Java工作流引擎 JBoss jBPM 3.1.2 演示示例

jBPM是由JBoss开发的工作流和业务流程管理引擎，可以用于创建不同人、不同应用程序、不同服务之间交互的业务流程。jBPM还提供了一个可视化的业务流程设计器。jBPM包含下列组件：运行时引擎（一个POJO库），图形化设计器（一个Eclipse插件），基于Hibernate的持久化，基于JSF的web控制台，BPEL扩展等。

Hello World示例

流程定义是一个可管理的包含了节点和节点间交付件的流程图。Hello World示例流程包含三个节点。为了查看节点间如何相互配合，将不使用任何设计工具来定义一个简单的流程。下图显示了Hello World示例流程的流程图定义：



Hello World示例流程图

public void testHelloWorldProcess() {
ProcessDefinition processDefinition = ProcessDefinition.parseXmlString(
  "<process-definition>" +
  "  <start-state>" +
  "    <transition to='s' />" +
  "  </start-state>" +
  "  <state name='s'>" +
  "    <transition to='end' />" +
  "  </state>" +
  "  <end-state name='end' />" +
  "</process-definition>"
);
ProcessInstance processInstance = new ProcessInstance(processDefinition);
Token token = processInstance.getRootToken();
assertSame(processDefinition.getStartState(), token.getNode());
token.signal();
assertSame(processDefinition.getNode("s"), token.getNode());
token.signal();
assertSame(processDefinition.getNode("end"), token.getNode());
}


数据库示例

jBPM基本特性之一是能够在jBPM数据库中持久化执行过程中处于等待状态的流程。数据库示例将展示如何在jBPM数据库中存储一个流程实例。该示例可能涉及到jBPM上下文。为不同的用户代码创建Separate方法。举例来说，webapplication中的一段用户代码开始一个流程并在数据库中持久化。之后，一个消息驱动Bean（MDB）加载该流程实例继续执行流程。

public class HelloWorldDbTest extends TestCase {
  static JbpmConfiguration jbpmConfiguration = null;
  static {
    jbpmConfiguration = JbpmConfiguration.parseXmlString(
      "<jbpm-configuration>" +
      "  <jbpm-context>" +
      "    <service name='persistence' " +
      "             factory='org.jbpm.persistence.db.DbPersistenceServiceFactory' />" +
      "  </jbpm-context>" +
      "  <string name='resource.hibernate.cfg.xml' " +
      "          value='hibernate.cfg.xml' />" +
      "  <string name='resource.business.calendar' " +
      "          value='org/jbpm/calendar/jbpm.business.calendar.properties' />" +
      "  <string name='resource.default.modules' " +
      "          value='org/jbpm/graph/def/jbpm.default.modules.properties' />" +
      "  <string name='resource.converter' " +
      "          value='org/jbpm/db/hibernate/jbpm.converter.properties' />" +
      "  <string name='resource.action.types' " +
      "          value='org/jbpm/graph/action/action.types.xml' />" +
      "  <string name='resource.node.types' " +
      "          value='org/jbpm/graph/node/node.types.xml' />" +
      "  <string name='resource.varmapping' " +
      "          value='org/jbpm/context/exe/jbpm.varmapping.xml' />" +
      "</jbpm-configuration>"
    );
  } 
  public void setUp() {
    jbpmConfiguration.createSchema();
  } 
  public void tearDown() {
    jbpmConfiguration.dropSchema();
  }
  public void testSimplePersistence() {
    deployProcessDefinition();
    processInstanceIsCreatedWhenUserSubmitsWebappForm();
    theProcessInstanceContinuesWhenAnAsyncMessageIsReceived();
  }
  public void deployProcessDefinition() {
    ProcessDefinition processDefinition = ProcessDefinition.parseXmlString(
      "<process-definition name='hello world'>" +
      "  <start-state name='start'>" +
      "    <transition to='s' />" +
      "  </start-state>" +
      "  <state name='s'>" +
      "    <transition to='end' />" +
      "  </state>" +
      "  <end-state name='end' />" +
      "</process-definition>"
    );
    JbpmContext jbpmContext = jbpmConfiguration.createJbpmContext();
    try {
      jbpmContext.deployProcessDefinition(processDefinition);

