# File lib/sdb/right_sdb_interface.rb, line 418
    def query(domain_name, query_expression = nil, max_number_of_items = nil, next_token = nil)
      query_expression = query_expression_from_array(query_expression) if query_expression.is_a?(Array)
      @last_query_expression = query_expression
      #
      request_params = { 'DomainName'       => domain_name,
                         'QueryExpression'  => query_expression,
                         'MaxNumberOfItems' => max_number_of_items,
                         'NextToken'        => next_token }
      link   = generate_request("Query", request_params)
      result = request_info( link, QSdbQueryParser.new )
      # return result if no block given
      return result unless block_given?
      # loop if block if given
      begin
        # the block must return true if it wanna continue 
        break unless yield(result) && result[:next_token]
        # make new request
        request_params['NextToken'] = result[:next_token]
        link   = generate_request("Query", request_params)
        result = request_info( link, QSdbQueryParser.new )
      end while true
    rescue Exception
      on_exception
    end