开源工作流Fireflow源码分析之流程文件解析

    Java要解析xml并不困难，fireflow的作者是采用dom4j来解析.具体解析的类为:Dom4JPDLParser,另外还有一个类Dom4JFPDLSerializer,它的作用是将工作流模型写成Xml.

   1):如何配置xml解析器的，作者提供了两个模式，一个是开发阶段用的definitionService4FileSystem,一个是实施阶段的definitionService4DBMS 

  

 <bean id="definitionService4FileSystem"
		class="org.fireflow.engine.definition.DefinitionService4FileSystem">
        <property name="definitionFiles">
            <list>
                <value>
	      /process_definition/LeaveApplicationProcess.xml
                </value>
            </list>
        </property>
</bean>

    <bean id="runtimeContext"
          class="org.fireflow.engine.RuntimeContext"
          init-method="initialize">
      …… 
 <property name="definitionService">
            <ref local="definitionService4FileSystem"/>
        </property>
      ……
    </bean>

     2）：如果是开发阶段，系统启动的时候会自动解析xml,并进行缓存.如果是实施阶段，启动的时候不会解析，只要第一次用到，系统进行解析.

注意，开发阶段缓存workflowProcess的作用就是加快测试的过程，没有什么其它的意义，作者真正缓存的对象是工作流网实例,这是后话。

     

//开发阶段的definitionService4FileSystem:如果配置了xml就进行解析.
public void setDefinitionFiles(List<String> workflowProcessFileNames)
            throws IOException, FPDLParserException,EngineException {
        if (workflowProcessFileNames != null) {
            Dom4JFPDLParser parser = new Dom4JFPDLParser();
            for (int i = 0; i < workflowProcessFileNames.size(); i++) {
                InputStream inStream = this.getClass().getResourceAsStream(
                        workflowProcessFileNames.get(i).trim());
                if (inStream == null) {
                    throw new IOException("没有找到名称为" + workflowProcessFileNames.get(i) + "的流程定义文件");
                }
                
                WorkflowProcess workflowProcess = parser.parse(inStream);

                WorkflowDefinition workflowDef = new WorkflowDefinition();
                workflowDef.setVersion(new Integer(1));

                workflowDef.setWorkflowProcess(workflowProcess);

                String latestVersionKey = workflowProcess.getId() + "_V_" + workflowDef.getVersion();
                workflowDefinitionMap.put(latestVersionKey, workflowDef);
                latestVersionKeyMap.put(workflowProcess.getId(), latestVersionKey);

            }
        }

//实施阶段如何处理的呢, definitionService4DBMS处理的就是从数据库里得到xml定义的字符串
//通过流程ID从数据库里得到流程定义的字符串
    public WorkflowDefinition getWorkflowDefinitionByProcessIdAndVersionNumber(String id, Integer version) {
        return rtCtx.getPersistenceService().findWorkflowDefinitionByProcessIdAndVersionNumber(id, version);
    }
真正的读操作在流程定义对象(WorkflowDefinition)的getWorkflowprocess方法

//WorkflowDefinition.java,得到工作流模型
public WorkflowProcess getWorkflowProcess() throws RuntimeException{
        if (workflowProcess == null) {
            if (this.processContent != null && !this.processContent.trim().equals("")) {

                ByteArrayInputStream in = null;
                try {
                    Dom4JFPDLParser parser = new Dom4JFPDLParser();//采用dom4j来解析xml
                    in = new ByteArrayInputStream(this.processContent.getBytes("utf-8"));
                    this.workflowProcess = parser.parse(in);

                } catch (UnsupportedEncodingException ex) {
                    Logger.getLogger(WorkflowDefinition.class.getName()).log(Level.SEVERE, null, ex);
                    throw new RuntimeException(ex.getMessage());
                } catch (IOException ex) {
                    Logger.getLogger(WorkflowDefinition.class.getName()).log(Level.SEVERE, null, ex);
                    throw new RuntimeException(ex.getMessage());
                } 
                catch(FPDLParserException ex){
                    Logger.getLogger(WorkflowDefinition.class.getName()).log(Level.SEVERE, null, ex);
                    throw new RuntimeException(ex.getMessage());
                } finally {
                    try {
                        in.close();
                    } catch (IOException ex) {
                        Logger.getLogger(WorkflowDefinition.class.getName()).log(Level.SEVERE, null, ex);
                    }
                }

