Partial Documentation for ActiveModel::StateMachine

activemodel/lib/active_model/state_machine.rb

@@ -1,4 +1,113 @@
 module ActiveModel
+  # ==== Examples
+  #
+  #    class TrafficLight
+  #      include ActiveModel::StateMachine
+  #
+  #      state_machine do
+  #        state :red
+  #        state :green
+  #        state :yellow
+  #        state :blink
+  #
+  #        event :change_color do
+  #          transitions :to => :red, :from => [:yellow],
+  #            :on_transition => :catch_runners
+  #          transitions :to => :green, :from => [:red]
+  #          transitions :to => :yellow, :from => [:green]
+  #        end
+  #
+  #        event :defect do
+  #          transitions :to => :blink, :from => [:yellow, :red, :green]
+  #        end
+  #
+  #        event :repair do
+  #          transitions :to => :red, :from => [:blink]
+  #        end
+  #      end
+  #
+  #      def catch_runners
+  #        puts "That'll be $250."
+  #      end
+  #    end
+  #
+  #    light = TrafficLight.new
+  #    light.current_state        # => :red
+  #    light.change_color         # => true
+  #    light.current_state        # => :green
+  #    light.green?               # => true
+  #    light.change_color!        # => true
+  #    light.current_state        # => :yellow
+  #    light.red?                 # => false
+  #    light.change_color         # => true
+  #    "That'll be $250."
+  #
+  #
+  #  * The initial state for TrafficLight is red which is the first state defined.
+  #
+  #      # Want to know the initial_state?
+  #      TrafficLight.state_machine.initial_state      # => :red
+  #
+  #  * On a succesful transition to red (from yellow), the local +catch_runners+
+  #    method is executed
+  #
+  #  * The object acts differently depending on its current state, for instance,
+  #    the change_color! method has a different action depending on the current
+  #    color of the light
+  #
+  #  * Get the possible events for a state
+  #
+  #      TrafficLight.state_machine.events_for(:red)   # => [:change_color, :defect]
+  #      TrafficLight.state_machine.events_for(:blink) # => [:repair]
+  #
+  #
+  # The StateMachine also supports the following features :
+  #
+  #  * Success callbacks on event transition
+  #
+  #      event :sample, :success => :we_win do
+  #        ...
+  #      end
+  #
+  #  * Enter and exit callbacks par state
+  #
+  #      state :open, :enter => [:alert_twitter, :send_emails], :exit => :alert_twitter
+  #
+  #  * Guards on transition
+  #
+  #      event :close do
+  #        # You may only close the store if the safe is locked!!
+  #        transitions :to => :closed, :from => :open, :guard => :safe_locked?
+  #      end
+  #
+  #  * Setting the initial state
+  #
+  #      state_machine :initial => :yellow do
+  #        ...
+  #      end
+  #
+  #  * Named the state machine, to have more than one
+  #
+  #      class Stated
+  #        include ActiveModel::StateMachine
+  #
+  #        strate_machine :name => :ontest do
+  #        end
+  #
+  #        state_machine do
+  #        end
+  #      end
+  #
+  #      # Get the state of the <tt>:ontest</tt> state machine
+  #      stat.current_state(:ontest)
+  #      # Get the initial state
+  #      Stated.state_machine(:ontest).initial_state
+  #
+  #  * Changing the state
+  #
+  #      stat.current_state(:default, :astate)    # => :astate
+  #      # But you must give the name of the state machine, here <tt>:default</tt>
+  #
   module StateMachine
     autoload :Event, 'active_model/state_machine/event'
     autoload :Machine, 'active_model/state_machine/machine'