BlogJava-雪山飞鹄-随笔分类-jbpm4

Jbpm3中设置fork按条件执行

雪山飞鹄 — Thu, 16 Jun 2011 03:45:00 GMT

流程定义文件

xml version="1.0" encoding="UTF-8"?>

<process-definition
  xmlns="urn:jbpm.org:jpdl-3.2"  name="forkjoin">
   <start-state name="开始">
      <transition name="to join" to="fork">transition>
   start-state>
   <fork name="fork">
         <script>
             <variable name="transitionNames" access="write">variable>
             <expression>
                 transitionNames=new ArrayList();
                 if(param>100){
                     transitionNames.add("to node1");
                     transitionNames.add("to node2");
                 }else{
                     transitionNames.add("to node3");
                     transitionNames.add("to node4");
                 }
             expression>
         script>
      <transition name="to node1" to="node1">transition>
      <transition name="to node2" to="node2">transition>
      <transition name="to node3" to="node3">transition>
      <transition name="to node4" to="node4">transition>
   fork>
   <join name="join">
      <transition name="to 结束" to="结束">transition>
   join>
   <end-state name="结束">end-state>
   <node name="node1">
      <transition name="to join" to="join">transition>
      <event type="node-enter">
          <script>
              print("经过"+node.getName());
          script>
      event>
   node>
   <node name="node2">
      <transition name="to join" to="join">transition>
      <event type="node-enter">
          <script>
              print("经过"+node.getName());
          script>
      event>
   node>
   <node name="node3">
      <transition name="to join" to="join">transition>
      <event type="node-enter">
          <script>
              print("经过"+node.getName());
          script>
      event>
   node>
   <node name="node4">
      <transition name="to join" to="join">transition>
      <event type="node-enter">
          <script>
              print("经过"+node.getName());
          script>
      event>
   node>
process-definition>

工作机制:是通过在fork节点添加标签，在script内部设置
切记此处access属性设置为write
和

        transitionNames=new ArrayList();
        if(param>100){
         transitionNames.add("to node1");
         transitionNames.add("to node2");
        }else{
         transitionNames.add("to node3");
         transitionNames.add("to node4");
        }

上面在流程实例上下文中定义了一个变量param,当param大于100时，执行node1和node2节点
测试一下:

package com.jbpm;

import org.jbpm.graph.def.ProcessDefinition;
import org.jbpm.graph.exe.ProcessInstance;

public class TestForkJoin {

    public static void main(String[] args) {
        ProcessDefinition processDefinition=ProcessDefinition.parseXmlResource("forkjoin/processdefinition.xml");
        ProcessInstance processInstance=new ProcessInstance(processDefinition);
        processInstance.getContextInstance().setVariable("param", 200);
        //processInstance.signal();
        System.err.println("当前节点是:"+processInstance.getRootToken().getNode().getName());
        processInstance.signal();
        System.err.println("当前节点是:"+processInstance.getRootToken().getNode().getName());
    }
}

运行结果
当前节点是:开始
11:44:07,703 [main] DEBUG GraphElement : event 'before-signal' on 'StartState(开始)' for 'Token(/)'
11:44:07,703 [main] DEBUG GraphElement : event 'node-leave' on 'StartState(开始)' for 'Token(/)'
11:44:07,718 [main] DEBUG GraphElement : event 'transition' on 'Transition(to join)' for 'Token(/)'
11:44:07,718 [main] DEBUG GraphElement : event 'node-enter' on 'Fork(fork)' for 'Token(/)'
11:44:07,719 [main] DEBUG Script : script input: {node=Fork(fork), param=200, token=Token(/), task=null, executionContext=ExecutionContext[Token(/)], taskInstance=null}
11:44:07,814 [main] DEBUG Script : script output: {transitionNames=[to node1, to node2]}
11:44:07,830 [main] DEBUG GraphElement : event 'node-leave' on 'Fork(fork)' for 'Token(/to node1)'
11:44:07,830 [main] DEBUG GraphElement : event 'transition' on 'Transition(to node1)' for 'Token(/to node1)'
11:44:07,830 [main] DEBUG GraphElement : event 'node-enter' on 'Node(node1)' for 'Token(/to node1)'
11:44:07,830 [main] DEBUG GraphElement : executing action 'Script(10f6d3)'
11:44:07,830 [main] DEBUG Token : token[0] is locked by token[0]
11:44:07,830 [main] DEBUG Script : script input: {node=Node(node1), param=200, token=Token(/to node1), task=null, executionContext=ExecutionContext[Token(/to node1)], taskInstance=null}
经过node1
11:44:07,861 [main] DEBUG Script : script output: {}
11:44:07,861 [main] DEBUG Token : token[0] is unlocked by token[0]
11:44:07,861 [main] DEBUG GraphElement : event 'node-leave' on 'Node(node1)' for 'Token(/to node1)'
11:44:07,861 [main] DEBUG GraphElement : event 'transition' on 'Transition(to join)' for 'Token(/to node1)'
11:44:07,861 [main] DEBUG GraphElement : event 'node-enter' on 'Join(join)' for 'Token(/to node1)'
11:44:07,861 [main] DEBUG Join : join will not yet reactivate parent: found concurrent token 'Token(/to node2)'
11:44:07,861 [main] DEBUG GraphElement : event 'node-leave' on 'Fork(fork)' for 'Token(/to node2)'
11:44:07,861 [main] DEBUG GraphElement : event 'transition' on 'Transition(to node2)' for 'Token(/to node2)'
11:44:07,861 [main] DEBUG GraphElement : event 'node-enter' on 'Node(node2)' for 'Token(/to node2)'
11:44:07,861 [main] DEBUG GraphElement : executing action 'Script(cfec48)'
11:44:07,861 [main] DEBUG Token : token[0] is locked by token[0]
11:44:07,861 [main] DEBUG Script : script input: {node=Node(node2), param=200, token=Token(/to node2), task=null, executionContext=ExecutionContext[Token(/to node2)], taskInstance=null}
经过node2