            }
        }
        return workflowProcess;
    }

      3）：弄清楚工作流模型和xml之间的对应关系。这个比较简单，只要看一下WorkflowProcess.java文件，和一个xml例子，就一目了然，

作者的源文件上解释很全

      

public class WorkflowProcess extends AbstractWFElement {

	/**
	 * 流程数据项，运行时转换为流程变量进行存储。
	 */
	private List<DataField> dataFields = new ArrayList<DataField>();

	/**
	 * 全局Task
	 */
	private List<Task> tasks = new ArrayList<Task>();

	/**
	 * 流程环节
	 */
	private List<Activity> activities = new ArrayList<Activity>();

	/**
	 * 转移
	 */
	private List<Transition> transitions = new ArrayList<Transition>();

	/**
	 * 循环
	 */
	private List<Loop> loops = new ArrayList<Loop>();

	/**
	 * 同步器
	 */
	private List<Synchronizer> synchronizers = new ArrayList<Synchronizer>();

	/**
	 * 开始节点
	 */
	private StartNode startNode = null;

	/**
	 * 结束节点
	 */
	private List<EndNode> endNodes = new ArrayList<EndNode>();

	// 其他属性
	/**
	 * 资源文件（在1.0中暂时未使用）
	 */
	private String resourceFile = null;

	/**
	 * 资源管理器（在1.0中暂时未使用）
	 */
	private String resourceManager = null;

	/**
	 * 本流程全局的任务实例创建器。 如果没有设置，引擎将使用DefaultTaskInstanceCreator来创建TaskInstance。
	 */
	protected String taskInstanceCreator = null;

	/**
	 * 本流程全局的FormTask
	 * Instance运行器。如果没有设置，引擎将使用DefaultFormTaskInstanceRunner来运行TaskInstance。
	 */
	protected String formTaskInstanceRunner = null;

	/**
	 * 本流程全局的ToolTask
	 * Instance运行器。如果没有设置，引擎将使用DefaultToolTaskInstanceRunner来运行TaskInstance。
	 */
	protected String toolTaskInstanceRunner = null;

	/**
	 * 本流程全局的SubflowTask
	 * Instance运行器。如果没有设置，引擎将使用DefaultSubflowTaskInstanceRunner来运行TaskInstance。
	 */
	protected String subflowTaskInstanceRunner = null;

	/**
	 * 本流程全局的FormTask Instance 终结评价器，用于告诉引擎该实例是否可以结束。<br/>
	 * 如果没有设置，引擎使用缺省实现DefaultFormTaskInstanceCompletionEvaluator。
	 */
	protected String formTaskInstanceCompletionEvaluator = null;

	/**
	 * 本流程全局的ToolTask Instance 终结评价器，用于告诉引擎该实例是否可以结束。<br/>
	 * 如果没有设置，引擎使用缺省实现DefaultToolTaskInstanceCompletionEvaluator。
	 */
	protected String toolTaskInstanceCompletionEvaluator = null;

	/**
	 * 本流程全局的SubflowTask Instance 终结评价器，用于告诉引擎该实例是否可以结束。<br/>
	 * 如果没有设置，引擎使用缺省实现DefaultSubflowTaskInstanceCompletionEvaluator。
	 */
	protected String subflowTaskInstanceCompletionEvaluator = null;
 …….
}

