jBPM(一)：jbpm 基础

BPM：Business Process Management 业务流程管理

jBPM是一个可扩展、灵活的能够实现工作流/业务流程管理的企业级开发框架，提供了流程定义、流程部署、流程执行、流程管理等功能。

jBPM的核心为processEngine, 通过processEngine获得各种service接口来对流程进行操作，所以jbpm与ssh整合，就是将processEngine交给spring进行管理。

核心代码：

<bean id="springHelper" class="org.jbpm.pvm.internal.processengine.SpringHelper" /> 
<bean id="processEngine" factory-bean="springHelper" 
      factory-method="createProcessEngine" />

SpringHelper源码：

public class SpringHelper implements ApplicationContextAware {
  
  protected ApplicationContext applicationContext;
  protected String jbpmCfg = "jbpm.cfg.xml";

  public void setJbpmCfg(String jbpmCfg) {
    this.jbpmCfg = jbpmCfg;
  }

  public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
    this.applicationContext = applicationContext;
  }
  
  protected ProcessEngine createProcessEngine() {
    return new ConfigurationImpl()
      .springInitiated(applicationContext)
      .setResource(jbpmCfg)
      .buildProcessEngine();
  }
  
}

jbpm.cfg.xml代码：

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

<jbpm-configuration>

  <import resource="jbpm.default.cfg.xml" />
  <import resource="jbpm.businesscalendar.cfg.xml" />
  <import resource="jbpm.tx.hibernate.cfg.xml" />
  <import resource="jbpm.tx.spring.cfg.xml" />
  <import resource="jbpm.jpdl.cfg.xml" />
  <import resource="jbpm.bpmn.cfg.xml" />
  <import resource="jbpm.identity.cfg.xml" />
  <import resource="jbpm.console.cfg.xml" />

  <process-engine-context>
     <string name="spring.cfg" value="classpath:/applicationContext.xml"/>
  </process-engine-context> 

</jbpm-configuration>

加载Spring配置文件时，如果Spring配置文件中所定义的Bean类实现了ApplicationContextAware 接口，那么在加载Spring配置文件时，会自动调用ApplicationContextAware 接口中的
public void setApplicationContext(ApplicationContext context) throws BeansException方法，获得ApplicationContext对象。前提必须在Spring配置文件中指定该类。