Builder Pattern

# Code to create a venue, without using a builder...
class Venue
  attr_accessor :staff
  attr_accessor :menu
  attr_accessor :seating
  
  def initialize(bar_size = :small, menu = Menu.new, staff =[])
    @staff = staff
    @menu = menu
    @bar = bar
  end
end

class Dinner
  #code for creating basic dinner menu items
end

class American < Dinner
  # code for american dishes
end

class SmallPlates < Dinner
  #code for creating small plates
end

class Menu
  attr_accessor :dinner
  attr_accessor :number_of_menu_items
  def initialize(dinner = American.new, number_of_items = 10)
    @dinner = dinner
    @number_of_items = number_of_items
  end
end

class Schedule
  attr_reader :employee
  attr_reader :shift
  attr_reader :position

  def initialize(employee, shift, position)
    @employee = employee
    @shift = shift
    @position = position
  end
end

fall_menu = Menu.new(SmallPlates.new, 20)
staff = []
staff << Schedule.new(:Indra, :pm, :waitress)
staff << Schedule.new(:LaToya, :pm, :bartender)
staff << Schedule.new(:Tony, :pm, :floor_manager)

venue = Venue.new(:small, fall_menu, staff)

  # The better way? Use a builder class to assemble all of the components of
  # this complex object.

class VenueBuilder
  attr_reader :venue

  def initialize 
    @venue = Venue.new
  end

  def small_plates(has_smallplates_based_menu = true)
    @venue.menu.dinner = SmallPlates.new
  end

  def bar_size=(bar_size)
    @venue.bar_size = bar_size
  end

  def number_of_menu_items(number)
    @venue.menu.number_of_menu_items = number
  end

  def add_staff
    @venue.staff << Schedule.new(:Indra, :pm, :waitress)
  end
end

builder = VenueBuilder.new
builder.small_plates
builder.bar_size(large)
builder.number_of_menu_items(20)
builder.add_staff

venue = builder.venue

# Polymorphic builders:


# Lets say we want to build 2 different types of venues;
# A special events space and a live music venue.

class EventSpace < Venue
  # lots of code to make a special event space
end

class LiveMusicSpace < Venue
  #omitted code
end

# An events space and a live music space will have things in common.
# We can stick those things into an abstract base builder
# and then create an EventSpaceBuilder and a LiveMusicBuilder
# to handle individual instances of each class.

class VenueBuilder
  attr_reader :venues

  def small_plates(has_smallplates_based_menu = true)
    @venue.menu.dinner = SmallPlates.new
  end

  def stage(has_stage=true)
    @venue.stage = Stage.new
  end
end

class EventSpaceBuilder < VenueBuilder
  def initialize
    @venue = EventSpace.new
  end

  def bar_size=(bar_size)
    @venue.bar_size = bar_size
  end

  def number_of_menu_items(number)
    @venue.menu.number_of_menu_items = number
  end

  def add_staff
    @venue.staff << Schedule.new(:Indra, :pm, :waitress)
  end
end

class LiveMusicSpaceBuilder < VenueBuilder
  def initialize
    @venue = LiveMusicSpace.new
  end

  def bar_size=(bar_size)
    raise "The bar at any live music venue must be large" unless bar_size ==
    :large
  end

  def number_of_menu_items(number)
    @venue.menu.number_of_menu_items = number
  end

  def add_staff
    @venue.staff << Schedule.new(:MikeFinnagan, :pm, :soundguy)
  end
end