jBPM-4.4：主流程（process）与子流程（sub-process）之间交换数据

现在假设存在这样一个流程：

首先需要进行复杂的鉴权，而且可能随着需求的变化而变化，这导致鉴权的流程也是时刻可能变化的。而只有当鉴权成功以后，才能执行实际的交易操作，例如向外部系统发送请求报文获取某些交易的数据。

这时，可以考虑将鉴权流程独立做成一个子流程，然后将其嵌入到主流程中去，适应局部流程变化而无需修改全局流程的问题，在子流程与主流程之间实际要做的就是约定数据的交换协议，即确定数据在子流程与主流程之间的流入与流出。

下面通过一个实际例子来说明并实践。

首先，定义主流程。

主流程包含鉴权的子流程，鉴权通过之后，收集鉴权过程中获取到的交易必需的数据，组装请求报文，流程定义如图所示：

对应的流程定义文件main-process.jpdl.xml，如下所示：

 <?xml version="1.0" encoding="UTF-8"?><process name="MainProcess" xmlns="http://jbpm.org/4.4/jpdl"><start g="347,93,48,48"><transition g="-123,-22" name="to SubCheckProcess" to="SubCheckProcess"/></start><sub-process g="297,173,149,40" name="SubCheckProcess" sub-process-key="SubCheckProcess"><parameter-in subvar="myRequest" var="myRequest"/><parameter-out subvar="myRequest" var="myRequest"/> <transition g="-114,-22" name="to ExternalRequest" to="ExternalRequest"/></sub-process><end g="347,329,48,48" name="end"/> <custom class="com.umpay.workflow.jbpm.handler.ExternalRequestHandler" g="306,245,131,52" name="ExternalRequest"> <transition g="-43,-22" name="to end" to="end"/> </custom></process>

上面，sub-process-key="SubCheckProcess"表示一个嵌入主流程中的鉴权子流程。通过流程定义文件内容，可以看到，在主流程与子流程之间交换数据，是通过变量myRequest来实现的：

<sub-process g="297,173,149,40" name="SubCheckProcess" sub-process-key="SubCheckProcess"><parameter-in subvar="myRequest" var="myRequest"/><parameter-out subvar="myRequest" var="myRequest"/> <transition g="-114,-22" name="to ExternalRequest" to="ExternalRequest"/>

<parameter-in>元素表示从主流程MainProcess中流入到子流程SubCheckProcess中变量为myRequest，而var="myRequest"表示在主流程中变量名称，而subvar="myRequest"表示在子流程中可以通过获取到myRequest变量从而得到数据。同理，<parameter-out>元素表示从子流程SubCheckProcess中流出到MainProcess中，将数据又传回主流程中，继续后续流程的操作。

另外，主流程在执行完子流程后，又执行了ExternalRequest结点，对应的处理类为com.umpay.workflow.jbpm.handler.ExternalRequestHandler，如下所示：

package com.umpay.workflow.jbpm.handler;import java.util.Map;import org.jbpm.api.activity.ActivityBehaviour;import org.jbpm.api.activity.ActivityExecution;public class ExternalRequestHandler implements ActivityBehaviour {@Overridepublic void execute(ActivityExecution execution) throws Exception {Map<String, Object> myRequest = (Map<String, Object>)execution.getVariable("myRequest");System.out.println("Main process variables: " + myRequest);}}

