[rules-users] rules for promotional offers

[Sandeep Bandela]

Hi Wolfgang,
This is what I did initially but for product > 2 I didnt find a generic way
to do this. following is my first rule. I didnt use field names because it
was giving error that member is not accessible. I will attach the errors of
each case in a few mins.

rule "Apply 10% discount if you purchase 2 items"
    dialect "java"
    when
        $s1 : CartItem( getProductId() == 236061, !isProcessed())
        $s2 : CartItem( getProductId() == 236061, getId() != $s1.getId(),
!isProcessed())
        $m : RuleMessage()
 then
        $m.addMessage("Found item1: " + $s1.getName() + " id:
"+$s1.getId());
        $m.addMessage("Found item2: " + $s2.getName() + " id:
"+$s2.getId());
        modify($s1){
        setProcessed(true),
        setPromoItemDiscount($s1.getPrice() * 0.1),
        setPromoId("1"),
        setBundleId(bundler.getId()),
        setAggrigatorId(1)
        };
        modify($s2){
        setProcessed(true),
        setPromoItemDiscount($s2.getPrice() * 0.1),
        setPromoId("1"),
        setBundleId(bundler.getId()),
        setAggrigatorId(1)
        };
        bundler.increment();
end

2011/9/9 Wolfgang Laun <wolfgang.laun at gmail.com>

> Your rule exhibits procedural thinking. (For an aspiring rule programmer
> his is typical teething troubles.)
>
> There's no need to collect all A's and B's in order to determine their
> number being greater than one or two - this is achieved automatically by a
> simple triple match rule. Consider
>
> rule "2A - 1B"
> when
>    $a1: CartItem( productId == "A", processed == false )
>    $a2: CartItem( this != $a1, productId == "A", processed == false )
>    $b: CartItem( productId == "B", processed == false )
> then
>    modify( $a1 ){...}
>    modify( $a2 ){...}
>    modify( $b ){...}
> end
>
> Note:
>
>    - The modify is essential. (When you say "doesn't work", always provide
>    details.)
>    - Use the field name rather than the getter call - it improves
>    readability.
>    - I'm not sure whether 5.2.0 final handles boolean fields correctly -
>    IIRC, there were some issues. It's possible that CartItem(..., !processed)
>    works.
>
> -W
>
> 2011/9/8 Sandeep Bandela <gibsosmat at gmail.com>
>
>> Hi,
>> I am new to rules engine, after going through the examples shipped
>> (shopping.drl, petstore.drl)
>> I am trying to implement promotional discounting using drools 5.2.0 final,
>> stateful session. assume cart has all the items that customer wants to buy,
>> I am trying to bundle them together with the existing offers
>>
>> rule "Buy X units of Product A and Get Y units of Product B Free"
>>     dialect "java"
>> when
>>     $itemsA : ArrayList( size >= 2) from collect( CartItem( getProductId()
>> == "A", !isProcessed()))
>>     $itemsB : ArrayList( size >= 1) from collect( CartItem( getProductId()
>> == "B", !isProcessed()))
>> then
>>     // current scenario buy 2*A and get 1*B
>>     int x = 2;
>>     int y = 1;
>>     for(int i=0 ; i < x ; i++){
>>         CartItem $ci = (CartItem) $itemsA.get(i);
>>         // modify($ci){setProcessed(true) ... } dosent work
>>         $ci.setProcessed(true);
>>         $ci.setItemDiscount(0.0);
>>         $ci.setBundleId(bundler.getId());
>>     }
>>
>>     for(int i=0 ; i < y  ; i++){
>>         CartItem $ci = (CartItem) $itemsB.get(i);
>>         $ci.setProcessed(true);
>>         $ci.setItemDiscount($ci.getPrice());
>>         $ci.setBundleId(bundler.getId());
>>     }
>>     // global counter to identify bundled items
>>     bundler.increment();
>> end
>>
>> the above rule calculates only for 1 set of offer i.e first 2*A & 1*B are
>> considered, rest in the cart are not bundled.
>> if customer buys 4*A + 2*B it dosent consider it. am I missing anything?
>> is this the right way to do it?
>> any feedback is appreciated.
>>
>>
>>
>>
>> --
>> Regards,
>> Sandeep Bandela.
>>
>>
>> _______________________________________________
>> rules-users mailing list
>> rules-users at lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/rules-users
>>
>>
>
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>


-- 
Regards,
Sandeep Bandela.
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