From f033833fb9f48927995e8bc521ae032888813989 Mon Sep 17 00:00:00 2001 From: David Heinemeier Hansson Date: Thu, 16 Dec 2004 16:56:30 +0000 Subject: Improving documentation... git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@191 5ecf4fe2-1ee6-0310-87b1-e25e094e27de --- activerecord/lib/active_record/acts/list.rb | 256 ++++++++++++++-------------- 1 file changed, 124 insertions(+), 132 deletions(-) (limited to 'activerecord/lib/active_record/acts/list.rb') diff --git a/activerecord/lib/active_record/acts/list.rb b/activerecord/lib/active_record/acts/list.rb index 5d16f9a0c9..bf4bd74597 100644 --- a/activerecord/lib/active_record/acts/list.rb +++ b/activerecord/lib/active_record/acts/list.rb @@ -1,38 +1,35 @@ module ActiveRecord - # Mixins are a way of decorating existing Active Record models with additional behavior. If you for example - # want to keep a number of Documents in order, you can include Mixins::List, and all of the sudden be able to - # call document.move_to_bottom. - module Acts - # This mixin provides the capabilities for sorting and reordering a number of objects in list. - # The class that has this mixin included needs to have a "position" column defined as an integer on - # the mapped database table. Further more, you need to implement the scope_condition if you want - # to separate one list from another. - # - # Todo list example: - # - # class TodoList < ActiveRecord::Base - # has_many :todo_items, :order => "position" - # end - # - # class TodoItem < ActiveRecord::Base - # include ActiveRecord::Mixins::List - # belongs_to :todo_list - # - # private - # def scope_condition - # "todo_list_id = #{todo_list_id}" - # end - # end - # - # todo_list.first.move_to_bottom - # todo_list.last.move_higher - module List + module Acts #:nodoc: + module List #:nodoc: def self.append_features(base) super base.extend(ClassMethods) end + # This act provides the capabilities for sorting and reordering a number of objects in list. + # The class that has this specified needs to have a "position" column defined as an integer on + # the mapped database table. + # + # Todo list example: + # + # class TodoList < ActiveRecord::Base + # has_many :todo_items, :order => "position" + # end + # + # class TodoItem < ActiveRecord::Base + # belongs_to :todo_list + # acts_as_list :scope => :todo_list + # end + # + # todo_list.first.move_to_bottom + # todo_list.last.move_higher module ClassMethods + # Configuration options are: + # + # * +column+ - specifies the column name to use for keeping the position integer (default: position) + # * +scope+ - restricts what is to be considered a list. Given a symbol, it'll attach "_id" (if that hasn't been already) and use that + # as the foreign key restriction. It's also possible to give it an entire string that is interpolated if you need a tighter scope than + # just a foreign key. Example: acts_as_list :scope => 'todo_list_id = #{todo_list_id} AND completed = 0' def acts_as_list(options = {}) configuration = { :column => "position", :scope => "1" } configuration.update(options) if options.is_a?(Hash) @@ -40,7 +37,7 @@ module ActiveRecord configuration[:scope] = "#{configuration[:scope]}_id".intern if configuration[:scope].is_a?(Symbol) && configuration[:scope].to_s !~ /_id$/ class_eval <<-EOV - include InstanceMethods + include ActiveRecord::Acts::List::InstanceMethods def position_column '#{configuration[:column]}' @@ -54,132 +51,127 @@ module ActiveRecord after_create :add_to_list_bottom EOV end + end - module InstanceMethods - def move_lower - return unless lower_item - - self.class.transaction do - lower_item.decrement_position - increment_position - end + # All the methods available to a record that has had acts_as_list specified. + module InstanceMethods + def move_lower + return unless lower_item + + self.class.transaction do + lower_item.decrement_position + increment_position end + end - def move_higher - return unless higher_item + def move_higher + return unless higher_item - self.class.transaction do - higher_item.increment_position - decrement_position - end + self.class.transaction do + higher_item.increment_position + decrement_position 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 + def move_to_top + self.class.transaction do + increment_positions_on_higher_items + assume_top_position end - + end + - # 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 + 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 first? + self.send(position_column) == 1 + end + + def last? + self.send(position_column) == bottom_position_in_list + end - def increment_position - update_attribute position_column, self.send(position_column).to_i + 1 + 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 decrement_position - update_attribute position_column, self.send(position_column).to_i - 1 + + def lower_item + self.class.find_first( + "#{scope_condition} AND #{position_column} = #{(send(position_column).to_i + 1).to_s}" + ) end - - - # Querying the position - - def first? - self.send(position_column) == 1 + + def bottom_position_in_list + item = bottom_item + item ? item.send(position_column) : 0 end - - def last? - self.send(position_column) == bottom_position_in_list + + def bottom_item + self.class.find_first( + "#{scope_condition} ", + "#{position_column} DESC" + ) 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 assume_bottom_position + update_attribute position_column, bottom_position_in_list.to_i + 1 + end - def lower_item - self.class.find_first( - "#{scope_condition} AND #{position_column} = #{(send(position_column).to_i + 1).to_s}" - ) - end + def assume_top_position + update_attribute position_column, 1 + end - def bottom_position_in_list - item = bottom_item - item ? item.send(position_column) : 0 - 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 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_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 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 - end - end + def increment_positions_on_all_items + self.class.update_all( + "#{position_column} = (#{position_column} + 1)", "#{scope_condition}" + ) + end + end end end end \ No newline at end of file -- cgit v1.2.3