grails install-plugin drools-gorm

class JbpmService {
        static transactional = true
        /** The kstore is automatically declared by the drools-gorm plugin */
        def kstore
        /**
         * Returns a SessionConfiguration containing Drools services
         * implementations for Grails.
         *
         * @return a SessionConfiguration containing Drools services
         * implementations for Grails.
         */
        def getGORMSessionConfig() {
            Properties properties = new Properties();
            properties.setProperty("drools.commandService",
                    SingleSessionCommandService.class.getName());
            properties.setProperty("drools.processInstanceManagerFactory",
                    GormProcessInstanceManagerFactory.class.getName());
            properties.setProperty("drools.workItemManagerFactory",
                    GormWorkItemManagerFactory.class.getName());
            properties.setProperty("drools.processSignalManagerFactory",
                    GormSignalManagerFactory.class.getName());
            return new SessionConfiguration(properties);
        }
        /**
         * Construct a kbase with an example flow.
         *
         * @return a KnowledgeBase containing an example flow.
         */
        def KnowledgeBase createKbase() {
            KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder();
            kbuilder.add(ResourceFactory.newClassPathResource("helloWord.rf"),
                    ResourceType.BPMN2);
            if (kbuilder.hasErrors()) {
                throw new IllegalStateException("error compiling 'helloWord.rf':n"
                        + kbuilder.errors);
            }
            return kbuilder.newKnowledgeBase();
        }
        /**
         * Start the a process.
         *
         * @param processId  the process id to start.
         * @return the id of the process instance.
         */
        def startProcess(String processId) {
            Environment env = KnowledgeBaseFactory.newEnvironment()
            StatefulKnowledgeSession ksession = kstore.newStatefulKnowledgeSession(createKbase(),
                    getGORMSessionConfig(),
                    env)
            ProcessInstance pi = ksession.startProcess(processId)
            def pid = pi.id
            ksession.dispose()
            return pid
        }
    }