Flowable流程图有效性检验，可自定义规则

针对符合Bpmn规范的流程图（本质为xml文件）进行一些规则校验，例如：必须包含UserTask节点、指定节点审核人不能少于两人、必须设置某某属性等，具体规则自行定义。

1、主要方法

package com.lc.workflow.common.utils;

import com.lc.common.core.exception.CustomException;
import com.lc.common.core.utils.StringUtils;
import org.flowable.bpmn.converter.BpmnXMLConverter;
import org.flowable.bpmn.model.BpmnModel;
import org.flowable.validation.ProcessValidator;
import org.flowable.validation.ProcessValidatorFactory;
import org.flowable.validation.ValidationError;
import org.flowable.validation.validator.ValidatorSet;

import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.util.List;

/**
 * flowable流程图xml校验
 *
 * @author lsy
 * @date 2022/06/16 11:20
 **/
public class FlowableModelValidateUtil {

    public static Object validateModel(String xmlStr) {
        if (StringUtils.isBlank(xmlStr)) {
            throw new CustomException("xmlStr不能为空");
        }
        try {
            // 把xml转换成BpmnModel对象
            InputStream inputStream = new ByteArrayInputStream(xmlStr.getBytes());
            XMLInputFactory xmlInputFactory = XMLInputFactory.newInstance();
            XMLStreamReader xmlStreamReader = xmlInputFactory.createXMLStreamReader(inputStream);
            BpmnXMLConverter bpmnXMLConverter = new BpmnXMLConverter();
            BpmnModel bpmnModel = bpmnXMLConverter.convertToBpmnModel(xmlStreamReader);
            // 模板验证
            ProcessValidator validator = new ProcessValidatorFactory().createDefaultProcessValidator();
            ValidatorSet validatorSet = new ValidatorSet("My Validator");
            // new MyFlowableValidator()为自定义实现的规则校验器
            validatorSet.addValidator(new MyFlowableValidator());
            validator.getValidatorSets().add(validatorSet);
            List<ValidationError> errorList = validator.validate(bpmnModel);
            if (errorList.isEmpty()) {
                return true;
            } else {
                return errorList;
            }
        } catch (XMLStreamException e) {
            throw new CustomException(e.getMessage());
        }
    }

}

2、自定义规则校验器

package com.lc.workflow.common.validator;

import com.lc.common.core.utils.StringUtils;
import org.apache.commons.collections4.CollectionUtils;
import org.flowable.bpmn.model.BpmnModel;
import org.flowable.bpmn.model.Process;
import org.flowable.bpmn.model.StartEvent;
import org.flowable.bpmn.model.UserTask;
import org.flowable.validation.ValidationError;
import org.flowable.validation.validator.ProcessLevelValidator;

import java.util.List;

/**
 * 自定义规则校验器
 *
 * @author lsy
 * @date 2022/06/16 14:30
 **/
public class MyFlowableValidator extends ProcessLevelValidator {
    @Override
    protected void executeValidation(BpmnModel bpmnModel, Process process, List<ValidationError> errors) {
        List<UserTask> userTaskList = process.findFlowElementsOfType(UserTask.class);
        if (CollectionUtils.isEmpty(userTaskList)) {
            errors.add(validationErrorFactory(null, null, "can not find UserTask", true));
        } else {
            userTaskList.stream().filter(task -> StringUtils.isBlank(task.getName())).forEach(s -> {
                errors.add(validationErrorFactory(s.getId(), s.getName(), "UserTask missing name", true));
            });
            userTaskList.stream().filter(task -> StringUtils.isBlank(task.getAssignee())
                    && CollectionUtils.isEmpty(task.getCandidateUsers())
                    && CollectionUtils.isEmpty(task.getCandidateGroups())).forEach(s -> {
                errors.add(validationErrorFactory(s.getId(), s.getName(), "can not find UserTask recipient", false));
            });
        }
        List<StartEvent> startEventList = process.findFlowElementsOfType(StartEvent.class);
        if (CollectionUtils.isEmpty(startEventList)) {
            errors.add(validationErrorFactory(null, null, "can not find StartEvent", true));
        }
    }

    private ValidationError validationErrorFactory(String activityId, String activityName, String msg, boolean warning) {
        ValidationError validationError = new ValidationError();
        validationError.setActivityId(activityId);
        validationError.setActivityName(activityName);
        validationError.setDefaultDescription(msg);
        validationError.setWarning(warning);
        return validationError;
    }
}