Scheduling and thread pooling in Spring tutorial

The Spring Framework contains integration classes for scheduling support and thread pooling.

The scheduling support classes act as a wrapper for the java Quartz Scheduler

They are as follows:

org.springframework.scheduling.quartz.QuartzJobBean
org.springframework.scheduling.quartz.JobDetailBean
org.springframework.scheduling.quartz.SimpleTriggerBean
org.springframework.scheduling.quartz.CronTriggerBean
org.springframework.scheduling.quartz.SchedulerFactoryBean

Some of the thread pooling support classes are as follows:

org.springframework.scheduling.quartz.SimpleThreadPoolTaskExecutor
org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor

Please see below a simple example using Spring Framework's Quartz scheduling and threadpooling features:

UML Diagram of example using Spring's scheduling and thread pooling features

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Please see below example Code:

MonitorJob.java

import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;
import org.springframework.context.ApplicationContext;
import org.springframework.scheduling.quartz.QuartzJobBean;

public class MonitorJob extends QuartzJobBean {

   private int timeout;

   private static final String APPLICATION_CONTEXT_KEY = "applicationContext";


   public void setTimeout(int timeout){
     this.timeout = timeout;
   }

   @Override
   protected void executeInternal(JobExecutionContext context) throws JobExecutionException {
     // TODO Auto-generated method stub

     processJobs(context);
     }

   private ApplicationContext getApplicationContext(JobExecutionContext context )
throws Exception {

     ApplicationContext appCtx = null;
     appCtx = (ApplicationContext)context.getScheduler().getContext().get(APPLICATION_CONTEXT_KEY);

     if (appCtx == null) {
       throw new JobExecutionException(
"No application context available in scheduler context for key \"" + APPLICATION_CONTEXT_KEY + "\"");
     }
     return appCtx;
   }

   private void processJobs(JobExecutionContext context) {

     MonitorProcessDelegate procDelegate = null;

     try {

         ApplicationContext ctx = getApplicationContext(context);
         procDelegate = (MonitorProcessDelegate)ctx.getBean("MonitorProcessDelegate");

     }catch (Exception e) { e.printStackTrace();}

     System.out.println("Running job monitor");

     procDelegate.ListBusinessExceptionCases();
     procDelegate.ListActiveProcesses();

     }
   }

MonitorProcessDelegate.java

import org.springframework.core.task.TaskExecutor;

public class MonitorProcessDelegate {

   private class ActiveProcesses implements Runnable {

   // code for identifying and listing active processes

     public void run() {
       .....
     }
   }

   private class BusinessExceptionCasesBacklog implements Runnable {

   // code for identifying and listing business exception cases

     public void run() {
       .....
     }
   }

   private TaskExecutor taskExecutor;

   public MonitorProcessDelegate;(TaskExecutor taskExecutor) {

     this.taskExecutor = taskExecutor;
   }

   public void ListActiveProcesses() {

     taskExecutor.execute(new ActiveProcesses());

   }

public void ListBusinessExceptionCases() {

     taskExecutor.execute(new BusinessExceptionCasesBacklog());

   }
}

Spring's Dispatcher servlet's configuration file settings

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