[rules-users] New to rules engine - help in defining rules

[Edson Tirelli]

   Jeevan,

   Same idea. You need a helper class that will accumulate your value.

   []s
   Edson

Jeevan Tambuluri wrote:

> Thanks Edson! The rule pattern you suggested works for me. Any such 
> pattern to simulate "accumulate" in 3.0.x?
>
> Jeevan
>
> Edson Tirelli wrote:
>
>>
>>    Jeevan,
>>
>>    You are right: the simplest way would be use "forall". 
>> Unfortunatelly it is only available in trunk.
>>    To do it in 3.0.x you will need either a helper attribute or a 
>> helper class. For instance, you may add a "branchLength" attribute to 
>> the tree and define 2 rules:
>>
>> rule "define length"
>> when
>>     $t : Tree( branchLength == -1 )
>>     Branch( mytree == $t, $bl : branch_length )
>> then
>>     $t.setBranchLength( $bl.intValue() );
>>     modify( $t );
>> end
>>
>> rule "check length"
>> when
>>    $t : Tree( $bl : branchLength != -1 )
>>    exists Branch( mytree == $t, branch_length != $bl )
>> then
>>    // do something because the branch has a different length
>> end
>>
>>   There are several variations but you will need 2 rules to emulate 
>> this.
>>   Hopefully the new version will be out soon solving this kind of 
>> problem.
>>
>>   []s
>>   Edson
>>
>> Jeevan Tambuluri wrote:
>>
>>> Hello all,
>>>
>>> I am looking for a way to define rules for the following problem:
>>>
>>> class Tree {
>>> ...
>>> }
>>>
>>> class Branch {
>>>    Tree  mytree;
>>>     int     branch_length;
>>> ...
>>> }
>>>
>>> Let's say I have a fact called Tree and another fact called Branch. 
>>> Brach identifies which tree it belongs to.
>>> Now, I want to write a rule to say that all branches in a tree must 
>>> be of same length.
>>> How do I do this with/without using accumulate or forall?
>>>
>>> Thanks a lot for any help,
>>>
>>> J
>>>
>>> _______________________________________________
>>> rules-users mailing list
>>> rules-users at lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/rules-users
>>>
>>
>>
>
>
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-- 
 Edson Tirelli
 Software Engineer - JBoss Rules Core Developer
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