Module: Measured::Rails::ActiveRecord::ClassMethods

Defined in:
lib/measured/rails/active_record.rb

Instance Method Summary collapse

Instance Method Details

#measured(measured_class, *fields) ⇒ Object

Raises:



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# File 'lib/measured/rails/active_record.rb', line 5

def measured(measured_class, *fields)
  options = fields.extract_options!
  options = {}.merge(options)

  measured_class = measured_class.constantize if measured_class.is_a?(String)

  raise Measured::Rails::Error, "Expecting #{ measured_class } to be a subclass of Measured::Measurable" if !measured_class.is_a?(Class) || !measured_class.ancestors.include?(Measured::Measurable)

  options[:class] = measured_class

  fields.map(&:to_sym).each do |field|
    raise Measured::Rails::Error, "The field #{ field } has already been measured" if measured_fields.keys.include?(field)
    measured_fields[field] = options

    # Reader to retrieve measured object
    define_method(field) do
      value = public_send("#{ field }_value")
      unit = public_send("#{ field }_unit")

      return nil unless value && unit

      instance = instance_variable_get("@measured_#{ field }")
      new_instance = begin
        measured_class.new(value, unit)
      rescue Measured::UnitError
        nil
      end

      if instance && instance == new_instance
        instance
      else
        instance_variable_set("@measured_#{ field }", new_instance)
      end
    end

    # Writer to assign measured object
    define_method("#{ field }=") do |incoming|
      if incoming.is_a?(measured_class)
        instance_variable_set("@measured_#{ field }", incoming)
        value_field_name = "#{ field }_value"
        public_send("#{ value_field_name }=", incoming.value.round(self.column_for_attribute(value_field_name).precision))
        public_send("#{ field }_unit=", incoming.unit)
      else
        instance_variable_set("@measured_#{ field }", nil)
        public_send("#{ field }_value=", nil)
        public_send("#{ field }_unit=", nil)
      end
    end

    # Writer to override unit assignment
    define_method("#{ field }_unit=") do |incoming|
      incoming = measured_class.conversion.to_unit_name(incoming) if measured_class.valid_unit?(incoming)
      write_attribute("#{ field }_unit", incoming)
    end

  end
end

#measured_fields ⇒ Object 



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# File 'lib/measured/rails/active_record.rb', line 63

def measured_fields
  @measured_fields ||= {}
end