Samples and examples of application framework for Launch Academy

object_hierarchy.png

StudentGradePrinter.rb

# Sample ReportOutputter & child class (FileOutputter)
class ReportOutputter
  attr_accessort :report_generator

  def initialize(report_generator)
    @report_generator = report_generator
  end 

  def write
    print_all_students
    print_average_grades
    print_min_grade
    print_std_dev
  end 

  protected
  def print_all_students 
    @report_generator.sort_students.each{|s| write_line(s.last_name + ", " + s.first_name + ": " + s.average)
  end 

  def print_average_grades;
  def print_max_grade;
  def print_min_grade;
  def print_std_dev;

  def write_line
    raise NoMethodError, "Must be implemented in child class!"
  end 

end


class FileOutputter << ReportOutputter
  def initialize
    @file = File.open("Student_Report", "w")
  end 

  def write_line(line)
     @file.write(line) 
   end 
end

# Sample use of case statement for conciseness
def letter_grade
  case
  when average >= 90; return "A" 
  when average >= 80; return "B" 
  when average >= 70; return "C" 
  else; return "F" 
  end 
end

# Sample Application Level Object for "owning" responsibility of creating other classes that have Single Responsiblity
class StudentGradePrinter

        file_reader = FileReader.new(input_file)
        students = file_reader.get_students
        report_generator = ReportGenerator.new(students)
        report_generator.generate_report

        outputters = []
        outputters << FileOutputter.new
        outputters << ConsoleOutputter.new

        outputters.each { |o| o.write(report_generator) }

end