lib/mobility/backend/orm_delegator.rb in mobility-0.1.20 vs lib/mobility/backend/orm_delegator.rb in mobility-0.2.0

@@ -6,28 +6,38 @@
 
 @example KeyValue backend for AR model
   class Post < ActiveRecord::Base
     # ...
   end
-  Mobility::Backend::KeyValue.for(Post)
-  #=> Mobility::Backend::ActiveRecord::KeyValue
+  Mobility::Backends::KeyValue.for(Post)
+  #=> Mobility::Backends::ActiveRecord::KeyValue
 
 =end
     module OrmDelegator
       # @param [Class] model_class Class of model
       # @return [Class] Class of backend to use for model
       def for(model_class)
+        namespace = name.split('::'.freeze)
         if Loaded::ActiveRecord && model_class < ::ActiveRecord::Base
-          const_get(name.split("::".freeze).insert(-2, "ActiveRecord".freeze).join("::".freeze))
+          require_backend("active_record", namespace.last.underscore)
+          const_get(namespace.insert(-2, "ActiveRecord".freeze).join("::".freeze))
         elsif Loaded::Sequel && model_class < ::Sequel::Model
-          const_get(name.split("::".freeze).insert(-2, "Sequel".freeze).join("::".freeze))
+          require_backend("sequel", namespace.last.underscore)
+          const_get(namespace.insert(-2, "Sequel".freeze).join("::".freeze))
         else
-          raise ArgumentError, "#{name.split('::'.freeze).last} backend can only be used by ActiveRecord or Sequel models".freeze
+          raise ArgumentError, "#{namespace.last} backend can only be used by ActiveRecord or Sequel models".freeze
         end
       end
 
-      def self.included(base)
-        base.extend(self)
+      private
+
+      def require_backend(orm, backend)
+        begin
+          orm_backend = "mobility/backends/#{orm}/#{backend}"
+          require orm_backend
+        rescue LoadError => e
+          raise unless e.message =~ /#{orm_backend}/
+        end
       end
     end
   end
 end