当进入配置定时器元素时,定时器被创建,当流程一直处于这个活动时候,定时器可以触发,直到到到截止时间(duedate),当流程离开活动,定时器就会被取消。
timer的属性:
持续时间表达式包含下列语法:
[<Base Date> {+|-}] quantity [business] {second | seconds | minute | minutes | hour | hours | day | days | week | weeks | month | months | year | years}
这里的 Base Date 是一个 EL。 quantity 是一个正整数。 添加额外的 business 意味着 只有工作时间应该被计算在持续时间内。 如果没有指定 business,持续时间会使用绝对时间间隔。注意:'business'还不支持对 base date 进行减法运算!
下面是一些jbpm开发文档中的简单的例子:
下面的例子用法都是可行的
<timer name="daysBeforeHoliday" duedate="5 business days">...</timer>
<timer name="pensionDate" duedate="#{dateOfBirth} + 65 years" >...</timer>
<timer name="pensionReminder" duedate="#{dateOfPension} - 1 year" >...</timer>
<timer name="fireWorks" duedate="#{chineseNewYear} repeat="1 year" >...</timer>
<reminder name="hitBoss" duedate="#{payRaiseDay} + 3 days" repeat="1 week" />
<reminder name="hitBoss" duedate="#{payRaiseDay} + 3 days" repeat="#{iritationFactor}"
/>
但是,下面的例子,在'business'的结合运算中使用减法,是不被支持的,会抛出一个异常,会导致持续时间变成一个过去的事件。
<reminder name="toGoOrNotToGo" duedate="#{goLive} - 3 business days"/>
要想定时器起作用,必须修改jbpm.cfg.xml文件,将预先注释掉的<import resource="jbpm.jobexecutor.cfg.xml" />去掉注释。
jbpm4.x中带的jbpm.jobexecutor.cfg.xml的内容是没有详细配置的,但是,它会执行默认的配置。
原始的配置文件内容是:
<?xml version="1.0" encoding="UTF-8"?> <jbpm-configuration> <process-engine-context> </process-engine-context> </jbpm-configuration>
可以对该配置文件进行详细的配置,修改后的内容:
<?xml version="1.0" encoding="UTF-8"?> <jbpm-configuration> <process-engine-context> <job-executor threads="4" idle="30000" idle-max="60000" lock="3600000" /> </process-engine-context> </jbpm-configuration>
对配置中的参数讲解:
启用 jobExecutor 是非常简单的,只要添加下面的几行代码 到 jbpm.cfg.xml 文件中(使用默认配置):<import resource="jbpm.jobexecutor.cfg.xml" />还有更多属性,可以更好的调整 JobExecutor:
· threads: 定义了 JobexecutorThreadsd 的数目(默认3 个线程)
· idle: 以毫秒为单位的,派发器组件 在数据库中找不到新 job 时的等待时间(默认 5 秒)
· idle-max: 当出现一个异常时 空闲间隔会翻倍,直到达到'idle-max (回退机制用来避免从一个错误的数
据库一直读取数据)。
· lock-millis: 以毫秒为单位, 一个job 会被锁定,在派发器读取之后。 这可以预防多个 JobExecutorThreads
访问一条记录,会出现死锁。 (比如,在集群中使用)。
下面记录一下定时器在不同元素中的用法:
1.定时器流向,在Transition中配置定时器:
<?xml version="1.0" encoding="UTF-8"?> <process name="TimerTransitionTest" xmlns="http://jbpm.org/4.4/jpdl"> <start g="19,50,48,48"> <transition to="guardedWait" /> </start> <state g="98,46,127,52" name="guardedWait"> <transition name="timeout" to="escalation" g="-49,-22"> <timer duedate="10 minutes" /> </transition> <transition g="-16,-17" name="go on" to="next step" /> </state> <state g="287,52,83,53" name="next step" /> <state name="escalation" g="122,174,80,40" /> </process>
测试类TestTimer.java
package com.lujinyong.timer.transition; import static org.junit.Assert.assertEquals; import static org.junit.Assert.assertTrue; import java.util.ArrayList; import java.util.Collections; import java.util.List; import java.util.Set; import org.jbpm.api.Configuration; import org.jbpm.api.Execution; import org.jbpm.api.ExecutionService; import org.jbpm.api.ManagementService; import org.jbpm.api.ProcessEngine; import org.jbpm.api.ProcessInstance; import org.jbpm.api.job.Job; import org.junit.Test; public class TestTimer { /** * * @Description: 部署流程 * @Auther: lujinyong * @Date: 2013-6-24 下午03:41:01 */ @Test public void testDeploy1() { // 1.get processEngine ProcessEngine processEngine = Configuration.getProcessEngine(); processEngine .getRepositoryService() .createDeployment() .addResourceFromClasspath( "com/lujinyong/timer/transition/TimerTransitionTest.jpdl.xml") .addResourceFromClasspath( "com/lujinyong/timer/transition/TimerTransitionTest.png").deploy(); } /** * * @Description: 