[Improvement-3369][api] Introduce api service interface for ProcessDefinitionService (#3371)

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 * The ASF licenses this file to You under the Apache License, Version 2.0

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 *    http://www.apache.org/licenses/LICENSE-2.0

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package org.apache.dolphinscheduler.api.service;

import org.apache.dolphinscheduler.common.graph.DAG;

import org.apache.dolphinscheduler.common.model.TaskNode;

import org.apache.dolphinscheduler.common.model.TaskNodeRelation;

import org.apache.dolphinscheduler.common.process.ProcessDag;

import org.apache.dolphinscheduler.common.utils.*;

import org.apache.dolphinscheduler.dao.entity.ProcessData;

import org.apache.dolphinscheduler.dao.entity.ProcessInstance;

import org.apache.dolphinscheduler.dao.utils.DagHelper;

import java.util.List;

/**

 * base DAG service

 */

public class BaseDAGService extends BaseService{

    /**

     * process instance to DAG

     *

     * @param processInstance input process instance

     * @return process instance dag.

     */

    public static DAG<String, TaskNode, TaskNodeRelation> processInstance2DAG(ProcessInstance processInstance) {

        String processDefinitionJson = processInstance.getProcessInstanceJson();

        ProcessData processData = JSONUtils.parseObject(processDefinitionJson, ProcessData.class);

        List<TaskNode> taskNodeList = processData.getTasks();

        ProcessDag processDag = DagHelper.getProcessDag(taskNodeList);

        return DagHelper.buildDagGraph(processDag);

    }

}