[rules-users] Nested properties and memberOf

[Edson Tirelli]

   It does short circuit on "constraints". Not on patterns.

   The problem is your assumption that rules are executed in order. They are
not. Check the manual for "Conflict Resolution".

   Also, the LHS of rules are executed at "insert"/"modify" time, so the LHS
of both rules will be executed before any of them is fired.

   The shortest syntax for your case is to use an mvel inline eval using the
null-safe navigation:

rule X
    dialect "mvel"
when
    ...
    CreditTransferTransactionInformation10( eval( !( accountNumbers contains
dbtrAcct.?id.?othr.?id ) ) )
    ...

   Of course, you can do all the null checks in the pattern itself, avoiding
the need to use the mvel syntax.

   Edson


2010/7/16 Meeraj Kunnumpurath <mkunnumpurath at googlemail.com>

> Thanks Dave.
>
> I think the '||' on rule 1 is getting short-circuited. However, it is the
> '&&' on rule 2 that is not getting short circuited.
>
> Kind regards
> Meeraj
>
> 2010/7/16 David Sinclair <dsinclair at chariotsolutions.com>
>
> Drools doesn't use short circuit evaluation, so all of those ORs are going
>> to be evaluated. You may want to consider re-writing your rules or you can
>> use MVEL's null safe navigation for this. dbtrAcct.?id == null,
>> dbtrAcct.?id.?othr == nulll, etc.
>>
>> dave
>>
>>
>>
>> 2010/7/16 Meeraj Kunnumpurath <mkunnumpurath at googlemail.com>
>>
>>>  Hi,
>>>
>>> I have the following rules,
>>>
>>> global java.util.Set accountNumbers;
>>>
>>> rule "rule 1"
>>> when
>>>     $d : Document()
>>>     $c : CreditTransferTransactionInformation (dbtrAcct == null ||
>>> dbtrAcct.id == null || dbtrAcct.id.othr == null || dbtrAcct.id.othr.id== null) from $d.cstmrCdtTrfInitn.cdtTrfTxInf
>>>     $i : InternalInfo() from $c.internalInfo
>>> then
>>>     $i.setStatus(PaymentStatus.INVALID);
>>>     $i.setErrorCode("PR002");
>>>     $i.setAdditionalInfo("Account number is null");
>>> end
>>>
>>> rule "rule 2"
>>> when
>>>     $d : Document()
>>>     $c : CreditTransferTransactionInformation(internalInfo.status !=
>>> PaymentStatus.INVALID && dbtrAcct.id.othr.id not memberOf
>>> accountNumbers) from $d.cstmrCdtTrfInitn.cdtTrfTxInf
>>>     $i : InternalInfo() from $c.internalInfo
>>> then
>>>     $i.setStatus(PaymentStatus.INVALID);
>>>     $i.setErrorCode("PR002");
>>>     $i.setAdditionalInfo("Account number not available in the routing
>>> table");
>>> end
>>>
>>> My assumption is rule 1 and rule 2 will be executed in the order they
>>> appear. Rule 1 checks all the nested attributes are not null and set the
>>> status as invalid if any of them is null. Rule 2 uses the and operator and
>>> checks the nested attribute is in the collection defined by the global, only
>>> if the object is valid. I assume the LHS of rule 2 will be short circuited
>>> if the object is invalid. However, if any of the nested property is null I
>>> get the following exception from MVEL.
>>>
>>> Caused by: [Error: unable to access property (null parent): id]
>>> [Near : {... Unknown ....}]
>>>              ^
>>> [Line: 1, Column: 0]
>>>     at
>>> org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.getMethod(ReflectiveAccessorOptimizer.java:861)
>>>
>>> Regards
>>> Meeraj
>>>
>>> _______________________________________________
>>> rules-users mailing list
>>> rules-users at lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/rules-users
>>>
>>>
>>
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>
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>


-- 
  Edson Tirelli
  JBoss Drools Core Development
  JBoss by Red Hat @ www.jboss.com
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