The {KIE_SERVER} Java client API provides a lightweight approach to invoking a remote DMN service either through the REST or JMS interfaces of {KIE_SERVER}. This approach reduces the number of runtime dependencies necessary to interact with a KIE base. Decoupling the calling code from the decision definition also increases flexibility by enabling them to iterate independently at the appropriate pace.

For more information about the {KIE_SERVER} Java client API, see

• {KIE_SERVER} is installed and configured, including a known user name and credentials for a user with the kie-server role. For installation options, see

• A KIE container is deployed in {KIE_SERVER} in the form of a KJAR that includes the DMN model, ideally compiled as an executable model for more efficient execution:

  mvn clean install -DgenerateDMNModel=yes

  For more information about project packaging and deployment and executable models, see

• You have the container ID of the KIE container containing the DMN model. If more than one model is present, you must also know the model namespace and model name of the relevant model.

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

   <!-- Required for the {KIE_SERVER} Java client API -->
   <dependency>
     <groupId>org.kie.server</groupId>
     <artifactId>kie-server-client</artifactId>
     <version>${{PRODUCT_INIT}.version}</version>
   </dependency>

   The <version> is the Maven artifact version for {PRODUCT} currently used in your project (for example, {MAVEN_ARTIFACT_VERSION}).

2. Instantiate a KieServicesClient instance with the appropriate connection information.

   Example:

   KieServicesConfiguration conf =
       KieServicesFactory.newRestConfiguration(URL, USER, PASSWORD); // (1)
   
   conf.setMarshallingFormat(MarshallingFormat.JSON);  // (2)
   
   KieServicesClient kieServicesClient = KieServicesFactory.newKieServicesClient(conf);

   1. The connection information:

      • Example URL: http://localhost:8080/kie-server/services/rest/server

      • The credentials should reference a user with the kie-server role.

   2. The Marshalling format is an instance of org.kie.server.api.marshalling.MarshallingFormat. It controls whether the messages will be JSON or XML. Options for Marshalling format are JSON, JAXB, or XSTREAM.

3. Obtain a DMNServicesClient from the KIE server Java client connected to the related {KIE_SERVER} by invoking the method getServicesClient() on the KIE server Java client instance:

   DMNServicesClient dmnClient = kieServicesClient.getServicesClient(DMNServicesClient.class );

   The dmnClient can now execute decision services on {KIE_SERVER}.

4. Execute the decision services for the desired model.

   Example:

   for (Integer age : Arrays.asList(1,12,13,64,65,66)) {
       DMNContext dmnContext = dmnClient.newContext(); // (1)
       dmnContext.set("Age", age);  // (2)
       ServiceResponse<DMNResult> serverResp =   // (3)
           dmnClient.evaluateAll($kieContainerId,
                                 $modelNamespace,
                                 $modelName,
                                 dmnContext);
   
       DMNResult dmnResult = serverResp.getResult();  // (4)
       for (DMNDecisionResult dr : dmnResult.getDecisionResults()) {
           log.info("Age: " + age + ", " +
                    "Decision: '" + dr.getDecisionName() + "', " +
                    "Result: " + dr.getResult());
       }
   }

   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 the DMN Decisions defined in the DMN model:

      • $kieContainerId is the ID of the container where the KJAR containing the DMN model is deployed

      • $modelNamespace is the namespace for the model.

      • $modelName is the name for the model.

   4. The DMN Result object is available from the server response.

   At this point, the dmnResult contains all the decision results from the evaluated DMN model.

   You can also execute only a specific DMN decision in the model by using alternative methods of the DMNServicesClient.

   Note	If the KIE container only contains one DMN model, you can omit $modelNamespace and $modelName because the {KIE_SERVER} API selects it by default.

Directly interacting with the REST endpoints of {KIE_SERVER} provides the most separation between the calling code and the decision logic definition. The calling code is completely free of direct dependencies, and you can implement it in an entirely different development platform such as node.js or .net. The examples in this section demonstrate Nix-style curl commands but provide relevant information to adapt to any REST client.

For more information about the {KIE_SERVER} REST API, see

• {KIE_SERVER} is installed and configured, including a known user name and credentials for a user with the kie-server role. For installation options, see

• A KIE container is deployed in {KIE_SERVER} in the form of a KJAR that includes the DMN model, ideally compiled as an executable model for more efficient execution:

  mvn clean install -DgenerateDMNModel=yes

  For more information about project packaging and deployment and executable models, see

• You have the container ID of the KIE container containing the DMN model. If more than one model is present, you must also know the model namespace and model name of the relevant model.

• You have the DMN model deployed. For more information about project deployment, see

1. Determine the base URL for accessing the {KIE_SERVER} REST API endpoints. This requires knowing the following values (with the default local deployment values as an example):

   • Host (localhost)

   • Port (8080)

   • Root context (kie-server)

   • Base REST path (services/rest/)

2. Determine user authentication requirements.

   When users are defined directly in the {KIE_SERVER} configuration, HTTP Basic authentication is used and requires the user name and password. Successful requests require that the user have the kie-server role.

   The following example demonstrates how to add credentials to a curl request:

   curl -u username:password <request>

   If {KIE_SERVER} is configured with Red Hat Single Sign-On, the request must include a bearer token:

   curl -H "Authorization: bearer $TOKEN" <request>

3. Specify the format of the request and response. The REST API endpoints work with both JSON and XML formats and are set using request headers:

   JSON

   curl -H "accept: application/json" -H "content-type: application/json"

   XML

   curl -H "accept: application/xml" -H "content-type: application/xml"

4. (Optional) Query the container for a list of deployed decision models:

   [GET] server/containers/{containerId}/dmn

   Example curl request:

   1. Execute the model: