private static Long getLongMapValue(String mapName, Map<?, ?> map, String key) {
        Number value = getMapValue(mapName, map, key, Number.class);
        Preconditions.checkArgument(value instanceof Long || value instanceof Integer,
                "Expected Long or Integer for entry '%s' in map annotation '%s', got %s.",
                key, mapName, value.getClass().getName());
        return value.longValue();
    }
The sorting specified in the YQL+ query last parsed.

@return a Sorting instance or null
container-search/src/main/java/com/yahoo/search/yql/YqlParser.java