Refactoring and Namespaces

Code Samples

After extracting code in to a common module, we can create the report method to display our different reports and only send in the appropriate data. Our Inventoryable module now looks like this:

module Inventoryable

  def self.included(klass)
    klass.extend(ClassMethods)
    klass.extend(Enumerable)
  end

  module ClassMethods
    def create(attributes)
      object = new(attributes)
      instances.push(object)
      return object
    end

    def instances
      @instances ||= []
    end

    def each(&block)
      instances.each(&block)
    end

    def report(title, items)
      puts "-" * 50
      puts title
      puts "-" * 50
      items.each do |item|
        line = []
        line.push("Item: #{item.attributes[:name]}")
        line.push("Stock: #{item.stock_count}")
        if item.attributes.include?(:size)
          line.push("Size: #{item.attributes[:size]}")
        end
        puts line.join("\t")
      end
      puts "-" * 50
      puts "\n"
    end

    def in_stock_report
      title = "#{self.to_s} In Stock Report"
      reportable = instances.select{ |instance| instance.in_stock? }
      report(title, reportable)
    end

    def out_of_stock_report
      title = "#{self.to_s} Out Of Stock Report"
      reportable = instances.select{ |instance| !instance.in_stock? }
      report(title, reportable)
    end

  end

  def stock_count
    @stock_count ||= 0
  end

  def stock_count=(number)
    @stock_count = number
  end

  def in_stock?
    stock_count > 0
  end

end

Then we go through and put our Shirt, Pant, and Accessory modules in their own Treehouse namespace. This is done to avoid potential conflicts.

module Treehouse
  class Shirt
    include Inventoryable
    attr_accessor :attributes

    def initialize(attributes)
      @attributes = attributes
    end
  end

  class Pant
    include Inventoryable
    attr_accessor :attributes

    def initialize(attributes)
      @attributes = attributes
    end
  end

  class Accessory
    include Inventoryable
    attr_accessor :attributes

    def initialize(attributes)
      @attributes = attributes
    end
  end
end

Finally, we can reference them as follows:

shirt = Treehouse::Shirt.create(name: "MTF", size: "L")
shirt.stock_count = 10

shirt = Treehouse::Shirt.create(name: "MTF2", size: "L")

shirt = Treehouse::Shirt.create(name: "MTF", size: "M")
shirt.stock_count = 9

pant = Treehouse::Pant.create(name: "Jeans", size: "M")
pant.stock_count = 2

pant = Treehouse::Pant.create(name: "Jeans", size: "S")
pant.stock_count = 4

accessory = Treehouse::Accessory.create(name: "Belt", size: "M")
accessory.stock_count = 1

accessory = Treehouse::Accessory.create(name: "Belt", size: "L")
accessory.stock_count = 1

accessory = Treehouse::Accessory.create(name: "Necklace")
accessory.stock_count = 1

Treehouse::Shirt.in_stock_report
Treehouse::Pant.in_stock_report
Treehouse::Accessory.in_stock_report

Treehouse::Shirt.out_of_stock_report