1:34 a.m.
I'm running into an NPE using Drools 4.0.7, and I'm stumped by it (stacktrace
below). I made some changes to seemingly unrelated code, and this error started
showing up. It would help me to understand what's going on if someone could
tell me roughly what's going on here. Since the error is thrown by generated
code (in what I assume is a shadow proxy), I can't tell what the offending null
pointer is. I'm not even entirely sure what's triggering the bug (it happens
half an hour into the run of big multi-threaded application with about 40K
objects in the working memory).
Is this happening because:
*) getRli_nums() in one of my PRRecord objects is returning a null value?
*) There is a null PRRecord object backing the shadow proxy?
*) Some other thing is null?
*) I'm running into a bug in Drools?
I stuck in this rule:
when
$pr : PRRecord( rli_nums == null )
then
System.out.println($pr.getId());
end
And it didn't print anything, so I'm inclined to think that this is not a simple
matter of something returning a null value...
I'll be most appreciative of any help I can get.
Here's the stacktrace:
java.lang.NullPointerException
at
org.drools.base.net.juniper.dash.data.PRRecord13409648$getRli_nums.getValue(Unknown
Source)
at
org.drools.base.ClassFieldExtractor.getValue(ClassFieldExtractor.java:127)
at
org.drools.base.evaluators.BaseMemberOfEvaluator.evaluateCachedRight(BaseMemberOfEvaluator.java:45)
at
org.drools.rule.VariableRestriction.isAllowedCachedRight(VariableRestriction.java:89)
at
org.drools.rule.VariableConstraint.isAllowedCachedRight(VariableConstraint.java:81)
at
org.drools.common.DoubleBetaConstraints.isAllowedCachedRight(DoubleBetaConstraints.java:164)
at org.drools.reteoo.JoinNode.retractObject(JoinNode.java:189)
at
org.drools.reteoo.CompositeObjectSinkAdapter.propagateRetractObject(CompositeObjectSinkAdapter.java:375)
at org.drools.reteoo.ObjectTypeNode.retractObject(ObjectTypeNode.java:189)
at org.drools.reteoo.Rete.retractObject(Rete.java:215)
at org.drools.reteoo.ReteooRuleBase.retractObject(ReteooRuleBase.java:211)
at
org.drools.reteoo.ReteooWorkingMemory.doRetract(ReteooWorkingMemory.java:79)
at
org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1250)
at
org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1203)
at
net.juniper.dash.data.DataSource.reconcileAssertedRecords(DataSource.java:409)
--
Dirk Bergstrom dirk(a)juniper.net
_____________________________________________
Juniper Networks Inc., Computer Geek
Tel: 408.745.3182 Fax: 408.745.8905
8:14 a.m.
Dirk,
The problem seems not related to shadow facts, but to constraint
resolution and fact data extraction. It might be a bug or not... need more
info.
In any case, the offending rule is not the one you showed. The
offending rule contains a double beta constraint in a join:
org.drools.common.
DoubleBetaConstraints.isAllowedCachedRight(DoubleBetaConstraints.java:164)
at org.drools.reteoo.JoinNode.retractObject(JoinNode.java:189)
Can you narrow it down? Did you tried with Drools 5.0.1?
[]s
Edson
2009/6/24 Dirk Bergstrom <dirk(a)juniper.net>
I'm running into an NPE using Drools 4.0.7, and I'm stumped
by it
(stacktrace
below). I made some changes to seemingly unrelated code, and this error
started
showing up. It would help me to understand what's going on if someone
could
tell me roughly what's going on here. Since the error is thrown by
generated
code (in what I assume is a shadow proxy), I can't tell what the offending
null
pointer is. I'm not even entirely sure what's triggering the bug (it
happens
half an hour into the run of big multi-threaded application with about 40K
objects in the working memory).
Is this happening because:
*) getRli_nums() in one of my PRRecord objects is returning a null value?
*) There is a null PRRecord object backing the shadow proxy?
