JBoss 系列四十一：jBPM5示例之 Timer Event

在BPM流程中，经常需要在执行某个任务之前或之后停顿一段时间，jBPM5中使用Timer Event完成这一操作，如下为DelayTimerEvent流程：

如图，DelayTimerEvent流程共有三个节点，Before Timer，Timer，After Timer。Before Timer为Script Task节点，运行状态该节点执行的Java代码如下：

timeBeforeTimer = System.currentTimeMillis();
System.out.println("Before Timer - " + new SimpleDateFormat("yyyyy-mm-dd hh:mm:ss").format( new Date((Long)timeBeforeTimer)));
kcontext.setVariable("timeBeforeTimer", timeBeforeTimer);

Timer为Timer Event节点，该节点设定的Timer Delay为5秒钟，即当流程运行到此节点后停顿5秒钟后继续进行。
After Timer为Script Task节点，运行状态该节点执行的Java代码如下：

Long timeAfter = System.currentTimeMillis();
System.out.println("After  Timer - " +  new SimpleDateFormat("yyyyy-mm-dd hh:mm:ss").format( new Date(timeAfter)));
timerExecutionTime = timeAfter - (Long) timeBeforeTimer;
kcontext.setVariable("timerExecutionTime", timerExecutionTime);

• DelayTimerEvent流程运行代码：https://github.com/kylinsoong/.../DelayTimerEventStart.java
• DelayTimerEvent流程：https://github.com/kylinsoong/.../delayTimerEventProcess.bpmn

运行org.jbpm.quickstarts.event.DelayTimerEventStart会运行DelayTimerEvent流程，DelayTimerEventStart代码如下：

package org.jbpm.quickstarts.event;

import org.drools.runtime.StatefulKnowledgeSession;
import org.drools.runtime.process.ProcessInstance;
import org.drools.runtime.process.WorkflowProcessInstance;
import org.jbpm.quickstarts.QuickStartBase;

public class DelayTimerEventStart extends QuickStartBase {

	public static void main(String[] args) {
		new DelayTimerEventStart().test();
	}

	@SuppressWarnings("static-access")
	public void test() {
		StatefulKnowledgeSession ksession = createKnowledgeSession("quickstarts/delayTimerEventProcess.bpmn");
		ProcessInstance process = ksession.startProcess("org.jbpm.quickstarts.delaytimereventprocess");
		try {
			Thread.currentThread().sleep(6000);
		} catch (InterruptedException e) {	
		}
		Long timerExecutionTime = (Long) ((WorkflowProcessInstance)process).getVariable("timerExecutionTime");
		System.out.println("The Process Execute Time: " + timerExecutionTime);
		ksession.dispose();
	}

}

DelayTimerEvent流程运行输出结果如下：

Before Timer - 02013-20-30 03:20:29
After  Timer - 02013-20-30 03:20:34
The Process Execute Time: 5006

如上结果流程执行的时间为5006毫秒，即是由于Timer Delay节点设定5秒钟导致。