Quartz job scheduler

Quartz Job Scheduler
http://www.opensymphony.com/quartz/

What is Quartz?

Quartz is a full-featured, open source job scheduling system that can be integrated with, or used along side virtually any J2EE or J2SE application - from the smallest stand-alone application to the largest e-commerce system. Quartz can be used to create simple or complex schedules for executing tens, hundreds, or even tens-of-thousands of jobs; jobs whose tasks are defined as standard Java components or EJBs. The Quartz Scheduler includes many enterprise-class features, such as JTA transactions and clustering.

Quartz is freely usable, licensed under the Apache 2.0 license.

Usage

If your application has tasks that need to occur at given moments in time, or if your system has recurring maintenance jobs then Quartz may be your ideal solution.

Sample uses of job scheduling with Quartz:

• Driving Workflow: As a new order is initially placed, schedule a Job to fire in exactly 2 hours, that will check the status of that order, and trigger a warning notification if an order confirmation message has not yet been received for the order, as well as changing the order's status to 'awaiting intervention'.
• System Maintenance: Schedule a job to dump the contents of a database into an XML file every business day (all weekdays except holidays) at 11:30 PM.

Semi complete listing of Quartz features.

Using Quartz

JobDetail jobDetail = new JobDetail("myJob",               // job name
                                      sched.DEFAULT_GROUP,   // job group (you can also specify 'null' to use the default group)
                                      DumbJob.class);        // the java class to execute

Trigger trigger = TriggerUtils.makeDailyTrigger(8, 30);
trigger.setStartTime(new Date());
trigger.setName("myTrigger");

sched.scheduleJob(jobDetail, trigger);

Now consider the job class "DumbJob" defined as such:

DumbJob

public class DumbJob implements Job {

public DumbJob() {
}

public void execute(JobExecutionContext context)
throws JobExecutionException
{
System.err.println("DumbJob is executing.");
}
}

Setting Values in a JobDataMap (passing configuration/data to job)

jobDetail.getJobDataMap().put("jobSays", "Hello World!");
jobDetail.getJobDataMap().put("myFloatValue", 3.141f);
jobDetail.getJobDataMap().put("myStateData", new ArrayList());

Here's a quick example of getting data from the JobDataMap during the job's execution:

Getting Values from a JobDataMap

public class DumbJob implements Job {

public DumbJob() {
}

public void execute(JobExecutionContext context)
throws JobExecutionException
{
String instName = context.getJobDetail().getName();
String instGroup = context.getJobDetail().getGroup();

JobDataMap dataMap = context.getJobDetail().getJobDataMap();

String jobSays = dataMap.getString("jobSays");
float myFloatValue = dataMap.getFloat("myFloatValue");
ArrayList state = (ArrayList)dataMap.get("myStateData");
state.add(new Date());

System.err.println("Instance " + instName + " of DumbJob says: " + jobSays);
}
}