public static boolean rescheduleExpiration(Cache cache, Object key, int newExpTime) {
    ScheduledFuture f = expiryFutures.get(key);
    if (f != null) {
      if (f.cancel(false)) {
        ScheduledFuture f2 =
            expiryExecutor.schedule(new ExpiryTask(cache, key), newExpTime, TimeUnit.SECONDS);
        expiryFutures.put(key, f2);
        return true;
      }
    }
    return false;
  }
reschedules expiration for a key only if one was previously scheduled

@return true if successfully rescheduled, false otherwise
geode-memcached/src/main/java/org/apache/geode/internal/memcached/commands/StorageCommand.java