一、什么是多實(shí)例減簽，多實(shí)例加簽

比如配置了一個多實(shí)例用戶實(shí)例，由三人串行或者并行執(zhí)行，那么現(xiàn)在的需求是某個個例不需要那么多人了，只需要兩個人也就是減少一個人，這樣的操作稱為減簽操作。

反之，當(dāng)需要添加一個人員參與會簽時的操作，就稱之為加簽操作。

二、多實(shí)例減簽（僅支持6版本）

思路

通過多實(shí)例運(yùn)轉(zhuǎn)過程很容易能夠理清如何實(shí)現(xiàn)減簽操作，如果需要明白運(yùn)轉(zhuǎn)過程可以參考activiti6.0源碼剖析之多實(shí)例運(yùn)轉(zhuǎn)過程

以該流程圖為例說明

并行流程.png

減簽可以從兩種角度去看：被減掉的是以已經(jīng)執(zhí)行成功來做，還是壓根就當(dāng)作沒有存在過
根據(jù)上述兩種角度可以大致理清以下思路

• 首先根據(jù)需要減掉的任務(wù)Id獲取到該任務(wù)ID所屬的三級執(zhí)行實(shí)例

• 然后根據(jù)三級執(zhí)行實(shí)例ID或者多多實(shí)例執(zhí)行實(shí)例的父級實(shí)例（二級實(shí)例）

• 通過二級執(zhí)行實(shí)例刪除需要減掉的三級執(zhí)行實(shí)例數(shù)據(jù)，任務(wù)數(shù)據(jù)

• 根據(jù)二級執(zhí)行實(shí)例獲取nrOfInstances,nrOfCompletedInstances，nrOfActiveInstances,loopCounter變量，并根據(jù)并行或者串行多實(shí)例，根據(jù)上述兩種角度進(jìn)行相應(yīng)的變更

  • 如果是串行多實(shí)例減簽
    正常執(zhí)行完成的角度上：nrOfCompletedInstances 加 1，nrOfActiveInstances保持1不變，loopCounter 加 1
    非正常完成的角度上：nrOfInstances 減 1，loopCounter 加 1

  • 如果是并行多實(shí)例減簽
    正常執(zhí)行完成的角度上：nrOfCompletedInstances 加 1，nrOfActiveInstances 減 1，
    非正常完成的角度上：nrOfInstances 減 1，nrOfActiveInstances 減 1，

實(shí)戰(zhàn)

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();

        //根據(jù)任務(wù)id獲取任務(wù)實(shí)例
        TaskEntity taskEntity = taskEntityManager.findById(taskId);
        //根據(jù)執(zhí)行實(shí)例ID獲取三級執(zhí)行實(shí)例
        ExecutionEntity execution = executionEntityManager.findById(taskEntity.getExecutionId());
        //首先判斷當(dāng)前任務(wù)是否是屬于多實(shí)例節(jié)點(diǎn)
        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("沒有找到多實(shí)例");
        }
        if(!(activityElement.getBehavior() instanceof MultiInstanceActivityBehavior)){
            throw new RuntimeException("此節(jié)點(diǎn)不是多實(shí)例節(jié)點(diǎn)");
        }
        DeploymentManager deploymentManager = commandContext.getProcessEngineConfiguration().getDeploymentManager();
        ProcessDefinition definition = deploymentManager.findDeployedProcessDefinitionById(processDefinitionId);
        //判斷是否是5的版本
        if(Activiti5Util.isActiviti5ProcessDefinition(commandContext,definition)){
            throw new RuntimeException("不支持5版本");
        }

        boolean isSequential = loopCharacteristics.isSequential();
        //獲取二級執(zhí)行實(shí)例
        ExecutionEntity sencondExecution = execution.getParent();
        //刪除所要刪除的實(shí)例相關(guān)數(shù)據(jù)
        if(!isSequential){
            //并行多實(shí)例
            executionEntityManager.deleteChildExecutions(execution,"減簽",false);
            executionEntityManager.deleteExecutionAndRelatedData(execution,"減簽",true);
        }

