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>