jbpm4 java活动如何使用动态参数

在jbpm4中使用java活动的时候我们需要从外部传入参数,在例子中没有说明如何实现。

下面以jbpm的自带的例子为例：

首先我们修改例子的配置文件：

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

<process name="Java" xmlns="http://jbpm.org/4.4/jpdl">

  <start g="20,20,48,48">
    <transition to="greet" />
  </start>

  <java name="greet"
        class="org.jbpm.examples.java.JohnDoe"
        method="hello"
        var="answer"
        g="96,16,83,52">

    <field name="state"><string value="fine"/></field>
        <arg>
            <ref object="msg"/>
        </arg>
        <!-- 
            <string value="Hi, how are you?"/></arg>
         -->
    <transition to="shake hand" />
  </java>

  <java name="shake hand"
        expr="#{hand}"
        method="shake"
        var="hand"
        g="215,17,99,52">

    <arg><object expr="#{joesmoe.handshakes.force}"/></arg>
    <arg><object expr="#{joesmoe.handshakes.duration}"/></arg>

    <transition to="wait" />
  </java>

  <state name="wait" g="352,17,88,52"/>

</process>

我们修改了xml文件，在arg把 <string value="Hi, how are you?"/></arg>
 修改为 <ref object="msg"/>
java代码修改为：

package org.jbpm.examples.java;

import java.util.HashMap;
import java.util.Map;

import org.jbpm.api.ProcessInstance;
import org.jbpm.test.JbpmTestCase;


/**
 * @author Tom Baeyens
 */
public class JavaInstantiateTest extends JbpmTestCase {

  String deploymentId;
  
  protected void setUp() throws Exception {
    super.setUp();
    
    deploymentId = repositoryService.createDeployment()
        .addResourceFromClasspath("org/jbpm/examples/java/process.jpdl.xml")
        .deploy();
  }

  protected void tearDown() throws Exception {
    repositoryService.deleteDeploymentCascade(deploymentId);
    
    super.tearDown();
  }

  public void testJavaInstantiate() {
    Map<String, Object> variables = new HashMap<String, Object>();
    variables.put("hand", new Hand());
    variables.put("joesmoe", new JoeSmoe());
    variables.put("msg", "Hi, how are you?");
    
    ProcessInstance processInstance = executionService.startProcessInstanceByKey("Java", variables);
    String pid = processInstance.getId();
    
    String answer = (String) executionService.getVariable(pid, "answer");
    assertEquals("I'm fine, thank you.", answer);

    Hand hand = (Hand) executionService.getVariable(pid, "hand");
    assertTrue(hand.isShaken());
  }
}

我们在java代码中加入了 variables.put("msg", "Hi, how are you?"); 其中msg作为java的参数传入。