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我使用來自JBoss工作流引擎的流程定義語言jPDL：jBPM。在JBPM中集成子流程定義JPDL
欲一個非常簡單的過程定義圖表整合：基本上，予有一個主流程定義（簡單/ processdefinition.xml中），包括：
- 一個開始節點，
- 一個進程狀態節點，
- 一個結束節點。
這裏是圖的定義：含有
<process-definition
xmlns="urn:jbpm.org:jpdl-3.2"
name="simple">
<start-state name="start">
<transition name="to_state" to="process-state">
<action name="action" class="com.sample.action.MessageActionHandler">
<message>
Going to the sub-state!
</message>
</action>
</transition>
<event type="node-leave">
<action class="com.sample.action.MessageActionHandler">
<message>
Start.
</message>
</action>
</event>
</start-state>
<process-state name="process-state">
<sub-process name="subsimple" binding="late"/>
<variable access="read,write" name="message" mapped-name="message"> </variable>
<event type="node-enter">
<action class="com.sample.action.MessageActionHandler"></action>
</event>
<transition to="end" name="to_end"></transition>
</process-state>
<end-state name="end">
<event type="node-enter">
<action class="com.sample.action.MessageActionHandler">
<message>
End.
</message>
</action>
</event>
</end-state>
</process-definition>
在我所限定的子過程圖形處理狀態節點（subsimple/processdefinition.xml中）：
- a開始節點，
- 狀態節點，
- 終端節點。
這裏是圖的定義：
<process-definition
xmlns="urn:jbpm.org:jpdl-3.2"
name="subsimple">
<start-state name="start">
<transition name="to_state" to="first">
<action name="action" class="com.sample.action.MessageActionHandler">
<message>Going to the first state!</message>
</action>
</transition>
<event type="node-leave">
<action class="com.sample.action.MessageActionHandler">
<message>
Start.
</message>
</action>
</event>
</start-state>
<state name="first">
<event type="node-enter">
<action class="com.sample.action.MessageActionHandler">
<message>
In first state !!
</message>
</action>
</event>
<transition name="to_end" to="end">
<action name="action" class="com.sample.action.MessageActionHandler">
<message>
About to go out of sub-process !
</message>
</action>
</transition>
</state>
<end-state name="end">
<event type="node-enter">
<action class="com.sample.action.MessageActionHandler">
<message>
End.
</message>
</action>
</event>
</end-state>
</process-definition>
這裏是的ActionHandler分配給每一個事件和轉換：
public class MessageActionHandler implements ActionHandler {
private static final long serialVersionUID = 1L;
String message;
public void execute(ExecutionContext context) throws Exception {
context.getContextInstance().setVariable("message", message);
System.out.println(context.getContextInstance().getVariable("message"));
}
}
最終，這裏是主類從中我開始了整個過程：
public class testJBPM {
public static void main(String[] args) {
ProcessDefinition processDefinition = ProcessDefinition
.parseXmlResource("simple/processdefinition.xml");
// Create an instance of the process definition.
ProcessInstance instance = new ProcessInstance(processDefinition);
// Move the process instance from its start state to the first state.
instance.signal();
// Move the process instance to the end state.
instance.signal();
}
}
正如我在JBoss論壇上看到的，我在主進程定義中正確設置了子進程綁定binding=late。然後我嘗試不同的方式來實例化的子進程的流程定義，但我總是試圖進入子狀態/子流程節點時出現以下異常：
Exception in thread "main" org.jbpm.JbpmException: can't create a process instance when processDefinition is null
at org.jbpm.graph.exe.ProcessInstance.<init>(ProcessInstance.java:128)
at org.jbpm.graph.exe.ProcessInstance.<init>(ProcessInstance.java:92)
at org.jbpm.graph.exe.Token.createSubProcessInstance(Token.java:624)
at org.jbpm.graph.node.ProcessState.execute(ProcessState.java:164)
at org.jbpm.graph.def.Node.enter(Node.java:319)
at org.jbpm.graph.def.Transition.take(Transition.java:151)
at org.jbpm.graph.def.Node.leave(Node.java:394)
at org.jbpm.graph.node.StartState.leave(StartState.java:70)
at org.jbpm.graph.exe.Token.signal(Token.java:195)
at org.jbpm.graph.exe.Token.signal(Token.java:140)
at org.jbpm.graph.exe.ProcessInstance.signal(ProcessInstance.java:271)
at com.sample.main.testJBPM.main(testJBPM.java:21)
任何人可以給我通知：如何管理子流程定義和使用？