refactor store_accessor

1 files changed, 38 insertions, 6 deletions

diff --git a/activerecord/lib/active_record/store.rb b/activerecord/lib/active_record/store.rb
index 8ea0ea239f..df7f58c81f 100644
--- a/activerecord/lib/active_record/store.rb
+++ b/activerecord/lib/active_record/store.rb
@@ -37,6 +37,28 @@ module ActiveRecord
   # The stored attribute names can be retrieved using +stored_attributes+.
   #
   #   User.stored_attributes[:settings] # [:color, :homepage]
+  #
+  # == Overwriting default accessors
+  #
+  # All stored values are automatically available through accessors on the Active Record
+  # object, but sometimes you want to specialize this behavior. This can be done by overwriting
+  # the default accessors (using the same name as the attribute) and calling
+  # <tt>read_store_attribute(store_attribute_name, attr_name)</tt> and
+  # <tt>write_store_attribute(store_attribute_name, attr_name, value)</tt> to actually
+  # change things.
+  #
+  #   class Song < ActiveRecord::Base
+  #     # Uses a stored integer to hold the volume adjustment of the song
+  #     store :settings, accessors: [:volume_adjustment]
+  #
+  #     def volume_adjustment=(decibels)
+  #       write_store_attribute(:settings, :volume_adjustment, decibels.to_i)
+  #     end
+  #
+  #     def volume_adjustment
+  #       read_store_attribute(:settings, :volume_adjustment).to_i
+  #     end
+  #   end
   module Store
     extend ActiveSupport::Concern
 
@@ -55,15 +77,11 @@ module ActiveRecord
         keys = keys.flatten
         keys.each do |key|
           define_method("#{key}=") do |value|
-            attribute = initialize_store_attribute(store_attribute)
-            if value != attribute[key]
-              send :"#{store_attribute}_will_change!"
-              attribute[key] = value
-            end
+            write_store_attribute(store_attribute, key, value)
           end
 
           define_method(key) do
-            initialize_store_attribute(store_attribute)[key]
+            read_store_attribute(store_attribute, key)
           end
         end
 
@@ -72,6 +90,20 @@ module ActiveRecord
       end
     end
 
+    protected
+      def read_store_attribute(store_attribute, key)
+        attribute = initialize_store_attribute(store_attribute)
+        attribute[key]
+      end
+
+      def write_store_attribute(store_attribute, key, value)
+        attribute = initialize_store_attribute(store_attribute)
+        if value != attribute[key]
+          send :"#{store_attribute}_will_change!"
+          attribute[key] = value
+        end
+      end
+
     private
       def initialize_store_attribute(store_attribute)
         attribute = send(store_attribute)