[rules-users] Contains substring in the LHS with regular expression capturing groups?

[Waruzjan Shahbazian]

The pluggable operators example looks very cool  :-) , I just have one 
more question about the performance. I suppose that if I use eval() with 
indexOf(), there would be no caching? Isn't that one of the benefits of 
using the "drools" operators, since ( if they work on the same way as in 
the example in the trunk anyway) they do use caching. Anyway, if  I do 
some benchmarks about this I would let you now!

About the backwards compatibility: Thats cool, as long as what I did was 
not a not recommended way. The costes for the few possible changes in 
the feature are indeed affordable to pay.

Waruzjan

Edson Tirelli schreef:
>    I really don't know about perf differences in this case. I guess best
> thing would be for you do give a try (and let us know please). :) It
> probably will depend on the java implementation of the matches() against
> indexOf() method. I guess indexOf is faster, but don't know if it is
> significant difference.
>    Regarding pluggable operators, here you have one example:
>
> http://anonsvn.labs.jboss.com/labs/jbossrules/trunk/drools-core/src/main/java/org/drools/base/evaluators/MatchesEvaluatorsDefinition.java
>
>     Regarding using the descriptor classes, I would say it is the
> recommended way for generated rules, since you avoid the "text
> generation"+"parsing" cost of the rules. Although, as much as we try to keep
> backward compatibility, we can't guarantee there will be no breaks, since we
> are always adding new features and the descriptor model must usually change
> to support them what may eventually break backward compatibility. Even with
> that, I think it is an affordable cost to pay (fixing eventual breaks on
> version updates) compared to your runtime application robustness.
>
>    []s
>    Edson
>
>
>
> 2007/12/14, Waruzjan Shahbazian <wshahbazian at xiam.nl>:
>   
>> Hi,
>>
>> Thanks for the reply. I wanted to be sure that there wasn't any more
>> efficient way to check a substring in a string, or do you think that
>> eval() with a indexOf() call would be more efficient than matches() with
>> regular expression?. Since I can't group the results, the speed is the
>> only issue here.
>>
>> In my application I am creating the PackageDescr myself with some
>> "template" RuleDescr's (which are being filled in with the, limited,
>> user input in the Swing GUI) and the package is being build with the
>> builder. If the regular expression methode in the matches operator is
>> the best way to check a substring in a string, I can use variabeles
>> (which are the user inputs) to fill the regular expression. So I don't
>> really need a new operator for this. But I am interessted how the
>> development of a new operator would be, so maybe you could tell me where
>> I need to be to do so :-) .
>>
>> In the attachment  is the classe diagram of the PackageDescr with the
>> linked classes as I have understood and used in my application. Of
>> course not every operation and attribute is included, but maybe this
>> could be helpfull for someone else who wants to create PackageDescr's
>> directly.
>>
>> I suppose the public methodes used in this operation are going to be
>> supported by the following drools versions? Or should I have used the
>> DRL and XML ? =-O
>>
>> Thanks,
>>
>> Waruzjan
>>
>> Edson Tirelli schreef:
>>     
>>>    Yes, you may use matches. The other alternative is using an eval and
>>>       
>> a
>>     
>>> regular indexOf() call to check for the existance of the substring.
>>>       
>> Drools
>>     
>>> up to versions 4.0.x is JSE 1.4 compliant, so you can't use contains()
>>> method.  In trunk, you may also develop your own operator and plug it
>>>       
>> into
>>     
>>> the engine... although, it is not documented yet, but if you want to
>>>       
>> try, I
>>     
>>> can guide you through. And if you want to contribute docs after that,
>>>       
>> even
>>     
>>> better. :)
>>>
>>>    It is not possible to capture groups and reuse in the RHS. I'm
>>>       
>> thinking
>>     
>>> about a way to bind variables to arbitrary values in the LHS. If we
>>> implement that, than it would be possible for you to do that, but not
>>> possible at this moment.
>>>
>>>    Edson
>>>
>>> 2007/12/14, Waruzjan Shahbazian <wshahbazian at xiam.nl>:
>>>
>>>       
>>>> Hi,
>>>>
>>>> I need to check in the LHS of my rule if  a given String contains an
>>>> given substring. What is the best way to do that? I can use regular
>>>> expression with matches, but is that the best (fastest) solution?
>>>> (STRING matches "(?i).*SUBSTRING.*"). And can I use regulare
>>>>         
>> expressions
>>     
>>>> capturing groups and than use the results of the groups in the RHS? If
>>>> not, what is the best methode to do that?
>>>>
>>>> Thanks,
>>>>
>>>> Waruzjan
>>>> _______________________________________________
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>>>> https://lists.jboss.org/mailman/listinfo/rules-users
>>>>
>>>>
>>>>         
>>>
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>>     
>
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