Activiti 5.3提供了子流程的实现，包括两种基于子流程的实现：
一种是内嵌子流程：子流程元素<subProcess>内嵌在主流程元素<process>之内，只能在该流程中使用该子流程，外部是无法访问到的。这种子流程一般作为局部通用逻辑处理，或者因为特定业务需要，使得比较复杂的单个主流程设计清晰直观；
另一种是调用子流程：首先实现一个流程，在另一个流程中可以调用该流程，通常可以定义一些通用的流程作为这种调用子流程，供其他多个流程定义复用。这种子流程使用<callActivity>元素来进行调用，间接地嵌入到主流程中，用起来比较方便。
内嵌子流程
实现的基于内嵌子流程的流程，示例如图所示：
对应的流程定义文件SubProcessTest.MySubprocess.bpmn20.xml，内容如下所示：
<?xml version="1.0" encoding="UTF-8"?><definitions id="definitions"xmlns="/spec/BPMN/0524/MODEL" xmlns:activiti="/bpmn"targetNamespace="Examples"><process id="MySubprocess" name="My Subprocess"><startEvent id="theStart" /><sequenceFlow id="flow1" sourceRef="theStart" targetRef="subProcess" /><subProcess id="subProcess"><startEvent id="subProcessStart" /><sequenceFlow id="flow2" sourceRef="subProcessStart" targetRef="subProcessFork" /><parallelGateway id="subProcessFork" /><sequenceFlow id="flow3" sourceRef="subProcessFork" targetRef="task1" /><sequenceFlow id="flow4" sourceRef="subProcessFork" targetRef="task2" /><userTask id="task1" name="Check bank" activiti:candidateGroups="engineering"><extensionElements><activiti:taskListener event="complete"class="org.shirdrn.workflow.activiti.subprocess.CheckBankTask" /></extensionElements></userTask><sequenceFlow id="flow5" sourceRef="task1" targetRef="subProcessJoin" /><userTask id="task2" name="Investigate software" activiti:candidateGroups="engineering" ><extensionElements><activiti:taskListener event="complete"class="org.shirdrn.workflow.activiti.subprocess.CheckMerchantTask" /></extensionElements></userTask><sequenceFlow id="flow6" sourceRef="task2" targetRef="subProcessJoin" /><parallelGateway id="subProcessJoin" /><sequenceFlow id="flow7" sourceRef="subProcessJoin" targetRef="subProcessEnd" /><endEvent id="subProcessEnd" /></subProcess><sequenceFlow id="flow10" sourceRef="subProcess" targetRef="taskAfterSubProcess" /><userTask id="taskAfterSubProcess" name="Collect message" activiti:candidateGroups="engineering" ><extensionElements><activiti:taskListener event="complete"class="org.shirdrn.workflow.activiti.subprocess.CollectMessageTask" /></extensionElements></userTask><sequenceFlow id="flow11" sourceRef="taskAfterSubProcess" targetRef="theEnd" /><endEvent id="theEnd" /></process></definitions>
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流程定义中，实现了3个TaskListener，对应的代码分别如下所示：
package org.shirdrn.workflow.activiti.subprocess;import java.util.HashMap;import java.util.logging.Logger;import org.activiti.engine.delegate.DelegateTask;import org.activiti.engine.impl.pvm.delegate.TaskListener;public class CheckBankTask implements TaskListener {private final Logger log = Logger.getLogger(CheckBankTask.class.getName());@SuppressWarnings("unchecked")public void notify(DelegateTask delegateTask) {log.info("i am CheckBankTask.");System.out.println("in : " + delegateTask.getVariables());((HashMap<String, Object>)delegateTask.getVariables().get("in")).put("next", "CheckBankTask");((HashMap<String, Object>)delegateTask.getVariables().get("out")).put("reponse", "subprocess:CheckBankTask->CheckMerchantTask");}}
package org.shirdrn.workflow.activiti.subprocess;import java.util.HashMap;public class CheckMerchantTask implements TaskListener {private final Logger log = Logger.getLogger(CheckMerchantTask.class.getName());@SuppressWarnings("unchecked")public void notify(DelegateTask delegateTask) {log.info("i am CheckMerchantTask.");System.out.println("in : " + delegateTask.getVariables());((HashMap<String, Object>)delegateTask.getVariables().get("in")).put("previous", "CheckMerchantTask");}}
package org.shirdrn.workflow.activiti.subprocess;import java.util.Map;public class CollectMessageTask implements TaskListener {private final Logger log = Logger.getLogger(CollectMessageTask.class.getName());@SuppressWarnings("unchecked")public void notify(DelegateTask delegateTask) {log.info("i am CollectMessageTask.");System.out.println("out : " + (Map<String, Object>)delegateTask.getVariables().get("out"));System.out.println("all : " + delegateTask.getVariables());}}
