Quartz Scheduler Listener Example

INTRODUCTION

Quartz Scheduler

• It is a library supports scheduling automated Jobs to run in Java applications
• Support for a simple standalone Java application to large scale enterprise applications.
• Jobs scheduling configuration can be done through XML Configuration or through the Java program itself.
• It is free & an open source library.

This post will explain the implementation of Quartz Scheduler Listener. Listener helps to monitor the various jobs running through the Quartz Scheduler.

SOFTWARES & TOOLS

1. Eclipse (Mars2)
2. Quartz Library.

COMPONENTS

1. Scheduler - will pick the job and start the process.
2. Job - defined with what should be executed.
3. Listener - will monitor the job.

EXAMPLE

First, Create a Job (MyJob.java)

import org.quartz.Job; import org.quartz.JobDataMap; import org.quartz.JobExecutionContext; import org.quartz.JobExecutionException; public class MyJob implements Job {  @Override  public void execute(JobExecutionContext jobExecutionContext) throws JobExecutionException {    // Write/call your actual business functions.    for (int i = 0; i <= 1000; i++) {      // just to show some delay for job.    }    System.out.println("****My Details*******");    JobDataMap jobDetails = jobExecutionContext.getJobDetail().getJobDataMap();    System.out.println("First Name: " + jobDetails.getString("FirstName"));    System.out.println("Last Name: " + jobDetails.getString("LastName"));    System.out.println("City Name: " + jobDetails.getString("City"));  } }

Create a Job Constants (MyJobConstants.java)

public interface MyJobConstants {  int JOB_REPEAT_COUNT = 3;  int JOB_REPEAT_INTERVAL = 2; }

Now, Create a Scheduler(MyScheduler.java)

import org.quartz.JobBuilder; import org.quartz.JobDetail; import org.quartz.JobKey; import org.quartz.Scheduler; import org.quartz.SimpleScheduleBuilder; import org.quartz.Trigger; import org.quartz.TriggerBuilder; import org.quartz.TriggerKey; import org.quartz.impl.StdSchedulerFactory; public class MyScheduler {  // Set Job details  public void scheduleJob() throws Exception {    JobKey jobKey = new JobKey("RanjithJob", "RanjithGroup");    JobDetail jobDetail = JobBuilder.newJob(MyJob.class).withIdentity(jobKey).build();    /**     * Set required values to the JobDetail object, so that it can be retrieved     * when executing the job.     */    jobDetail.getJobDataMap().put("FirstName", "Ranjith");    jobDetail.getJobDataMap().put("LastName", "Sekar");    jobDetail.getJobDataMap().put("City", "Chennai");        // Setting the start time of the job.    MyJobListener.jobStartTime = System.currentTimeMillis();    // Trigger the Job    triggerJob(jobDetail);  }  // Trigger the job  private void triggerJob(JobDetail jobDetail) throws Exception {    TriggerKey triggerKey = new TriggerKey("MyTriggerKey", "MyTriggerGroup"        + System.currentTimeMillis());    /**     * Create Trigger and mention schedule details like: when it should trigger     * and how many times it should execute     */    Trigger trigger = TriggerBuilder        .newTrigger()        .withIdentity(triggerKey)        .withSchedule(            SimpleScheduleBuilder.repeatSecondlyForTotalCount(MyJobConstants.JOB_REPEAT_COUNT,                MyJobConstants.JOB_REPEAT_INTERVAL)).build();    // Create Scheduler    Scheduler scheduler = new StdSchedulerFactory().getScheduler();    scheduler.getListenerManager().addJobListener(new MyJobListener());    scheduler.start();    scheduler.scheduleJob(jobDetail, trigger);  } }

Create a Listener (MyJobListener.java)

import org.quartz.JobExecutionContext; import org.quartz.JobExecutionException; import org.quartz.JobListener; import org.quartz.SchedulerException; public class MyJobListener implements JobListener {  static int completedJobCount;  public static long jobStartTime;  @Override  public String getName() {    // define your own job name.    return "MYJOB";  }  @Override  public void jobExecutionVetoed(JobExecutionContext jobExecutionContext) {    // Not sure user of this method.    System.out.println("Entering - jobExecutionVetoed()");  }  @Override  public void jobToBeExecuted(JobExecutionContext jobExecutionContext) {    // Entry point for every Job    System.out.println("\nEntering - jobToBeExecuted()");    System.out.println("Job Name: " + jobExecutionContext.getJobDetail().getKey().getName());    System.out.println("Exiting - jobToBeExecuted()");  }  @Override  public void jobWasExecuted(JobExecutionContext jobExecutionContext, JobExecutionException jobExecutionException) {    // Exit point for every job    System.out.println("Entering - jobWasExecuted()");    String jobName = jobExecutionContext.getJobDetail().getKey().getName();    System.out.println("Job Name: " + jobName);    // Stop the scheduler once its completes all the scheduled jobs.    completedJobCount = completedJobCount + 1;    System.out.println("Job: " + jobName + " completed in " + (System.currentTimeMillis() - jobStartTime)        + " milliseconds.");    if (completedJobCount == MyJobConstants.JOB_REPEAT_COUNT) {      try {        jobExecutionContext.getScheduler().shutdown();      } catch (SchedulerException e) {        // TODO Auto-generated catch block        e.printStackTrace();      }    }    System.out.println("Exiting - jobWasExecuted()");  } }

Finally, Create a Client (TestMyJob.java) to test the Quartz Scheduler.

public class TestMyJob {  public static void main(String[] args) throws Exception {    MyScheduler myScheduler = new MyScheduler();    myScheduler.scheduleJob();  } }

OUTPUT

Entering - jobToBeExecuted() Job Name: RanjithJob Exiting - jobToBeExecuted() ****My Details******* First Name: Ranjith Last Name: Sekar City Name: Chennai Entering - jobWasExecuted() Job Name: RanjithJob Job: RanjithJob completed in 113 milliseconds. Exiting - jobWasExecuted() Entering - jobToBeExecuted() Job Name: RanjithJob Exiting - jobToBeExecuted() ****My Details******* First Name: Ranjith Last Name: Sekar City Name: Chennai Entering - jobWasExecuted() Job Name: RanjithJob Job: RanjithJob completed in 2005 milliseconds. Exiting - jobWasExecuted() Entering - jobToBeExecuted() Job Name: RanjithJob Exiting - jobToBeExecuted() ****My Details******* First Name: Ranjith Last Name: Sekar City Name: Chennai Entering - jobWasExecuted() Job Name: RanjithJob Job: RanjithJob completed in 4004 milliseconds. Exiting - jobWasExecuted()