    } finally {
      jbpmContext.close();
    }
  }
  public void processInstanceIsCreatedWhenUserSubmitsWebappForm() {
    JbpmContext jbpmContext = jbpmConfiguration.createJbpmContext();
    try {
      GraphSession graphSession = jbpmContext.getGraphSession();     
      ProcessDefinition processDefinition = graphSession.findLatestProcessDefinition("hello world");
      ProcessInstance processInstance = new ProcessInstance(processDefinition);
      Token token = processInstance.getRootToken();
      assertEquals("start", token.getNode().getName());
      token.signal();
      assertEquals("s", token.getNode().getName());
      jbpmContext.save(processInstance);
    } finally {
      jbpmContext.close();
    }
  }
  public void theProcessInstanceContinuesWhenAnAsyncMessageIsReceived() {
    JbpmContext jbpmContext = jbpmConfiguration.createJbpmContext();
    try {
      GraphSession graphSession = jbpmContext.getGraphSession();
      ProcessDefinition processDefinition = graphSession.findLatestProcessDefinition("hello world");
      List processInstances = graphSession.findProcessInstances(processDefinition.getId());
      ProcessInstance processInstance = (ProcessInstance) processInstances.get(0);
      processInstance.signal();
      assertTrue(processInstance.hasEnded());
      jbpmContext.save(processInstance);
    } finally {
      jbpmContext.close();
    }
  }
}




上下文示例：流程变量

流程变量包含了流程执行期间的上下文信息。流程变量类似一个java.util.Map类型的名称/值对，并且是java对象。流程变量是流程实例的组成部分。以免事件复杂化，该示例仅仅演示处理流程变量的API，没有包括持久化处理。


ProcessDefinition processDefinition = ProcessDefinition.parseXmlString(
  "<process-definition>" +
  "  <start-state>" +
  "    <transition to='s' />" +
  "  </start-state>" +
  "  <state name='s'>" +
  "    <transition to='end' />" +
  "  </state>" +
  "  <end-state name='end' />" +
  "</process-definition>"
);

ProcessInstance processInstance = new ProcessInstance(processDefinition);
ContextInstance contextInstance = processInstance.getContextInstance();
contextInstance.setVariable("amount", new Integer(500));
contextInstance.setVariable("reason", "i met my deadline");
processInstance.signal();
assertEquals(new Integer(500), contextInstance.getVariable("amount"));
assertEquals("i met my deadline", contextInstance.getVariable("reason"));



任务分配示例

任务分配示例演示如何给用户分配任务。因为分离jBPM工作流引擎和组织模型，处理参与者的表现语言始终受到很多限制。因此，你必须实现一个包含处理任务参与者的任务分配器。

public void testTaskAssignment() {
  ProcessDefinition processDefinition = ProcessDefinition.parseXmlString(
    "<process-definition name='the baby process'>" +
    "  <start-state>" +
    "    <transition name='baby cries' to='t' />" +
    "  </start-state>" +
    "  <task-node name='t'>" +
    "    <task name='change nappy'>" +
    "      <assignment class='org.jbpm.tutorial.taskmgmt.NappyAssignmentHandler' />" +
    "    </task>" +
    "    <transition to='end' />" +
    "  </task-node>" +
    "  <end-state name='end' />" +
    "</process-definition>"
  );
  ProcessInstance processInstance =
      new ProcessInstance(processDefinition);
  Token token = processInstance.getRootToken();
  token.signal();
  assertSame(processDefinition.getNode("t"), token.getNode());
  TaskInstance taskInstance = (TaskInstance)processInstance
        .getTaskMgmtInstance()
        .getTaskInstances()
        .iterator().next();
  assertEquals("papa", taskInstance.getActorId() );
  taskInstance.end();
  assertSame(processDefinition.getNode("end"), token.getNode());
}