define_callback.rb

# coding: utf-8

require 'active_support/callbacks'

class Record
  include ActiveSupport::Callbacks
  define_callbacks :save
  # define_callbacks :kill

  def save
    run_callbacks :save do
      puts "- save"
    end
  end

  set_callback :save, :before, :saving_message
  def saving_message
    puts "saving..."
    return true
  end

  set_callback :save, :after do |object|
    puts object
    puts "saved"
  end

  # def kill
  #   run_callbacks :kill do
  #     puts "- kill"
  #   end
  # end

  # set_callback :kill, :before, :kill_message
  # def kill_message
  #   puts "before kill....."
  # end

end

person = Record.new
person.save
person.kill

# ---output---
# saving...
# - save
# saved