[JBoss JIRA] Created: (JBRULES-1511) Can only reason over sub-objects if you use the From Conditional Element
2:04 p.m.
Can only reason over sub-objects if you use the From Conditional Element
------------------------------------------------------------------------
Key: JBRULES-1511
URL: http://jira.jboss.com/jira/browse/JBRULES-1511
Project: JBoss Drools
Issue Type: Bug
Security Level: Public (Everyone can see)
Components: Reteoo
Affects Versions: 4.0.4
Reporter: Aaron Dixon
Assigned To: Mark Proctor
It appears that you MUST use the From Condition Element to reason over sub-objects or else
Drools yields unpredictable behavior.
The first two rules below appear to be semantically equivalent. However the
"bad" rule (the rule that does not use the from conditional element) does not
get activated correctly when there is another rule (see the third rule) that modifies the
age sub-property before the first two rules are activated:
rule "Older than 20 - Good"
salience -100
when
person : Person( )
Details( age > 20 ) from person.details
then
System.out.println( "Older than 20 (good) : " + person );
end
rule "Older than 20 - Bad"
salience -100
when
person : Person( details.age > 20 )
then
System.out.println( "Older than 20 (bad) : " + person );
end
rule "30 is the new 20"
when
person : Person( details.age == 30 )
then
person.getDetails().setAge( 20 );
System.out.println( "Now 20 : " + person );
update( person );
end
Given that the "bad" rule is semantically equivalent to the second rule, Drools
should treat both rules the same in the engine. See the referenced forum thread for
further justification for this claim.
Also, see the attached zip for an executable example.
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2:06 p.m.
New subject: [JBoss JIRA] Updated: (JBRULES-1511) Can only reason over sub-objects if you use the From Conditional Element
[ http://jira.jboss.com/jira/browse/JBRULES-1511?page=all ]
Aaron Dixon updated JBRULES-1511:
---------------------------------
Attachment: drools-issue.zip
Can only reason over sub-objects if you use the From Conditional
Element
------------------------------------------------------------------------
Key: JBRULES-1511
URL: http://jira.jboss.com/jira/browse/JBRULES-1511
Project: JBoss Drools
Issue Type: Bug
Security Level: Public(Everyone can see)
Components: Reteoo
Affects Versions: 4.0.4
Reporter: Aaron Dixon
Assigned To: Mark Proctor
Attachments: drools-issue.zip
It appears that you MUST use the From Condition Element to reason over sub-objects or
else Drools yields unpredictable behavior.
The first two rules below appear to be semantically equivalent. However the
"bad" rule (the rule that does not use the from conditional element) does not
get activated correctly when there is another rule (see the third rule) that modifies the
age sub-property before the first two rules are activated:
rule "Older than 20 - Good"
salience -100
when
person : Person( )
Details( age > 20 ) from person.details
then
System.out.println( "Older than 20 (good) : " + person );
end
rule "Older than 20 - Bad"
salience -100
when
person : Person( details.age > 20 )
then
System.out.println( "Older than 20 (bad) : " + person );
end
rule "30 is the new 20"
when
person : Person( details.age == 30 )
then
person.getDetails().setAge( 20 );
System.out.println( "Now 20 : " + person );
update( person );
end
Given that the "bad" rule is semantically equivalent to the second rule, Drools
should treat both rules the same in the engine. See the referenced forum thread for
further justification for this claim.
Also, see the attached zip for an executable example.
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3 p.m.
New subject: [JBoss JIRA] Updated: (JBRULES-1511) Can only reason over sub-objects if you use the From Conditional Element
[ http://jira.jboss.com/jira/browse/JBRULES-1511?page=all ]
Aaron Dixon updated JBRULES-1511:
---------------------------------
Affects Version/s: 4.0.5
Can only reason over sub-objects if you use the From Conditional
Element
------------------------------------------------------------------------
Key: JBRULES-1511
URL: http://jira.jboss.com/jira/browse/JBRULES-1511
Project: JBoss Drools
Issue Type: Bug
Security Level: Public(Everyone can see)
Components: Reteoo
Affects Versions: 4.0.4, 4.0.5
Reporter: Aaron Dixon
Assigned To: Mark Proctor
Attachments: drools-issue.zip
It appears that you MUST use the From Condition Element to reason over sub-objects or
else Drools yields unpredictable behavior.
