Module: EnumeratedField::ClassMethods

Defined in:
lib/enumerated_field.rb

Instance Method Summary collapse

Instance Method Details

#enum_field(field_name, values_array, options = {}) ⇒ Object

ex. enum_field(:league, [[‘National Football League’, :nfl], [‘Major League Baseball’, :mlb]]) field_name typically corresponds to the database column name values_array is a double array (not a hash to preserve order for when order matters.. ie select options)



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# File 'lib/enumerated_field.rb', line 15

def enum_field(field_name, values_array, options = {})
  values_hash = ActiveSupport::HashWithIndifferentAccess.new
  values_array.each { |value, key| values_hash[key] = value }
  default_options = {
    :validate => true,
    :allow_nil => false,
    :allow_blank => false,
  }
  options = default_options.merge(options)

  # returns the values_array for this field, useful for providing to
  # options_for_select when constructing forms
  enumerated_class = class << self; self; end
  enumerated_class.class_eval do
    define_method("#{field_name}_values") do |*options|
      options = options.first || {}
      if options[:first_option]
        [[options[:first_option], '']] + values_array
      else
        values_array
      end
    end
  end

  class_eval do

    unless options[:validate] == false
      valid_values = values_hash.keys
      values_hash.keys.map do |key|
        if key.is_a?(String) and not key.blank?
          valid_values << key.to_sym
        else
          valid_values << key.to_s
        end
      end
      validates field_name, :inclusion => valid_values,
        :allow_nil => options[:allow_nil], :allow_blank => options[:allow_blank]
    end

    values_hash.each do |key, value|
      const_name = "#{field_name}_#{key}".upcase.gsub(/[^\w_]/, "_").to_sym
      const_set(const_name, key)
    end

    define_method("#{field_name}_values") do |*options|
      self.class.send("#{field_name}_values", *options)
    end

    # returns display value for the current value of the field
    define_method("#{field_name}_display") do
      values_hash[send(field_name)]
    end

    # returns display value for the given value of the field
    define_method("#{field_name}_display_for") do |key|
      values_hash[key]
    end

    define_method("#{field_name}_value_for") do |key|
      values_hash.invert[key]
    end

    # defines question methods for each possible value of the field
    # ex.  object.league_nfl?  which returns true if the objects league 
    # field is currently set to nfl otherwise false
    values_hash.keys.each do |key|
      define_method("#{field_name}_#{key}?") { send(field_name).to_s == key.to_s }
    end

    if defined? ActiveRecord::Base and ancestors.include? ActiveRecord::Base
      values_hash.keys.each do |key|
        scope "#{field_name}_#{key}", where(field_name => key)
      end
    end

  end
end