private static TimeZone getTimeZone(String name) {
        ZoneCache cache = zoneCache.get();
        if (cache == null) {
            cache = new ZoneCache();
            zoneCache.set(cache);
        }
        TimeZone timeZone = cache.get(name);
        if (timeZone == null) {
            timeZone = TimeZone.getTimeZone(name);
            cache.put(name, timeZone);
        }
        return timeZone;
    }
This searcher is responsible for turning the "select" parameter into a corresponding {@link GroupingRequest}. It will
also parse any "timezone" parameter as the timezone for time expressions such as {@link
com.yahoo.search.grouping.request.DayOfMonthFunction} and {@link com.yahoo.search.grouping.request.HourOfDayFunction}.

@author Simon Thoresen Hult
container-search/src/main/java/com/yahoo/search/grouping/GroupingQueryParser.java