class ActionView::Helpers::AtomFeedHelper::AtomFeedBuilder

def entry(record, options = {})

* :id: The ID for this entry. Defaults to "tag:#{@view.request.host},#{@feed_options[:schema_date]}:#{record.class}/#{record.id}"
* :url: The URL for this entry. Defaults to the polymorphic_url for the record.
* :updated: Time of update. Defaults to the updated_at attribute on the record if one such exists.
* :published: Time first published. Defaults to the created_at attribute on the record if one such exists.

Options:

Creates an entry tag for a specific record and prefills the id using class and id. 
def entry(record, options = {})
  @xml.entry do
    @xml.id(options[:id] || "tag:#{@view.request.host},#{@feed_options[:schema_date]}:#{record.class}/#{record.id}")
    if options[:published] || (record.respond_to?(:created_at) && record.created_at)
      @xml.published((options[:published] || record.created_at).xmlschema)
    end
    if options[:updated] || (record.respond_to?(:updated_at) && record.updated_at)
      @xml.updated((options[:updated] || record.updated_at).xmlschema)
    end
    @xml.link(:rel => 'alternate', :type => 'text/html', :href => options[:url] || @view.polymorphic_url(record))
    yield AtomBuilder.new(@xml)
  end
end

def initialize(xml, view, feed_options = {}) 

def initialize(xml, view, feed_options = {})
  @xml, @view, @feed_options = xml, view, feed_options
end

def updated(date_or_time = nil)

Accepts a Date or Time object and inserts it in the proper format. If nil is passed, current time in UTC is used. 
def updated(date_or_time = nil)
  @xml.updated((date_or_time || Time.now.utc).xmlschema)
end