fluke/devops-service/db/validators/base.rb

module Validators
  class Base

    def initialize(model, options={})
      @model = model
      @options = options
    end

    def validate!
      raise InvalidRecord.new(message) unless valid?
    end

    def valid?
      raise 'override me'
    end

    def message
      raise 'override me'
    end

    class << self
      private

      # this method delegates @valid? and @message methods to helper validator, passed as block
      def delegate_to_helper_validator(&block)

        define_method :helper_validator do
          @helper_validator ||= self.instance_eval(&block)
        end

        define_method :valid? do
          self.helper_validator.valid?
        end

        define_method :message do
          self.helper_validator.message
        end
      end
    end

  end
end