The Access Controls provide us the method which allows us to set access to classes , methods and other members in Ruby. They help us to bind the components to maintain the security of the methods throughout the project.

Ruby provides us with three types of access controls:

1. Public
2. Protected
3. Private

Public

The public method can be accessed by everyone inside and outside the class. It means that any instance of the class is free to call them. By default, all methods are set to public.

class Bike
  def bike_name
    "Avenger 220"         
  end
  private
    def bike_type
      "Cruiser"
    end
  protected
    def bike_chasis_number
      "AQZXS69870"
    end
end
b = Bike.new
b.bike_name           #This will be called successfully.
b.bike_type           #This Will give an access violation error 
b.bike_chasis_number  #This will give an access violation error

Private

This can be accessed only inside its own class. If you try to access it outside the class it will give an error. Therefore private method can only be called inside the class in which it is defined and also the sub-classes of this class.

class X
  def main_function
    function12
  end
  private
    def function12
      puts "This is from #{self.class}"
    end
  end
class Y < X
  def main_function
    function12
  end
end
X.new.main_function # output will be: This is from X 
Y.new.main_function # output will be: This is from Y

 Protected

Protected methods are like private methods that can only be called by the objects of their own class or by the subclass of the class in which they are declared. They can explicitly be called by using the self-method.

class X
  def main_function
    function12
  end
  protected
    def function12
      puts "This is from #{self.class}"
    end
  end
class X < Y
  def main_function
    function12
  end
end
class Z < X
  def main_function
    self.function12
  end
end
X.new.main_function # output will give: This is from X 
Y.new.main_function # output will give: This is from Y 
Z.new.main_function # output will give: This is from Z