# File lib/active_record/validations.rb, line 621
      def validates_numericality_of(*attr_names)
        configuration = { :message => ActiveRecord::Errors.default_error_messages[:not_a_number], :on => :save,
                           :only_integer => false, :allow_nil => false }
        configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash)

        if configuration[:only_integer]
          validates_each(attr_names,configuration) do |record, attr_name,value|
            record.errors.add(attr_name, configuration[:message]) unless record.send("#{attr_name}_before_type_cast").to_s =~ /^[+-]?\d+$/
          end
        else
          validates_each(attr_names,configuration) do |record, attr_name,value|
           next if configuration[:allow_nil] and record.send("#{attr_name}_before_type_cast").nil?
            begin
              Kernel.Float(record.send("#{attr_name}_before_type_cast").to_s)
            rescue ArgumentError, TypeError
              record.errors.add(attr_name, configuration[:message])
            end
          end
        end
      end