CODEWITHSUNDEEP
javaspringdroolsrule-engine
Django
Django

Reputation: 43

Executing multiple Drools rules in chain - Spring Java application

I integrated Drools with my Java Spring application via Maven dependencies. I created KieContainer bean: 

@Bean
public KieContainer kieContainer (){
    KieServices kieServices = KieServices.Factory.get();
    KieFileSystem kieFileSystem = kieServices.newKieFileSystem();

    File dir = new File("src/main/resources/rules");
    File[] directoryListing = dir.listFiles();
    if (directoryListing != null) {
        for (File child : directoryListing) {
            kieFileSystem.write(child.getName(), "UTF-8");
        }
    }

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

    KieModule kieModule = kieBuilder.getKieModule();
    return kieServices.newKieContainer(kieModule.getReleaseId());

}

When I debug this, I can see that both my .drl files under /src/main/resources/rules location have been added successfully!

Furthermore, I've created KieSession:

public String executeRule(FieldCDO field, ContractCDO contract, FieldValueCDO fieldValue){
    KieSession kieSession = kieContainer.newKieSession();
    kieSession.setGlobal("fieldValue", fieldValue);
    kieSession.insert(field);
    kieSession.fireAllRules();
    kieSession.dispose();}

Then, I created jUnit test from which I called method from above executeRule(), and passed objects FieldCDO, ContractCDO, FieldValueCDO.

My Rules look like this. Rule1.drl: 

import com.calliduscloud.clma.domain.FieldCDO;
import com.calliduscloud.clma.domain.ContractCDO;
import com.calliduscloud.clma.domain.FieldValueCDO;

global com.calliduscloud.clma.domain.FieldValueCDO fieldValue;

dialect "mvel"

rule "Change contract field value 1"
     when
          field: FieldCDO(id == 1)
          contract: ContractCDO(id == 1);
     then
         fieldValue.setFieldValue("11111");
end

Rule2.drl: 

import com.calliduscloud.clma.domain.FieldCDO;
import com.calliduscloud.clma.domain.ContractCDO;
import com.calliduscloud.clma.domain.FieldValueCDO;

global com.calliduscloud.clma.domain.FieldValueCDO fieldValue;

dialect "mvel"

rule "Change contract field value 2"
     when
          field: FieldCDO(id == 1)
          contract: ContractCDO(id == 1);
     then
         fieldValue.setFieldValue("22222");
end

But, when I call executeRule() method, it breaks at the line where I add global variable into the KieSession:

kieSession.setGlobal("fieldValue", fieldValue);

The error is:

java.lang.RuntimeException: Unexpected global [fieldValue]

When I execute just one rule by calling the same code, it all passes without the problems. But when I have these two rules in chain, this problem occurs.

If someone has some idea, please write if you have time.

Thanks, Dejan

Upvotes: 2

Views: 4150

Answers (2)

sivateja challagulla
sivateja challagulla

Reputation: 11

Your process of loading drool files in to KieFileSystem is wrong.
Change it to the following to get it working.

@Bean
    public KieContainer kieContainer() {
        KieServices kieServices = KieServices.Factory.get();
 
        KieFileSystem kieFileSystem = kieServices.newKieFileSystem();
        File dir = new File("src/main/resources/rules");
        File[] directoryListing = dir.listFiles();
        if (directoryListing != null) {
            for (File child : directoryListing) {
                kieFileSystem.write(ResourceFactory.newFileResource(child));
            }
        }
        KieBuilder kieBuilder = kieServices.newKieBuilder(kieFileSystem);
        kieBuilder.buildAll();
        KieModule kieModule = kieBuilder.getKieModule();
 
        return kieServices.newKieContainer(kieModule.getReleaseId());
    }

Upvotes: 1

salaboy
salaboy

Reputation: 4133

The problem might be related to define the global in both DRL files. Notice that the KieBuilder will load both DRL files to construct the KieBase. I would try to put the global and the import in a separate DRL file to make sure that it get loaded first. If you create a reproducer and put it in GitHub I can give it a try.

Upvotes: 0

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