The first two rules below appear to be semantically equivalent. However the
"bad" rule (the rule that does not use the from conditional element) does not
get activated correctly when there is another rule (see the third rule) that modifies the
age sub-property before the first two rules are activated:
rule "Older than 20 - Good"
salience -100
when
person : Person( )
Details( age > 20 ) from person.details
then
System.out.println( "Older than 20 (good) : " + person );
end
rule "Older than 20 - Bad"
salience -100
when
person : Person( details.age > 20 )
then
System.out.println( "Older than 20 (bad) : " + person );
end
rule "30 is the new 20"
when
person : Person( details.age == 30 )
then
person.getDetails().setAge( 20 );
System.out.println( "Now 20 : " + person );
update( person );
end
Given that the "bad" rule is semantically equivalent to the second rule, Drools
should treat both rules the same in the engine. See the referenced forum thread for
further justification for this claim.
Also, see the attached zip for an executable example.
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11:35 a.m.
New subject: [JBoss JIRA] Updated: (JBRULES-1511) Can only reason over sub-objects if you use the From Conditional Element
[ http://jira.jboss.com/jira/browse/JBRULES-1511?page=all ]
Mark Proctor updated JBRULES-1511:
----------------------------------
Assignee: Edson Tirelli (was: Mark Proctor)
Can only reason over sub-objects if you use the From Conditional
Element
------------------------------------------------------------------------
Key: JBRULES-1511
URL: http://jira.jboss.com/jira/browse/JBRULES-1511
Project: JBoss Drools
Issue Type: Bug
Security Level: Public(Everyone can see)
Components: Reteoo
Affects Versions: 4.0.4, 4.0.5
Reporter: Aaron Dixon
Assigned To: Edson Tirelli
Attachments: drools-issue.zip
It appears that you MUST use the From Condition Element to reason over sub-objects or
else Drools yields unpredictable behavior.
The first two rules below appear to be semantically equivalent. However the
"bad" rule (the rule that does not use the from conditional element) does not
get activated correctly when there is another rule (see the third rule) that modifies the
age sub-property before the first two rules are activated:
rule "Older than 20 - Good"
salience -100
when
person : Person( )
Details( age > 20 ) from person.details
then
System.out.println( "Older than 20 (good) : " + person );
end
rule "Older than 20 - Bad"
salience -100
when
person : Person( details.age > 20 )
then
System.out.println( "Older than 20 (bad) : " + person );
end
rule "30 is the new 20"
when
person : Person( details.age == 30 )
then
person.getDetails().setAge( 20 );
System.out.println( "Now 20 : " + person );
update( person );
end
Given that the "bad" rule is semantically equivalent to the second rule, Drools
should treat both rules the same in the engine. See the referenced forum thread for
further justification for this claim.
Also, see the attached zip for an executable example.
--
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2:59 p.m.
New subject: [JBoss JIRA] Closed: (JBRULES-1511) Can only reason over sub-objects if you use the From Conditional Element
[ http://jira.jboss.com/jira/browse/JBRULES-1511?page=all ]
Edson Tirelli closed JBRULES-1511.
----------------------------------
Resolution: Rejected
Can only reason over sub-objects if you use the From Conditional
Element
------------------------------------------------------------------------
Key: JBRULES-1511
URL: http://jira.jboss.com/jira/browse/JBRULES-1511
Project: JBoss Drools
Issue Type: Bug
Security Level: Public(Everyone can see)
Components: Reteoo
Affects Versions: 4.0.4, 4.0.5
Reporter: Aaron Dixon
Assigned To: Edson Tirelli
Fix For: 5.0.0-M1
Attachments: drools-issue.zip
It appears that you MUST use the From Condition Element to reason over sub-objects or
else Drools yields unpredictable behavior.
