In Ruby on Rails, access control plays a crucial role in determining which methods or attributes of a class can be accessed from outside the class. Rails provides three access control levels: private, protected, and public. Let’s explore each of these levels and their implications in Rails development.

I. Private Methods

  • Definition: Private methods can only be called from within the same class or module. They cannot be accessed from outside the class, even by instances of the class.
  • Usage: Private methods are typically used for internal implementation details that should not be exposed to external code.
  • Example:
    class MyClass
  private

  def my_private_method
    # Implementation details
  end
end

II. Protected Methods

  • Definition: Protected methods can be called within the same class, as well as by instances of subclasses. However, they cannot be accessed from outside the class hierarchy.
  • Usage: Protected methods are often used to define common behavior shared among subclasses.
  • Example:
    class MyClass
  protected

  def my_protected_method
    # Implementation details
  end
end

III. Public Methods

  • Definition: Public methods can be called from anywhere, both within and outside the class. They define the interface of the class and are accessible by any object.
  • Usage: Public methods are used to expose functionality that should be accessible to external code.
  • Example:
    class MyClass
  def my_public_method
    # Implementation details
  end
end

IV. When to Use Each Access Control Level

  • Private: Use private methods for internal implementation details that should not be accessible outside the class.
  • Protected: Use protected methods when you want to share behavior among subclasses but restrict access from external code.
  • Public: Use public methods to define the interface of the class and expose functionality to external code.

V. Conclusion

Understanding access control levels in Rails—private, protected, and public—provides essential insights into defining the visibility and accessibility of methods within your application. By appropriately applying these access control levels, you can maintain encapsulation, ensure code integrity, and improve the overall design of your Rails application.