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE fpdl:WorkflowProcess PUBLIC "-//Nieyun Chen//ProcessDefinition//CN" "FireFlow_Process_Definition_Language.dtd">
<fpdl:WorkflowProcess DisplayName="LeaveApplicationProcess" Id="LeaveApplicationProcess" Name="LeaveApplicationProcess" ResourceFile="" ResourceManager="" xmlns:fpdl="http://www.fireflow.org/Fireflow_Process_Definition_Language">
  <fpdl:DataFields>
    <fpdl:DataField DataType="INTEGER" DisplayName="请假天数" Id="LeaveApplicationProcess.leaveDays" InitialValue="1" Name="leaveDays"/>
    <fpdl:DataField DataType="BOOLEAN" DisplayName="审批意见" Id="LeaveApplicationProcess.approvalFlag" InitialValue="false" Name="approvalFlag"/>
  </fpdl:DataFields>
  <fpdl:StartNode DisplayName="" Id="LeaveApplicationProcess.START_NODE" Name="START_NODE">
    <fpdl:ExtendedAttributes>
      <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.height" Value="20"/>
      <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.width" Value="20"/>
      <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.x" Value="18"/>
      <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.y" Value="86"/>
    </fpdl:ExtendedAttributes>
  </fpdl:StartNode>
  <fpdl:Tasks/>
  <fpdl:Activities>
    <fpdl:Activity CompletionStrategy="ALL" DisplayName="申请" Id="LeaveApplicationProcess.Fulfill_The_ApplicationForm_Activity" Name="Fulfill_The_ApplicationForm_Activity">
      <fpdl:ExtendedAttributes>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.height" Value="60"/>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.width" Value="100"/>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.x" Value="97"/>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.y" Value="65"/>
      </fpdl:ExtendedAttributes>
      <fpdl:Tasks>
        <fpdl:Task CompletionStrategy="ANY" DefaultView="EDITFORM" DisplayName="填写请假单" Id="LeaveApplicationProcess.Fulfill_The_ApplicationForm_Activity.Fulfill_The_ApplicationForm_Task" LoopStrategy="REDO" Name="Fulfill_The_ApplicationForm_Task" Priority="1" Type="FORM">
          <fpdl:Performer DisplayName="当前用户" Name="Self">
            <fpdl:Description/>
            <fpdl:AssignmentHandler>org.fireflow.example.leaveapplication.workflowextension.CurrentUserAssignmentHandler</fpdl:AssignmentHandler>
          </fpdl:Performer>
          <fpdl:EditForm DisplayName="请假申请表" Name="ApplicationForm">
            <fpdl:Description/>
            <fpdl:Uri>/org/fireflow/example/leaveapplication/bizpages/SubmitApplication.jsp</fpdl:Uri>
          </fpdl:EditForm>
        </fpdl:Task>
      </fpdl:Tasks>
      <fpdl:TaskRefs/>
    </fpdl:Activity>
    <fpdl:Activity CompletionStrategy="ALL" DisplayName="部门经理审批" Id="LeaveApplicationProcess.DepartmentManager_Approve_Activity" Name="DepartmentManager_Approve_Activity">
      <fpdl:ExtendedAttributes>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.height" Value="60"/>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.width" Value="100"/>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.x" Value="279"/>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.y" Value="66"/>
      </fpdl:ExtendedAttributes>
      <fpdl:Tasks>
        <fpdl:Task CompletionStrategy="ANY" DefaultView="EDITFORM" DisplayName="审批请假单" Id="LeaveApplicationProcess.DepartmentManager_Approve_Activity.Approval_Task" LoopStrategy="REDO" Name="Approval_Task" Priority="1" Type="FORM">
          <fpdl:Performer DisplayName="部门经理" Name="DepartmentManager">
            <fpdl:Description/>
            <fpdl:AssignmentHandler>org.fireflow.example.leaveapplication.workflowextension.RoleDepartmentBasedAssignmentHandler</fpdl:AssignmentHandler>
          </fpdl:Performer>
          <fpdl:EditForm DisplayName="请假审批表单" Name="ApprovalForm">
            <fpdl:Description/>
            <fpdl:Uri>/org/fireflow/example/leaveapplication/bizpages/ApproveLeaveApplication.jsp</fpdl:Uri>
          </fpdl:EditForm>
        </fpdl:Task>
      </fpdl:Tasks>
      <fpdl:TaskRefs/>
    </fpdl:Activity>