然后，实现子流程。

子流程定义，如图所示：

对应的流程定义文件sub-check-process.jpdl.xml，内容如下所示：

<?xml version="1.0" encoding="UTF-8"?><process name="SubCheckProcess" xmlns="http://jbpm.org/4.4/jpdl"><start g="332,2,48,52"> <transition g="-112,-22" name="to CheckCustomer" to="CheckCustomer"/></start> <custom class="com.umpay.workflow.jbpm.handler.CheckCustomerHandler" g="302,86,108,52" name="CheckCustomer"> <transition g="-52,-22" name="to fork1" to="fork1"/> </custom> <custom class="com.umpay.workflow.jbpm.handler.CheckMerHandler" g="186,250,92,52" name="CheckMer"> <transition g="-58,-8" name="to join1" to="join1"/> </custom> <custom class="com.umpay.workflow.jbpm.handler.CheckBankHandler" g="310,250,92,52" name="CheckBank"> <transition name="to join1" to="join1" g="0,-13"/> </custom> <custom class="com.umpay.workflow.jbpm.handler.CheckGoodsHandler" g="434,250,92,52" name="CheckGoods"> <transition name="to join1" to="join1" g="21,-4"/> </custom> <custom class="com.umpay.workflow.jbpm.handler.CheckMerBankHandler" g="295,414,122,52" name="CheckMerBank"> <transition name="to CheckGoodsBank" to="CheckGoodsBank" g="-124,-22"/> </custom> <custom class="com.umpay.workflow.jbpm.handler.CheckGoodsBankHandler" g="289,498,134,52" name="CheckGoodsBank"> <transition name="to end1" to="end1" g="-50,-22"/> </custom> <fork g="332,170,48,48" name="fork1"> <transition g="-80,-22" name="to CheckMer" to="CheckMer"/> <transition g="-46,-13" name="to CheckBank" to="CheckBank"/> <transition g="1,-21" name="to CheckGoods" to="CheckGoods"/> </fork> <join g="332,334,48,48" name="join1"> <transition name="to CheckMerBank" to="CheckMerBank" g="-109,-22"/> </join> <end g="332,582,48,52" name="end1"/></process>

上面对应了6个处理类，实现分别如下所示：

package com.umpay.workflow.jbpm.handler;import java.util.Map;import org.jbpm.api.activity.ActivityBehaviour;import org.jbpm.api.activity.ActivityExecution;public class CheckCustomerHandler implements ActivityBehaviour {@Overridepublic void execute(ActivityExecution execution) throws Exception {Map<String, Object> myRequest = (Map<String, Object>)execution.getVariable("myRequest");String mobileId = (String)myRequest.get("mobileId");// get system user id : userId=20110001674myRequest.put("userId", "20110001674");execution.setVariables(myRequest);}}

package com.umpay.workflow.jbpm.handler;import java.util.Map;import org.jbpm.api.activity.ActivityBehaviour;import org.jbpm.api.activity.ActivityExecution;public class CheckMerHandler implements ActivityBehaviour {@Overridepublic void execute(ActivityExecution execution) throws Exception {Map<String, Object> myRequest = (Map<String, Object>)execution.getVariable("myRequest");String mobileId = (String)myRequest.get("mobileId");// get system user id : userId=20110001674myRequest.put("userId", "20110001674");execution.setVariables(myRequest);}}

package com.umpay.workflow.jbpm.handler;import java.util.Map;import org.jbpm.api.activity.ActivityBehaviour;import org.jbpm.api.activity.ActivityExecution;public class CheckBankHandler implements ActivityBehaviour {@Overridepublic void execute(ActivityExecution execution) throws Exception {Map<String, Object> myRequest = (Map<String, Object>)execution.getVariable("myRequest");String mobileId = (String)myRequest.get("mobileId");// get system user id : userId=20110001674myRequest.put("userId", "20110001674");execution.setVariables(myRequest);}}

package com.umpay.workflow.jbpm.handler;import java.util.Map;import org.jbpm.api.activity.ActivityBehaviour;import org.jbpm.api.activity.ActivityExecution;public class CheckGoodsHandler implements ActivityBehaviour {@Overridepublic void execute(ActivityExecution execution) throws Exception {Map<String, Object> myRequest = (Map<String, Object>)execution.getVariable("myRequest");String goodsId = (String)myRequest.get("goodsId");// get goods countmyRequest.put("goodsCount", "2000");execution.setVariables(myRequest);}}

