Design Pattern: State and Combination Locks

lock.rb

class Lock
  attr_reader :cleared_state, :entered_pin_one_state, 
              :entered_pin_two_state, :entered_pin_three_state, 
              :unlocked_state, :entered_wrong_pin_state
  attr_accessor :state
  
  def initialize
    @cleared_state = ClearedState.new(self)
    @entered_pin_one_state = EnteredPinOneState.new(self)
    @entered_pin_two_state = EnteredPinTwoState.new(self)
    @entered_pin_three_state = EnteredPinThreeState.new(self)
    @unlocked_state = UnlockedState.new(self)
    @entered_wrong_pin_state = EnteredWrongPinState.new(self)
    
    @state = cleared_state
  end
  
  def show_current_state
    puts "currently in #{state.state_name}"
  end
  
  def dial_to(number)
    state.dial_to(number)
  end
  
  def clear
    state.clear
  end
  
  def pull_to_open
    state.pull_to_open
  end
  
  def push_to_lock    
    state.push_to_lock
  end
end