Activiti 5.3：子流程（subProcess）

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="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:activiti="http://activiti.org/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="http://my.oschina.net/arthor" class="referer" target="_blank">@author</a> shirdrn
 */
public class MySubProcessTest extends AbstractTest {
 
    @Override
    protected void initialize() throws Exception {
        Deployment deployment = repositoryService
        .createDeployment()
        .addClasspathResource(
                "diagrams/SubProcessTest.MySubprocess.bpmn20.xml")
        .deploy();  
        deploymentId = deployment.getId();
    }
 
    @Override
    protected void destroy() throws Exception {
        repositoryService.deleteDeployment(deploymentId, true); 
    }
     
    public void testSubProcess() {
        // prepare data packet
        Map<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 instance
        ProcessInstance pi = runtimeService.startProcessInstanceByKey("MySubprocess", variables);
         
        // enter subprocess
        List<Task> tasks = taskService.createTaskQuery().processInstanceId(pi.getId()).orderByTaskName().asc().list();
        assertEquals(2, tasks.size());
         
        for(Task task : tasks) {
            taskService.complete(task.getId());
        }
         
        // leave subprocess
        Task 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");
        taskService.complete(collectTask.getId(), taskVariables);
    }
 
}

运行结果信息，如下所示：

2011-3-24 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={}}
2011-3-24 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}}
2011-3-24 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="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:activiti="http://activiti.org/bpmn" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:omgdc="http://www.omg.org/spec/DD/20100524/DC" xmlns:omgdi="http://www.omg.org/spec/DD/20100524/DI" typeLanguage="http://www.w3.org/2001/XMLSchema" expressionLanguage="http://www.w3.org/1999/XPath" targetNamespace="http://www.activiti.org/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());
     
    @Override
    public void execute(DelegateExecution execution) throws Exception {
        // varOutFromMainprocess<->varInSubprocess
        String 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="http://www.omg.org/spec/BPMN/20100524/MODEL"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:activiti="http://activiti.org/bpmn"
    xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:omgdc="http://www.omg.org/spec/DD/20100524/DC"
    xmlns:omgdi="http://www.omg.org/spec/DD/20100524/DI" typeLanguage="http://www.w3.org/2001/XMLSchema"
    expressionLanguage="http://www.w3.org/1999/XPath" targetNamespace="http://www.activiti.org/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());
     
    @Override
    public 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());
     
    @Override
    public void execute(DelegateExecution execution) throws Exception {
        // varInSubprocess<->varOutFromSubprocess
        String 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="http://my.oschina.net/arthor" class="referer" target="_blank">@author</a> shirdrn
 */
public class MainprocessTest extends AbstractTest {
 
    @Override
    protected 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());
    }
 
    @Override
    protected void destroy() throws Exception {
        for(String deployment : deploymentIdList) {
            repositoryService.deleteDeployment(deployment, true);   
        }
    }
     
    public void testSubProcess() {
        // prepare data packet
        Map<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 instance
        ProcessInstance 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：

2011-3-24 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={}}
2011-3-24 17:52:13 org.shirdrn.workflow.activiti.subprocess.Initialization execute
信息: I am Initialization in mainprocess.
2011-3-24 17:52:13 org.shirdrn.workflow.activiti.subprocess.Initialization execute
信息: in mainprocess set(varOutFromMainprocess): AAAA
2011-3-24 17:52:13 org.shirdrn.workflow.activiti.subprocess.BusinessCheck execute
信息: in subprocess get(varInSubprocess): AAAA
2011-3-24 17:52:13 org.shirdrn.workflow.activiti.subprocess.BusinessCheck execute
信息: variavles={varInSubprocess=AAAA}
2011-3-24 17:52:13 org.shirdrn.workflow.activiti.subprocess.BusinessCheck execute
信息: I am BusinessCheck in subprocess.
2011-3-24 17:52:13 org.shirdrn.workflow.activiti.subprocess.BusinessCheck execute
信息: in subprocess set(varInSubprocess): AAAA
2011-3-24 17:52:13 org.shirdrn.workflow.activiti.subprocess.DoTransaction execute
信息: in mainprocess get(varOutFromSubprocess): BBBB
2011-3-24 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}
2011-3-24 17:52:13 org.shirdrn.workflow.activiti.subprocess.DoTransaction execute
信息: I am DoTransaction in mainprocess.

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