package com.umpay.workflow.jbpm.handler;import java.util.Map;import org.jbpm.api.activity.ActivityBehaviour;import org.jbpm.api.activity.ActivityExecution;public class CheckMerBankHandler implements ActivityBehaviour {@Overridepublic void execute(ActivityExecution execution) throws Exception {Map<String, Object> myRequest = (Map<String, Object>)execution.getVariable("myRequest");String merId = (String)myRequest.get("merId");String bankId = (String)myRequest.get("bankId");// get mer bank relationshipmyRequest.put("mbr","mbr_" + merId + "_" + bankId);execution.setVariables(myRequest);}}

package com.umpay.workflow.jbpm.handler;import java.util.Map;import org.jbpm.api.activity.ActivityBehaviour;import org.jbpm.api.activity.ActivityExecution;public class CheckGoodsBankHandler implements ActivityBehaviour {@Overridepublic void execute(ActivityExecution execution) throws Exception {Map<String, Object> myRequest = (Map<String, Object>)execution.getVariable("myRequest");String goodsId = (String)myRequest.get("goodsId");String bankId = (String)myRequest.get("bankId");// get goods bank relationshipmyRequest.put("gbr", "gbr_" + goodsId + "_" + bankId);execution.setVariables(myRequest);}}

在执行子流程的过程中，在每一个节点处处理，都模拟了“获取到一些额外的必需数据”。

最后，测试用例。

测试用例，如下所示：

package com.umpay.workflow.jbpm.process;import java.util.HashMap;import java.util.Map;import junit.framework.TestCase;import org.jbpm.api.Execution;import org.jbpm.api.ProcessEngine;import org.jbpm.api.ProcessInstance;import org.springframework.context.support.ClassPathXmlApplicationContext;public class MainProcessTest extends TestCase {private ProcessEngine processEngine;private String mainProcessDeploymentId;private String subCheckProcessDeploymentId;protected void setUp() throws Exception {super.setUp();ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");ctx.start();this.processEngine = (ProcessEngine) ctx.getBean("processEngine");mainProcessDeploymentId = this.processEngine.getRepositoryService().createDeployment().addResourceFromClasspath("com/umpay/workflow/jbpm/jpdl/main-process.jpdl.xml").deploy();subCheckProcessDeploymentId = this.processEngine.getRepositoryService().createDeployment().addResourceFromClasspath("com/umpay/workflow/jbpm/jpdl/sub-check-process.jpdl.xml").deploy();}protected void tearDown() throws Exception {this.processEngine.getRepositoryService().deleteDeploymentCascade(mainProcessDeploymentId);this.processEngine.getRepositoryService().deleteDeploymentCascade(subCheckProcessDeploymentId);super.tearDown();}public void testMyProcess() {// initialize request dataMap<String, Object> myRequest = new HashMap<String, Object>();myRequest.put("merId", "001");myRequest.put("mobileId", "13800138000");myRequest.put("goodsId", "030");myRequest.put("bankId", "CMPAY010");Map<String, Object> variables = new HashMap<String, Object>();variables.put("myRequest", myRequest);ProcessInstance processInstance = null;// start a process instance// it can execute a process automaticallyprocessInstance = this.processEngine.getExecutionService().startProcessInstanceByKey("MainProcess", variables);assertEquals(Execution.STATE_ENDED, processInstance.getState());}}

上述程序，开始要需要部署流程，主流程和子流程需要单独部署，实际是在这个具体的例子中，存在两个流程，它们在执行自己的实例的时候是独立的。在流程启动之前，需要根据流程执行需要，输入在流程中能够获取到的数据（Key+Value的形式）。接着就可以运行了，可以看到，最终可以看到流程数据的集合 ：

Main process variables: {goodsId=030, mobileId=13800138000, userId=20110001674, merId=001, goodsCount=2000, mbr=mbr_001_CMPAY010, gbr=gbr_030_CMPAY010, bankId=CMPAY010}

这里，数据集合{userId=20110001674, goodsCount=2000, mbr=mbr_001_CMPAY010, gbr=gbr_030_CMPAY010}都是在执行处理的时候获取到的交易操作所需要的数据。