code: public JSONArray construct(boolean server){
          JSONArray jobArray = new JSONArray();
          String cron = generateCron();
          if (cron == null) return null;
          jobArray.put(cron);
          if (server) {
              if (job == null) return null;
              jobArray.put(job);
          } else {
              JSONArray empty = new JSONArray();
              empty.put("");
              empty.put("");
              jobArray.put(empty);
          }
          JSONArray timer = new JSONArray();
          timer.put(ID);
          if (server) timer.put(getOnOff());
          timer.put(jobArray);
          return timer;
      }
docs: Construct the message the vacuum sends to the controlling device or the device sends to the vacuum.
  @param server True if the constructed message is in the format from vacuum to controlling device.
  @return The constructed message.