Activiti7 回退与会签

1.  回退（驳回）

回退的思路就是动态更改节点的流向。先遇水搭桥，最后再过河拆桥。

具体操作如下：

1. 取得当前节点的信息
2. 取得当前节点的上一个节点的信息
3. 保存当前节点的流向
4. 新建流向，由当前节点指向上一个节点
5. 将当前节点的流向设置为上面新建的流向
6. 当前节点完成任务
7. 将当前节点的流向还原
8. 取得之前上个节点的执行人
9. 设置上个节点的assignee为之前的执行人

代码实现起来可能是这样的： 

@Test
public void huitui() throws Exception {
    ProcessEngine processEngine = ProcessEngines.getDefaultProcessEngine();
    TaskService taskService = processEngine.getTaskService();
    Task task = taskService.createTaskQuery().processInstanceId("55001").singleResult();
    backProcess(task);
}

/**
 * 驳回 / 回退
 * 按照这种方法，可以回退至任意节点
 * @param task
 * @throws Exception
 */
public void backProcess(Task task) throws Exception {
    ProcessEngine processEngine = ProcessEngines.getDefaultProcessEngine();
    HistoryService historyService = processEngine.getHistoryService();
    RepositoryService repositoryService = processEngine.getRepositoryService();
    TaskService taskService = processEngine.getTaskService();

    String processInstanceId = task.getProcessInstanceId();

    //  获取所有历史任务（按创建时间降序）
    List<HistoricTaskInstance> hisTaskList = historyService.createHistoricTaskInstanceQuery()
            .processInstanceId(processInstanceId)
            .orderByTaskCreateTime()
            .desc()
            .list();

    List<HistoricActivityInstance> hisActivityList = historyService.createHistoricActivityInstanceQuery()
            .processInstanceId(processInstanceId).list();

    if (CollectionUtils.isEmpty(hisTaskList) || hisTaskList.size() < 2) {
        return;
    }

    //  当前任务
    HistoricTaskInstance currentTask = hisTaskList.get(0);
    //  前一个任务
    HistoricTaskInstance lastTask = hisTaskList.get(1);
    //  当前活动
    HistoricActivityInstance currentActivity = hisActivityList.stream().filter(e -> currentTask.getId().equals(e.getTaskId())).collect(Collectors.toList()).get(0);
    //  前一个活动
    HistoricActivityInstance lastActivity = hisActivityList.stream().filter(e -> lastTask.getId().equals(e.getTaskId())).collect(Collectors.toList()).get(0);

    BpmnModel bpmnModel = repositoryService.getBpmnModel(task.getProcessDefinitionId());

    //  获取前一个活动节点
    FlowNode lastFlowNode = (FlowNode) bpmnModel.getMainProcess().getFlowElement(lastActivity.getActivityId());
    //  获取当前活动节点
    FlowNode currentFlowNode = (FlowNode) bpmnModel.getMainProcess().getFlowElement(currentActivity.getActivityId());

    //  临时保存当前活动的原始方向
    List<SequenceFlow> originalSequenceFlowList = new ArrayList<>();
    originalSequenceFlowList.addAll(currentFlowNode.getOutgoingFlows());
    //  清理活动方向
    currentFlowNode.getOutgoingFlows().clear();

    //  建立新方向
    SequenceFlow newSequenceFlow = new SequenceFlow();
    newSequenceFlow.setId("newSequenceFlowId");
    newSequenceFlow.setSourceFlowElement(currentFlowNode);
    newSequenceFlow.setTargetFlowElement(lastFlowNode);
    List<SequenceFlow> newSequenceFlowList = new ArrayList<>();
    newSequenceFlowList.add(newSequenceFlow);
    //  当前节点指向新的方向
    currentFlowNode.setOutgoingFlows(newSequenceFlowList);

    //  完成当前任务
    taskService.complete(task.getId());

    //  重新查询当前任务
    Task nextTask = taskService.createTaskQuery().processInstanceId(processInstanceId).singleResult();
    if (null != nextTask) {
        taskService.setAssignee(nextTask.getId(), lastTask.getAssignee());
    }

    //  恢复原始方向
    currentFlowNode.setOutgoingFlows(originalSequenceFlowList);
}