*) Some other thing is null?
*) I'm running into a bug in Drools?
I stuck in this rule:
when
$pr : PRRecord( rli_nums == null )
then
System.out.println($pr.getId());
end
And it didn't print anything, so I'm inclined to think that this is not a
simple
matter of something returning a null value...
I'll be most appreciative of any help I can get.
Here's the stacktrace:
java.lang.NullPointerException
at
org.drools.base.net.juniper.dash.data.PRRecord13409648$getRli_nums.getValue(Unknown
Source)
at
org.drools.base.ClassFieldExtractor.getValue(ClassFieldExtractor.java:127)
at
org.drools.base.evaluators.BaseMemberOfEvaluator.evaluateCachedRight(BaseMemberOfEvaluator.java:45)
at
org.drools.rule.VariableRestriction.isAllowedCachedRight(VariableRestriction.java:89)
at
org.drools.rule.VariableConstraint.isAllowedCachedRight(VariableConstraint.java:81)
at
org.drools.common.DoubleBetaConstraints.isAllowedCachedRight(DoubleBetaConstraints.java:164)
at org.drools.reteoo.JoinNode.retractObject(JoinNode.java:189)
at
org.drools.reteoo.CompositeObjectSinkAdapter.propagateRetractObject(CompositeObjectSinkAdapter.java:375)
at
org.drools.reteoo.ObjectTypeNode.retractObject(ObjectTypeNode.java:189)
at org.drools.reteoo.Rete.retractObject(Rete.java:215)
at
org.drools.reteoo.ReteooRuleBase.retractObject(ReteooRuleBase.java:211)
at
org.drools.reteoo.ReteooWorkingMemory.doRetract(ReteooWorkingMemory.java:79)
at
org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1250)
at
org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1203)
at
net.juniper.dash.data.DataSource.reconcileAssertedRecords(DataSource.java:409)
--
Dirk Bergstrom dirk(a)juniper.net
_____________________________________________
Juniper Networks Inc., Computer Geek
Tel: 408.745.3182 Fax: 408.745.8905
_______________________________________________
rules-users mailing list
rules-users(a)lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users
--
Edson Tirelli
JBoss Drools Core Development
JBoss by Red Hat @ www.jboss.com
1:09 p.m.
Edson Tirelli was heard to exclaim, On 06/24/09 06:14:
The problem seems not related to shadow facts, but to
constraint
resolution and fact data extraction. It might be a bug or not... need
more info.
I've also seen the following stacktrace:
java.lang.ArrayIndexOutOfBoundsException: 40440
at org.drools.util.TupleIndexHashTable.toArray(TupleIndexHashTable.java:217)
at org.drools.reteoo.CollectNode.retractObject(CollectNode.java:260)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateRetractObject(SingleObjectSinkAdapter.java:32)
at org.drools.reteoo.AlphaNode.retractObject(AlphaNode.java:164)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateRetractObject(SingleObjectSinkAdapter.java:32)
at org.drools.reteoo.AlphaNode.retractObject(AlphaNode.java:164)
at
org.drools.reteoo.CompositeObjectSinkAdapter.propagateRetractObject(CompositeObjectSinkAdapter.java:366)
at org.drools.reteoo.ObjectTypeNode.retractObject(ObjectTypeNode.java:189)
at org.drools.reteoo.Rete.retractObject(Rete.java:215)
at org.drools.reteoo.ReteooRuleBase.retractObject(ReteooRuleBase.java:211)
at
org.drools.reteoo.ReteooWorkingMemory.doRetract(ReteooWorkingMemory.java:79)
at
org.drools.common.AbstractWorkingMemory.retract(AbstractWorkingMemory.java:1023)
at
org.drools.common.AbstractWorkingMemory.retract(AbstractWorkingMemory.java:982)
at
net.juniper.dash.data.DataSource.reconcileAssertedRecords(DataSource.java:362)
In any case, the offending rule is not the one you showed. The
offending rule contains a double beta constraint in a join:
I know it's not in that rule. It must be in this one, since it's the only one
that uses rli_nums:
$npi : NPIRecord( )
$pr : PRRecord( npi == "", rli != "" )
$rli : RLIRecord( id memberOf $pr.rli_nums, npi_program == $npi.synopsis )
Can you narrow it down? Did you tried with Drools 5.0.1?
