observing.rb in activemodel-3.0.0.beta4

- old
+ new

@@ -1,19 +1,15 @@
-require 'observer'
 require 'singleton'
 require 'active_support/core_ext/array/wrap'
 require 'active_support/core_ext/module/aliasing'
 require 'active_support/core_ext/string/inflections'
+require 'active_support/core_ext/string/conversions'
 
 module ActiveModel
   module Observing
     extend ActiveSupport::Concern
 
-    included do
-      extend Observable
-    end
-
     module ClassMethods
       # Activates the observers assigned. Examples:
       #
       #   # Calls PersonObserver.instance
       #   ActiveRecord::Base.observers = :person_observer
@@ -39,10 +35,30 @@
       # Instantiate the global Active Record observers.
       def instantiate_observers
         observers.each { |o| instantiate_observer(o) }
       end
 
+      def add_observer(observer)
+        unless observer.respond_to? :update
+          raise ArgumentError, "observer needs to respond to `update'"
+        end
+        @observer_instances ||= []
+        @observer_instances << observer
+      end
+
+      def notify_observers(*arg)
+        if defined? @observer_instances
+          for observer in @observer_instances
+            observer.update(*arg)
+          end
+        end
+      end
+
+      def count_observers
+        @observer_instances.size
+      end
+
       protected
         def instantiate_observer(observer) #:nodoc:
           # string/symbol
           if observer.respond_to?(:to_sym)
             observer = observer.to_s.camelize.constantize.instance
@@ -54,11 +70,10 @@
         end
 
         # Notify observers when the observed class is subclassed.
         def inherited(subclass)
           super
-          changed
           notify_observers :observed_class_inherited, subclass
         end
     end
 
     private
@@ -68,10 +83,9 @@
       #   notify_observers(:before_save)
       #   ...
       #   notify_observers(:after_save)
       # end
       def notify_observers(method)
-        self.class.changed
         self.class.notify_observers(method, self)
       end
   end
 
   # Observer classes respond to lifecycle callbacks to implement trigger-like