Workflow engine

Premises

• ActiveRecord
• Each state is a separate object.

Features

• State can be as rich in functionality was wanted.
• No data is ever lost. History is always saved.
• It is possible to track every single transition done in the workflow.
• Advancing a state is as easy as creating a state object and calling "save".
• Can transition to same state.
• Minimal code to define workflow and states.

Simple example for a Bulb with two states:

class Bulb < ActiveRecord::Base
  include Control::Workflow
  
  has_many :ons
  has_many :offs
end

class On < ActiveRecord::Base
  include Control::State
    
  belongs_to :bulb
end

class Off < ActiveRecord::Base
  include Control::State

  belongs_to :bulb
  next_states :on # optional, to constrain possible next states, can also specify :none to make a state final
end

def example
  my_bulb = Bulb.new
  
  my_on = On.new do |o|
    o.bulb = my_bulb
  end
  
  my_off = Off.new do |o|
    o.bulb = my_bulb
  end
  
  # Check possible states for my bulb. (On, Off)
  my_bulb.states
  
  # Transitions the bulb to the "On" state
  my_on.save
  
  # Transitions the bulb to the "Off" state
  my_off.save
  
  # Every transition is recorded. (On -> Off)
  my_bulb.transitions
  
  # Bulb knows which state is current. (Off)
  my_bulb.current_state
end

Installing:

1. Add control gem to gemfile.

   gem 'control'

   or

   gem 'control', :git => 'git://github.com/zeto/control.git' # Edge

2. Generate tables (run rake db:migrate after)

   $ rails generate control_install

Testing the gem:

$ bundle
$ rake