I haven't tried any of the 5.x series. Is there a guide to migrating my code
from 4.0 to 5.0? I looked on the jboss site, the wiki, the blog, and this
mailing list, but I didn't find anything. I'm under a lot of time pressure, and
changing to 5.0 doesn't look like a quick fix...
2009/6/24 Dirk Bergstrom <dirk(a)juniper.net
<mailto:dirk@juniper.net>>
I'm running into an NPE using Drools 4.0.7, and I'm stumped by it
(stacktrace
below). I made some changes to seemingly unrelated code, and this
error started
showing up. It would help me to understand what's going on if
someone could
tell me roughly what's going on here. Since the error is thrown by
generated
code (in what I assume is a shadow proxy), I can't tell what the
offending null
pointer is. I'm not even entirely sure what's triggering the bug
(it happens
half an hour into the run of big multi-threaded application with
about 40K
objects in the working memory).
Is this happening because:
*) getRli_nums() in one of my PRRecord objects is returning a null
value?
*) There is a null PRRecord object backing the shadow proxy?
*) Some other thing is null?
*) I'm running into a bug in Drools?
I stuck in this rule:
when
$pr : PRRecord( rli_nums == null )
then
System.out.println($pr.getId());
end
And it didn't print anything, so I'm inclined to think that this is
not a simple
matter of something returning a null value...
I'll be most appreciative of any help I can get.
Here's the stacktrace:
java.lang.NullPointerException
at
org.drools.base.net.juniper.dash.data.PRRecord13409648$getRli_nums.getValue(Unknown
Source)
at
org.drools.base.ClassFieldExtractor.getValue(ClassFieldExtractor.java:127)
at
org.drools.base.evaluators.BaseMemberOfEvaluator.evaluateCachedRight(BaseMemberOfEvaluator.java:45)
at
org.drools.rule.VariableRestriction.isAllowedCachedRight(VariableRestriction.java:89)
at
org.drools.rule.VariableConstraint.isAllowedCachedRight(VariableConstraint.java:81)
at
org.drools.common.DoubleBetaConstraints.isAllowedCachedRight(DoubleBetaConstraints.java:164)
at org.drools.reteoo.JoinNode.retractObject(JoinNode.java:189)
at
org.drools.reteoo.CompositeObjectSinkAdapter.propagateRetractObject(CompositeObjectSinkAdapter.java:375)
at
org.drools.reteoo.ObjectTypeNode.retractObject(ObjectTypeNode.java:189)
at org.drools.reteoo.Rete.retractObject(Rete.java:215)
at
org.drools.reteoo.ReteooRuleBase.retractObject(ReteooRuleBase.java:211)
at
org.drools.reteoo.ReteooWorkingMemory.doRetract(ReteooWorkingMemory.java:79)
at
org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1250)
at
org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1203)
at
net.juniper.dash.data.DataSource.reconcileAssertedRecords(DataSource.java:409)
--
Dirk Bergstrom dirk(a)juniper.net
_____________________________________________
Juniper Networks Inc., Computer Geek
Tel: 408.745.3182 Fax: 408.745.8905
5:43 p.m.
Dirk
Drools 5 is mostly backward compatible with Drools 4. You don't need to
migrate to the new API, although it is recommended.
Anyway, I understand your concern. My wild wild guess is that the
memberOf operator is complaining about a null in that constraint. If that is
the case, it is a bug. I fixed some bugs like that in Drools 5 trunk:
https://jira.jboss.org/jira/browse/JBRULES-2102
[]s
Edson
2009/6/24 Dirk Bergstrom <dirk(a)juniper.net>
Edson Tirelli was heard to exclaim, On 06/24/09 06:14:
> The problem seems not related to shadow facts, but to constraint
> resolution and fact data extraction. It might be a bug or not... need
> more info.
