private static void exportHashCode(Collection<Field> fieldSet, Writer out, int ind, String hcBase) throws IOException {
        out.write(ind(ind)+"@Override public int hashCode() {\n");
        out.write(ind(ind+1)+"int hc = "+hcBase+";\n");
        for (Field field: fieldSet) {
            out.write(ind(ind+1)+"hc += "+getter(field.getName())+"()!=null ? "+getter(field.getName())+"().hashCode() : 0;\n");
        }
        out.write(ind(ind+1)+"return hc;\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