AlterEgo is my favorite Ruby state machine for the following reasons:
1. It's not dependent on ActiveRecord - it can be used on plain Ruby objects. 2. It most closely follows the GOF State Pattern because it allows for polymorphic behavior based on state.
Out of the box, AlterEgo doesn't play nicely with ActiveRecord because it stores state in @state, whereas subclasses of ActiveRecord::Base persist their attributes hash.
This mixin overrides the AlterEgo's accessor methods for state to allow it to be properly persisted to a database, as well as serialized/unserialized as json, yml, and xml.
As a Ruby Gem
gem install alter-ego-activerecord
OR as a Rails plugin
script/plugin install git://github.com/pavlos/alter-ego-activerecord.git
Make sure the table your class maps to has a state column of type varchar, string, etc.
# you'll only need the following two lines if you're NOT using # alter-ego-activerecord as a plugin gem 'alter-ego-activerecord' require 'alter_ego/active_record_adapter' class Example < ActiveRecord::Base include AlterEgo # include this first include AlterEgo::ActiveRecordAdapter # Your code here end