Re: [rules-users] Programatically adding rules toKnowledgeBase/StatefulKnowledgeSession

Here is a method cut & pasted from working code in a validation class used by some of my unit tests. I think it does what you are asking. private ValidationResult addDrlToKnowledgeBase(String drlAsString ) { ValidationResult retval = null; try { KnowledgeBuilder kBuilder = KnowledgeBuilderFactory.newKnowledgeBuilder(); Reader rdr = new StringReader(drlAsString); Resource resource = ResourceFactory.newReaderResource(rdr); kBuilder.add(resource, ResourceType.DRL); if (kBuilder.hasErrors()) { retval = ValidationResult.newInstance("DRL errors: " + kBuilder.getErrors().toString(), null, null); } else { knowledgeSession.getKnowledgeBase().addKnowledgePackages(kBuilder.getKno wledgePackages()); retval = ValidationResult.newInstance(); } } catch(Exception ex) { retval = ValidationResult.newInstance(ex.getMessage(), null, ex); } return retval; } The type of the instance variable "knowledgeSession" is "StatefulKnowledgeSession". Ignore the class "ValidationResult", it is a custom class used for returning results from this validation helper class. Hope this helps. -Nathan Bell From: rules-users-bounces(a)lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of Pierre de Leusse Sent: Thursday, November 18, 2010 8:14 AM To: 'Rules Users List' Subject: [rules-users] Programatically adding rules toKnowledgeBase/StatefulKnowledgeSession Hello all, I'm trying to add rules through my java code to a KnowledgeBase and I cannot find any easy way to do so. So far, the only solution I could think of, is to write the rule as DRL in a file that is "observed" by a KnowledgeAgent (same with a RuleAgent I suppose). Is it possible to create a new KnowledgePackage with the same name as the existing one and load it into the KnowledgeBuilder? I manage to remove rules using the following code: statefulKnowledgeSession.getKnowledgeBase().removeRule(knowledgeSetName, ruleName); I thought that there would be a addRule method somewhere but not luck so far. The code I'm using to create my KnowledgeBase and StatefulKnowledgeSession is shown below. All the best, Pierre StatefulKnowledgeSession creation code: StatefulKnowledgeSession ksession; KnowledgeBuilder kbuilder; KnowledgeBase kbase; kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder(); kbuilder.add(ResourceFactory.newFileResource(Demo.class.getResource(Demo .drlFile).getPath()), ResourceType.DRL); if (kbuilder.hasErrors()) { System.out.println(kbuilder.getErrors()); } kbase = KnowledgeBaseFactory.newKnowledgeBase(); kbase.addKnowledgePackages(kbuilder.getKnowledgePackages()); ksession = kbase.newStatefulKnowledgeSession(); ksession.insert(...); ... ksession.fireAllRules();