The first two rules below appear to be semantically equivalent. However the
"bad" rule (the rule that does not use the from conditional element) does not
get activated correctly when there is another rule (see the third rule) that modifies the
age sub-property before the first two rules are activated:
rule "Older than 20 - Good"
salience -100
when
person : Person( )
Details( age > 20 ) from person.details
then
System.out.println( "Older than 20 (good) : " + person );
end
rule "Older than 20 - Bad"
salience -100
when
person : Person( details.age > 20 )
then
System.out.println( "Older than 20 (bad) : " + person );
end
rule "30 is the new 20"
when
person : Person( details.age == 30 )
then
person.getDetails().setAge( 20 );
System.out.println( "Now 20 : " + person );
update( person );
end
Given that the "bad" rule is semantically equivalent to the second rule, Drools
should treat both rules the same in the engine. See the referenced forum thread for
further justification for this claim.
Also, see the attached zip for an executable example.
--
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-
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2:59 p.m.
New subject: [JBoss JIRA] Updated: (JBRULES-1511) Can only reason over sub-objects if you use the From Conditional Element
[ http://jira.jboss.com/jira/browse/JBRULES-1511?page=all ]
Edson Tirelli updated JBRULES-1511:
-----------------------------------
Fix Version/s: 5.0.0-M1
This is a known limitation In 4.0.x, all predicates must be time constant, and any
expression using nested accessors are converted into predicates. From the documentation:
==========
6.5.2.1.3. Nested Accessors
Drools does allow for nested accessors in in the field constraints using the MVEL accessor
graph notation. Field constraints involving nested accessors are actually re-written as an
MVEL dialect inline-eval. Care should be taken when using nested accessors as the Working
Memory is not aware of any of the nested values, and do not know when they change; they
should be considered immutable while any of their parent references are inserted into the
Working Memory. If you wish to modify a nested value you should remove he parent objects
first and re-assert afterwards. If you only have a single parent at the root of the graph,
when in the MVEL dialect, you can use the 'modify' keyword and its block setters
to write the nested accessor assignments while retracting and inserting the the root
parent object as required. Nested accessors can be used either side of the operator
symbol.
==============
So, to avoid this and related problems, you can either ensure your predicates and
expressions using nested accessors are immutable, or use the modify block instead of the
update keyword.
In your example, that means changing your first rule to:
rule "30 is the new 20"
when
person : Person( $d : details, $a : details.age == 30 )
then
System.out.println( "Now 20 : " + person );
modify( person ) {
getDetails().setAge( 20 )
}
end
More details: http://blog.athico.com/2007/12/modify-block-for-java-dialect.html
Having said that, this problem is fixed in 5.0 with the new matching algorithm, but there
is nothing more we can do about it in 4.0.x.
[]s
Edson
Can only reason over sub-objects if you use the From Conditional
Element
------------------------------------------------------------------------
Key: JBRULES-1511
URL: http://jira.jboss.com/jira/browse/JBRULES-1511
Project: JBoss Drools
Issue Type: Bug
Security Level: Public(Everyone can see)
Components: Reteoo
Affects Versions: 4.0.4, 4.0.5
Reporter: Aaron Dixon
Assigned To: Edson Tirelli
Fix For: 5.0.0-M1
Attachments: drools-issue.zip
It appears that you MUST use the From Condition Element to reason over sub-objects or
else Drools yields unpredictable behavior.
The first two rules below appear to be semantically equivalent. However the
"bad" rule (the rule that does not use the from conditional element) does not
get activated correctly when there is another rule (see the third rule) that modifies the
age sub-property before the first two rules are activated:
rule "Older than 20 - Good"
salience -100
when
person : Person( )
Details( age > 20 ) from person.details
then
System.out.println( "Older than 20 (good) : " + person );
end
rule "Older than 20 - Bad"
salience -100
when
person : Person( details.age > 20 )
then
System.out.println( "Older than 20 (bad) : " + person );
end
rule "30 is the new 20"
when
person : Person( details.age == 30 )
then
person.getDetails().setAge( 20 );
System.out.println( "Now 20 : " + person );
update( person );
end
Given that the "bad" rule is semantically equivalent to the second rule, Drools
should treat both rules the same in the engine. See the referenced forum thread for
further justification for this claim.
Also, see the attached zip for an executable example.
--
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6627
days inactive
6638
days old
5 comments
3 participants
participants (3)
-
Aaron Dixon (JIRA) -
Edson Tirelli (JIRA)
-
Mark Proctor (JIRA)