I've also seen the following stacktrace:
java.lang.ArrayIndexOutOfBoundsException: 40440
at
org.drools.util.TupleIndexHashTable.toArray(TupleIndexHashTable.java:217)
at org.drools.reteoo.CollectNode.retractObject(CollectNode.java:260)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateRetractObject(SingleObjectSinkAdapter.java:32)
at org.drools.reteoo.AlphaNode.retractObject(AlphaNode.java:164)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateRetractObject(SingleObjectSinkAdapter.java:32)
at org.drools.reteoo.AlphaNode.retractObject(AlphaNode.java:164)
at
org.drools.reteoo.CompositeObjectSinkAdapter.propagateRetractObject(CompositeObjectSinkAdapter.java:366)
at
org.drools.reteoo.ObjectTypeNode.retractObject(ObjectTypeNode.java:189)
at org.drools.reteoo.Rete.retractObject(Rete.java:215)
at
org.drools.reteoo.ReteooRuleBase.retractObject(ReteooRuleBase.java:211)
at
org.drools.reteoo.ReteooWorkingMemory.doRetract(ReteooWorkingMemory.java:79)
at
org.drools.common.AbstractWorkingMemory.retract(AbstractWorkingMemory.java:1023)
at
org.drools.common.AbstractWorkingMemory.retract(AbstractWorkingMemory.java:982)
at
net.juniper.dash.data.DataSource.reconcileAssertedRecords(DataSource.java:362)
> In any case, the offending rule is not the one you showed. The
> offending rule contains a double beta constraint in a join:
I know it's not in that rule. It must be in this one, since it's the only
one
that uses rli_nums:
$npi : NPIRecord( )
$pr : PRRecord( npi == "", rli != "" )
$rli : RLIRecord( id memberOf $pr.rli_nums, npi_program == $npi.synopsis )
> Can you narrow it down? Did you tried with Drools 5.0.1?
I haven't tried any of the 5.x series. Is there a guide to migrating my
code
from 4.0 to 5.0? I looked on the jboss site, the wiki, the blog, and this
mailing list, but I didn't find anything. I'm under a lot of time
pressure, and
changing to 5.0 doesn't look like a quick fix...
> 2009/6/24 Dirk Bergstrom <dirk(a)juniper.net <mailto:dirk@juniper.net>>
>
> I'm running into an NPE using Drools 4.0.7, and I'm stumped by it
> (stacktrace
> below). I made some changes to seemingly unrelated code, and this
> error started
> showing up. It would help me to understand what's going on if
> someone could
> tell me roughly what's going on here. Since the error is thrown by
> generated
> code (in what I assume is a shadow proxy), I can't tell what the
> offending null
> pointer is. I'm not even entirely sure what's triggering the bug
> (it happens
> half an hour into the run of big multi-threaded application with
> about 40K
> objects in the working memory).
>
> Is this happening because:
>
> *) getRli_nums() in one of my PRRecord objects is returning a null
> value?
>
> *) There is a null PRRecord object backing the shadow proxy?
>
> *) Some other thing is null?
>
> *) I'm running into a bug in Drools?
>
> I stuck in this rule:
>
> when
> $pr : PRRecord( rli_nums == null )
> then
> System.out.println($pr.getId());
> end
>
> And it didn't print anything, so I'm inclined to think that this is
> not a simple
> matter of something returning a null value...
>
> I'll be most appreciative of any help I can get.
