@Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((fields == null)
                ? 0
                : fields.hashCode());
        return result;
    }
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