测试用例，代码如下所示：
package org.shirdrn.workflow.activiti.subprocess;import java.util.HashMap;import java.util.List;import java.util.Map;import org.activiti.engine.repository.Deployment;import org.activiti.engine.runtime.ProcessInstance;import org.activiti.engine.task.Task;import org.shirdrn.workflow.activiti.AbstractTest;/*** <a href="/arthor" class="referer" target="_blank">@author</a> shirdrn*/public class MySubProcessTest extends AbstractTest {@Overrideprotected void initialize() throws Exception {Deployment deployment = repositoryService.createDeployment().addClasspathResource("diagrams/SubProcessTest.MySubprocess.bpmn20.xml").deploy(); deploymentId = deployment.getId();}@Overrideprotected void destroy() throws Exception {repositoryService.deleteDeployment(deploymentId, true); }public void testSubProcess() {// prepare data packetMap<String, Object> variables = new HashMap<String, Object>();Map<String, Object> subVariables = new HashMap<String, Object>();variables.put("maxTransCount", 1000000);variables.put("merchant", new Merchant("ICBC"));variables.put("protocol", "UM32");variables.put("repository", "10.10.38.99:/home/shirdrn/repository");variables.put("in", subVariables);variables.put("out", new HashMap<String, Object>());// start process instanceProcessInstance pi = runtimeService.startProcessInstanceByKey("MySubprocess", variables);// enter subprocessList<Task> tasks = taskService.createTaskQuery().processInstanceId(pi.getId()).orderByTaskName().asc().list();assertEquals(2, tasks.size());for(Task task : tasks) {plete(task.getId());}// leave subprocessTask collectTask = taskService.createTaskQuery().processInstanceId(pi.getId()).singleResult();assertEquals("Collect message", collectTask.getName());Map<String, Object> taskVariables = new HashMap<String, Object>();taskVariables.put("att", "anything you need");taskService.setVariable(collectTask.getId(), "oper", "shirdrn");plete(collectTask.getId(), taskVariables);}}
运行结果信息，如下所示：
-3-24 17:36:36 org.shirdrn.workflow.activiti.subprocess.CheckBankTask notify信息: i am CheckBankTask.in : {protocol=UM32, repository=10.10.38.99:/home/shirdrn/repository, merchant=Merchant[ICBC], maxTransCount=1000000, in={}, out={}}-3-24 17:36:36 org.shirdrn.workflow.activiti.subprocess.CheckMerchantTask notify信息: i am CheckMerchantTask.in : {protocol=UM32, repository=10.10.38.99:/home/shirdrn/repository, merchant=Merchant[ICBC], maxTransCount=1000000, in={next=CheckBankTask}, out={reponse=subprocess:CheckBankTask->CheckMerchantTask}}-3-24 17:36:36 org.shirdrn.workflow.activiti.subprocess.CollectMessageTask notify信息: i am CollectMessageTask.out : {reponse=subprocess:CheckBankTask->CheckMerchantTask}all : {protocol=UM32, repository=10.10.38.99:/home/shirdrn/repository, merchant=Merchant[ICBC], oper=shirdrn, att=anything you need, maxTransCount=1000000, in={previous=CheckMerchantTask, next=CheckBankTask}, out={reponse=subprocess:CheckBankTask->CheckMerchantTask}}
调用子流程
实现的子流程，示例如图所示：
对应的流程定义文件Subprocess.Check.bpmn20.xml，如下所示：
<?xml version="1.0" encoding="UTF-8"?><definitions xmlns="/spec/BPMN/0524/MODEL" xmlns:xsi="/2001/XMLSchema-instance" xmlns:activiti="/bpmn" xmlns:bpmndi="/spec/BPMN/0524/DI" xmlns:omgdc="/spec/DD/0524/DC" xmlns:omgdi="/spec/DD/0524/DI" typeLanguage="/2001/XMLSchema" expressionLanguage="/1999/XPath" targetNamespace="/test"><process id="CheckSubprocess" name="CheckSubprocess"><startEvent id="startevent4" name="Start"></startEvent><serviceTask id="servicetask4" name="Check User" activiti:class="org.shirdrn.workflow.activiti.subprocess.BusinessCheck"></serviceTask><endEvent id="endevent4" name="End"></endEvent><sequenceFlow id="flow7" name="" sourceRef="startevent4" targetRef="servicetask4"></sequenceFlow><sequenceFlow id="flow8" name="" sourceRef="servicetask4" targetRef="endevent4"></sequenceFlow></process></definitions>
