场景：本章主要描述 正在执行会签任务 如何进行回退操作。
会签任务进行回退操作
上一章：[flowable 上一节点任务撤回-（2）会签任务（已完成）
]（https://www.jianshu.com/p/93fc02bb31d7）
下一章：[flowable 上一节点任务撤回-（4）多重网关]（https://www.jianshu.com/p/9801acf01ceb）环境：
springboot：2.2.0.RELEASE
flowable：6.4.2git地址：https://github.com/oldguys/flowable-modeler-demo/tree/branch_with_flowable_examples
所有章节：
会签原理分析请参考上一章！
- 不同于 已完成任务， 正在执行任务会签任务回退不需要 考虑节点任务的跳转，所以不需要 对 历史任务 处理痕迹这些进行操作，只需要修改任务（execution依然存在）就行了。
- 但是在前一章的基础上，又出现了 手动添加 已完成execution的问题，（回退任务的execution已经被删掉）所以此处需要解决由上一章引出的 一种解决方案。
根据 Execution 生命周期的问题，可以只作为判定是否需要 删除已完成任务 execution。
步骤：
配置父级 execution 参数
nrOfActiveInstances = 原本nrOfActiveInstances +1
nrOfCompletedInstances = 原本nrOfCompletedInstances - 1判定回退任务的 execution是否被删除掉，如果还存在，则直接修改 execution，对任务进行重新生成。如果 execution 已经被删除，即: 改流程已经到达下一个任务节点，已经进行过 回退，则需要删除 完成任务回退增加的 Execution（参考上一章）。
注意使用 ：CommandContextUtil.getAgenda(commandContext).planContinueMultiInstanceOperation(newExecution, executionEntity, loopCounter);进行任务创建。
- 如果是串行会签，则需要删除 下一完成任务，如果是并行，则忽略。
基于模板方法模式，构建编写通用 RollbackOperateStrategy.process() 操~作
由于 正在执行 会签的特殊性，不需要维护边界节点的相关数据，所以这里在 实现策略类中，重写 process() 方法
@Override
public void process(CommandContext commandContext, String assignee, Map<String, Object> variables) {
this.commandContext = commandContext;
this.assignee = assignee;
this.variables = variables;
// 串行会签
if (paramsTemplate.getCurrentTaskElement().getBehavior() instanceof SequentialMultiInstanceBehavior) {
isSequential = true;
} else if (paramsTemplate.getCurrentTaskElement().getBehavior() instanceof MultiInstanceActivityBehavior) {
isSequential = false;
}
LOGGER.info("创建实例");
createExecution();
}
创建execution
@Override
public void createExecution() {
HistoricTaskInstance hisTask = paramsTemplate.getHisTask();
List<Task> currentTaskList = CommandContextUtil.getTaskService(commandContext)
.createTaskQuery()
.processInstanceId(hisTask.getProcessInstanceId())
.taskDefinitionKey(hisTask.getTaskDefinitionKey())
.list();
if (currentTaskList.isEmpty()) {
String msg = "当前会签任务已经完成";
throw new FlowableRuntimeException(msg);
}
if (!isSequential) {
LOGGER.info("处理并行会签");
processMultiInstance();
} else {
LOGGER.info("处理串行会签");
processSequentialInstance();
}
}
处理串行会签 processSequentialInstance
/**
* 处理串行会签
* 串行特殊场景 : 下一个顺序执行人已完成任务，当前历史任务不可回退
* a -> b -> c -> d
* b 任务完成时， a 任务不可回退
*/
private void processSequentialInstance() {
HistoricTaskInstance hisTask = paramsTemplate.getHisTask();
// 确认是否具有下一线性完成任务
existNextFinishedTask(hisTask);
// 进行任务回退操作
ExecutionEntity executionEntity = processCommon(hisTask);
if (executionEntity.getId().equals(hisTask.getExecutionId())) {
log.info("未生成过下一节点");
// 移除正在执行任务
List<TaskEntity> taskEntityList = CommandContextUtil.getTaskService(commandContext).findTasksByExecutionId(executionEntity.getId());
taskEntityList.forEach(obj -> {
LOGGER.info("移除正在当前任务记录 [ id = " + obj.getId() + " ] ");
CommandContextUtil.getTaskService(commandContext).deleteTask(obj, true);
HistoricTaskInstance historicTaskInstance = CommandContextUtil.getHistoricTaskService(commandContext).getHistoricTask(obj.getId());
CommandContextUtil.getHistoricTaskService(commandContext).deleteHistoricTask((HistoricTaskInstanceEntity) historicTaskInstance);
});
// 配置任务执行人
executionEntity.setVariable(assigneeExpr, assignee);
// 计数器前置一位
int loopCounter = (int) executionEntity.getVariable(RollbackConstants.MultiInstanceConstants.LOOP_COUNTER);
