2010/7/16 David Sinclair <dsinclair@chariotsolutions.com>

Ah, sorry, didn't realize that syntax wasn't supported in Drools. That being said, your rules may not fire in the order they are defined. (I forget what the default behavior as far as which rule would be activated first if all conditions were satisfied).

What exactly are you trying to accomplish? It may be easier to write rules if you assert more of your object model into WM as opposed to the deep nesting. You'll also get performance improvements by doing so.

dave

2010/7/16 Meeraj Kunnumpurath <mkunnumpurath@googlemail.com>
Hi Dave,

I tried the null-safe navigation as below,

rule "Check debtor account number exists"
    salience 1
when
    $c : CreditTransferTransactionInformation10(dbtrAcct.?id.?othr.?id not memberOf accountNumbers)
    eval(!accountNumbers.contains($accountNumber))
then
    System.err.println($c.getInternalInfo().getStatus());
    System.err.println("Rule 2 executed");
end

I get the error

[29,57]: [ERR 102] Line 29:57 mismatched input '?' expecting 'identifier' in rule "Check debtor account number exists" in pattern CreditTransferTransactionInformation10
[29,61]: [ERR 102] Line 29:61 mismatched input '?' expecting 'identifier' in rule "Check debtor account number exists" in pattern CreditTransferTransactionInformation10
[29,67]: [ERR 102] Line 29:67 mismatched input '?' expecting 'identifier' in rule "Check debtor account number exists" in pattern CreditTransferTransactionInformation10

Thanks
Meeraj

On Fri, Jul 16, 2010 at 5:04 PM, Meeraj Kunnumpurath <mkunnumpurath@googlemail.com> wrote:

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@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@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

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