Sihui

class StandardCarBuilder
  def build
    car = ''
    # 1. build car frame
    car << "This is a standard car\n"
    # 2. add an engine
    car << "  with an engine\n"
    # 3. add front wheels
    car << "  with two front wheels\n"
    # 4. add back wheels

Sihui

class OreoCheesecake
  def make_crust
    puts 'making OreoCheesecake curst'
  end
  
  def add_layers
    puts 'making OreoCheesecake layers'
  end
  
  def bake

Sihui

class ActorProxy
  attr_reader :schedule, :preference, :actor
  
  def initialize(schedule, preference, actor)
    @schedule = schedule
    @preference = preference
    @actor = actor
  end
  
  def handle(request)

Sihui

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)

Sihui

class EnteredPinThreeState
  attr_reader :lock, :state_name
  
  def initialize(lock)
    @lock = lock
    @state_name = 'Entered Pin Three State'
  end
  
  def dial_to(number)
    lock.state = lock.entered_wrong_pin_state

Sihui

class UnlockedState
  attr_reader :lock, :state_name
  
  def initialize(lock)
    @lock = lock
    @state_name = 'Unlocked State'
  end
  
  def dial_to(number)
    puts 'The lock is unlocked. Dial does nothing.'

Sihui

class EnteredWrongPinState
  attr_reader :lock, :state_name
  
  def initialize(lock)
    @lock = lock
    @state_name = 'Entered Wrong Pin State'
  end
  
  def dial_to(number)
    puts "The lock is in #{state_name}. Dial does nothing."

Sihui

class EnteredPinTwoState
  attr_reader :lock, :state_name
  
  def initialize(lock)
    @lock = lock
    @state_name = 'Entered Pin Two State'
  end
  
  def dial_to(number)
    if number == 9

Sihui

class EnteredPinOneState
  attr_reader :lock, :state_name
  
  def initialize(lock)
    @lock = lock
    @state_name = 'Entered Pin One State'
  end
  
  def dial_to(number)
    if number == 8

Sihui

class ClearedState
  attr_reader :lock, :state_name
  
  def initialize(lock)
    @lock = lock
    @state_name = 'Cleared State'
  end
  
  def dial_to(number)
    if number == 7