public static String listMessageCounterHistory(final MessageCounter counter) throws Exception { List<DayCounter> history = counter.getHistory(); DayCounterInfo[] infos = new DayCounterInfo[history.size()]; for (int i = 0; i < infos.length; i++) { DayCounter dayCounter = history.get(i); long[] counters = dayCounter.getCounters(); GregorianCalendar date = dayCounter.getDate(); DateFormat dateFormat = DateFormat.getDateInstance(DateFormat.SHORT); String strData = dateFormat.format(date.getTime()); infos[i] = new DayCounterInfo(strData, counters); } return DayCounterInfo.toJSON(infos); }