Turning a Product into a LineItem

What is the name of the Design pattern to turn a Product into a LineItem?

Maybe there are several, if so, what are the names of them?

(examples are in Ruby)

Making Product responsible for converting:

class Product
  attr_accessor :price

  def to_line_item
    LineItem.new(price: self.price)
  end
end

class LineItem
  attr_accessor :price
end

product = Product.new
product.price = 12.00
line_item = product.to_line_item
line_item.price #=> 12.00

Making LineItem responsible for converting:

class Product
  attr_accessor :price
end

class LineItem
  attr_accessor :price

  def from_product(product)
    self.new(price: product.price)
  end
end

product = Product.new
product.price = 12.00
line_item = product.to_line_item
line_item.price #=> 12.00

Having an intermediate (Factory?) convert:

class Product
  attr_accessor :price
end

class LineItem
  attr_accessor :price
end

class LineItemBuilder
  def self.create(product)
    LineItem.new(price: product.price)
  end
end

product = Product.new
product.price = 12.00
line_item = LineItemBuilder.create(product)
line_item.price #=> 12.00

Which of these three are the most common implemented to create a Foo from a Bar?

Two notes:

• In our case, the mapping from Product to Line Item is a tad more complex: more attributes (which don't always map 1-to-1 in both classes)
• LineItem gets fed not just product, but some additional attributes (:user_provided_note, for example)