>
> Here's the stacktrace:
>
> java.lang.NullPointerException
> at
>
org.drools.base.net.juniper.dash.data.PRRecord13409648$getRli_nums.getValue(Unknown
> Source)
> at
>
org.drools.base.ClassFieldExtractor.getValue(ClassFieldExtractor.java:127)
> at
>
org.drools.base.evaluators.BaseMemberOfEvaluator.evaluateCachedRight(BaseMemberOfEvaluator.java:45)
> at
>
org.drools.rule.VariableRestriction.isAllowedCachedRight(VariableRestriction.java:89)
> at
>
org.drools.rule.VariableConstraint.isAllowedCachedRight(VariableConstraint.java:81)
> at
>
org.drools.common.DoubleBetaConstraints.isAllowedCachedRight(DoubleBetaConstraints.java:164)
> at org.drools.reteoo.JoinNode.retractObject(JoinNode.java:189)
> at
>
org.drools.reteoo.CompositeObjectSinkAdapter.propagateRetractObject(CompositeObjectSinkAdapter.java:375)
> at
>
org.drools.reteoo.ObjectTypeNode.retractObject(ObjectTypeNode.java:189)
> at org.drools.reteoo.Rete.retractObject(Rete.java:215)
> at
>
org.drools.reteoo.ReteooRuleBase.retractObject(ReteooRuleBase.java:211)
> at
>
org.drools.reteoo.ReteooWorkingMemory.doRetract(ReteooWorkingMemory.java:79)
> at
>
org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1250)
> at
>
org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1203)
> at
>
net.juniper.dash.data.DataSource.reconcileAssertedRecords(DataSource.java:409)
--
Dirk Bergstrom dirk(a)juniper.net
_____________________________________________
Juniper Networks Inc., Computer Geek
Tel: 408.745.3182 Fax: 408.745.8905
_______________________________________________
rules-users mailing list
rules-users(a)lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users
--
Edson Tirelli
JBoss Drools Core Development
JBoss by Red Hat @ www.jboss.com
11:40 a.m.
Edson Tirelli was heard to exclaim, On 06/24/09 15:43:
Drools 5 is mostly backward compatible with Drools 4. You
don't need
to migrate to the new API, although it is recommended.
Ahh, that's good to know. You might want to mention that somewhere in the
release notes, or on the website. It would probably improve the adoption rate.
Anyway, I understand your concern. My wild wild guess is that
the
memberOf operator is complaining about a null in that constraint.
Nope, it's stranger than that. The problem arose because I'd changed the
hashCode() method of the base Record class to a final method. I un-finalized
the method, and the NPEs stopped happening.
I don't understand how this could cause a problem, but I'm pretty sure it's a
bug in Drools. Once I get some free time, I'm going to test the code with 5.0,
and I'll see if the bug shows up there.
2009/6/24 Dirk Bergstrom <dirk(a)juniper.net
<mailto:dirk@juniper.net>>
Edson Tirelli was heard to exclaim, On 06/24/09 06:14:
> The problem seems not related to shadow facts, but to constraint
> resolution and fact data extraction. It might be a bug or not... need
> more info.
I've also seen the following stacktrace:
java.lang.ArrayIndexOutOfBoundsException: 40440
at
org.drools.util.TupleIndexHashTable.toArray(TupleIndexHashTable.java:217)
at
org.drools.reteoo.CollectNode.retractObject(CollectNode.java:260)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateRetractObject(SingleObjectSinkAdapter.java:32)
at org.drools.reteoo.AlphaNode.retractObject(AlphaNode.java:164)
at
org.drools.reteoo.SingleObjectSinkAdapter.propagateRetractObject(SingleObjectSinkAdapter.java:32)
at org.drools.reteoo.AlphaNode.retractObject(AlphaNode.java:164)
at
org.drools.reteoo.CompositeObjectSinkAdapter.propagateRetractObject(CompositeObjectSinkAdapter.java:366)
at
org.drools.reteoo.ObjectTypeNode.retractObject(ObjectTypeNode.java:189)
at org.drools.reteoo.Rete.retractObject(Rete.java:215)
at
org.drools.reteoo.ReteooRuleBase.retractObject(ReteooRuleBase.java:211)
at
org.drools.reteoo.ReteooWorkingMemory.doRetract(ReteooWorkingMemory.java:79)
at
org.drools.common.AbstractWorkingMemory.retract(AbstractWorkingMemory.java:1023)
at
org.drools.common.AbstractWorkingMemory.retract(AbstractWorkingMemory.java:982)
at
net.juniper.dash.data.DataSource.reconcileAssertedRecords(DataSource.java:362)
> In any case, the offending rule is not the one you showed. The
> offending rule contains a double beta constraint in a join:
I know it's not in that rule. It must be in this one, since it's
the only one
that uses rli_nums:
$npi : NPIRecord( )
$pr : PRRecord( npi == "", rli != "" )
$rli : RLIRecord( id memberOf $pr.rli_nums, npi_program ==
$npi.synopsis )
> Can you narrow it down? Did you tried with Drools 5.0.1?
