public void addTable(NativeTable table) {
        NativeTable existing = tables.get(table.getType().getName());
        if (existing != null) {
            // TODO: Throw?
            return;
        }
        tables.put(table.getType().getName(), table);
    }
The rank settings of a field used for native rank features.

@author geirst
config-model/src/main/java/com/yahoo/schema/derived/FieldRankSettings.java