Re: [rules-dev] Re: [rules-users] No globals in functions?

How about a ThreadLocal? --- On Wed, 10/15/08, David Sinclair <dsinclair(a)chariotsolutions.com&gt; wrote: > From: David Sinclair <dsinclair(a)chariotsolutions.com&gt; > Subject: [rules-dev] Re: [rules-users] No globals in functions? > To: "Edson Tirelli" <tirelli(a)post.com&gt; > Cc: "Mark Proctor" <mproctor(a)codehaus.org&gt;, "Rules Dev List" <rules-dev(a)lists.jboss.org&gt; > Date: Wednesday, October 15, 2008, 12:53 PM > What about injecting the globals into the classes and doing > reflection to > invoke the method dynamically? That way we would only need > to change the > JavaFunctionBuilder to rewrite the calls to the globals? > For example > > function foo() { > global.bar(abx); > } > > gets re-written as > > function foo() { > method.invoke(global, [abx]); > } > > methods would be cached and such. Or do you guys not want > the reflection in > there? > > > On Wed, Oct 15, 2008 at 1:45 PM, Edson Tirelli > <tirelli(a)post.com&gt; wrote: > > >> It may be invoked by a consequence, an eval, a >> > predicate, or a return > >> value constraint. >> >> If you fix it for the consequence in >> > JavaConsequenceBuilder, the others > >> will work the same. You will have to change the java.g >> > grammar as I > >> mentioned in my previousre e-mail to make it work. >> >> []s >> Edson >> >> 2008/10/14 David Sinclair >> > <dsinclair(a)chariotsolutions.com&gt; > >> Edson, >> >>> Changing the builder shouldn't be too much of >>> > a problem. If I make the > >>> changes you suggested, how does the global >>> > actually get passed to the > >>> method? For example if something defined a >>> > function like > >>> void function doX(int abc) { >>> ... >>> global.doY(bcd); >>> } >>> and I rewrite it to be >>> >>> void function doX(int abc, GlobalType global) { >>> ... >>> } >>> >>> Who is the invoker of the method? >>> >>> thanks >>> >>> dave >>> >>> >>> >>> On Mon, Oct 13, 2008 at 3:24 PM, Edson Tirelli >>> > <tirelli(a)post.com&gt; wrote: > >>>> Hi Dave, >>>> >>>> Excellent! >>>> I will try to explain the current situation >>>> > and one possible solution, > >>>> but you may have better ideas. >>>> >>>> Functions in Drools are compiled as simple >>>> > static methods in a > >>>> generated java class. We use MVEL Templates to >>>> > generate the code of the > >>>> class and the static method. >>>> >>>> Take a look at JavaFunctionBuilder.java >>>> > class for the code generation > >>>> call and at javaFunction.mvel for the code >>>> > template. > >>>> Now, the problem with globals is that they >>>> > are scoped to sessions, not > >>>> rulebases, so you can not resolve them until >>>> > runtime. You can not for > >>>> instance, make them a static reference of the >>>> > generated class and set it at > >>>> rulebase compilation time. >>>> >>>> So, my suggestion would be to: >>>> >>>> 1. at compile time, use >>>> > JavaDialect.analyzeBlock() method to analyze and > >>>> find out what are the globals that are used by >>>> > the funcion method code. > >>>> 2. modify the code generation to add >>>> > parameters to that in the method > >>>> call. So, if "log" is a global and >>>> > if the function is declared like this: > >>>> function void someFunction( String param ) { >>>> // ... code ... >>>> log.something(...); >>>> // ... code ... >>>> } >>>> >>>> you detect the use of "log" and >>>> > add it as a parameter of the generated > >>>> method: >>>> >>>> ... >>>> public static void someFunction( Logger log, >>>> > String Param ) { > >>>> ... >>>> } >>>> ... >>>> >>>> This way, at runtime we can inject the >>>> > parameter into the call. You > >>>> can look at JavaConsequenceBuilder.java and >>>> > javaInvokers.mvel to see how we > >>>> do kind-of the same thing for consequences. >>>> >>>> 3. Now the most interesting part. :) We use >>>> > an ANTLR grammar for parsing > >>>> Java code blocks. You need to change the >>>> > parser to rewrite any function call > >>>> the user is doing in his code to inject the >>>> > log parameter transparently. I > >>>> did the very same thing for modify blocks: >>>> >>>> modify( $something ) { >>>> ... >>>> } >>>> >>>> It is not hard once you get the hang of