Added that Active Records will automatically record creation and/or update timestamps of database objects if fields of the names created_at/created_on or updated_at/updated_on are present. [Tobias Luetke] Added acts_as_tree that can decorates an existing class with a many to many relationship with itself. Added acts_as_list that can decorates an existing class with methods like move_higher/lower, move_to_top/bottom.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@176 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

1 files changed, 118 insertions, 103 deletions

diff --git a/activerecord/lib/active_record/mixins/list.rb b/activerecord/lib/active_record/mixins/list.rb
index bec4b33651..16a60d7b6c 100644
--- a/activerecord/lib/active_record/mixins/list.rb
+++ b/activerecord/lib/active_record/mixins/list.rb
@@ -28,141 +28,156 @@ module ActiveRecord
     #   todo_list.last.move_higher
     module List
       def self.append_features(base)
-        super        
-        base.before_destroy :remove_from_list
-        base.after_create   :add_to_list_bottom
+        super
+        base.extend(ClassMethods)
       end
       
-      # can be overriden
-      
-      def position_column
-        "position"
-      end
+      module ClassMethods
+        def acts_as_list(options = {})
+          configuration = { :column => "position", :scope => "1" }
+          configuration.update(options) if options.is_a?(Hash)
+          
+          class_eval <<-EOV
+            include InstanceMethods
 
-      # Moving around on the list
+            def position_column
+              '#{configuration[:column]}'
+            end
 
-      def move_lower
-        return unless lower_item
-
-        self.class.transaction do
-          lower_item.decrement_position
-          increment_position
+            def scope_condition
+              "#{configuration[:scope]} = \#{#{configuration[:scope]}}"
+            end
+            
+            before_destroy :remove_from_list
+            after_create   :add_to_list_bottom
+          EOV
         end
-      end
+        
+        module InstanceMethods
+          def move_lower
+            return unless lower_item
 
-      def move_higher
-        return unless higher_item
+            self.class.transaction do
+              lower_item.decrement_position
+              increment_position
+            end
+          end
 
-        self.class.transaction do
-          higher_item.increment_position
-          decrement_position
-        end
-      end
+          def move_higher
+            return unless higher_item
+
+            self.class.transaction do
+              higher_item.increment_position
+              decrement_position
+            end
+          end
     
-      def move_to_bottom
-        self.class.transaction do
-          decrement_positions_on_lower_items
-          assume_bottom_position
-        end
-      end
+          def move_to_bottom
+            self.class.transaction do
+              decrement_positions_on_lower_items
+              assume_bottom_position
+            end
+          end
 
-      def move_to_top
-        self.class.transaction do
-          increment_positions_on_higher_items
-          assume_top_position
-        end
-      end
+          def move_to_top
+            self.class.transaction do
+              increment_positions_on_higher_items
+              assume_top_position
+            end
+          end
     
 
-      # Entering or existing the list
+          # Entering or existing the list
     
-      def add_to_list_top
-        increment_positions_on_all_items
-      end
+          def add_to_list_top
+            increment_positions_on_all_items
+          end
 
-      def add_to_list_bottom
-        assume_bottom_position
-      end
+          def add_to_list_bottom
+            assume_bottom_position
+          end
 
-      def remove_from_list
-        decrement_positions_on_lower_items
-      end
+          def remove_from_list
+            decrement_positions_on_lower_items
+          end
 
 
-      # Changing the position
+          # Changing the position
 
-      def increment_position
-        update_attribute position_column, self.send(position_column).to_i + 1
-      end
+          def increment_position
+            update_attribute position_column, self.send(position_column).to_i + 1
+          end
     
-      def decrement_position
-        update_attribute position_column, self.send(position_column).to_i - 1
-      end
+          def decrement_position
+            update_attribute position_column, self.send(position_column).to_i - 1
+          end
     
     
-      # Querying the position
+          # Querying the position
     
-      def first?
-        self.send(position_column) == 1
-      end
+          def first?
+            self.send(position_column) == 1
+          end
     
-      def last?
-        self.send(position_column) == bottom_position_in_list
-      end
+          def last?
+            self.send(position_column) == bottom_position_in_list
+          end
 
-      private
-        # Overwrite this method to define the scope of the list changes
-        def scope_condition() "1" end
+          private
+            # Overwrite this method to define the scope of the list changes
+            def scope_condition() "1" end
     
-        def higher_item
-          self.class.find_first(
-            "#{scope_condition} AND #{position_column} = #{(send(position_column).to_i - 1).to_s}"
-          )
-        end
+            def higher_item
+              self.class.find_first(
+                "#{scope_condition} AND #{position_column} = #{(send(position_column).to_i - 1).to_s}"
+              )
+            end
     
-        def lower_item
-          self.class.find_first(
-            "#{scope_condition} AND #{position_column} = #{(send(position_column).to_i + 1).to_s}"
-          )
-        end
+            def lower_item
+              self.class.find_first(
+                "#{scope_condition} AND #{position_column} = #{(send(position_column).to_i + 1).to_s}"
+              )
+            end
     
-        def bottom_position_in_list
-          item = bottom_item
-          item ? item.send(position_column) : 0
-        end
+            def bottom_position_in_list
+              item = bottom_item
+              item ? item.send(position_column) : 0
+            end
     
-        def bottom_item
-          self.class.find_first(
-            "#{scope_condition} ",
-            "#{position_column} DESC"
-          )
-        end
+            def bottom_item
+              self.class.find_first(
+                "#{scope_condition} ",
+                "#{position_column} DESC"
+              )
+            end
 
-        def assume_bottom_position
-          update_attribute position_column, bottom_position_in_list.to_i + 1
-        end
+            def assume_bottom_position
+              update_attribute position_column, bottom_position_in_list.to_i + 1
+            end
       
-        def assume_top_position
-          update_attribute position_column, 1
-        end
+            def assume_top_position
+              update_attribute position_column, 1
+            end
       
-        def decrement_positions_on_lower_items
-          self.class.update_all(
-            "#{position_column} = (#{position_column} - 1)",  "#{scope_condition} AND #{position_column} > #{send(position_column).to_i}"
-          )
-        end
+            def decrement_positions_on_lower_items
+              self.class.update_all(
+                "#{position_column} = (#{position_column} - 1)",  "#{scope_condition} AND #{position_column} > #{send(position_column).to_i}"
+              )
+            end
       
-        def increment_positions_on_higher_items
-          self.class.update_all(
-            "#{position_column} = (#{position_column} + 1)",  "#{scope_condition} AND #{position_column} < #{send(position_column)}"
-          )
-        end
+            def increment_positions_on_higher_items
+              self.class.update_all(
+                "#{position_column} = (#{position_column} + 1)",  "#{scope_condition} AND #{position_column} < #{send(position_column)}"
+              )
+            end
 
-        def increment_positions_on_all_items
-          self.class.update_all(
-            "#{position_column} = (#{position_column} + 1)",  "#{scope_condition}"
-          )
-        end
+            def increment_positions_on_all_items
+              self.class.update_all(
+                "#{position_column} = (#{position_column} + 1)",  "#{scope_condition}"
+              )
+            end
+        end     
+      end
     end
   end
 end
\ No newline at end of file