Example of "Composition Over Inheritance" Concept

composition_over_inheritance.rb

class Vehicle; end

class Car < Vehicle
  def initialize
    # A composition to separate standalone Engine class.
    # That permit to create a class Bicycle without give it
    # the property of an engine Vehicle.
    @engine = GasolineEngine.new
  end

  def move_to_gasoline
    
  end
end

class Engine; end

class GasolineEngine < Engine
  def start
    puts 'Gasoline Engine is started.'
  end

  def start
    puts 'Gasoline Engine is stopped.'
  end
end

class DieselEngine < Engine
  def start
    puts 'Diesel Engine is started.'
  end

  def start
    puts 'Diesel Engine is stopped.'
  end
end