[Java] Quartz Quick Start (Job & Trigger)

Tutorial Lesson 2 quote:

Jobs can be created and stored in the job scheduler independent of a trigger, and many triggers can be associated with the same job. Another benefit of this loose-coupling is the ability to configure jobs that remain in the scheduler after their associated triggers have expired, so that that it can be rescheduled later, without having to re-define it. It also allows you to modify or replace a trigger without having to re-define its associated job.

A good design principle is to use loose-coupling between the objects.

We continue this application.

1. New a Java class: HelloJob.java
   

   package demo;
   
   import org.quartz.Job;
   import org.quartz.JobExecutionContext;
   import org.quartz.JobExecutionException;
   
   public class HelloJob implements Job {
       public void execute(JobExecutionContext context) throws JobExecutionException {
           System.err.println("Hello! HelloJob is executing.");
       }
   }
   

2. Modify QuartzTest.java:
   

   package demo;
   
   import org.quartz.JobDetail;
   import org.quartz.Scheduler;
   import org.quartz.SchedulerException;
   import org.quartz.Trigger;
   import org.quartz.impl.StdSchedulerFactory;
   
   import static org.quartz.TriggerBuilder.*;
   import static org.quartz.JobBuilder.*;
   import static org.quartz.SimpleScheduleBuilder.*;
   
   public class QuartzTest {
       public static void run() {
           try {        
               Scheduler scheduler = StdSchedulerFactory.getDefaultScheduler();
               scheduler.start();
   
               JobDetail job = newJob(HelloJob.class)
                       .withIdentity("job1", "group1")
                       .build();
   
               Trigger trigger = newTrigger()
                       .withIdentity("trigger1", "group1")
                       .startNow()
                       .withSchedule(simpleSchedule()
                               .withIntervalInSeconds(40)
                               .repeatForever())
                       .build();
   
               scheduler.scheduleJob(job, trigger);
   
               Thread.sleep(60000);
               
               scheduler.shutdown();
           } catch (SchedulerException e) {
               e.printStackTrace();
           } catch (InterruptedException e) {
               e.printStackTrace();
           }
       }
   }
   

3. Run:
   

   29 [main] INFO org.quartz.impl.StdSchedulerFactory - Using default implementation for ThreadExecutor
   32 [main] INFO org.quartz.simpl.SimpleThreadPool - Job execution threads will use class loader of thread: main
   49 [main] INFO org.quartz.core.SchedulerSignalerImpl - Initialized Scheduler Signaller of type: class org.quartz.core.SchedulerSignalerImpl
   50 [main] INFO org.quartz.core.QuartzScheduler - Quartz Scheduler v.2.0.2 created.
   51 [main] INFO org.quartz.simpl.RAMJobStore - RAMJobStore initialized.
   52 [main] INFO org.quartz.core.QuartzScheduler - Scheduler meta-data: Quartz Scheduler (v2.0.2) 'DefaultQuartzScheduler' with instanceId 'NON_CLUSTERED'
     Scheduler class: 'org.quartz.core.QuartzScheduler' - running locally.
     NOT STARTED.
     Currently in standby mode.
     Number of jobs executed: 0
     Using thread pool 'org.quartz.simpl.SimpleThreadPool' - with 10 threads.
     Using job-store 'org.quartz.simpl.RAMJobStore' - which does not support persistence. and is not clustered.
   
   52 [main] INFO org.quartz.impl.StdSchedulerFactory - Quartz scheduler 'DefaultQuartzScheduler' initialized from default resource file in Quartz package: 'quartz.properties'
   52 [main] INFO org.quartz.impl.StdSchedulerFactory - Quartz scheduler version: 2.0.2
   52 [main] INFO org.quartz.core.QuartzScheduler - Scheduler DefaultQuartzScheduler_$_NON_CLUSTERED started.
   Hello! HelloJob is executing.
   29106 [Timer-0] INFO org.quartz.utils.UpdateChecker - New Quartz update(s) found: 2.1.0 [http://www.terracotta.org/kit/reflector?kitID=default&pageID=QuartzChangeLog]
   Hello! HelloJob is executing.
   60074 [main] INFO org.quartz.core.QuartzScheduler - Scheduler DefaultQuartzScheduler_$_NON_CLUSTERED shutting down.
   60074 [main] INFO org.quartz.core.QuartzScheduler - Scheduler DefaultQuartzScheduler_$_NON_CLUSTERED paused.
   60074 [main] INFO org.quartz.core.QuartzScheduler - Scheduler DefaultQuartzScheduler_$_NON_CLUSTERED shutdown complete.
   

   You should see the greeting 'Hello! HelloJob is executing.' twice.
   

Enjoy!