class ActiveFedora::QualifiedDublinCoreDatastream

Fields can still be overridden if more specificity is desired (see ActiveFedora::Datastream#fields method).
Fedora Dublin Core XML datastreams structure.
This implementation features customized xml generators and deserialization routines to handle the
The implementation of this class defines the terms from the Qualified Dublin Core specification.
This class represents a Qualified Dublin Core Datastream. A special case of ActiveFedora::MetdataDatastream

def self.from_xml(tmpl, el) # :nodoc:

:nodoc: 
def self.from_xml(tmpl, el) # :nodoc:
  tmpl.fields.each do |z|
    fname = z.first
    fspec = z.last
    node = "dcterms:#{fspec[:xml_node] ? fspec[:xml_node] : fname}"
    attr_modifier= "[@xsi:type='#{fspec[:encoding]}']" if fspec[:encoding]
    query = "./foxml:datastreamVersion[last()]/foxml:xmlContent/dc/#{node}#{attr_modifier}"
    el.elements.each(query) do |f|
       tmpl.send("#{fname}_append", f.text)
     end
  end
  tmpl.instance_variable_set(:@dirty, false)
  tmpl
end

def initialize(attrs=nil)

when this method returns. Each term is marked as a multivalue string.
Constructor. this class will call self.field for each DCTERM. In short, all DCTERMS fields will already exist 
def initialize(attrs=nil)
  super
  DCTERMS.each do |el|
    field el, :string, :multiple=>true
  end
  self
end

def set_blob_for_save # :nodoc:

:nodoc: 
def set_blob_for_save # :nodoc:
  self.blob = self.to_dc_xml
end

def to_dc_xml

Render self as a Fedora DC xml document. 
def to_dc_xml
  #TODO: pull the modifiers up into MDDS
  xml = REXML::Document.new("<dc xmlns:dcterms='http://purl.org/dc/terms/' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'/>")
  fields.each do |field_name,field_info|
    el = REXML::Element.new("dcterms:#{field_name.to_s}")
    if field_info.class == Hash
      field_info.each do |k, v|
        case k
        when :element_attrs
         v.each{|k,v| el.add_attribute(k.to_s, v.to_s)}
        when :values, :type
          # do nothing to the :values array
        when :xml_node
          el.name = "dcterms:#{v}"
        when :encoding, :encoding_scheme
          el.add_attribute("xsi:type", v)
        when :multiple
          next
        else
          el.add_attribute(k.to_s, v)
        end
      end
      field_info = field_info[:values]
    end
    field_info.each do |val|
      el = el.clone
      el.text = val.to_s
      xml.root.elements.add(el)
    end
  end
  return xml.to_s
end