[rules-users] RE: questions on guvnor and drools 5.0

Thu Jun 4 10:06:03 EDT 2009

Hi Shawn,

I'm also currently evaluating Guvnor.  I certainly don't have all the 
answers but maybe I can share what I have learned so far.  I've put my 
comments below.

Steve Ronderos 

rules-users-bounces at lists.jboss.org wrote on 06/04/2009 08:14:30 AM:

> [image removed] 
> 
> [rules-users] RE: questions on guvnor and drools 5.0
> 
> Garner, Shawn 
> 
> to:
> 
> rules-users at lists.jboss.org
> 
> 06/04/2009 08:19 AM
> 
> Sent by:
> 
> rules-users-bounces at lists.jboss.org
> 
> Please respond to Rules Users List
> 
> Sorry it's been a few days and I haven't gotten any response on any 
> questions/statements below. 
> 
> I've used drools in the past but am pretty new to some features of 
> drools still and new to Guvnor.  I wrote a proof of concept drools/
> Guvnor app and these are the things I don't like or have questions 
around.
> 
> I was wondering if other people have the same problems or am I going
> about things wrong?  Are there work arounds or is there plans to 
> expand/change functionality?  Maybe I should ask the dev list?
> 
> SG
> 
> -----Original Message-----
> From: G, S 
> Sent: Monday, June 01, 2009 3:28 PM
> To: 'rules-users at lists.jboss.org'
> Subject: questions on guvnor and drools 5.0
> 
> I was wondering if somebody can help me with some questions:
> 
> 1) Is there any more detail on how to setup Guvnor with a database?

Guvnor uses Apache Jackrabbit for persistence.  You can find a pretty good 
walk through on the Drools blog 
http://blog.athico.com/2008/08/tuning-guvnor.html.  Additional information 
about configuring the repository can be found on the Apache Jackrabbit 
site.  http://jackrabbit.apache.org/jackrabbit-configuration.html

> 2) How do you use the test scenarios with complex object structures?
>    -eg Create a fact in working memory that has another Object in it
> which in turn has a list of Objects in it.
>    -Seems like any Fact in working memory is assumed to only have 
> only primitive values like Strings or numbers.
>    -We would like a more depth of objects where objects have a deep 
> relationship to other objects at least 2-4 levels deep.

I'm not sure, haven't used that feature of Guvnor much yet.

> 3) Why add ruleflow-group to the rule definition instead of adding 
> the rule to a ruleflow-group?  If the ruleflow-group is part of the 
> rule then you can't use the same rule in multiple ruleflow-groups 
> and leads to copy and maintaining the rule in two different spots.

Should probably ask the dev group this one.

> 4)  DSL seems to be very inconvenient to edit in a text box 
> especially when it wraps.  Why not a table where you can add rows 
> and each row is a translation.  Also there are no examples how to do
> translation into Drools syntax that is multiple lines long and not 
> just a single line.

I haven't used DSLs much either yet.  Maybe ask the dev group this one 
also.

> 5) Is Java 5 Type Enumerations supported?  I was assuming I'd get a 
> list of values if a field was an Enumeration.

Not sure

> 6) There seems to be a vast functionality difference between the 
> Guvnor decision tables and examples that use spreadsheets.

I believe that Guvnor decision tables are not as full featured as the 
spreadsheet based version, but you can still upload spreadsheets to Guvnor 
as decision tables.

> 7) Guvnor lost the ability to select variables for use in other 
> statements.  Functionality was in BRMS of drools 4.0.7

I don't understand the question.  Are you talking about assigning a 
pattern or an attribute in a pattern to a variable for use in another 
statement in the LHS or RHS?  If so clicking on the fact type or field 
restriction that gives you that option.

> 8) I was not able to insert a fact using a constructor that needed 
> parameter values.  Seems like it assumes everything is a bean but I 
> couldn't find this requirement stated in the documentation anywhere.
> Examples in documentation show inserting facts with constructor 
parameters.

Are you talking about in the Guided Rules Editor? I haven't tried this, 
but it sounds like a bug.  Maybe ask the dev team.

> 9) It would be nice when you upload a domain model jar that you 
> could explore the objects and fields somehow.

I agree, being able to traverse the model that you include would be nice. 
Maybe ask the dev team if there are plans for such a feature or create a 
request in the Guvnor JIRA. https://jira.jboss.org/jira/browse/JBRULES

> 10) When you write a rule using one particular editor it would be 
> nice if you could switch to another editor. Switch between Guided, 
> DSL, Technical, etc.

Agreed.  Some other posters on the email group have discussed this before. 
 As it stands the different editors aren't equally as powerful.  Some 
rules can not be represented in the Guided editor since it does not have 
anything capable of "from" (I think).  Maybe ask the dev team about this 
and possibly create a feature request.

> 11) It seems hard to reorder the statements in a when or then block.
> If I put them in the wrong order I have to delete them all.  Would 
> be nice if a statement could be moved up or down.

Agreed.  I don't believe this is possible in the Guided editor (aside from 
maybe editing the .brl file directly via WebDAV) maybe ask the dev team 
and create a feature request.

> 12) When calling a method on an object the choices only showed me 
> public methods that take in one parameter.  I had a method with two 
> parameters and it wouldn't show me the method.  I had to do a DSL or
> custom drools statement to get around it.

Sounds like a bug.  Talk to the dev team or file a request.

> 13) Guvnor seems to limit the drools syntax.  I couldn't do a "from 
> $collection" statement without a custom drools statement line.

I believe this is a known limitation and I want to say I've seen a feature 
request to add this to the Guided editor.

> 14) It would be nice if I could declare a global dialect "java" for 
> all the rules.

Agreed.  Feature request.

> 15) It would be nice to define an existing agenda-group as part of a
> ruleflow-group without adding the ruleflow-group on the rules in 
> that agenda-group.

I'm not that familiar with agenda-groups or ruleflow-groups.  Sorry I 
can't help on this one.

> 
> Thanks,
> SG
> 
> 
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