I haven't tried any of the 5.x series. Is there a guide to
migrating my code
from 4.0 to 5.0? I looked on the jboss site, the wiki, the blog,
and this
mailing list, but I didn't find anything. I'm under a lot of time
pressure, and
changing to 5.0 doesn't look like a quick fix...
> 2009/6/24 Dirk Bergstrom <dirk(a)juniper.net
<mailto:dirk@juniper.net> <mailto:dirk@juniper.net
<mailto:dirk@juniper.net>>>
>
> I'm running into an NPE using Drools 4.0.7, and I'm stumped by it
> (stacktrace
> below). I made some changes to seemingly unrelated code, and this
> error started
> showing up. It would help me to understand what's going on if
> someone could
> tell me roughly what's going on here. Since the error is
thrown by
> generated
> code (in what I assume is a shadow proxy), I can't tell what the
> offending null
> pointer is. I'm not even entirely sure what's triggering the bug
> (it happens
> half an hour into the run of big multi-threaded application with
> about 40K
> objects in the working memory).
>
> Is this happening because:
>
> *) getRli_nums() in one of my PRRecord objects is returning a null
> value?
>
> *) There is a null PRRecord object backing the shadow proxy?
>
> *) Some other thing is null?
>
> *) I'm running into a bug in Drools?
>
> I stuck in this rule:
>
> when
> $pr : PRRecord( rli_nums == null )
> then
> System.out.println($pr.getId());
> end
>
> And it didn't print anything, so I'm inclined to think that
this is
> not a simple
> matter of something returning a null value...
>
> I'll be most appreciative of any help I can get.
>
> Here's the stacktrace:
>
> java.lang.NullPointerException
> at
>
org.drools.base.net.juniper.dash.data.PRRecord13409648$getRli_nums.getValue(Unknown
> Source)
> at
>
org.drools.base.ClassFieldExtractor.getValue(ClassFieldExtractor.java:127)
> at
>
org.drools.base.evaluators.BaseMemberOfEvaluator.evaluateCachedRight(BaseMemberOfEvaluator.java:45)
> at
>
org.drools.rule.VariableRestriction.isAllowedCachedRight(VariableRestriction.java:89)
> at
>
org.drools.rule.VariableConstraint.isAllowedCachedRight(VariableConstraint.java:81)
> at
>
org.drools.common.DoubleBetaConstraints.isAllowedCachedRight(DoubleBetaConstraints.java:164)
> at
org.drools.reteoo.JoinNode.retractObject(JoinNode.java:189)
> at
>
org.drools.reteoo.CompositeObjectSinkAdapter.propagateRetractObject(CompositeObjectSinkAdapter.java:375)
> at
>
org.drools.reteoo.ObjectTypeNode.retractObject(ObjectTypeNode.java:189)
> at org.drools.reteoo.Rete.retractObject(Rete.java:215)
> at
>
org.drools.reteoo.ReteooRuleBase.retractObject(ReteooRuleBase.java:211)
> at
>
org.drools.reteoo.ReteooWorkingMemory.doRetract(ReteooWorkingMemory.java:79)
> at
>
org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1250)
> at
>
org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1203)
> at
>
net.juniper.dash.data.DataSource.reconcileAssertedRecords(DataSource.java:409)
--
Dirk Bergstrom dirk(a)juniper.net
_____________________________________________
Juniper Networks Inc., Computer Geek
Tel: 408.745.3182 Fax: 408.745.8905
4:36 p.m.
