# File lib/active_record/validations.rb, line 840
      def validates_numericality_of(*attr_names)
        configuration = { :on => :save, :only_integer => false, :allow_nil => false }
        configuration.update(attr_names.extract_options!)


        numericality_options = ALL_NUMERICALITY_CHECKS.keys & configuration.keys

        (numericality_options - [ :odd, :even ]).each do |option|
          raise ArgumentError, ":#{option} must be a number" unless configuration[option].is_a?(Numeric)
        end

        validates_each(attr_names,configuration) do |record, attr_name, value|
          raw_value = record.send("#{attr_name}_before_type_cast") || value

          next if configuration[:allow_nil] and raw_value.nil?

          if configuration[:only_integer]
            unless raw_value.to_s =~ /\A[+-]?\d+\Z/
              record.errors.add(attr_name, configuration[:message] || ActiveRecord::Errors.default_error_messages[:not_a_number])
              next
            end
            raw_value = raw_value.to_i
          else
           begin
              raw_value = Kernel.Float(raw_value)
            rescue ArgumentError, TypeError
              record.errors.add(attr_name, configuration[:message] || ActiveRecord::Errors.default_error_messages[:not_a_number])
              next
            end
          end

          numericality_options.each do |option|
            case option
              when :odd, :even
                record.errors.add(attr_name, configuration[:message] || ActiveRecord::Errors.default_error_messages[option]) unless raw_value.to_i.method(ALL_NUMERICALITY_CHECKS[option])[]
              else
                message = configuration[:message] || ActiveRecord::Errors.default_error_messages[option]
                message = message % configuration[option] if configuration[option]
                record.errors.add(attr_name, message) unless raw_value.method(ALL_NUMERICALITY_CHECKS[option])[configuration[option]]
            end
          end
        end
      end