Before you can use the scheduler, it needs to be instantiated (who’d have guessed?). To do this, you use a SchedulerFactory. Some users of Quartz may keep an instance of a factory serialized in a JNDI store, others may find it just as easy (or easier) to instantiate and use a factory instance directly (such as in the example below).
Once a scheduler is instantiated, it can be started, placed in stand-by mode, and shutdown. Note that once a scheduler is shutdown, it cannot be restarted without being re-instantiated. Triggers do not fire (jobs do not execute) until the scheduler has been started, nor while it is in the paused state.
Here’s a quick snippet of code, that instantiates and starts a scheduler, and schedules a job for execution:
SchedulerFactory schedFact = new org.quartz.impl.StdSchedulerFactory(); Scheduler sched = schedFact.getScheduler(); sched.start(); JobDetail jobDetail = new JobDetail("myJob", null, DumbJob.class); Trigger trigger = TriggerUtils.makeHourlyTrigger(); // fire every hour trigger.setStartTime(TriggerUtils.getEvenHourDate(new Date())); // start on the next even hour trigger.setName("myTrigger"); sched.scheduleJob(jobDetail, trigger);
As you can see, working with quartz is rather simple. In Lesson 2 we’ll give a quick overview of Jobs and Triggers, so that you can more fully understand this example.