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Is it possible to reference rules from both a .drl and .xls within the same program in JBoss Drools?

I am looking through Drools as a possibility for a rules application use case. I am able to get Drools to reference the rule-set from a .xls file and a .drl file independently of each other at this point in time. However, in my case there are times where the rules do not exist as a .xls file and will be programmed within a .drl file. Because of this, I am wondering if within the same program execution, both files could be used depending on certain input criteria? For example, if State == "GA" then use .xls, else if State == "FL" then use .drl.

I have read on the different KieConcepts and understand them at a high-level, and I believe that I would have to create each rule file as a separate KieContainer and then load them into a single KieBase based on the definitions given to each here. However when it comes to this step I get confused as to how this is accomplished. I have two separate instances already created, would I be able to simply combine these two in one program using a KieBase?

The .xls Implementation

public static void main (String[] args)   {
    try {
        KieServices ks = KieServices.Factory.get();
        // add excel sheet to knowledge base
        Resource dt = ResourceFactory.newClassPathResource("dtables/StateInterest.xls");
        KieFileSystem kieFileSystem = ks.newKieFileSystem().write(dt);

        KieBuilder kieBuilder = ks.newKieBuilder(kieFileSystem);
        kieBuilder.buildAll();

        KieRepository kieRepository = ks.getRepository();

        ReleaseId krDefaultReleaseID = kieRepository.getDefaultReleaseId();
        KieContainer kieContainer = ks.newKieContainer(krDefaultReleaseID);

        KieSession kSession = kieContainer.newKieSession();

        // go !
        StateInterestRequest stateInterestRequest = new StateInterestRequest();
        stateInterestRequest.setPolicyIssueState("GA");
        stateInterestRequest.setPolicyIssueDate("10/2018");

        kSession.insert(stateInterestRequest);
        kSession.fireAllRules();

The .drl Implementation

public static final void main(String[] args) {
    try {
        KieServices ks = KieServices.Factory.get();
        KieContainer kContainer = ks.getKieClasspathContainer();
        KieSession kSession = kContainer.newKieSession("ksession-rules");

        // go !
        StateInterestRequest stateInterestRequest = new StateInterestRequest();
        stateInterestRequest.setPolicyIssueState("FL");
        stateInterestRequest.setPolicyIssueDate("2008-03-04");      

        kSession.insert(stateInterestRequest);
        kSession.fireAllRules();

As an addendum, if possible would this be accomplished through the main() of the final combined program, or within the rules themselves?

Solution

  • Yes, you can combine both types of files in one project. You can have written rules in xls format, which will match State "GA" and rules written in a DRL file which will match other states. I recommend reading the Drools documentation first, so you get the basic concepts of rules, KJars etc. [1]. I think this chapter could be helpful to you [2].

    [1] https://docs.jboss.org/drools/release/7.16.0.Final/drools-docs/html_single/index.html
    [2] https://docs.jboss.org/drools/release/7.16.0.Final/drools-docs/html_single/index.html#_builddeployutilizeandrunsection