第7章 DMN model execution

Procedure

1. In your client application, add the following dependencies to the relevant classpath of your Java project:

   <!-- Required for the DMN runtime API -->
   <dependency>
     <groupId>org.kie</groupId>
     <artifactId>kie-dmn-core</artifactId>
     <version>${rhdm.version}</version>
   </dependency>
   
   <!-- Required if not using classpath KIE container -->
   <dependency>
     <groupId>org.kie</groupId>
     <artifactId>kie-ci</artifactId>
     <version>${rhdm.version}</version>
   </dependency>

   Copy to Clipboard

   The <version> is the Maven artifact version for Red Hat Decision Manager currently used in your project (for example, 7.48.0.Final-redhat-00004).

   注記

   Instead of specifying a Red Hat Decision Manager <version> for individual dependencies, consider adding the Red Hat Business Automation bill of materials (BOM) dependency to your project pom.xml file. The Red Hat Business Automation BOM applies to both Red Hat Decision Manager and Red Hat Process Automation Manager. When you add the BOM files, the correct versions of transitive dependencies from the provided Maven repositories are included in the project.

   Example BOM dependency:

   <dependency>
     <groupId>com.redhat.ba</groupId>
     <artifactId>ba-platform-bom</artifactId>
     <version>7.10.0.redhat-00004</version>
     <scope>import</scope>
     <type>pom</type>
   </dependency>

   Copy to Clipboard

   For more information about the Red Hat Business Automation BOM, see What is the mapping between RHDM product and maven library version?.

2. Create a KIE container from classpath or ReleaseId:

   KieServices kieServices = KieServices.Factory.get();
   
   ReleaseId releaseId = kieServices.newReleaseId( "org.acme", "my-kjar", "1.0.0" );
   KieContainer kieContainer = kieServices.newKieContainer( releaseId );

   Copy to Clipboard

   Alternative option:

   KieServices kieServices = KieServices.Factory.get();
   
   KieContainer kieContainer = kieServices.getKieClasspathContainer();

   Copy to Clipboard

3. Obtain DMNRuntime from the KIE container and a reference to the DMN model to be evaluated, by using the model namespace and modelName:

   DMNRuntime dmnRuntime = KieRuntimeFactory.of(kieContainer.getKieBase()).get(DMNRuntime.class);
   
   String namespace = "http://www.redhat.com/_c7328033-c355-43cd-b616-0aceef80e52a";
   String modelName = "dmn-movieticket-ageclassification";
   
   DMNModel dmnModel = dmnRuntime.getModel(namespace, modelName);

   Copy to Clipboard

4. Execute the decision services for the desired model:

   DMNContext dmnContext = dmnRuntime.newContext();  

   1

   
   
   for (Integer age : Arrays.asList(1,12,13,64,65,66)) {
       dmnContext.set("Age", age);  

   2

   
       DMNResult dmnResult =
           dmnRuntime.evaluateAll(dmnModel, dmnContext);  

   3

   
   
       for (DMNDecisionResult dr : dmnResult.getDecisionResults()) {  

   4

   
           log.info("Age: " + age + ", " +
                    "Decision: '" + dr.getDecisionName() + "', " +
                    "Result: " + dr.getResult());
     }
   }

   Copy to Clipboard

   1

   Instantiate a new DMN Context to be the input for the model evaluation. Note that this example is looping through the Age Classification decision multiple times.

   2

   Assign input variables for the input DMN context.

   3

   Evaluate all DMN decisions defined in the DMN model.

   4

   Each evaluation may result in one or more results, creating the loop.

   This example prints the following output:

   Age 1 Decision 'AgeClassification' : Child
   Age 12 Decision 'AgeClassification' : Child
   Age 13 Decision 'AgeClassification' : Adult
   Age 64 Decision 'AgeClassification' : Adult
   Age 65 Decision 'AgeClassification' : Senior
   Age 66 Decision 'AgeClassification' : Senior

   Copy to Clipboard

   If the DMN model was not previously compiled as an executable model for more efficient execution, you can enable the following property when you execute your DMN models:

   -Dorg.kie.dmn.compiler.execmodel=true

   Copy to Clipboard