class MapModelBindingHelper {

    public void initContext(MapModelRenderingContext context) {

        FormDefinition form = context.getRootForm();

        Map<String, PropertyType> modelProperties = generateModelDefinition(form,
                                                                            context);

        Map<String, Object> content = DataBinder.forMap(modelProperties).getModel();

        Map<String, Object> contextModel = context.getModel() != null ? context.getModel() : new HashMap<>();

        prepareMapContent(content,
                          form,
                          contextModel,
                          context);

        context.setModel(content);
    }

}