executionEntity.setVariable(RollbackConstants.MultiInstanceConstants.LOOP_COUNTER, loopCounter - 1);
// 将任务重新激活
executionEntity.setActive(true);
// 创建新任务
CommandContextUtil.getAgenda(commandContext).planContinueProcessInCompensation(executionEntity);
} else {
log.info("已生成过下一任务节点,无法找到当前 execution");
List<Task> taskList = CommandContextUtil.getTaskService(commandContext).createTaskQuery()
.processInstanceId(hisTask.getProcessInstanceId())
.taskDefinitionKey(hisTask.getTaskDefinitionKey())
.list();
Task currentTask = taskList.get(0);
Integer currentLoopCounter = (Integer) runtimeService.getVariableLocal(currentTask.getExecutionId(), RollbackConstants.MultiInstanceConstants.LOOP_COUNTER);
List<String> assigneeList = (List<String>) runtimeService.getVariableLocal(currentTask.getProcessInstanceId(), assigneeListExpr);
if (StringUtils.isEmpty(hisTask.getAssignee())) {
throw new FlowableRuntimeException("没有找到历史任务执行人,无法进行 执行顺序判断");
}
int index = assigneeList.indexOf(hisTask.getAssignee());
if (index == -1) {
throw new FlowableRuntimeException("执行人不存在于初始参数,无法进行 执行顺序判断");
}
if (index != currentLoopCounter - 1) {
throw new FlowableRuntimeException("任务执行人不是 当前执行人的前位 , 不合法回退");
}
// 持久化变量
assigneeList.set(index, assignee);
runtimeService.setVariableLocal(currentTask.getProcessInstanceId(), assigneeListExpr, assigneeList);
// 修改变量
ExecutionEntity newExecution = CommandContextUtil.getExecutionEntityManager(commandContext).findById(currentTask.getExecutionId());
newExecution.setVariableLocal(RollbackConstants.MultiInstanceConstants.LOOP_COUNTER, currentLoopCounter - 1);
newExecution.setVariableLocal(assigneeExpr, assignee);
// 创建新任务
CommandContextUtil.getAgenda(commandContext).planContinueMultiInstanceOperation(newExecution, executionEntity, currentLoopCounter - 1);
// 移除当前任务
CommandContextUtil.getTaskService(commandContext).deleteTask((TaskEntity) currentTask, true);
// 移除历史任务
HistoricTaskInstance historicTaskInstance = CommandContextUtil.getHistoricTaskService(commandContext).getHistoricTask(currentTask.getId());
CommandContextUtil.getHistoricTaskService(commandContext).deleteHistoricTask((HistoricTaskInstanceEntity) historicTaskInstance);
}
// 移除当前历史任务
removeHisTask(hisTask);
}
processMultiInstance
/**
* 处理并行会签
*/
private void processMultiInstance() {
HistoricTaskInstance hisTask = paramsTemplate.getHisTask();
// 通用操作部分
ExecutionEntity executionEntity = processCommon(hisTask);
// 未生成过下一节点
if (executionEntity.getId().equals(hisTask.getExecutionId())) {
log.info("未生成过下一节点");
// 配置任务执行人
executionEntity.setVariable(assigneeExpr, assignee);
// 将任务重新激活
executionEntity.setActive(true);
// 创建新任务
CommandContextUtil.getAgenda(commandContext).planContinueProcessInCompensation(executionEntity);
} else {
log.info("已生成过下一任务节点,无法找到当前 execution");
List<HistoricVariableInstance> historicVariableInstanceList = CommandContextUtil.getHistoricVariableService().findHistoricVariableInstancesByQueryCriteria(
new HistoricVariableInstanceQueryImpl()
.processInstanceId(hisTask.getProcessInstanceId())
.executionId(hisTask.getExecutionId())
);
Map<String, Object> hisVarMap = historicVariableInstanceList.stream().collect(Collectors.toMap(HistoricVariableInstance::getVariableName, item -> item.getValue()));
// 流程执行变量
Integer loopCounter = (Integer) hisVarMap.get(RollbackConstants.MultiInstanceConstants.LOOP_COUNTER);
List<ExecutionEntity> executionEntities = CommandContextUtil.getExecutionEntityManager(commandContext)