Oh, ok. Then it is shadow proxy related. :)
Shadow proxies can't override final methods, and if they can't override
them, they can not safely prevent hashcode changes at unsafe points... and
that causes all kind of problems with hashmaps that are used internally.
Drools 5 no longer requires shadow proxies. One more reason to move
forward. :)
[]s
Edson
2009/6/25 Dirk Bergstrom <dirk(a)juniper.net>
Edson Tirelli was heard to exclaim, On 06/24/09 15:43:
> Drools 5 is mostly backward compatible with Drools 4. You don't need
> to migrate to the new API, although it is recommended.
Ahh, that's good to know. You might want to mention that somewhere in the
release notes, or on the website. It would probably improve the adoption
rate.
> Anyway, I understand your concern. My wild wild guess is that the
> memberOf operator is complaining about a null in that constraint.
Nope, it's stranger than that. The problem arose because I'd changed the
hashCode() method of the base Record class to a final method. I
un-finalized
the method, and the NPEs stopped happening.
I don't understand how this could cause a problem, but I'm pretty sure it's
a
bug in Drools. Once I get some free time, I'm going to test the code with
5.0,
and I'll see if the bug shows up there.
> 2009/6/24 Dirk Bergstrom <dirk(a)juniper.net <mailto:dirk@juniper.net>>
>
> Edson Tirelli was heard to exclaim, On 06/24/09 06:14:
> > The problem seems not related to shadow facts, but to
constraint
> > resolution and fact data extraction. It might be a bug or not...
need
> > more info.
>
> I've also seen the following stacktrace:
>
> java.lang.ArrayIndexOutOfBoundsException: 40440
> at
>
org.drools.util.TupleIndexHashTable.toArray(TupleIndexHashTable.java:217)
> at
> org.drools.reteoo.CollectNode.retractObject(CollectNode.java:260)
> at
>
org.drools.reteoo.SingleObjectSinkAdapter.propagateRetractObject(SingleObjectSinkAdapter.java:32)
> at
org.drools.reteoo.AlphaNode.retractObject(AlphaNode.java:164)
> at
>
org.drools.reteoo.SingleObjectSinkAdapter.propagateRetractObject(SingleObjectSinkAdapter.java:32)
> at
org.drools.reteoo.AlphaNode.retractObject(AlphaNode.java:164)
> at
>
org.drools.reteoo.CompositeObjectSinkAdapter.propagateRetractObject(CompositeObjectSinkAdapter.java:366)
> at
>
org.drools.reteoo.ObjectTypeNode.retractObject(ObjectTypeNode.java:189)
> at org.drools.reteoo.Rete.retractObject(Rete.java:215)
> at
>
org.drools.reteoo.ReteooRuleBase.retractObject(ReteooRuleBase.java:211)
> at
>
org.drools.reteoo.ReteooWorkingMemory.doRetract(ReteooWorkingMemory.java:79)
> at
>
org.drools.common.AbstractWorkingMemory.retract(AbstractWorkingMemory.java:1023)
> at
>
org.drools.common.AbstractWorkingMemory.retract(AbstractWorkingMemory.java:982)
> at
>
net.juniper.dash.data.DataSource.reconcileAssertedRecords(DataSource.java:362)
>
> > In any case, the offending rule is not the one you showed.
The
> > offending rule contains a double beta constraint in a join:
>
> I know it's not in that rule. It must be in this one, since it's
> the only one
> that uses rli_nums:
>
> $npi : NPIRecord( )
> $pr : PRRecord( npi == "", rli != "" )
> $rli : RLIRecord( id memberOf $pr.rli_nums, npi_program ==
> $npi.synopsis )
>
> > Can you narrow it down? Did you tried with Drools 5.0.1?