        //獲取二級執(zhí)行實(shí)例關(guān)聯(lián)的變量
        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);
        //更新二級執(zhí)行實(shí)例關(guān)聯(lián)的變量
        if(isNormalComplete){
            //正常完成
            sencondExecution.setVariable(NUMBER_OF_COMPLETED_INSTANCES,nrOfCompletedInstances+1 );
            if(isSequential){
                //串行多實(shí)例
                Integer loopCounter =getLoopVariable(execution,collectionElementIndexVariable);
                execution.setVariableLocal(collectionElementIndexVariable,loopCounter+1);
            }else{
                //并行多實(shí)例
                sencondExecution.setVariableLocal(NUMBER_OF_ACTIVE_INSTANCES,nrOfActiveInstances-1);
            }
        }else{
            //非正常（就當(dāng)作沒有過此任務(wù)）
            sencondExecution.setVariableLocal(NUMBER_OF_INSTANCES,nrOfInstances-1);
            if(isSequential){
                //串行多實(shí)例
                Integer loopCounter = (Integer) execution.getVariable(collectionElementIndexVariable);
                execution.setVariableLocal(collectionElementIndexVariable,loopCounter+1);
            }else{
                //并行多實(shí)例
                //并行多實(shí)例
                sencondExecution.setVariableLocal(NUMBER_OF_ACTIVE_INSTANCES,nrOfActiveInstances-1);
            }
        }
        //刪除任務(wù)
        taskEntityManager.delete(taskId);

        //觸發(fā)流程運(yùn)轉(zhuǎn)
        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、并行多實(shí)例加簽

思路

• 根據(jù)業(yè)務(wù)需求獲取到多實(shí)例父級執(zhí)行實(shí)例
• 判斷當(dāng)前節(jié)點(diǎn)是否是并行多實(shí)例
• 根據(jù)多實(shí)例父級實(shí)例創(chuàng)建多實(shí)例執(zhí)行實(shí)例（也就是新加的人員所在執(zhí)行實(shí)例）
• 為新建的多實(shí)例執(zhí)行實(shí)例設(shè)置當(dāng)前處理節(jié)點(diǎn)
• 更改多實(shí)例父級執(zhí)行實(shí)例的變量

  nrOfInstances+1
  nrOfActiveInstances+1

• 通知該活動開始
• 獲取行為類
• 執(zhí)行行為類

實(shí)戰(zhàn)

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();
        //獲取多實(shí)例父級執(zhí)行實(shí)例
        ExecutionEntity multiExecutionEntity = executionEntityManager.findById(multiRootExecutionId);
        //判斷當(dāng)前執(zhí)行實(shí)例的節(jié)點(diǎn)是否是多實(shí)例節(jié)點(diǎn)
        BpmnModel bpmnModel = ProcessDefinitionUtil.getBpmnModel(multiExecutionEntity.getProcessDefinitionId());
        Activity miActivityElement = (Activity) bpmnModel.getFlowElement(multiExecutionEntity.getCurrentActivityId());
        MultiInstanceLoopCharacteristics loopCharacteristics = miActivityElement.getLoopCharacteristics();
        if(loopCharacteristics == null){
            throw new ActivitiException("此節(jié)點(diǎn)不是多實(shí)例節(jié)點(diǎn)");
        }
        //判斷是否是并行多實(shí)例
        if(loopCharacteristics.isSequential()){
            throw new ActivitiException("此節(jié)點(diǎn)為串行節(jié)點(diǎn)");

        }
        //創(chuàng)建新的子實(shí)例
        ExecutionEntity childExecution = executionEntityManager.createChildExecution(multiExecutionEntity);
        //獲取并為新的執(zhí)行實(shí)例設(shè)置當(dāng)前活動節(jié)點(diǎn)
        UserTask currentFlowElement = (UserTask) multiExecutionEntity.getCurrentFlowElement();
        //設(shè)置處理人
        currentFlowElement.setAssignee(addUserTaskAssign);
        childExecution.setCurrentFlowElement(currentFlowElement);

        //獲取設(shè)置變量
        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);

        //通知活動開始
        HistoryManager historyManager = commandContext.getHistoryManager();
        historyManager.recordActivityStart(childExecution);
        //獲取處理行為類
        ParallelMultiInstanceBehavior prallelMultiInstanceBehavior = (ParallelMultiInstanceBehavior) miActivityElement.getBehavior();
        AbstractBpmnActivityBehavior innerActivityBehavior = prallelMultiInstanceBehavior.getInnerActivityBehavior();
        //執(zhí)行
        innerActivityBehavior.execute(childExecution);
        return null;
    }

}