WSO2 BPMN Rule Task provides features for executing Drools rules in WSO2 Enterprise Integrator(EI)/BPS in BPMN process work flows. It has been implemented using a BPMN service task and the Drools files are designed to be managed in BPS registry.

1. Clone this repository and build it using maven:

   git clone https://github.com/imesh/wso2-bpmn-rule-task.git
   mvn clean install

2. Copy the following JAR files to the lib/ directory of the WSO2 EI/BPS server:

   cp target/bpmn-rule-task-1.0-SNAPSHOT.jar ${WSO2_EI_HOME}/dropins/
   cp target/dependency/drools-compiler-6.0.1.Final.jar ${WSO2_EI_HOME}/lib/
   cp target/dependency/drools-core-6.0.1.Final.jar ${WSO2_EI_HOME}/lib/
   cp target/dependency/kie-api-6.0.1.Final.jar ${WSO2_EI_HOME}/lib/
   cp target/dependency/kie-internal-6.0.1.Final.jar ${WSO2_EI_HOME}/lib/
   cp target/dependency/mvel2-2.1.8.Final.jar ${WSO2_EI_HOME}/lib/

3. Implement a BPMN process work flow using WSO2 Developer Studio and add a service task to it. Then click on the service task and add the following class name under main config:

   

   org.wso2.carbon.bpmn.rule.task.RuleTask
   

4. Upload a Drools rule file to WSO2 EI/BPS registry path /_system/config/rules/ using the Carbon console:

   package com.sample
   
   global String var1;
   global Integer var2;
   
   rule "Rule 1"
       when
           value: Object (true)
       then
           System.out.println( "Fact: " + value);
           System.out.println( "var1: " + var1);
           System.out.println( "var2: " + var2);
   end
   

5. Provide its resource path using a documentation field in the above service task with the name drlRegPath as follows:

   

   drlRegPath = conf:/rules/sample.drl
   

6. Now define required global variables of the Drools rule file using the prefix global_ and facts using fact_ as follows:

   

7. Generate the deployment artifact of the above BPMN process work flow and deploy it in WSO2 EI/BPS server.

8. Once deployed, invoke the process flow using the BPMN explorer.