>
> I haven't tried any of the 5.x series. Is there a guide to
> migrating my code
> from 4.0 to 5.0? I looked on the jboss site, the wiki, the blog,
> and this
> mailing list, but I didn't find anything. I'm under a lot of time
> pressure, and
> changing to 5.0 doesn't look like a quick fix...
>
> > 2009/6/24 Dirk Bergstrom <dirk(a)juniper.net
> <mailto:dirk@juniper.net> <mailto:dirk@juniper.net
> <mailto:dirk@juniper.net>>>
> >
> > I'm running into an NPE using Drools 4.0.7, and I'm stumped by
it
> > (stacktrace
> > below). I made some changes to seemingly unrelated code, and
this
> > error started
> > showing up. It would help me to understand what's going on if
> > someone could
> > tell me roughly what's going on here. Since the error is
> thrown by
> > generated
> > code (in what I assume is a shadow proxy), I can't tell what
the
> > offending null
> > pointer is. I'm not even entirely sure what's triggering the
bug
> > (it happens
> > half an hour into the run of big multi-threaded application
with
> > about 40K
> > objects in the working memory).
> >
> > Is this happening because:
> >
> > *) getRli_nums() in one of my PRRecord objects is returning a
null
> > value?
> >
> > *) There is a null PRRecord object backing the shadow proxy?
> >
> > *) Some other thing is null?
> >
> > *) I'm running into a bug in Drools?
> >
> > I stuck in this rule:
> >
> > when
> > $pr : PRRecord( rli_nums == null )
> > then
> > System.out.println($pr.getId());
> > end
> >
> > And it didn't print anything, so I'm inclined to think that
> this is
> > not a simple
> > matter of something returning a null value...
> >
> > I'll be most appreciative of any help I can get.
> >
> > Here's the stacktrace:
> >
> > java.lang.NullPointerException
> > at
> >
>
org.drools.base.net.juniper.dash.data.PRRecord13409648$getRli_nums.getValue(Unknown
> > Source)
> > at
> >
>
org.drools.base.ClassFieldExtractor.getValue(ClassFieldExtractor.java:127)
> > at
> >
>
org.drools.base.evaluators.BaseMemberOfEvaluator.evaluateCachedRight(BaseMemberOfEvaluator.java:45)
> > at
> >
>
org.drools.rule.VariableRestriction.isAllowedCachedRight(VariableRestriction.java:89)
> > at
> >
>
org.drools.rule.VariableConstraint.isAllowedCachedRight(VariableConstraint.java:81)
> > at
> >
>
org.drools.common.DoubleBetaConstraints.isAllowedCachedRight(DoubleBetaConstraints.java:164)
> > at
> org.drools.reteoo.JoinNode.retractObject(JoinNode.java:189)
> > at
> >
>
org.drools.reteoo.CompositeObjectSinkAdapter.propagateRetractObject(CompositeObjectSinkAdapter.java:375)
> > at
> >
>
org.drools.reteoo.ObjectTypeNode.retractObject(ObjectTypeNode.java:189)
> > at org.drools.reteoo.Rete.retractObject(Rete.java:215)
> > at
> >
>
org.drools.reteoo.ReteooRuleBase.retractObject(ReteooRuleBase.java:211)
> > at
> >
>
org.drools.reteoo.ReteooWorkingMemory.doRetract(ReteooWorkingMemory.java:79)
> > at
> >
>
org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1250)
> > at
> >
>
org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1203)
> > at
> >
>
net.juniper.dash.data.DataSource.reconcileAssertedRecords(DataSource.java:409)
--
Dirk Bergstrom dirk(a)juniper.net
_____________________________________________
Juniper Networks Inc., Computer Geek
Tel: 408.745.3182 Fax: 408.745.8905
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--
Edson Tirelli
JBoss Drools Core Development
JBoss by Red Hat @ www.jboss.com
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5 comments
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Edson Tirelli