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1、工作流Activiti的学习总结（五） activiti的API和虚拟工作流测试activiti的API在activiti引擎中，你可以通过多种方式获取ProcessEngine对象，从ProcessEngine中获取各种服务对象，从而访问工作流/BPM方法。ProcessEngine和她的各种服务均为线程安全性服务。在整个项目中每一种服务仅需要保持一个引用。ProcessEngine processEngine = ProcessEngines.getDefaultProcessEngine(); RuntimeService runtimeService = processEngine.g
2、etRuntimeService(); RepositoryService repositoryService = processEngine.getRepositoryService(); TaskService taskService = processEngine.getTaskService(); ManagementService managementService = processEngine.getManagementService(); IdentityService identityService = processEngine.getIdentityService();
3、HistoryService historyService = processEngine.getHistoryService(); FormService formService = processEngine.getFormService();针对ProcessEngine的说明：ProcessEngine.getDefaultProcessEngine()在第一个被调用的时候初始化并创建一个流程引擎，在以后的调用中返回同一个引用的流程引擎对象。针对流程引擎中初始化方法为ProcessEngine.init().销毁方法的方法为ProcessEngine.destroy().Process
4、EngineConfiguration.createProcessEngineConfigurationFromInputStream(inputStream).buildProcessEngine()创建工作流引擎，ProcessEngine见扫描所有的activiti.cfg.xml文件和activiti-context.xml文件。 异常策略：在activiti中org.activiti.engine.ActivitiException类为所有异常的基类。ActivitiException为非检查性异常。例如：* * Called when the task is successfull
5、y executed. * param taskId the id of the task to complete, cannot be null. * throws ActivitiException when no task exists with the given id. */ void complete(String taskId);其他异常类如下：ActivitiWrongDbException: Thrown when the Activiti engine discovers a mismatch between the database schema version and
6、the engine version(schema版本和引擎版本不匹配报的错误). ActivitiOptimisticLockingException:Thrown when an optimistic locking occurs in the datastore caused by concurrent access of the same data entry. ActivitiClassLoadingException:Thrown when an class requested to load was not found or when error occurred while l
7、oading it (eg. JavaDelegates, TaskListeners, .). Activiti 的测试：activiti的测试支持Junit3和Junit4的单元测试。在junit3的单元测试中，org.activit.engine.test.ActivitiTestCase必须被继承。在setup（）方法中，流程引擎要初始化加载classpath下默认的activi.cfg.xml资源文件。针对不同的配置文件可能需要重新getConfigurationResource()方法。在ActivitiTestCase中可以使用org.activiti.engine.test.D
8、eployment注解方法。public class MyBusinessProcessTest extends ActivitiTestCase Deployment public void testSimpleProcess() runtimeService.startProcessInstanceByKey(simpleProcess); Task task = taskService.createTaskQuery().singleResult(); assertEquals(My Task, task.getName(); taskSplete(task.getId(); asser
9、tEquals(0, runtimeService.createProcessInstanceQuery().count(); 在junit4中org.activiti.engine.test.ActivitiRule Rule被采用。通过ActivitiRule中getter方法获取相关的服务。在Junit4同样功能的单元测试如下：public class MyBusinessProcessTest Rule public ActivitiRule activitiRule = new ActivitiRule(); Test Deployment public void ruleUsage
10、Example() RuntimeService runtimeService = activitiRule.getRuntimeService(); runtimeService.startProcessInstanceByKey(ruleUsage); TaskService taskService = activitiRule.getTaskService(); Task task = taskService.createTaskQuery().singleResult(); assertEquals(My Task, task.getName(); taskSplete(task.ge
11、tId(); assertEquals(0, runtimeService.createProcessInstanceQuery().count(); 在web环境中流程引擎的使用：由于processEngine是一个线程安全性的对象可以容易在多个线程中被共享。在web容器启动加载创建工作流引擎，在容器销毁销毁工作流引擎。可以ServletContextListener实现相关的功能。public class ProcessEnginesServletContextListener implements ServletContextListener public void contextIni
12、tialized(ServletContextEvent servletContextEvent) ProcessEngines.init(); public void contextDestroyed(ServletContextEvent servletContextEvent) ProcessEngines.destroy(); Activiti提供模拟流程的APIPvmProcessDefinition processDefinition = new ProcessDefinitionBuilder() .createActivity(a) .initial() .behavior(n
13、ew WaitState() .transition(b) .endActivity() .createActivity(b) .behavior(new WaitState() .transition(c) .endActivity() .createActivity(c) .behavior(new WaitState() .endActivity() .buildProcessDefinition(); PvmProcessInstance processInstance = processDefinition.createProcessInstance(); processInstan
14、ce.start(); PvmExecution activityInstance = processInstance.findExecution(a); assertNotNull(activityInstance); activityInstance.signal(null, null); activityInstance = processInstance.findExecution(b); assertNotNull(activityInstance); activityInstance.signal(null, null); activityInstance = processIns
15、tance.findExecution(c); assertNotNull(activityInstance); activiti中表达式activiti使用UEL(Unified Expression Lanuage)标记解析配置文件中表达式。UEL是EE6特性。activiti中Expressions支持两种方式：1.Value expression:在activiti中DelegateExecution是在上下文中是使用“execution”在表达式上下文被使用的。所有在使用值表达式是，所有变量和spring的beans使用execution将被隐藏，在表达式将不被执行。使用方法如下：$myVar $myBean.myProperty2.Method expression:使用方法访问的方式。常用方式如下：$printer.print() $myBean.addNewOrder(“orerName”) 备注：在activiti中expression支持解析的类型为原始类型，beans，lists,arrays和maps
