Module: Degu::HasEnum::ClassMethods

Defined in:
lib/degu/has_enum.rb

Instance Method Summary collapse

Instance Method Details

#has_enum(enum_name, options = {}) ⇒ Object

Use like this

class Furniture
  has_enum :colors, :column_name => :custom_color_type
end

Raises:

  • (ArgumentError) 


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# File 'lib/degu/has_enum.rb', line 16

def has_enum(enum_name, options={})

  enum_column = options.has_key?(:column_name) ? options[:column_name].to_s : "#{enum_name}_type"

  self.send("validate", "#{enum_column}_check_for_valid_type_of_enum")

  # throws a NameError if Enum Class doesn't exists
  enum_class = options.has_key?(:class_name) ? options[:class_name].to_s.constantize : enum_name.to_s.camelize.constantize

  # Enum must be a Renum::EnumeratedValue Enum
  raise ArgumentError, "expected Renum::EnumeratedValue" unless enum_class.superclass == Renum::EnumeratedValue

  define_method("reset_enum_changed") do
    @enum_changed = false
  end
  after_save :reset_enum_changed

  define_method("#{enum_name}") do
    begin
      return self[enum_column].present? ? enum_class[self[enum_column]] : nil
    rescue NameError => e
      return nil
    end
  end

  define_method("#{enum_column}=") do |enum_literal|
    unless enum_literal == self[enum_column]
      self[enum_column] = enum_literal
      @enum_changed = true
    end
  end

  define_method("#{enum_name}=") do |enum_to_set|
    old_value = self[enum_column]
    enum_resolved = enum_class[enum_to_set]
    if enum_to_set.to_s.strip.empty?
      self[enum_column] = nil
    elsif enum_resolved
      column_type = ((column_definition = self.class.columns_hash[enum_column]) and column_definition.type)
      self[enum_column] = case column_type
      when :integer
        enum_resolved.index
      else
        enum_resolved.name
      end
    else
      raise ArgumentError, "could not resolve #{enum_to_set.inspect}"
    end
    @enum_changed ||= self[enum_column] != old_value
  end

  define_method("#{enum_name}_has_changed?") do
    !!@enum_changed
  end

  enum_class.each do |enum|
    define_method("#{enum_name}_#{enum.underscored_name}?") do
      __send__(enum_name.to_sym) == enum
    end
  end

  define_method("#{enum_column}_check_for_valid_type_of_enum") do
    return true if self[enum_column].nil? || self[enum_column].to_s.empty?
    unless enum_class[self[enum_column]].present?
      self.errors.add(enum_column.to_sym, "Wrong type '#{self[enum_column]}' for enum '#{enum_name}'")
      return false
    end
    return true
  end
end