Module: ClassyEnum::Attributes

Defined in:
lib/classy_enum/attributes.rb

Instance Method Summary collapse

Instance Method Details

#classy_enum_attr(*args) ⇒ 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. If the enum class name is different than the field name, then an optional field name can be passed. 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
class Alarm < ActiveRecord::Base
  classy_enum_attr :alarm_priority, :enum => :priority
end



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# File 'lib/classy_enum/attributes.rb', line 21

def classy_enum_attr(*args)
  options = args.extract_options!

  attribute = args[0]

  enum = options[:enum] || attribute
  allow_blank = options[:allow_blank] || false
  allow_nil = options[:allow_nil] || false
  serialize_as_json = options[:serialize_as_json] || false

  reader_method = attribute.to_s

  if options.has_key? :suffix
    ActiveSupport::Deprecation.warn(':suffix option for classy_enum_attr is deprecated, and will be removed in ClassyEnum 3.0.', caller)
    reader_method += "_#{options[:suffix]}"
  end

  klass = enum.to_s.camelize.constantize

  valid_attributes = reader_method == attribute.to_s ? klass.all : klass.all.map(&:to_s)

  self.instance_eval do

    # Add ActiveRecord validation to ensure it won't be saved unless it's an option
    validates_inclusion_of attribute,
      :in => valid_attributes,
      :message => "must be one of #{klass.valid_options}",
      :allow_blank => allow_blank,
      :allow_nil => allow_nil

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

    # Define setter method that accepts either string or symbol for member
    define_method "#{attribute}=" do |value|
      value = value.to_s unless value.nil?
      super(value)
    end

    # Store the enum options so it can be later retrieved by Formtastic
    define_method "#{attribute}_options" do
      {:enum => enum, :allow_blank => allow_blank}
    end

  end

end