activiti 5.12中新增的动态bpmn模型部署

activiti是不错的工作流,最近发现5.12中可以通过在运行期间动态生成一个BPMN的流程模型,因为一般来说,是通过如activiti designer这样的工具,去画好一个BPMN图的,现在可以通过代码的方法去生成了.acitivti 核心工作组的老外提供了一个完整的DEMO来演示,
详细代码在:https://github.com/frederikheremans/activiti-dynamic-process中,
下面小结下,代码其实很简单,如下:

@Test
public void testDynamicDeploy() throws Exception {

//创建bpmn模型
  BpmnModel model = new BpmnModel();
  Process process = new Process();
  model.addProcess(process);
  process.setId("my-process");

//创建bpmn元素
  process.addFlowElement(createStartEvent());
  process.addFlowElement(createUserTask("task1", "First task", "fred"));
  process.addFlowElement(createUserTask("task2", "Second task", "john"));
  process.addFlowElement(createEndEvent());

  process.addFlowElement(createSequenceFlow("start", "task1"));
  process.addFlowElement(createSequenceFlow("task1", "task2"));
  process.addFlowElement(createSequenceFlow("task2", "end"));

  // 2.生成BPMN自动布局
  new BpmnAutoLayout(model).execute();

  // 3. 部署这个BPMN模型
  Deployment deployment = activitiRule.getRepositoryService().createDeployment()
    .addBpmnModel("dynamic-model.bpmn", model).name("Dynamic process deployment")
    .deploy();

  // 4. 启动流程实例
  ProcessInstance processInstance = activitiRule.getRuntimeService()
    .startProcessInstanceByKey("my-process");

  // 5 发起任务
  List tasks = activitiRule.getTaskService().createTaskQuery()
    .processInstanceId(processInstance.getId()).list();

  Assert.assertEquals(1, tasks.size());
  Assert.assertEquals("First task", tasks.get(0).getName());
  Assert.assertEquals("fred", tasks.get(0).getAssignee());

  // 6. 保存bpmn流程图 
  InputStream processDiagram = activitiRule.getRepositoryService()
    .getProcessDiagram(processInstance.getProcessDefinitionId());
  FileUtils.copyInputStreamToFile(processDiagram, new File("target/diagram.png"));

  // 7. 保存为bpmn.xml的xml类型文件
  InputStream processBpmn = activitiRule.getRepositoryService()
    .getResourceAsStream(deployment.getId(), "dynamic-model.bpmn");
  FileUtils.copyInputStreamToFile(processBpmn, 
    new File("target/process.bpmn20.xml"));
}

//创建task
protected UserTask createUserTask(String id, String name, String assignee) {
  UserTask userTask = new UserTask();
  userTask.setName(name);
  userTask.setId(id);
  userTask.setAssignee(assignee);
  return userTask;
}

//创建箭头
protected SequenceFlow createSequenceFlow(String from, String to) {
  SequenceFlow flow = new SequenceFlow();
  flow.setSourceRef(from);
  flow.setTargetRef(to);
  return flow;
}

protected StartEvent createStartEvent() {
  StartEvent startEvent = new StartEvent();
  startEvent.setId("start");
  return startEvent;
}

protected EndEvent createEndEvent() {
  EndEvent endEvent = new EndEvent();
  endEvent.setId("end");
  return endEvent;
}

   其实上面的注解已经比较清楚了.首先是 BpmnModel model = new BpmnModel();
创建一个BPMN模型;然后Process process = new Process();这里创建一个process,
并把这个process加到bpmn模型中去,当然要设置其id了;
  然后用 process.addFlowElement去不断创建BPMN中的每一个元素;
可以看到包括start,end,task,sequence等元素都可以通过new的方法分别创建;
   并且用new BpmnAutoLayout(model).execute();对BPMN元素进行自动布局;
3,4,5部分则比较好理解了;6和7则都是生成BPMN的实际jpg图和生成实际的XML文件
   最后会生成的BPMN图为: