[rules-users] Inheritance-Like Design Question
Edson Tirelli
ed.tirelli at gmail.com
Fri Mar 5 15:38:58 EST 2010
Hmmm, you should be receiving a duplicate variable declaration error...
would you please open a JIRA for us to double check what is happening and
fix the error message?
Meanwhile, try without repeating the constraints on the parent rule in
the child rule:
rule "Definitions TermContractions 1.1"
when
mpr : MPUFacade()
eval(!mpr.isImportant(Constants.FINDING_KEYWORD_Contractions_Frequency))
then
mpr.print("Rule Definitions TermContractions 1.1 Executed");
end
rule "TermContractions 2.8" extends "Definitions TermContractions
1.1"
when
eval(!mpr.isImportant(Constants.FINDING_KEYWORD_TEST))
then
mpr.print("Rule TermContractions 2.8 Executed");
end
Also, remember that unless you use some of the tricks I mentioned
before, both rules will fire.
[]s
Edson
2010/3/5 Moe Alkhafaji <moe.alkhafaji at medcpu.com>
> Here are the rules that I created (sorry for breaking that in multiple
> emails), I hope this is all the information needed:
>
> rule "Definitions TermContractions 1.1"
> when
> mpr : MPUFacade()
>
> eval(!mpr.isImportant(Constants.FINDING_KEYWORD_Contractions_Frequency))
> then
> mpr.print("Rule Definitions TermContractions 1.1 Executed");
> end
>
> rule "TermContractions 2.8" extends "Definitions TermContractions
> 1.1" <=== Line 11
> when
> mpr : MPUFacade()
>
> eval(!mpr.isImportant(Constants.FINDING_KEYWORD_Contractions_Frequency))
> eval(!mpr.isImportant(Constants.FINDING_KEYWORD_TEST))
> then
> mpr.print("Rule TermContractions 2.8 Executed");
> end
>
>
> On Fri, Mar 5, 2010 at 12:33 PM, Moe Alkhafaji <moe.alkhafaji at medcpu.com>wrote:
>
>> Specifically speaking, here is what I get on Eclipse when I do that:
>>
>>
>> nds.when cannot be resolved to a
>> type MPU/src/rules
>> EEphratOBMain.drl line 11
>> Syntax error on token ":", ;
>> expected MPU/src/rules
>> EEphratOBMain.drl line 11
>> Syntax error on token ""Definitions TermContractions 1.1"", . expected
>> MPU/src/rules EEphratOBMain.drl line 11
>> Syntax error on token "then", invalid
>> AssignmentOperator MPU/src/rules
>> EEphratOBMain.drl line 11
>> Syntax error, insert ";" to complete
>> Statement MPU/src/rules
>> EEphratOBMain.drl line 11
>> Syntax error, insert ";" to complete
>> Statement MPU/src/rules
>> EEphratOBMain.drl line 11
>> Syntax error, insert ";" to complete
>> Statement MPU/src/rules
>> EEphratOBMain.drl line 11
>>
>> Line 11 is:
>>
>> * rule "TermContractions 2.8" extends "Definitions TermContractions 1.1"*
>>
>> and "Definitions TermContractions 1.1" is another rule defined in the same
>> drl.
>>
>>
>>
>> On Fri, Mar 5, 2010 at 12:04 PM, Moe Alkhafaji <moe.alkhafaji at medcpu.com>wrote:
>>
>>> Thanks Edson, I will try that. However, I have one follow up question. I
>>> tried to use the "extends" command and it did not work (it gave me a syntax
>>> error). I am using the latest Drools 5.0 M1. Could it be because the Eclipse
>>> Drools plugin does not support this feature yet and if I ignore this error
>>> on Eclipse it would still work at runtime?
>>>
>>> Thanks!
>>>
>>> 2010/3/5 Edson Tirelli <ed.tirelli at gmail.com>
>>>
>>>
>>>> Although I noticed the other day that this is not documented yet,
>>>> Drools 5.0.x does support rule inheritance. In your case, it would be
>>>> written as:
>>>>
>>>> rule r1
>>>> when
>>>> A()
>>>> then
>>>> // do something
>>>> end
>>>>
>>>> rule r2 extends r1
>>>> when
>>>> B()
>>>> then
>>>> // do something else
>>>> end
>>>>
>>>> When using inheritance, the subrule will inherit the whole LHS of
>>>> the parent rule.
>>>>
>>>> Integration test here:
>>>>
>>>>
>>>> http://anonsvn.jboss.org/repos/labs/labs/jbossrules/trunk/drools-compiler/src/test/resources/org/drools/integrationtests/extend_rule_test.drl
>>>>
>>>> http://anonsvn.jboss.org/repos/labs/labs/jbossrules/trunk/drools-compiler/src/test/resources/org/drools/integrationtests/test_RuleExtend.drl
>>>>
>>>> In your case, you have an extra requirement that if a child rule
>>>> fires, you don't want the parent rule to fire. My suggestion is either doing
>>>> this with a logical condition, or adding drools.halt() on the consequence of
>>>> rules that should stop subsequent firings, or using activation-groups +
>>>> salience. Example, in the above case, you could have:
>>>>
>>>> rule r1
>>>> activation-group "example rules"
>>>> salience 10
>>>> when
>>>> A()
>>>> then
>>>> // do something
>>>> end
>>>>
>>>> rule r2 extends r1
>>>> activation-group "example rules"
>>>> salience 20
>>>> when
>>>> B()
>>>> then
>>>> // do something else
>>>> end
>>>>
>>>> Since rule 2 has a higher salience, if it activates it will fire
>>>> first, and due to the activation-group, it will cancel the activation of r1
>>>> preventing it to fire.
