class Protobuf::Field::BaseField

def initialized?(message_instance)
  value = message_instance.__send__(getter_method_name)
  case @rule
  when :required then
    ! value.nil? && (! kind_of?(MessageField) || value.initialized?)
  when :repeated then
    value.all? {|msg| ! kind_of?(MessageField) || msg.initialized? }
  when :optional then
    value.nil? || ! kind_of?(MessageField) || value.initialized?
  end
end