From c9d1ba41fd1195d4aaece2a4fc5c83273bd835bd Mon Sep 17 00:00:00 2001
From: schneems <richard.schneeman@gmail.com>
Date: Wed, 5 Sep 2012 15:51:20 -0700
Subject: Doc: sweepers only work on Active Record Models

In response to this rails issue: https://github.com/rails/rails/issues/3729
---
 guides/source/caching_with_rails.textile | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

(limited to 'guides/source/caching_with_rails.textile')

diff --git a/guides/source/caching_with_rails.textile b/guides/source/caching_with_rails.textile
index 9f1ac18814..577596ac0d 100644
--- a/guides/source/caching_with_rails.textile
+++ b/guides/source/caching_with_rails.textile
@@ -173,7 +173,9 @@ expire_fragment('all_available_products')
 
 h4. Sweepers
 
-Cache sweeping is a mechanism which allows you to get around having a ton of +expire_{page,action,fragment}+ calls in your code. It does this by moving all the work required to expire cached content into an +ActionController::Caching::Sweeper+ subclass. This class is an observer and looks for changes to an object via callbacks, and when a change occurs it expires the caches associated with that object in an around or after filter.
+Cache sweeping is a mechanism which allows you to get around having a ton of +expire_{page,action,fragment}+ calls in your code. It does this by moving all the work required to expire cached content into an +ActionController::Caching::Sweeper+ subclass. This class is an observer and looks for changes to an Active Record object via callbacks, and when a change occurs it expires the caches associated with that object in an around or after filter.
+
+TIP: Sweepers rely on the use of Active Record and Active Record Observers. The object you are observing must be an Active Record model.
 
 Continuing with our Product controller example, we could rewrite it with a sweeper like this:
 
-- 
cgit v1.2.3