    <fpdl:Activity CompletionStrategy="ALL" DisplayName="发送邮件" Id="LeaveApplicationProcess.Send_Email_Activity" Name="Send_Email_Activity">
      <fpdl:ExtendedAttributes>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.height" Value="60"/>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.width" Value="204"/>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.x" Value="540"/>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.y" Value="65"/>
      </fpdl:ExtendedAttributes>
      <fpdl:Tasks>
        <fpdl:Task DisplayName="邮件通知申请人审批结果" Execution="SYNCHR" Id="LeaveApplicationProcess.Send_Email_Activity.Send_Email_Task" LoopStrategy="REDO" Name="Send_Email_Task" Priority="1" Type="TOOL">
          <fpdl:Application DisplayName="邮件发送接口程序" Name="EmailSender">
            <fpdl:Description/>
            <fpdl:Handler>org.fireflow.example.leaveapplication.workflowextension.EmailSender</fpdl:Handler>
          </fpdl:Application>
        </fpdl:Task>
      </fpdl:Tasks>
      <fpdl:TaskRefs/>
    </fpdl:Activity>
  </fpdl:Activities>
  <fpdl:Synchronizers>
    <fpdl:Synchronizer DisplayName="" Id="LeaveApplicationProcess.Synchronizer1" Name="Synchronizer1">
      <fpdl:ExtendedAttributes>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.height" Value="20"/>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.width" Value="20"/>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.x" Value="228"/>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.y" Value="85"/>
      </fpdl:ExtendedAttributes>
    </fpdl:Synchronizer>
    <fpdl:Synchronizer DisplayName="" Id="LeaveApplicationProcess.Synchronizer2" Name="Synchronizer2">
      <fpdl:ExtendedAttributes>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.height" Value="20"/>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.width" Value="20"/>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.x" Value="450"/>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.y" Value="86"/>
      </fpdl:ExtendedAttributes>
    </fpdl:Synchronizer>
  </fpdl:Synchronizers>
  <fpdl:EndNodes>
    <fpdl:EndNode DisplayName="" Id="LeaveApplicationProcess.EndNode1" Name="EndNode1">
      <fpdl:ExtendedAttributes>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.height" Value="20"/>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.width" Value="20"/>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.x" Value="814"/>
        <fpdl:ExtendedAttribute Name="FIRE_FLOW.bounds.y" Value="85"/>
      </fpdl:ExtendedAttributes>
    </fpdl:EndNode>
  </fpdl:EndNodes>
  <fpdl:Transitions>
    <fpdl:Transition DisplayName="" From="LeaveApplicationProcess.START_NODE" Id="LeaveApplicationProcess.Transition1" Name="Transition1" To="LeaveApplicationProcess.Fulfill_The_ApplicationForm_Activity">
      <fpdl:Condition/>
    </fpdl:Transition>
    <fpdl:Transition DisplayName="" From="LeaveApplicationProcess.Fulfill_The_ApplicationForm_Activity" Id="LeaveApplicationProcess.Transition2" Name="Transition2" To="LeaveApplicationProcess.Synchronizer1">
      <fpdl:Condition/>
    </fpdl:Transition>
    <fpdl:Transition DisplayName="" From="LeaveApplicationProcess.Synchronizer1" Id="LeaveApplicationProcess.Transition3" Name="Transition3" To="LeaveApplicationProcess.DepartmentManager_Approve_Activity">
      <fpdl:Condition/>
    </fpdl:Transition>
    <fpdl:Transition DisplayName="" From="LeaveApplicationProcess.DepartmentManager_Approve_Activity" Id="LeaveApplicationProcess.Transition4" Name="Transition4" To="LeaveApplicationProcess.Synchronizer2">
      <fpdl:Condition/>
    </fpdl:Transition>
    <fpdl:Transition DisplayName="" From="LeaveApplicationProcess.Send_Email_Activity" Id="LeaveApplicationProcess.Transition11" Name="Transition11" To="LeaveApplicationProcess.EndNode1">
      <fpdl:Condition/>
    </fpdl:Transition>
    <fpdl:Transition DisplayName="" From="LeaveApplicationProcess.Synchronizer2" Id="LeaveApplicationProcess.Transition6" Name="Transition6" To="LeaveApplicationProcess.Send_Email_Activity">
      <fpdl:Condition/>
    </fpdl:Transition>
  </fpdl:Transitions>
</fpdl:WorkflowProcess>