activiti6.0源码剖析之多实例减签与加签操作

一、什么是多实例减签，多实例加签

比如配置了一个多实例用户实例，由三人串行或者并行执行，那么现在的需求是某个个例不需要那么多人了，只需要两个人也就是减少一个人，这样的操作称为减签操作。

反之，当需要添加一个人员参与会签时的操作，就称之为加签操作。

二、多实例减签（仅支持6版本）

思路

通过多实例运转过程很容易能够理清如何实现减签操作，如果需要明白运转过程可以参考activiti6.0源码剖析之多实例运转过程

以该流程图为例说明

并行流程.png

减签可以从两种角度去看：被减掉的是以已经执行成功来做，还是压根就当作没有存在过
根据上述两种角度可以大致理清以下思路

• 首先根据需要减掉的任务Id获取到该任务ID所属的三级执行实例

• 然后根据三级执行实例ID或者多多实例执行实例的父级实例（二级实例）

• 通过二级执行实例删除需要减掉的三级执行实例数据，任务数据

• 根据二级执行实例获取nrOfInstances,nrOfCompletedInstances，nrOfActiveInstances,loopCounter变量，并根据并行或者串行多实例，根据上述两种角度进行相应的变更

  • 如果是串行多实例减签
    正常执行完成的角度上：nrOfCompletedInstances 加 1，nrOfActiveInstances保持1不变，loopCounter 加 1
    非正常完成的角度上：nrOfInstances 减 1，loopCounter 加 1

  • 如果是并行多实例减签
    正常执行完成的角度上：nrOfCompletedInstances 加 1，nrOfActiveInstances 减 1，
    非正常完成的角度上：nrOfInstances 减 1，nrOfActiveInstances 减 1，

实战

public class DeleteMultiInstanceCmd implements Command {
    protected final String NUMBER_OF_INSTANCES = "nrOfInstances";
    protected final String NUMBER_OF_ACTIVE_INSTANCES = "nrOfActiveInstances";
    protected final String NUMBER_OF_COMPLETED_INSTANCES = "nrOfCompletedInstances";
    protected String collectionElementIndexVariable = "loopCounter";

    private String taskId;
    private Boolean isNormalComplete;

    public DeleteMultiInstanceCmd(String taskId,boolean isNormalComplete) {
        this.taskId = taskId;
        this.isNormalComplete = isNormalComplete;
    }

    public Object execute(CommandContext commandContext) {
           ExecutionEntityManager executionEntityManager = commandContext.getExecutionEntityManager();
        TaskEntityManager taskEntityManager = commandContext.getTaskEntityManager();

        //根据任务id获取任务实例
        TaskEntity taskEntity = taskEntityManager.findById(taskId);
        //根据执行实例ID获取三级执行实例
        ExecutionEntity execution = executionEntityManager.findById(taskEntity.getExecutionId());
        //首先判断当前任务是否是属于多实例节点
        String processDefinitionId = execution.getProcessDefinitionId();
        BpmnModel bpmnModel = ProcessDefinitionUtil.getBpmnModel(processDefinitionId);
        Activity activityElement = (Activity)bpmnModel.getFlowElement(execution.getCurrentActivityId());
        MultiInstanceLoopCharacteristics loopCharacteristics = activityElement.getLoopCharacteristics();
        if(loopCharacteristics == null){
            throw new RuntimeException("没有找到多实例");
        }
        if(!(activityElement.getBehavior() instanceof MultiInstanceActivityBehavior)){
            throw new RuntimeException("此节点不是多实例节点");
        }
        DeploymentManager deploymentManager = commandContext.getProcessEngineConfiguration().getDeploymentManager();
        ProcessDefinition definition = deploymentManager.findDeployedProcessDefinitionById(processDefinitionId);
        //判断是否是5的版本
        if(Activiti5Util.isActiviti5ProcessDefinition(commandContext,definition)){
            throw new RuntimeException("不支持5版本");
        }

        boolean isSequential = loopCharacteristics.isSequential();
        //获取二级执行实例
        ExecutionEntity sencondExecution = execution.getParent();
        //删除所要删除的实例相关数据
        if(!isSequential){
            //并行多实例
            executionEntityManager.deleteChildExecutions(execution,"减签",false);
            executionEntityManager.deleteExecutionAndRelatedData(execution,"减签",true);
        }

