SimpleStateMachine

Allow an Active Record or MongoMapper model to act as a finite state machine just as the popular plugin acts_as_state_machine but with many enhancements such as the possibility to have multiple states per object.

It can work together with the classic act_as_state_machine on the same project but both cannot be used at the same time for one given Active Record model. Moreover, simple_state_machine work standalone and doesn't require acts_as_state_machine.

You also get magic methods to check current state and a way to revert to previous state in database (or initial value for a new record) if something went wrong.

Dependencies

Ruby 1.8.7 or 1.9.2

Lazy dependencies

gem "active_record", ">= 3.0.0"
gem "mongo_mapper", "~> 0.9.0"

Usage

With ActiveRecord

  require "simple_state_machine/active_record"

  class Chicken < ActiveRecord::Base
    state_machine :user_state, [:pending, :active, :removed, :on_hold]
    state_machine :validation_state, [:waiting, :reviewed, :validated, :invalid]
    def user_activate!
      return false if !user_state_pending?
      self.user_state = :active
      save! rescue user_state_revert
      user_state_active?
    end
  end

  # And then you can do:

  c = Chicken.create # c.user_state = :pending
  c.user_activate! # c.user_state = :active

With MongoMapper

  require "simple_state_machine/mongo_mapper"

  class Chicken
    include MongoMapper::Document
    plugin SimpleStateMachine::MongoMapper

    state_machine :user_state, [:pending, :active, :removed, :on_hold]
    state_machine :validation_state, [:waiting, :reviewed, :validated, :invalid]
    def user_activate!
      return false if !user_state_pending?
      self.user_state = :active
      save! rescue user_state_revert
      user_state_active?
    end
  end

  # And then you can do:

  c = Chicken.create # c.user_state = :pending
  c.user_activate! # c.user_state = :active

SimpleStateMachine

Dependencies

Lazy dependencies

Usage

License