blah.rb

# This comes from GenericWebLibrary
class BaseComponent
end

# This comes from RestExtensionLibrary
class RestComponent < BaseComponent
end

# In a language with mixins you could do
module SomeFilterStuff
  def login_required; end
end

class MyBaseComponent < BaseComponent
  include SomeFilterStuff
end

class MyRestComponent < RestComponent
  include SomeFilterStuff
end

# without mixins what do you do?! My solution is
class BaseComponent
  def login_required; end
end