.findChildExecutionsByParentExecutionId(executionEntity.getId());
List<ExecutionEntity> linkExecutions = executionEntities.stream()
.filter(obj -> {
if (!obj.isActive()) {
Integer currentLoopCounter = (Integer) obj.getVariable(RollbackConstants.MultiInstanceConstants.LOOP_COUNTER);
if (currentLoopCounter.equals(loopCounter)) {
return true;
}
}
return false;
}).collect(Collectors.toList());
if (linkExecutions.isEmpty()) {
throw new FlowableRuntimeException("没有找到映射节点");
}
ExecutionEntity newExecution = linkExecutions.get(0);
newExecution.setCurrentFlowElement(paramsTemplate.getCurrentTaskElement());
newExecution.setActive(true);
newExecution.setVariables(hisVarMap);
newExecution.setVariable(assigneeExpr, assignee);
// 创建新任务
CommandContextUtil.getAgenda(commandContext).planContinueMultiInstanceOperation(newExecution, executionEntity, loopCounter);
}
// 移除当前历史任务
removeHisTask(hisTask);
}
通用处理父级execution逻辑
/**
* 通用处理逻辑
*
* @param hisTask
* @return
*/
private ExecutionEntity processCommon(HistoricTaskInstance hisTask) {
ExecutionEntity executionEntity = CommandContextUtil
.getExecutionEntityManager(commandContext).findById(hisTask.getExecutionId());
if (null == executionEntity) {
LOGGER.error("没有找到历史任务[ executionId = " + hisTask.getExecutionId() + " ]");
// List<ExecutionEntity> executionEntityList = CommandContextUtil
// .getExecutionEntityManager(commandContext)
// .findExecutionsByParentExecutionAndActivityIds(hisTask.getProcessInstanceId(), Collections.singletonList(hisTask.getTaskDefinitionKey()));
List<Task> taskEntityList = CommandContextUtil.getTaskService(commandContext)
.createTaskQuery()
.processInstanceId(hisTask.getProcessInstanceId())
.taskDefinitionKey(hisTask.getTaskDefinitionKey())
.list();
executionEntity = CommandContextUtil.getExecutionEntityManager(commandContext).findById(taskEntityList.get(0).getExecutionId());
}
ExecutionEntity parentExecutionEntity = CommandContextUtil
.getExecutionEntityManager(commandContext).findById(executionEntity.getParentId());
/**
* 将计数器 进行 前移
*/
int nrOfActiveInstances = (int) parentExecutionEntity.getVariable(RollbackConstants.MultiInstanceConstants.NR_OF_ACTIVE_INSTANCES);
int nrOfCompletedInstances = (int) parentExecutionEntity.getVariable(RollbackConstants.MultiInstanceConstants.NR_OF_COMPLETE_INSTANCES);
runtimeService.setVariable(parentExecutionEntity.getId(), RollbackConstants.MultiInstanceConstants.NR_OF_ACTIVE_INSTANCES, nrOfActiveInstances + 1);
runtimeService.setVariable(parentExecutionEntity.getId(), RollbackConstants.MultiInstanceConstants.NR_OF_COMPLETE_INSTANCES, nrOfCompletedInstances - 1);
return parentExecutionEntity;
}
移除历史任务：
public void existNextFinishedTask(HistoricTaskInstance hisTask) {
List<HistoricTaskInstance> list = CommandContextUtil.getHistoricTaskService().findHistoricTaskInstancesByQueryCriteria(
(HistoricTaskInstanceQueryImpl) new HistoricTaskInstanceQueryImpl()
.processInstanceId(hisTask.getProcessInstanceId())
.taskDefinitionKey(hisTask.getTaskDefinitionKey())
.finished()
.taskCompletedAfter(hisTask.getEndTime())
);
if (!list.isEmpty()) {
String msg = "串行会签回滚，已经具有下一线性完成任务,无法进行任务回退";
LOGGER.error(msg);
throw new FlowableRuntimeException(msg);
}
}
以上 完成对 上一节点任务撤回 架构设计 及 第 3 种情况 解决方案讲述。
git地址：https://github.com/oldguys/flowable-modeler-demo/tree/branch_with_flowable_examples
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