Activiti

activiti的API中，最终要的一个接口就是ProcessEngine,获取到ProcessEngine的实例，就获取了activiti体系中的所有api。重要的接口如下：

ProcessEngine processEngine = ProcessEngines.getDefaultProcessEngine();  

RuntimeService runtimeService = processEngine.getRuntimeService();
RepositoryService repositoryService = processEngine.getRepositoryService();
TaskService taskService = processEngine.getTaskService();
ManagementService managementService = processEngine.getManagementService();
IdentityService identityService = processEngine.getIdentityService();
HistoryService historyService = processEngine.getHistoryService();
FormService formService = processEngine.getFormService();