State machine setup.

state_machine_class.rb

class SomeClass < ActiveRecord::Base

  STATES = {:is_valid => 0, :needs_review => 1, :reviewed => 2, :is_invalid => 3}

  def initialize(*args)
    super(*args)
  end

  attr_accessible :state

  state_machine :state, :initial => STATES.key(0) do
    STATES.each do |key, value|
      state key, :value => value
    end

    event "set_#{STATES.key(0).to_s}".to_sym do
      transition all => STATES.key(0)
    end

    event "set_#{STATES.key(1).to_s}".to_sym do
      transition all => STATES.key(1)
    end

    event "set_#{STATES.key(2).to_s}".to_sym do
      transition all => STATES.key(2)
    end

    event "set_#{STATES.key(3).to_s}".to_sym do
      transition all => STATES.key(3)
    end

    state STATES.key(0) do
      #placeholder
    end

    state STATES.key(1) do
      #placeholder
    end

    state STATES.key(2) do
      #placeholder
    end

    state STATES.key(3) do
      #placeholder
    end
    
    after_transition :on => "set_#{STATES.key(3).to_s}".to_sym, :do => :mark_deleted #super method

  end
  
  def mark_valid
    self.fire_state_event("set_#{STATES.key(0).to_s}".to_sym)
  end

  def mark_invalid
    self.fire_state_event("set_#{STATES.key(3).to_s}".to_sym)
  end

  def mark_needs_review
    self.fire_state_event("set_#{STATES.key(1).to_s}".to_sym)
  end

  def mark_reviewed
    self.fire_state_event("set_#{STATES.key(2).to_s}".to_sym)
  end
  
end