Re: [rules-users] Where is my understanding of Drools global variables wrong?

Hello I tried what you proposed, it didn't do the trick. Then i reread the documentation and discovered: "Globals are not designed to share data between rules and they should never be used for that purpose. Rules always reason and react to the working memory state, so if you want to pass data from rule to rule, assert the data as facts into the working memory." Sadly, I was trying to do just that... I am sorry for the question in first place. I want to ask something (just to be sure). If I want to share data between rules (in my case transitional calculation results, that are missing in my model), the only way to do so is to pass them into some temporary facts?

Thanks again Best Regards, Milen -------- Оригинално писмо -------- От: Wolfgang Laun wolfgang.laun(a)gmail.com Относно: Re: [rules-users] Where is my understanding of Drools global variables wrong? До: Rules Users List Изпратено на: Понеделник, 2014, Февруари 3 18:09:26 EET The typical misunderstanding is that a global is a "variable" in the usual sense of the word. It is not. When you set a global, you store an object in a map, using the global's name as a key. Using a global in DRL code perfidiously and conveniently hides the way the global is made available to the code in a rule when you use the global's name just like any other variable: You write the global's name, but you use a local copy. If you intend to change the global existence of a global you'll have to use the API that's used to set up a global in the first place: get the session object, call setGlobal... Cheers Wolfgang On 03/02/2014, milen igrachev igrachev(a)abv.bg > wrote: > Hello, for the first time I have the need to define a global variables in > a > DRL file, and from what it seems from the documentation it shall be a > variable visible to all my rules in the > DRL file. However I don't see what I do wrong, but the modifications made > by > one rule are not visible to the others. Here is illustration of what I > have: > > [Fact model code] > public class TestPOJO { private int fieldOne; private String > fieldTwo; public int getFieldOne() {...} public void > setFieldOne(int fieldOne) {...} public String getFieldTwo() {...} > public void setFieldTwo(String fieldTwo) {...} } > [DRL rule code] > global java.lang.Double myGlobal; rule "Your First Rule" salience 2 > > when > > > > TestPOJO(fieldOne > 10) > > then > > > > System.out.println("This is rule #1"); > > > > System.out.println(myGlobal); > > > > myGlobal = 0.03; end rule "Your Second Rule" salience 1 > > when > > > > TestPOJO(fieldTwo == "true") > > then > > > > System.out.println("This is rule #2"); > > > > System.out.println(myGlobal); end > [Call to Drools] > TestPOJO myTestFact = new TestPOJO(); myTestFact.setFieldOne(15); > myTestFact.setFieldTwo("true"); > KieServices ks = KieServices.Factory.get(); KieContainer kContainer = > ks.getKieClasspathContainer(); KieSession kSession = > kContainer.newKieSession("ksession-rules"); > > kSession.insert(myTestFact); kSession.fireAllRules(); > kSession.dispose(); > [Output] > This is rule #1 null This is rule #2 null > > > [What I expect to have as output] This is rule #1 null This is rule > #2 > 0.03 > I used the salience to set rule order to be sure that rule one is > executed > before rule two, but my global value is never updated. > Can you please tell me where I do wrong? Can my expectations be met > somehow, > I need such type of internal rule variables to calculate temporary > values and pass them between rules? > > Thank you!!! > > Best Regards, Milen _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users