it. >>>> > It is a bit of "hand work" > >>>> though. Look at the >>>> > JavaConsequenceBuilder.fixModifyBlocks() for what I did. > >>>> Also, the ANTLR Java grammar is java.g. >>>> >>>> Let me know if you have questions or if you >>>> > have a better idea, and > >>>> welcome aboard! >>>> >>>> Cheers, >>>> Edson >>>> >>>> >>>> >>>> 2008/10/13 David Sinclair >>>> > <dsinclair(a)chariotsolutions.com&gt; > >>>> Hi Edson, >>>> >>>>> My name is dave sinclair. I started using >>>>> > Drools in early August of this > >>>>> year, but have a lot of experience with >>>>> > rules engines. I have worked > >>>>> primarily with ArtEntrprise and some with >>>>> > PegaRules. I would love to help > >>>>> with this project and thought that this >>>>> > may be the area to jump in on. > >>>>> I have the M2 code, and was reading it >>>>> > over the weekend. Mostly the core > >>>>> and some of the compilier. If you want to >>>>> > point me in the right direction on > >>>>> the global/functions I'd be happy to >>>>> > have a look. > >>>>> thanks >>>>> >>>>> dave >>>>> >>>>> >>>>> On Mon, Oct 13, 2008 at 9:59 AM, Bagwell, >>>>> > Allen F <afbagwe(a)sandia.gov&gt;wrote: > >>>>>> Edson, >>>>>> >>>>>> Thanks for the tip. I figured I'd >>>>>> > need to use a workaround like this. > >>>>>> Unfortunately I'm under a series >>>>>> > of tight development and test > >>>>>> deadlines all the way into early >>>>>> > summer. Otherwise, I'd have a look. > >>>>>> Hopefully someone else out there can >>>>>> > assist. > >>>>>> Thanks, >>>>>> -A >>>>>> >>>>>> ------------------------------ >>>>>> *From:* >>>>>> > rules-users-bounces(a)lists.jboss.org [mailto: > >>>>>> rules-users-bounces(a)lists.jboss.org] >>>>>> > *On Behalf Of *Edson Tirelli > >>>>>> *Sent:* Friday, October 10, 2008 5:46 >>>>>> > AM > >>>>>> *To:* Rules Users List >>>>>> *Subject:* Re: [rules-users] No >>>>>> > globals in functions? > >>>>>> Allen, >>>>>> >>>>>> There is a technical explanation >>>>>> > behind that and we never had the > >>>>>> time to find a way to overcome this >>>>>> > limitation. What you can do, although > >>>>>> not ideal, is to send the global as a >>>>>> > parameter: > >>>>>> funcion void foo( Logger log, String >>>>>> > cond ) > >>>>>> { >>>>>> ... >>>>>> } >>>>>> >>>>>> rule XYZ >>>>>> when >>>>>> then >>>>>> foo( log, someString ); >>>>>> end >>>>>> >>>>>> If you or anyone would like to help >>>>>> > improving this, let us know and > >>>>>> we can discuss ways into doing it. >>>>>> >>>>>> []s >>>>>> Edson >>>>>> >>>>>> 2008/10/9 Bagwell, Allen F >>>>>> > <afbagwe(a)sandia.gov&gt; > >>>>>>> There's probably an easy >>>>>>> > explanation for this. I was wondering about > >>>>>>> why functions inside of rule files >>>>>>> > can't access globals? > >>>>>>> For example, I have a log4j logger >>>>>>> > that I pass into my rule files via > >>>>>>> a global. The logger should never >>>>>>> > be a part of working memory. It's just > >>>>>>> there to capture valuable >>>>>>> > feedback. > >>>>>>> But I can't do this: >>>>>>> >>>>>>> global Logger log; >>>>>>> >>>>>>> function void foo(String cond) >>>>>>> { >>>>>>> if (cond == "error") >>>>>>> log.error("I saw an >>>>>>> > error"); > >>>>>>> } >>>>>>> >>>>>>> Because the compiler says that in >>>>>>> > the function it can't resolve 'log'. > >>>>>>> -A >>>>>>> >>>>>>> Allen F. Bagwell >>>>>>> e-mail: afbagwe(a)sandia.gov >>>>>>> phone: 505/284-4517 >>>>>>> fax: 505/ 844-7886 >>>>>>> >>>>>>> There is no monument dedicated to >>>>>>> > the memory of a committee. -- Lester > >>>>>>> J. Pourciau >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> > _______________________________________________ > >>>>>>> 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, a division of Red Hat @ >>>>>> > www.jboss.com > >>>>>> > _______________________________________________ > >>>>>> 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, a division of Red Hat @ www.jboss.com >>>> >>>> >>> >> -- >> Edson Tirelli >> JBoss Drools Core Development >> JBoss, a division of Red Hat @ www.jboss.com >> >> > _______________________________________________ > rules-dev mailing list > rules-dev(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-dev >