上面的流程定义，和通常定义流程的方式是相同的。流程中，对应的JavaDelegate的实现类，代码如下所示：
package org.shirdrn.workflow.activiti.subprocess;import java.util.logging.Logger;import org.activiti.engine.delegate.DelegateExecution;import org.activiti.engine.delegate.JavaDelegate;public class BusinessCheck implements JavaDelegate {private static final Logger log = Logger.getLogger(BusinessCheck.class.getName());@Overridepublic void execute(DelegateExecution execution) throws Exception {// varOutFromMainprocess<->varInSubprocessString varInSubprocess = (String)execution.getVariable("varInSubprocess");log.info("in subprocess get(varInSubprocess): " + varInSubprocess);log.info("variavles=" + execution.getVariables());execution.setVariable("s:bc", "Subprocess:BusinessCheck");log.info("I am BusinessCheck in subprocess."); execution.setVariable("varInSubprocess", "BBBB");log.info("in subprocess set(varInSubprocess): " + varInSubprocess);}}
该BusinessCheck类简单用来校验用户数据。
下面看一下主流程，如图所示：
上面的callSubprocess结点对应的就是流程定义中的<callActivity>元素，调用了外部流程。对应的流程定义文件Subprocess.Mainprocess.bpmn20.xml，如下所示：
<?xml version="1.0" encoding="UTF-8"?><definitions xmlns="/spec/BPMN/0524/MODEL"xmlns:xsi="/2001/XMLSchema-instance" xmlns:activiti="/bpmn"xmlns:bpmndi="/spec/BPMN/0524/DI" xmlns:omgdc="/spec/DD/0524/DC"xmlns:omgdi="/spec/DD/0524/DI" typeLanguage="/2001/XMLSchema"expressionLanguage="/1999/XPath" targetNamespace="/test"><process id="Mainprocess" name="Main Process"><startEvent id="startevent1" name="Start"></startEvent><sequenceFlow id="flow1" name="" sourceRef="startevent1" targetRef="servicetask1"></sequenceFlow><serviceTask id="servicetask1" name="System Initialization" activiti:class="org.shirdrn.workflow.activiti.subprocess.Initialization"></serviceTask><sequenceFlow id="flow2" name="" sourceRef="servicetask1" targetRef="callSubprocess"></sequenceFlow><callActivity id="callSubprocess" calledElement="CheckSubprocess" > <extensionElements> <activiti:in source="varOutFromMainprocess" target="varInSubprocess" /> <activiti:out source="varInSubprocess" target="varOutFromSubprocess" /> </extensionElements> </callActivity><sequenceFlow id="flow3" name="" sourceRef="callSubprocess" targetRef="servicetask2"></sequenceFlow><serviceTask id="servicetask2" name="Do Transaction" activiti:class="org.shirdrn.workflow.activiti.subprocess.DoTransaction"></serviceTask><sequenceFlow id="flow4" name="" sourceRef="servicetask2" targetRef="endevent1"></sequenceFlow><endEvent id="endevent1" name="End"></endEvent></process></definitions>
需要说明的是，对于主流程与子流程之间进行数据交换，需要在<callActivity>元素中进行配置，通过执行“传入”、“传出”变量的方式来进行。片段如下所示：
<callActivity id="callSubprocess" calledElement="CheckSubprocess" > <extensionElements> <activiti:in source="varOutFromMainprocess" target="varInSubprocess" /> <activiti:out source="varInSubprocess" target="varOutFromSubprocess" /> </extensionElements> </callActivity>
我们可以通过在主流程中设置一个变量为varOutFromMainprocess，并指定对应的输入数据，根据流程定义，会将变量 varOutFromMainprocess对应的值，传递给子流程中的变量varInSubprocess，只需要在子流程中获取变量 varInSubprocess的值即可。从子流程中传出数据的道理是类似的。上面实现了2个JavaDelegate处理类，代码分别如下所示：
package org.shirdrn.workflow.activiti.subprocess;import java.util.logging.Logger;public class Initialization implements JavaDelegate {private static final Logger log = Logger.getLogger(Initialization.class.getName());@Overridepublic void execute(DelegateExecution execution) throws Exception {log.info("variavles=" + execution.getVariables());execution.setVariable("m:i", "Mainprocess:Initialization");log.info("I am Initialization in mainprocess.");execution.setVariable("varOutFromMainprocess", "AAAA");log.info("in mainprocess set(varOutFromMainprocess): " + execution.getVariable("varOutFromMainprocess"));}}
