Used in combination with FedoraMigrate to idenitfy target Model Class if not obvious from Object Content Model. https://github.com/projecthydra-labs/fedora-migrate

class_finder.rb

class ClassFinder
  attr_reader :pid
  
  def initialize(pid)
    @pid = pid
  end
  
  def object
    @object ||= self.class.source_objects.select{|x| x.pid =~ /#{pid}/}.first
  end

  def self.repository_migrator
    @repository_migrator ||= FedoraMigrate::RepositoryMigrator.new
  end
  
  def self.source_objects
    @source_objects ||= repository_migrator.source_objects
  end
  
  def rels_ext
    pair = object.datastreams.find{|x| x.last.dsid === 'RELS-EXT'}
    pair.last if pair
  end
  
  def rel_ext_xml
    return unless rels_ext
    Nokogiri::XML(rels_ext.content)
  end
  
  def rdf_resource
    return unless rel_ext_xml
    rel_ext_xml.xpath("//rel:isMemberOf/@rdf:resource").select(&:present?).first
  end
  
  def rdf_resource_value
    return unless rdf_resource
    @rdf_resource_value ||= rdf_resource.value
  end
  
  def rdf_resource_name
    rdf_resource_value ? rdf_resource_value.split(':').last : pid
  end
end