aboutsummaryrefslogtreecommitdiffstats
path: root/activerecord/lib/active_record/observer.rb
diff options
context:
space:
mode:
Diffstat (limited to 'activerecord/lib/active_record/observer.rb')
-rw-r--r--activerecord/lib/active_record/observer.rb14
1 files changed, 14 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/observer.rb b/activerecord/lib/active_record/observer.rb
index cfdeae3592..6e4db637f5 100644
--- a/activerecord/lib/active_record/observer.rb
+++ b/activerecord/lib/active_record/observer.rb
@@ -125,6 +125,20 @@ module ActiveRecord
#
# Observers will not be invoked unless you define these in your application configuration.
#
+ # == Loading
+ #
+ # Observers register themselves in the model class they observe, since it is the class that
+ # notifies them of events when they occur. As a side-effect, when an observer is loaded its
+ # corresponding model class is loaded.
+ #
+ # Up to (and including) Rails 2.0.2 observers were instantiated between plugins and
+ # application initializers. Now observers are loaded after application initializers,
+ # so observed models can make use of extensions.
+ #
+ # If by any chance you are using observed models in the initialization you can still
+ # load their observers by calling <tt>ModelObserver.instance</tt> before. Observers are
+ # singletons and that call instantiates and registers them.
+ #
class Observer
include Singleton