Chapter 7. Configuring an embedded process engine and decision engine in Oracle WebLogic Server

An embedded engine is a light-weight workflow and rule engine that enables you to execute your decisions and business processes. An embedded engine can be part of a Red Hat Process Automation Manager application or it can be deployed as a service through OpenShift, Kubernetes, and Docker. You can embed an engine in a Red Hat Process Automation Manager application through the API or as a set of contexts and dependency injection (CDI) services.

If you intend to use an embedded engine with your Red Hat Process Automation Manager application, you must add Maven dependencies to your project by adding the Red Hat Business Automation bill of materials (BOM) files to the project’s pom.xml file. The Red Hat Business Automation BOM applies to both Red Hat Decision Manager and Red Hat Process Automation Manager. For more information about the Red Hat Business Automation BOM, see What is the mapping between Red Hat Process Automation Manager and the Maven library version?.

Procedure

  1. Declare the Red Hat Business Automation BOM in the pom.xml file:

    <dependencyManagement>
     <dependencies>
      <dependency>
       <groupId>com.redhat.ba</groupId>
       <artifactId>ba-platform-bom</artifactId>
       <version>7.5.1.redhat-00001</version>
       <type>pom</type>
       <scope>import</scope>
      </dependency>
     </dependencies>
    </dependencyManagement>
    <dependencies>
    <!-- Your dependencies -->
    </dependencies>
  2. Declare dependencies required for your project in the <dependencies> tag. After you import the product BOM into your project, the versions of the user-facing product dependencies are defined so you do not need to specify the <version> sub-element of these <dependency> elements. However, you must use the <dependency> element to declare dependencies which you want to use in your project.

    • For a basic Red Hat Process Automation Manager project, declare the following dependencies, depending on the features that you want to use:

      Embedded process engine dependencies

      <!-- Public KIE API -->
      <dependency>
        <groupId>org.kie</groupId>
        <artifactId>kie-api</artifactId>
      </dependency>
      
      <!-- Core dependencies for process engine -->
      <dependency>
        <groupId>org.jbpm</groupId>
        <artifactId>jbpm-flow</artifactId>
      </dependency>
      
      <dependency>
        <groupId>org.jbpm</groupId>
        <artifactId>jbpm-flow-builder</artifactId>
      </dependency>
      
      <dependency>
        <groupId>org.jbpm</groupId>
        <artifactId>jbpm-bpmn2</artifactId>
      </dependency>
      
      <dependency>
        <groupId>org.jbpm</groupId>
        <artifactId>jbpm-runtime-manager</artifactId>
      </dependency>
      
      <dependency>
        <groupId>org.jbpm</groupId>
        <artifactId>jbpm-persistence-jpa</artifactId>
      </dependency>
      
      <dependency>
        <groupId>org.jbpm</groupId>
        <artifactId>jbpm-query-jpa</artifactId>
      </dependency>
      
      <dependency>
        <groupId>org.jbpm</groupId>
        <artifactId>jbpm-audit</artifactId>
      </dependency>
      
      <dependency>
        <groupId>org.jbpm</groupId>
        <artifactId>jbpm-kie-services</artifactId>
      </dependency>
      
      <!-- Dependency needed for default WorkItemHandler implementations. -->
      <dependency>
        <groupId>org.jbpm</groupId>
        <artifactId>jbpm-workitems-core</artifactId>
      </dependency>
      
      <!-- Logging dependency. You can use any logging framework compatible with slf4j. -->
      <dependency>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
        <version>${logback.version}</version>
      </dependency>

    • For a Red Hat Process Automation Manager project that uses CDI, you typically declare the following dependencies:

      CDI-enabled process engine dependencies

      <dependency>
        <groupId>org.kie</groupId>
        <artifactId>kie-api</artifactId>
      </dependency>
      
      <dependency>
        <groupId>org.jbpm</groupId>
        <artifactId>jbpm-kie-services</artifactId>
      </dependency>
      
      <dependency>
        <groupId>org.jbpm</groupId>
        <artifactId>jbpm-services-cdi</artifactId>
      </dependency>

      Embedded decision engine dependencies

      <dependency>
        <groupId>org.drools</groupId>
        <artifactId>drools-compiler</artifactId>
      </dependency>
      
      <!-- Dependency for persistence support. -->
      <dependency>
        <groupId>org.drools</groupId>
        <artifactId>drools-persistence-jpa</artifactId>
      </dependency>
      
      <!-- Dependencies for decision tables, templates, and scorecards.
      For other assets, declare org.drools:business-central-models-* dependencies. -->
      <dependency>
        <groupId>org.drools</groupId>
        <artifactId>drools-decisiontables</artifactId>
      </dependency>
      <dependency>
        <groupId>org.drools</groupId>
        <artifactId>drools-templates</artifactId>
      </dependency>
      <dependency>
        <groupId>org.drools</groupId>
        <artifactId>drools-scorecards</artifactId>
      </dependency>
      
      <!-- Dependency for loading KJARs from a Maven repository using KieScanner. -->
      <dependency>
        <groupId>org.kie</groupId>
        <artifactId>kie-ci</artifactId>
      </dependency>

    • To use the Process Server, declare the following dependencies:

      Client application Process Server dependencies

      <dependency>
        <groupId>org.kie.server</groupId>
        <artifactId>kie-server-client</artifactId>
      </dependency>

    • To create a remote client for Red Hat Process Automation Manager, declare the following dependency:

      Client dependency

      <dependency>
        <groupId>org.uberfire</groupId>
        <artifactId>uberfire-rest-client</artifactId>
      </dependency>

    • When creating a JAR file that includes assets, such as rules and process definitions, specify the packaging type for your Maven project as kjar and use org.kie:kie-maven-plugin to process the kjar packaging type located under the <project> element. In the following example, ${kie.version} is the Maven library version listed in What is the mapping between Red Hat Process Automation Manager and the Maven library version?:

      <packaging>kjar</packaging>
      <build>
       <plugins>
        <plugin>
         <groupId>org.kie</groupId>
         <artifactId>kie-maven-plugin</artifactId>
         <version>${kie.version}</version>
         <extensions>true</extensions>
        </plugin>
       </plugins>
      </build>
  3. If you use a process engine or decision engine with persistence support in your project, you must declare the following hibernate dependencies in the dependencyManagement secion of your pom.xml file by copying the version.org.hibernate-4ee7 property from the Red Hat Business Automation BOM file:

    Hibernate dependencies

    <!-- hibernate dependencies -->
    <dependencyManagement>
      <dependencies>
        <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-entitymanager</artifactId>
        <version>${version.org.hibernate-4ee7}</version>
        </dependency>
    
        <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>${version.org.hibernate-4ee7}</version>
        </dependency>
      </dependencies>
    </dependencyManagement>