private static void exportSetFieldValue(Writer out, int ind) throws IOException {
        out.write(ind(ind)+"@Override public com.yahoo.document.datatypes.FieldValue setFieldValue(com.yahoo.document.Field field, com.yahoo.document.datatypes.FieldValue value) {\n");
        out.write(ind(ind+1)+"com.yahoo.document.ExtendedField ef = ensureExtended(field);\n");
        out.write(ind(ind+1)+"return (ef != null) ? ef.setFieldValue(this, value) : super.setFieldValue(field, value);\n");
        out.write(ind(ind)+"}\n\n");
    }
Exports the necessary overridden methods from Document/StructuredFieldValue
vespa-documentgen-plugin/src/main/java/com/yahoo/vespa/DocumentGenMojo.java