package org.shirdrn.workflow.activiti.subprocess;import java.util.logging.Logger;public class DoTransaction implements JavaDelegate {private static final Logger log = Logger.getLogger(DoTransaction.class.getName());@Overridepublic void execute(DelegateExecution execution) throws Exception {// varInSubprocess<->varOutFromSubprocessString varOutFromSubprocess = (String)execution.getVariable("varOutFromSubprocess");log.info("in mainprocess get(varOutFromSubprocess): " + varOutFromSubprocess);log.info("variavles=" + execution.getVariables());execution.setVariable("m:dt", "Mainprocess:DoTransaction");log.info("I am DoTransaction in mainprocess.");}}
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实现的测试用例，代码如下所示：
package org.shirdrn.workflow.activiti.subprocess;import java.util.HashMap;import java.util.Map;import org.activiti.engine.repository.Deployment;import org.activiti.engine.runtime.ProcessInstance;import org.shirdrn.workflow.activiti.AbstractTest;/*** <a href="/arthor" class="referer" target="_blank">@author</a> shirdrn*/public class MainprocessTest extends AbstractTest {@Overrideprotected void initialize() throws Exception {Deployment deployment = repositoryService.createDeployment().addClasspathResource("diagrams/Subprocess.Check.bpmn20.xml").deploy(); deploymentIdList.add(deployment.getId());deployment = repositoryService.createDeployment().addClasspathResource("diagrams/Subprocess.Mainprocess.bpmn20.xml").deploy(); deploymentIdList.add(deployment.getId());}@Overrideprotected void destroy() throws Exception {for(String deployment : deploymentIdList) {repositoryService.deleteDeployment(deployment, true); }}public void testSubProcess() {// prepare data packetMap<String, Object> variables = new HashMap<String, Object>();Map<String, Object> subVariables = new HashMap<String, Object>();variables.put("protocol", "UM32");variables.put("repository", "10.10.38.99:/home/shirdrn/repository");variables.put("in", subVariables);variables.put("out", new HashMap<String, Object>());// start process instanceProcessInstance pi = runtimeService.startProcessInstanceByKey("Mainprocess", variables);assertEquals(true, pi.isEnded());}}
代码中org.shirdrn.workflow.activiti.AbstractTest类可以参考：Activiti 5.3：流程活动自动与手工触发执行里面。上述测试程序运行结果如下所示：
-3-24 17:52:13 org.shirdrn.workflow.activiti.subprocess.Initialization execute信息: variavles={protocol=UM32, repository=10.10.38.99:/home/shirdrn/repository, in={}, out={}}-3-24 17:52:13 org.shirdrn.workflow.activiti.subprocess.Initialization execute信息: I am Initialization in mainprocess.-3-24 17:52:13 org.shirdrn.workflow.activiti.subprocess.Initialization execute信息: in mainprocess set(varOutFromMainprocess): AAAA-3-24 17:52:13 org.shirdrn.workflow.activiti.subprocess.BusinessCheck execute信息: in subprocess get(varInSubprocess): AAAA-3-24 17:52:13 org.shirdrn.workflow.activiti.subprocess.BusinessCheck execute信息: variavles={varInSubprocess=AAAA}-3-24 17:52:13 org.shirdrn.workflow.activiti.subprocess.BusinessCheck execute信息: I am BusinessCheck in subprocess.-3-24 17:52:13 org.shirdrn.workflow.activiti.subprocess.BusinessCheck execute信息: in subprocess set(varInSubprocess): AAAA-3-24 17:52:13 org.shirdrn.workflow.activiti.subprocess.DoTransaction execute信息: in mainprocess get(varOutFromSubprocess): BBBB-3-24 17:52:13 org.shirdrn.workflow.activiti.subprocess.DoTransaction execute信息: variavles={protocol=UM32, repository=10.10.38.99:/home/shirdrn/repository, varOutFromSubprocess=BBBB, varOutFromMainprocess=AAAA, in={}, out={}, m:i=Mainprocess:Initialization}-3-24 17:52:13 org.shirdrn.workflow.activiti.subprocess.DoTransaction execute信息: I am DoTransaction in mainprocess.
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