module SdbDal

class IndexDescription < DomainAttributeDescription
    include SdbFormatter
 attr_accessor :columns
  
    
  def initialize(name,columns)
    self.name=name
    self.columns=columns
    self.value_type =:string
    self.is_primary_key=false
  end
  
  def format_index_entry(attribute_descriptions,attribute_values)
   result=""
      columns.each do |column|
        if column.respond_to?(:transform)
          result << column.transform(attribute_values[column.source_column] )
        else
          result<<attribute_descriptions[column].format_for_sdb(attribute_values[column]).to_s
        end
        result<<"&"
      end
      result
  end
  
end
end