雪山飞鹄 2011-06-16 11:45 发表评论

跟我学JBPM4之State、Decision 、Task活动

雪山飞鹄 — Wed, 29 Sep 2010 05:52:00 GMT

摘要: 本文电子版文档下载 State、Decision 、Task活动详解: State表示一个等待状态。当流程实例执行到state节点时会暂停下来(处于等待状态),流程的执行会在外部触发器被调用之前一直等待(会暂停) Decision条件判断节点,表示在多条路径中选择一条。一个 decision 活动拥有很多个传出的转移。流程的执行到达一个 decision 活动时，会自动进行计算来决定采用哪... 阅读全文

雪山飞鹄 2010-09-29 13:52 发表评论

跟我一起学JBPM4之基础概念

雪山飞鹄 — Tue, 28 Sep 2010 08:44:00 GMT

摘要: 最近开始接触JBPM4，网上关于JBPM4的资料少之又少。大多是关于JBPM3的。而4跟3的API差异也较大。在学习过程中做了一点关于JBPM4的笔记。强烈期望JBPM4达人能贡献一些JBPM4方面的学习资料或视频教程或出版发行JBPM4的书籍之类的。本文电子版下载流程定义引擎: ProcessEngine processEngine; 获取: ... 阅读全文

雪山飞鹄 2010-09-28 16:44 发表评论

Tomcat6下使用jBPM-4出现 java.lang.LinkageError。javax/el/ExpressionFactory

雪山飞鹄 — Mon, 27 Sep 2010 06:56:00 GMT

因为tomcat6下的el-api.jar与jBPM-4使用的juel.jar产生冲突。

解决方法一：改用tomcat-5.5。

解决方法二：将juel.jar, juel-engine.jar, juel-impl.jar三个文件复制到tomcat的lib目录下，并删除tomcat6下的el-api.jar即可解决。

雪山飞鹄 2010-09-27 14:56 发表评论

jbpm4.3中数据库选择mysql注意事项

雪山飞鹄 — Sun, 26 Sep 2010 06:53:00 GMT

在运行jbpm4.3中例子时,若数据库选择为mysql，应注意修改jbpm.hibernate.cfg.xml中mysql的方言为org.hibernate.dialect.MySQL5InnoDBDialect

雪山飞鹄 2010-09-26 14:53 发表评论

jbpm4.3整合web工程时异常解决方案

雪山飞鹄 — Mon, 16 Aug 2010 09:46:00 GMT

近期刚开始接触jbpm，在整合web工程时遇到一异常，特有意思。记录下来，以免更多人少走弯路。

java.lang.LinkageError: loader constraint violation: when resolving interface method "javax.servlet.jsp.JspApplicationContext.getExpressionFactory()Ljavax/el/ExpressionFactory;" the class loader (instance of org/apache/jasper/servlet/JasperLoader) of the current class, org/apache/jsp/index_jsp, and the class loader (instance of org/apache/catalina/loader/StandardClassLoader) for resolved class, javax/servlet/jsp/JspApplicationContext, have different Class objects for the type javax/el/ExpressionFactory used in the signature
    at org.apache.jsp.index_jsp._jspInit(index_jsp.java:30)
    at org.apache.jasper.runtime.HttpJspBase.init(HttpJspBase.java:52)
    at org.apache.jasper.servlet.JspServletWrapper.getServlet(JspServletWrapper.java:159)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:329)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
    at java.lang.Thread.run(Thread.java:619)

从异常信息不难看出，是web容器 tomcat解析jsp页面时jar包冲突。
仔细查看jbpm4.3 lib目录下的jar包我们不难发现，罪魁祸首为juel.jar和juel-impl.jar
很显然原因就出在这两个jar包身上，从名字上不难发现juel-impl是前者的实现，因此这里采取的措施是保留juel-impl.jar删除juel.jar
重启tomcat,刷新web页面。问题迎刃而解。
刚开始接触jbpm，前阵子看了一下jbpm3的api，后来看了看jbpm4的API发现之间相差很大。小弟刚开始接触jbpm，希望达人指点。

雪山飞鹄 2010-08-16 17:46 发表评论