ActiveModel::Observing::ClassMethods

    # File lib/active_model/observing.rb, line 42
42:       def add_observer(observer)
43:         unless observer.respond_to? :update
44:           raise ArgumentError, "observer needs to respond to `update'"
45:         end
46:         @observer_instances ||= []
47:         @observer_instances << observer
48:       end

    # File lib/active_model/observing.rb, line 58
58:       def count_observers
59:         @observer_instances.size
60:       end

    # File lib/active_model/observing.rb, line 38
38:       def instantiate_observers
39:         observers.each { |o| instantiate_observer(o) }
40:       end

    # File lib/active_model/observing.rb, line 50
50:       def notify_observers(*arg)
51:         if defined? @observer_instances
52:           for observer in @observer_instances
53:             observer.update(*arg)
54:           end
55:         end
56:       end

    # File lib/active_model/observing.rb, line 33
33:       def observers
34:         @observers ||= []
35:       end

    # File lib/active_model/observing.rb, line 28
28:       def observers=(*values)
29:         @observers = values.flatten
30:       end

    # File lib/active_model/observing.rb, line 75
75:         def inherited(subclass)
76:           super
77:           notify_observers :observed_class_inherited, subclass
78:         end