Flowable implementation [select the next process reviewer]

principle:

1. Before the process form data is formally submitted for review, pass the process form data formData and the process execution instance ExecutionEntity to the interface
2. The interface obtains the current node information in the process definition and loops to find the outgoing line. SequenceFlow also needs to pay attention to what to do when encountering a gateway
3. Use variables to execute the outgoing SequenceFlow condition (similar to completing the submit task operation)
4. Find the first user task UserTask According to the information in this UserTask, we can get the process reviewer
5. The most important point is that when using variables to execute conditions in the third point, the variables will be persisted to the database, so we must operate in the transaction, and roll back the current transaction after the operation is completed to avoid data disorder.

Project complete source code link

The following is the entire code, this logic is for reference only

package com.nutzfw.core.plugin.flowable.cmd;

import org.apache.commons.collections.CollectionUtils;
import org.flowable.bpmn.model.*;
import org.flowable.common.engine.impl.interceptor.Command;
import org.flowable.common.engine.impl.interceptor.CommandContext;
import org.flowable.engine.impl.persistence.entity.ExecutionEntity;
import org.flowable.engine.impl.util.condition.ConditionUtil;

import java.util.List;
import java.util.Map;

/**
 * @author [email protected]
 * @date: 2019/7/9
 * 使用示例，一定要放到事务中，否则变量会入库，导致数据紊乱
 * try {
 * Trans.begin();
 * UserTask userTask = managementService.executeCommand(new FindNextUserTaskNodeCmd(execution, bpmnModel, vars));
 * System.out.println(userTask.getId());
 * } finally {
 * Trans.clear(true);
 * }
 */
public class FindNextUserTaskNodeCmd implements Command<UserTask> {

    private final ExecutionEntity execution;
    private final BpmnModel bpmnModel;
    private Map<String, Object> vars;
    /**
     * 返回下一用户节点
     */
    private UserTask nextUserTask;

    /**
     * @param execution 当前执行实例
     * @param bpmnModel 当前执行实例的模型
     * @param vars      参与计算流程条件的变量
     */
    public FindNextUserTaskNodeCmd(ExecutionEntity execution, BpmnModel bpmnModel, Map<String, Object> vars) {
        this.execution = execution;
        this.bpmnModel = bpmnModel;
        this.vars = vars;
    }

    /**
     * @param execution 当前执行实例
     * @param bpmnModel 当前执行实例的模型
     */
    public FindNextUserTaskNodeCmd(ExecutionEntity execution, BpmnModel bpmnModel) {
        this.execution = execution;
        this.bpmnModel = bpmnModel;
    }

    @Override
    public UserTask execute(CommandContext commandContext) {
        execution.setVariables(vars);
        FlowElement currentNode = bpmnModel.getFlowElement(execution.getActivityId());
        List<SequenceFlow> outgoingFlows = ((FlowNode) currentNode).getOutgoingFlows();
        if (CollectionUtils.isNotEmpty(outgoingFlows)) {
            this.findNextUserTaskNode(outgoingFlows, execution);
        }
        return nextUserTask;
    }


    void findNextUserTaskNode(List<SequenceFlow> outgoingFlows, ExecutionEntity execution) {
        sw:
        for (SequenceFlow outgoingFlow : outgoingFlows) {
            if (ConditionUtil.hasTrueCondition(outgoingFlow, execution)) {
                if (outgoingFlow.getTargetFlowElement() instanceof ExclusiveGateway) {
                    //只有排他网关才继续
                    ExclusiveGateway exclusiveGateway = (ExclusiveGateway) outgoingFlow.getTargetFlowElement();
                    findNextUserTaskNode(exclusiveGateway.getOutgoingFlows(), execution);
                } else if (outgoingFlow.getTargetFlowElement() instanceof UserTask) {
                    nextUserTask = (UserTask) outgoingFlow.getTargetFlowElement();
                    //找到第一个符合条件的userTask就跳出循环
                    break sw;
                }
            }
        }
    }
}

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