Provides an interface for a class to become a "plugin" to Quartz.
Plugins can do virtually anything you wish, though the most interesting ones will obviously interact with the scheduler in some way - either actively: by invoking actions on the scheduler, or passively: by being a JobListener, TriggerListener, and/or SchedulerListener.
If you use {@link org.quartz.impl.StdSchedulerFactory} to initialize your Scheduler, it can also create and initialize your plugins - look at the configuration docs for details.
If you need direct access your plugin, you can have it explicitly put a reference to itself in the Scheduler's SchedulerContext as part of its {@link #initialize(String,Scheduler)} method.
@author James House