问如何使用关闭钩子优雅地停止Guava AbstractScheduledService？

EN

class MyService extends AbstractScheduledService {

   // KEEP THIS VAR IN MIND W.R.T the SHUTDOWN_HOOK BELOW
   public static volatile boolean keepRunning = true;

   protected void startUp() throws Exception {
     // startup stuff
   }

   protected void runOneIteration() throws Exception {
     // main logic stuff
   }

   protected void shutDown() throws Exception {
     // shutdown stuff
   }

   protected Scheduler scheduler() {
     return Scheduler.newFixedRateSchedule(0, 1, TimeUnit.SECONDS);
   }
 }

final Thread mainThread = Thread.currentThread();
        LOGGER.debug("Adding the shutdown hook");
        Runtime.getRuntime().addShutdownHook(new Thread() {
            @Override
            public void run() {
                keepRunning = false;
                LOGGER.debug("The shutdown hook was engaged. Setting keepRunnning to false.");
                try {
                     // Is this appropriate?
                     mainThread.join();
                } catch (InterruptedException e) {
                    // handle exception here
                }
            }
        });