>>>>
>>>> Hope it helps.
>>>>
>>>> Edson
>>>>
>>>> 2010/3/5 malkhafaji <moe.alkhafaji at medcpu.com>
>>>>
>>>>
>>>>> Hello,
>>>>>
>>>>> I know, from searching this forum and posting before, that the concept
>>>>> of
>>>>> inheritance does not exist today in Drools. However, I have a need for
>>>>> it.
>>>>> Here is my specific situation:
>>>>>
>>>>> I have certain rules that have some generic conditions to be fired:
>>>>>
>>>>> Rule 1
>>>>> If A Then X end
>>>>>
>>>>> Rule 2
>>>>> If A, B Then Y end
>>>>>
>>>>> What I would like to do is, if Rule 2 is true, then I don't want Rule 1
>>>>> to
>>>>> execute. I have many and many of those rules, so combining all the
>>>>> conditions in less number of rules violates our design having rules
>>>>> being
>>>>> mutually exclusive. That is why I wanted to include this behavior as a
>>>>> natural inheritance behavior rather than forcing the flow with logic
>>>>> inside
>>>>> the rule itself (you will make rules aware of others this way).
>>>>>
>>>>> So, since there is not built-in feature that allows you to do that, do
>>>>> people suggest anything that I can do without having to mix Rule 1 and
>>>>> Rule
>>>>> 2 into one rule with complex conditional statements? Any ideas?
>>>>>
>>>>> The only thing I can think of is taking this logic processing outside
>>>>> of
>>>>> drools, which is something that I am not too excited about.
>>>>>
>>>>> Thanks.
>>>>>
>>>>> --
>>>>> View this message in context:
>>>>> http://n3.nabble.com/Inheritance-Like-Design-Question-tp430848p430848.html
>>>>> Sent from the Drools - User mailing list archive at Nabble.com.
>>>>> _______________________________________________
>>>>> rules-users mailing list
>>>>> rules-users at lists.jboss.org
>>>>> https://lists.jboss.org/mailman/listinfo/rules-users
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Edson Tirelli
>>>> JBoss Drools Core Development
>>>> JBoss by Red Hat @ www.jboss.com
>>>>
>>>> _______________________________________________
>>>> rules-users mailing list
>>>> rules-users at lists.jboss.org
>>>> https://lists.jboss.org/mailman/listinfo/rules-users
>>>>
>>>>
>>>
>>>
>>> --
>>> Moe Alkhafaji
>>> Chief Technology Officer, MedCPU
>>> Phone: (630) 290-1113
>>> Email: cto at medcpu.com
>>>
>>> This message contains information which may be confidential. Unless you
>>> are the addressee, you may not use, copy or disclose to anyone the message
>>> or any information contained in this message. If you have received this
>>> email in error, please notify cto at medcpu.com and please delete the
>>> message immediately. In order for the contents of this message to be binding
>>> on behalf of MedCPU it must be confirmed in writing by an authorized
>>> signatory of MedCPU. Our company accepts no liability for the content of
>>> this email unless it is so confirmed. The views or opinions presented herein
>>> do not necessarily represent those of the company.
>>>
>>
>>
>>
>> --
>> Moe Alkhafaji
>> Chief Technology Officer, MedCPU
>> Phone: (630) 290-1113
>> Email: cto at medcpu.com
>>
>> This message contains information which may be confidential. Unless you
>> are the addressee, you may not use, copy or disclose to anyone the message
>> or any information contained in this message. If you have received this
>> email in error, please notify cto at medcpu.com and please delete the
>> message immediately. In order for the contents of this message to be binding
>> on behalf of MedCPU it must be confirmed in writing by an authorized
>> signatory of MedCPU. Our company accepts no liability for the content of
>> this email unless it is so confirmed. The views or opinions presented herein
>> do not necessarily represent those of the company.
>>
>
>
>
> --
> Moe Alkhafaji
> Chief Technology Officer, MedCPU
> Phone: (630) 290-1113
> Email: cto at medcpu.com
>
> This message contains information which may be confidential. Unless you are
> the addressee, you may not use, copy or disclose to anyone the message or
> any information contained in this message. If you have received this email
> in error, please notify cto at medcpu.com and please delete the message
> immediately. In order for the contents of this message to be binding on
> behalf of MedCPU it must be confirmed in writing by an authorized signatory
> of MedCPU. Our company accepts no liability for the content of this email
> unless it is so confirmed. The views or opinions presented herein do not
> necessarily represent those of the company.
>
> _______________________________________________
> rules-users mailing list
> rules-users at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users
>
>
--
Edson Tirelli
JBoss Drools Core Development
JBoss by Red Hat @ www.jboss.com
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