Class-level observers

gistfile1.rb

require 'observer'

class BudgetsConsumer
  def self.update(val)
    puts "new value from enrollment consumer: #{val}"
  end
end

class EnrollmentsConsumer
  extend Observable

  def self.change_consumer(val)
    changed
    notify_observers(val)
  end
end

EnrollmentsConsumer.add_observer(BudgetsConsumer)
EnrollmentsConsumer.change_consumer(name: 'Jim')

#=> new value from enrollment consumer: {:name=>"Jim"}