code: public ICommonsSet <TriggerKey> getTriggerKeys (final GroupMatcher <TriggerKey> matcher) throws SchedulerException
    {
      validateState ();
  
      return m_aResources.getJobStore ().getTriggerKeys (_getOrDefault (matcher));
    }
docs: <p>
  Get the names of all the <code>{@link com.helger.quartz.ITrigger}s</code>
  in the matching groups.
  </p>