测试超时的情况,流向escalation * @Auther: lujinyong * @Date: 2013-6-24 下午05:38:35 */ @Test public void testTimerTransitionTimerFires() { ProcessEngine processEngine = Configuration.getProcessEngine(); ExecutionService executionService = processEngine.getExecutionService(); ManagementService managementService = processEngine.getManagementService(); ProcessInstance processInstance = executionService.startProcessInstanceByKey("TimerTransitionTest"); //查询定时器 Job job = managementService.createJobQuery() .processInstanceId(processInstance.getId()) .uniqueResult(); //假设定时器被触发了,通过编码执行定时器进行模拟 managementService.executeJob(job.getId()); processInstance = executionService.findProcessInstanceById(processInstance.getId()); Set<String> expectedActivityNames = Collections.singleton("guardedWait"); assertEquals(expectedActivityNames, processInstance.findActiveActivityNames()); assertEquals(Boolean.TRUE, executionService.getVariable(processInstance.getId(), "escalation")); } /** * * @Description: 测试未超时的情况,流向next step * @Auther: lujinyong * @Date: 2013-6-24 下午05:39:45 */ @Test public void testTimerTransitionContinueBeforeTimerFires() { ProcessEngine processEngine = Configuration.getProcessEngine(); ExecutionService executionService = processEngine.getExecutionService(); ManagementService managementService = processEngine.getManagementService(); ProcessInstance processInstance = executionService.startProcessInstanceByKey("TimerTransitionTest"); String executionId = processInstance.findActiveExecutionIn("guardedWait").getId(); executionService.signalExecutionById(executionId, "go on"); processInstance = executionService.findProcessInstanceById(processInstance.getId()); assertTrue(processInstance.isActive("next step")); List<Job> jobs = managementService.createJobQuery() .processInstanceId(processInstance.getId()) .list(); assertEquals(new ArrayList<Job>(), new ArrayList<Job>(jobs)); } }
如果创建一个项目,配置好数据库,则可以从数据库记录中看到详细的执行结果。下面就介绍一下配置jbpm的数据库:
首先在eclipse安装好jbpm的插件,我用的是jbpm4.4的,注意安装插件要在断网情况下安装,否则安装很慢。
创建一个web工程,将jbpm-4.4\lib下面的jar包放到项目中的lib目录下面。注意去掉report-engine.zip,gwt-console-jbpm.war,gwt-console-server-jbpm.war。
将配置文件放到src下面:配置文件是jbpm-4.4\examples\src下面的所有配置文件。
jbpm.hibernate.cfg.xml中配置数据库:
<?xml version="1.0" encoding="utf-8"?> <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <property name="hibernate.connection.url"> jdbc:mysql://127.0.0.1:3306/jbpm4?characterEcoding/=utf-8 </property> <property name="hibernate.connection.driver_class"> com.mysql.jdbc.Driver </property> <property name="hibernate.connection.username">root</property> <property name="hibernate.connection.password">root</property> <property name="hibernate.dialect"> org.hibernate.dialect.MySQLInnoDBDialect </property> <property name="hibernate.hbm2ddl.auto">update</property> <property name="hibernate.show_sql">true</property> <mapping resource="jbpm.repository.hbm.xml" /> <mapping resource="jbpm.execution.hbm.xml" /> <mapping resource="jbpm.history.hbm.xml" /> <mapping resource="jbpm.task.hbm.xml" /> <mapping resource="jbpm.identity.hbm.xml" /> </session-factory> </hibernate-configuration>
在src中一个包com.lujinyong.initdb,在该包中添加创建数据库的类CreateDB.java
package com.lujinyong.initdb; import org.hibernate.cfg.Configuration; import org.junit.Test; public class CreateDB { @Test public void test(){ Configuration configuration = new Configuration(); configuration.configure("jbpm.hibernate.cfg.xml"); configuration.buildSessionFactory(); } }
运行test()即可生成jbpm对应的数据库了。
暂时列出一个例子吧。