gistfile1.txt

# State machine
  
  # ensure default state is set.
  def before_create
     ensure_default_state
  end
  
  def ensure_default_state
     (self.state = Brief.default_state) if read_attribute(:state).blank?
  end
  
  # define states and associated actions
  
  state :draft, :default => true do
    handle :publish! do
      transition_to :published
      save!
    end    
  end
  
  state :published do 
    handle :close! do
      transition_to :closed
      save!
    end
    
    handle :review! do
      transition_to :peer_review
      save!
    end
  end
  
  state :peer_review do
    handle :close! do
      transition_to :closed
      save!
    end
  end
  
  state :closed
  
  # overwrite accessors so we can save to the database
  
  def state=(transition_to)
    write_attribute(:state, transition_to.to_s)
  end

  def state
    ensure_default_state
    read_attribute(:state)
  end

  # dynamically create some class level, and instance methods
  # for use with the statemachine defined states.
  class_eval do
    states.each do |state_name, state|
      # create a named scope for all the defined scopes
      named_scope state_name, :conditions => ["state = ?", state_name.to_s]
      
      # create a state_name? instance method for each state ..
      # for example @brief.draft? => true
      define_method("#{state_name}?", lambda { self.state == state_name }) 
    end
  end