom function included through
> 'import function' so you can then load the choices from some where else.  Or
> if RamOptions were an object in memory you could have a rule like:
>
> rule "RAM type"
>   when
>      $product: Product(type == "laptop");
>      $ramOptions: RAMOptions(type == "DDR");
>
>  then
>    $product.setValidRamOptions( $ramOptions.getList());
>  end
>
>
>
>
> Wendy
>
>
>
> ==================================
>
>
>
> Regards,
>
>
>
> Abhay Chaware
>
> Sr. Designer | KPIT Cummins Infosystems Ltd | Board: +91 020 6652 5000 |
> Extn: 2989  | abhay.chaware at kpitcummins.com |www.kpitcummins.com
>
> P Please consider the environment before printing this e-mail
>   ------------------------------
>
> *From:* rules-users-bounces at lists.jboss.org [mailto:
> rules-users-bounces at lists.jboss.org] *On Behalf Of *Wendy Mungovan
> *Sent:* Friday, May 06, 2011 5:47 PM
> *To:* Rules Users List
> *Subject:* Re: [rules-users] Basic rules question
>
>
>
> Abhay,
>   Q1:  I think that this will depend on how many different products you
> have.  If there is a small number it is more straight forward to have a rule
> for each one (so the 2nd option).  This allows all you logic to be in one
> place.  If there are a large number of products and writing a rule for each
> one is intractable you probably would want to look into some generalizations
> of the rules.  Is that helpful?
>
>   Q2: I'm not quite sure what you are getting at in Q2.  Are you trying to
> write validation rules or rules that are modifying the facts?
>
>
>
> Wendy
>  ------------------------------
>
> *From:* Abhay B. Chaware <Abhay.Chaware at kpitcummins.com>
> *To:* "rules-users at lists.jboss.org" <rules-users at lists.jboss.org>
> *Sent:* Fri, May 6, 2011 4:59:46 AM
> *Subject:* [rules-users] Basic rules question
>
> Hi
>
>
>
> I am a newbie to rule based applications and trying to get the concept of
> rules. I have couple of questions about rules to start with, not
> specifically about Drools though.
>
>
>
> Q1 - Should rules be data/model specific or can/should they be generic or
> both
>
> ==========================================================
>
> e.g.
>
> If selected product “TYPE” is “laptop”, then category “RAM” should have all
> “DDR” type items compatible ( selecting items matching certain property )
>
> OR
>
> If selected product is “IBM T42”, then category “RAM” should have “512MB
> DDR” , “1024MB DDR”, “2048MB DDR”  compatible. ( assigning individual items
> in rules )
>
> OR
>
> Combination of both
>
>
>
>
>
> Q2 – How should be the data modeled in above case
>
> ==========================================================
>
> e.g.
>
> in product master, each item ( e.g. T40, T42 ) should have a “TYPE” ( e.g.
> desktop or laptop ) , all items in category “RAM” should have a “TYPE” (
> e.g. DDR ) and then control the assignment of RAM options to the PRODUCT
> through Rule using “DDR” type ?
>
> OR
>
> in product master, each item ( e.g. T40, T42 ) should have a “TYPE” ( e.g.
> desktop or laptop ) , all items in category “RAM”  should have a
> “compatibleProduct” column ( e.g. desktop or laptop ) and control the
> assignment of RAM to PRODUCT through “dynamic” rules by selecting all the
> RAMs by passing the “TYPE” of the product to the database handler.
>
>
>
> Am I making my point clear ?
>
>
>
> Thanks
>
> Abhay
>
>
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