private Map<String, Integer> getFieldPositionMap() {
        if (fieldPositionMap != null) {
            return fieldPositionMap;
        }
        return updateFieldPositionbMap();
    }
Held in a set to prevent duplicates.
<p>
XMLTransient to force JAXB to use the setter
stroom-core-shared/src/main/java/stroom/statistics/impl/sql/shared/StatisticsDataSourceData.java