Module: ClassyEnum::ActiveRecord

Defined in:
lib/classy_enum/active_record.rb

Instance Method Summary collapse

Instance Method Details

#classy_enum_attr(attribute, options = {}) ⇒ Object

Class macro used to associate an enum with an attribute on an ActiveRecord model. This method is automatically added to all ActiveRecord models when the classy_enum gem is installed. Accepts an argument for the enum class to be associated with the model. ActiveRecord validation is automatically added to ensure that a value is one of its pre-defined enum members.

Example

# Associate an enum Priority with Alarm model's priority attribute
class Alarm < ActiveRecord::Base
  classy_enum_attr :priority
end

# Associate an enum Priority with Alarm model's alarm_priority attribute
classy_enum_attr :alarm_priority, :enum => 'Priority'

# Allow enum value to be nil
classy_enum_attr :priority, :allow_nil => true

# Allow enum value to be blank
classy_enum_attr :priority, :allow_blank => true

# Specifying a default enum value
classy_enum_attr :priority, :default => 'low'



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# File 'lib/classy_enum/active_record.rb', line 55

def classy_enum_attr(attribute, options={})
  enum              = (options[:enum] || options[:class_name] || attribute).to_s.camelize.constantize
  allow_blank       = options[:allow_blank] || false
  allow_nil         = options[:allow_nil] || false
  serialize_as_json = options[:serialize_as_json] || false
  default           = ClassyEnum._normalize_default(options[:default], enum)

  # Add ActiveRecord validation to ensure it won't be saved unless it's an option
  validates_inclusion_of attribute,
    :in          => enum,
    :allow_blank => allow_blank,
    :allow_nil   => allow_nil

  # Define getter method that returns a ClassyEnum instance
  define_method attribute do
    enum.build(read_attribute(attribute),
               :owner             => self,
               :serialize_as_json => serialize_as_json,
               :allow_blank       => (allow_blank || allow_nil)
              )
  end

  # Define setter method that accepts string, symbol, instance or class for member
  define_method "#{attribute}=" do |value|
    value = ClassyEnum._normalize_value(value, default, (allow_nil || allow_blank))
    super(value)
  end

  # Initialize the object with the default value if it is present
  # because this will let you store the default value in the
  # database and make it searchable.
  if default.present?
    after_initialize do
      value = read_attribute(attribute)

      if (value.blank? && !(allow_blank || allow_nil)) || (value.nil? && !allow_nil)
        send("#{attribute}=", default)
      end
    end
  end

end