gistfile1.txt

// BeancounterJob.java
package beancounter.jobs;

import org.jruby.Ruby;
import org.quartz.Job;
import org.quartz.JobDataMap;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;

public class BeancounterJob implements Job {
    public static final String RUNTIME_KEY = "beancounter.ruby.runtime";
    public static final String SCRIPT_KEY = "beancounter.ruby.job.script";

    public void execute(JobExecutionContext jobContext)
            throws JobExecutionException {
        JobDataMap dataMap = jobContext.getJobDetail().getJobDataMap();
        String script = dataMap.getString(SCRIPT_KEY);
        Ruby runtime = (Ruby)dataMap.get(RUNTIME_KEY);

        if (runtime == null) {
            throw new JobExecutionException(
                "There was no Ruby runtime in the job's data map under the key " + RUNTIME_KEY);
        }

        if (script == null || script.equals("")) {
            throw new JobExecutionException(
                "There was no Ruby script in the job's data map under the key " + SCRIPT_KEY);
        }

        runtime.evalScriptlet(script);
    }
}

-----------------------------------------------

# scheduler.rb
begin
  require 'quartz-1.6.0'
rescue LoadError
  # Let's hope the jar has already been loaded
end

module Beancounter

  def schedule_job(name, opts={})
    Beancounter::Scheduler.schedule_job(name, opts)
  end
  module_function :schedule_job

  class Scheduler
    include_class "org.quartz.JobDetail"
    include_class "org.quartz.CronTrigger"
    include_class "beancounter.jobs.BeancounterJob"
    
    FACTORY_KEY = org.quartz.ee.servlet.QuartzInitializerListener::QUARTZ_FACTORY_KEY
    JOB_GROUP = 'BeancounterJobsGroup'

    class << self
      def schedule_job(job_name, opts={})
        if scheduler
          Merb.logger.info "Scheduling #{job_name}"
          job_detail = make_job_detail(job_name, opts[:script])
          trigger = make_trigger(opts[:cron], job_detail.getName)
          scheduler.scheduleJob(job_detail, trigger)
        else
          Merb.logger.info "There's no scheduler available, so we can't schedule any jobs."
        end
      end
      
      def factory
        @factory ||= 
          defined?($servlet_context) ? $servlet_context.getAttribute(FACTORY_KEY) : nil
      end
    
      def scheduler
        @scheduler ||= factory.nil? ? nil : factory.getScheduler
      end
      
      def make_trigger(cron_expr, job_name, group=JOB_GROUP)
        name = "#{job_name}Trigger"
        Merb.logger.info "Creating a new CronTrigger named #{name} with cron expression '#{cron_expr}'"
        CronTrigger.new(name, group, job_name, group, cron_expr)
      end
      
      def make_job_detail(name, script)
        Merb.logger.info "Creating a new JobDetail named #{name} that will run this code: '#{script}'"
        detail = JobDetail.new(name, JOB_GROUP, BeancounterJob.java_class)
        detail.getJobDataMap.put(BeancounterJob::RUNTIME_KEY, JRuby.runtime)
        detail.getJobDataMap.put(BeancounterJob::SCRIPT_KEY, script)
        detail
      end
    end

  end
end

-----------------------------------------------
Then, in my init file, I use something like:

  Beancounter.schedule_job 'LedgerFileImport',
    :script => 'Beancounter::LedgerFileImporter.new.download_and_import',
    :cron => '0 0 0 * * ?'

to schedule a job.