MADS linkage

Gemfile

source 'https://rubygems.org'

gem 'active-fedora', github: 'projecthydra/active_fedora', branch: 'master'
gem 'linkeddata'

mads.rb

#!/usr/bin/env ruby

# mads demo using AF 7.0 rc3

require 'active-fedora'
require 'linkeddata'

# vocabulary
class MADS < RDF::Vocabulary("http://www.loc.gov/mads/rdf/v1#")
  # MADS classes
  property :ComplexSubject
  property :Topic
  property :MADSScheme

  # MADS properties
  property :isMemberOfMADSScheme

  # elementList and elementList values
  property :componentList
  property :elementList
  property :elementValue
  property :TopicElement
end

# scheme
class MadsScheme < ActiveFedora::Rdf::Resource
  configure type: MADS.MADSScheme
  configure base_uri: "http://library.ucsd.edu/ark:/20775/"
  property :name, predicate: RDF::RDFS.label
end

# topic
class MadsTopic < ActiveFedora::Rdf::Resource
  configure type: MADS.Topic
  property :name, predicate: MADS.authoritativeLabel
  property :scheme, predicate: MADS.isMemberOfMADSScheme, class_name: "MadsScheme"
  property :elementList, predicate: MADS.elementList, class_name: "MadsElementList"
  accepts_nested_attributes_for :scheme, :elementList
end
class MadsElementList < ActiveFedora::Rdf::List
  configure type: MADS.elementList
  property :topicElement, predicate: MADS.TopicElement, class_name: "MadsTopicElement"
  accepts_nested_attributes_for :topicElement
end
class MadsTopicElement < ActiveFedora::Rdf::Resource
  property :elementValue, predicate: MADS.elementValue
  configure :type => MADS.TopicElement
end

# complex subject
class MadsComplexSubjectDatastream < ActiveFedora::RdfxmlRDFDatastream
  resource_class.configure type: MADS.ComplexSubject
  resource_class.configure base_uri: "http://library.ucsd.edu/ark:/20775/"
  property :name, predicate: MADS.authoritativeLabel
  property :scheme, predicate: MADS.isMemberOfMADSScheme
  property :componentList, predicate: MADS.componentList, class_name: "MadsComponentList"
  accepts_nested_attributes_for :componentList, :topic, :scheme
  delegate :topic_attributes=, to: :componentList
  alias_method :topic, :componentList
end
class MadsComplexSubject < ActiveFedora::Base
  has_metadata :name => "damsMetadata", :type => MadsComplexSubjectDatastream
  has_attributes :name, :componentList, :scheme, datastream: "damsMetadata", multiple: false
  delegate :componentList_attributes=, to: :damsMetadata
  delegate :topic_attributes=, to: :damsMetadata
  delegate :scheme_attributes=, to: :damsMetadata
end
class MadsComponentList < ActiveFedora::Rdf::List
  configure type: MADS.componentList
  property :topic, predicate: MADS.Topic, class_name: "MadsTopic"
  accepts_nested_attributes_for :topic
end

# complex subject
complex_subject_params = {
  name: 'Civilization, Modern',
  scheme_attributes: [{
    id: 'http://library.ucsd.edu/ark:/20775/bb3333333x',
    name: 'Library of Congress Subject Headings'
  }],
  componentList_attributes: [{
    topic_attributes: [{
        id: 'http://library.ucsd.edu/ark:20775/bb2222222x',
        name: 'Civilization, Modern',
        elementList_attributes: [{
          topicElement_attributes: [{elementValue:"Civilization, Modern"}]
        }],
        scheme_attributes: [{
          id: 'http://library.ucsd.edu/ark:20775/bb4444444x',
          name: 'Library of Congress Subject Headings'
        }]
      }
    ]
  }]
}
sub = MadsComplexSubject.new(pid:'bb1111111x')
sub.attributes = complex_subject_params
puts sub.damsMetadata.content

output.rdf.xml

<?xml version='1.0' encoding='utf-8' ?>
<rdf:RDF xmlns:ns0='http://www.loc.gov/mads/rdf/v1#'
         xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'
         xmlns:rdfs='http://www.w3.org/2000/01/rdf-schema#'>
  <ns0:MADSScheme rdf:about='http://library.ucsd.edu/ark:20775/bb4444444x'>
    <rdfs:label>Library of Congress Subject Headings</rdfs:label>
  </ns0:MADSScheme>
  <ns0:ComplexSubject rdf:about='http://library.ucsd.edu/ark:/20775/bb1111111x'>
    <ns0:authoritativeLabel>Civilization, Modern</ns0:authoritativeLabel>
    <ns0:componentList rdf:parseType='Collection'>
      <ns0:Topic rdf:nodeID='g70290732937020'>
        <ns0:authoritativeLabel>Civilization, Modern</ns0:authoritativeLabel>
        <ns0:elementList rdf:parseType='Collection'>
          <ns0:TopicElement rdf:nodeID='g70290732966240'>
            <ns0:elementValue>Civilization, Modern</ns0:elementValue>
          </ns0:TopicElement>
        </ns0:elementList>
        <ns0:isMemberOfMADSScheme rdf:resource='http://library.ucsd.edu/ark:20775/bb4444444x' />
      </ns0:Topic>
    </ns0:componentList>
    <ns0:isMemberOfMADSScheme rdf:resource='http://library.ucsd.edu/ark:/20775/bb3333333x' />
  </ns0:ComplexSubject>
</rdf:RDF>

There's now a PR in for error messages in #attributes=. With that, your gist should fail at L97 with ArgumentError: No association found for name name'. Has it been defined yet?`.

Hopefully this resolves both issues.