Explaining the Template Method design pattern with a WebScraper

web_scraper.rb

class WebScraper

  def execute
    create_folders
    download_data
    parse_data
    write_output
  end
  
  def create_folder
    # Make directory
  end
  
  def download_data
    # Initialize Http client
  end
  
  def parse_data
    # Find all rows in table and put them in a hash
  end
  
  def write_output
    # Write hash to a CSV on filesystem
  end

end

class HTMLWebScraper < WebScraper
  
  def parse_data
    # customize how to extract the data into a hash and
    # let the superclass take care of the rest :) 
  end
  
end

class JSONWebScraper < WebScraper
  
  def download_data
    # initialize JSON client
    # save data to filesystem
  end
  
  def parse_data
    # read from file system
    # custom JSON parsing code
    # store results in hash
    # let the super class take care of the rest :)
  end
  
end

html_scraper = HTMLWebScraper.new
html_scraper.execute

json_scraper = JSONWebScraper.new
json_scraper.excute