move combined refworks/endnote exports to SolrResponse

app/controllers/bookmarks_controller.rb

@@ -39,17 +39,11 @@ def index
       additional_response_formats(format)
 
       format.endnote do 
-        # Just concatenate individual endnote exports with blank lines. Not
-        # every record can be exported as endnote -- only include those that
-        # can.
-        render :text => @document_list.collect {|d| d.export_as(:endnote) if d.export_formats.keys.include? :endnote}.join("\n"), :layout => false
+        render :text => @response.to_endnote, :layout => false
       end
 
       format.refworks_marc_txt do        
-        # Just concatenate individual refworks_marc_txt exports with blank lines. Not
-        # every record can be exported as refworks_marc_txt -- only include those that
-        # can.
-        render :text => @document_list.collect {|d| d.export_as(:refworks_marc_txt) if d.export_formats.keys.include? :refworks_marc_txt}.join("\n"), :layout => false
+        render :text => @response.to_refworks_marc_txt, :layout => false
       end
     end
   end

lib/blacklight/solr_response.rb

@@ -76,6 +76,22 @@ def grouped?
     self.has_key? "grouped"
   end
 
+  # Exports the entire list of #documents as an EndNote document;
+  # that is, the individual endnote documents separated by newlines. 
+  #
+  # Only documents that can be exported to endnote format are included. 
+  def to_endnote
+    documents.select {|d| d.export_formats.keys.include?(:endnote)}.collect {|d| d.export_as(:endnote)}.join("\n")
+  end
+
+  # Exports the entire list of #documents as "Refworks tagged MARC" format,
+  # that is individual documents separated by newlines. 
+  #
+  # Only documents that can be exported in this format are included. 
+  def to_refworks_marc_txt
+    documents.select {|d| d.export_formats.keys.include?(:refworks_marc_txt)}.collect {|d| d.export_as(:refworks_marc_txt)}.join("\n")
+  end
+
   private
 
     def force_to_utf8(value)