public RequirementsBuilder addRequireProperty(String name,RequirementsBuilder builder){
  addProperty(name,builder);
  requiredProperties.add(name);
  return this;
}

public RequirementsBuilder addRequireProperty ( String name , RequirementsBuilder builder ) { addProperty ( name , builder ) ; requiredProperties . add ( name ) ; return this ; }
add a required property of type object .
