code: private static String readObjectValue(String ref, TypeDef source, Property property) {
          return indent(ref) + "("+property.getTypeRef().toString()+")(" + ref + " instanceof Map ? ((Map)" + ref + ").getOrDefault(\"" + getterOf(source, property).getName() + "\", " + getDefaultValue(property)+") : "+ getDefaultValue(property)+")";
      }
docs: Returns the string representation of the code that reads an object property from a reference using a getter.
  @param ref           The reference.
  @param source        The type of the reference.
  @param property      The property to read.
  @return              The code.