        //获取二级执行实例关联的变量
        Integer nrOfInstances = (Integer) sencondExecution.getVariable(NUMBER_OF_INSTANCES);
        Integer nrOfActiveInstances = (Integer) sencondExecution.getVariable(NUMBER_OF_ACTIVE_INSTANCES);
        Integer nrOfCompletedInstances = (Integer) sencondExecution.getVariable(NUMBER_OF_COMPLETED_INSTANCES);
        //更新二级执行实例关联的变量
        if(isNormalComplete){
            //正常完成
            sencondExecution.setVariable(NUMBER_OF_COMPLETED_INSTANCES,nrOfCompletedInstances+1 );
            if(isSequential){
                //串行多实例
                Integer loopCounter =getLoopVariable(execution,collectionElementIndexVariable);
                execution.setVariableLocal(collectionElementIndexVariable,loopCounter+1);
            }else{
                //并行多实例
                sencondExecution.setVariableLocal(NUMBER_OF_ACTIVE_INSTANCES,nrOfActiveInstances-1);
            }
        }else{
            //非正常（就当作没有过此任务）
            sencondExecution.setVariableLocal(NUMBER_OF_INSTANCES,nrOfInstances-1);
            if(isSequential){
                //串行多实例
                Integer loopCounter = (Integer) execution.getVariable(collectionElementIndexVariable);
                execution.setVariableLocal(collectionElementIndexVariable,loopCounter+1);
            }else{
                //并行多实例
                //并行多实例
                sencondExecution.setVariableLocal(NUMBER_OF_ACTIVE_INSTANCES,nrOfActiveInstances-1);
            }
        }
        //删除任务
        taskEntityManager.delete(taskId);

        //触发流程运转
        ActivitiEngineAgenda agenda = commandContext.getAgenda();
        agenda.planContinueProcessInCompensation(execution);


        return null;
    }
    protected Integer getLoopVariable(DelegateExecution execution, String variableName) {
        Object value = execution.getVariableLocal(variableName);
        DelegateExecution parent = execution.getParent();
        while (value == null && parent != null) {
            value = parent.getVariableLocal(variableName);
            parent = parent.getParent();
        }
        return (Integer) (value != null ? value : 0);
    }
}

---

三、并行多实例加签

思路

• 根据业务需求获取到多实例父级执行实例
• 判断当前节点是否是并行多实例
• 根据多实例父级实例创建多实例执行实例（也就是新加的人员所在执行实例）
• 为新建的多实例执行实例设置当前处理节点
• 更改多实例父级执行实例的变量

  nrOfInstances+1
  nrOfActiveInstances+1

• 通知该活动开始
• 获取行为类
• 执行行为类

实战

public class AddMultiInstanceCmd implements Command {
    protected final String NUMBER_OF_INSTANCES = "nrOfInstances";
    protected final String NUMBER_OF_ACTIVE_INSTANCES = "nrOfActiveInstances";
    private String multiRootExecutionId;
    private String addUserTaskAssign;

    public AddMultiInstanceCmd(String multiRootExecutionId, String addUserTaskAssign) {
        this.multiRootExecutionId = multiRootExecutionId;
        this.addUserTaskAssign = addUserTaskAssign;
    }


    public Object execute(CommandContext commandContext) {
        ExecutionEntityManager executionEntityManager = commandContext.getExecutionEntityManager();
        //获取多实例父级执行实例
        ExecutionEntity multiExecutionEntity = executionEntityManager.findById(multiRootExecutionId);
        //判断当前执行实例的节点是否是多实例节点
        BpmnModel bpmnModel = ProcessDefinitionUtil.getBpmnModel(multiExecutionEntity.getProcessDefinitionId());
        Activity miActivityElement = (Activity) bpmnModel.getFlowElement(multiExecutionEntity.getCurrentActivityId());
        MultiInstanceLoopCharacteristics loopCharacteristics = miActivityElement.getLoopCharacteristics();
        if(loopCharacteristics == null){
            throw new ActivitiException("此节点不是多实例节点");
        }
        //判断是否是并行多实例
        if(loopCharacteristics.isSequential()){
            throw new ActivitiException("此节点为串行节点");

        }
        //创建新的子实例
        ExecutionEntity childExecution = executionEntityManager.createChildExecution(multiExecutionEntity);
        //获取并为新的执行实例设置当前活动节点
        UserTask currentFlowElement = (UserTask) multiExecutionEntity.getCurrentFlowElement();
        //设置处理人
        currentFlowElement.setAssignee(addUserTaskAssign);
        childExecution.setCurrentFlowElement(currentFlowElement);

        //获取设置变量
        Integer nrOfInstances = (Integer) multiExecutionEntity.getVariableLocal(NUMBER_OF_INSTANCES);
        Integer nrOfActiveInstances = (Integer) multiExecutionEntity.getVariableLocal(NUMBER_OF_ACTIVE_INSTANCES);

        multiExecutionEntity.setVariableLocal(NUMBER_OF_INSTANCES,nrOfInstances+1);
        multiExecutionEntity.setVariableLocal(NUMBER_OF_ACTIVE_INSTANCES,nrOfActiveInstances+1);

        //通知活动开始
        HistoryManager historyManager = commandContext.getHistoryManager();
        historyManager.recordActivityStart(childExecution);
        //获取处理行为类
        ParallelMultiInstanceBehavior prallelMultiInstanceBehavior = (ParallelMultiInstanceBehavior) miActivityElement.getBehavior();
        AbstractBpmnActivityBehavior innerActivityBehavior = prallelMultiInstanceBehavior.getInnerActivityBehavior();
        //执行
        innerActivityBehavior.execute(childExecution);
        return null;
    }

}