2007-12-10 20:58:07 +03:00
|
|
|
module ActiveRecord
|
|
|
|
module Acts #:nodoc:
|
|
|
|
module List #:nodoc:
|
|
|
|
def self.included(base)
|
|
|
|
base.extend(ClassMethods)
|
|
|
|
end
|
|
|
|
|
|
|
|
# This +acts_as+ extension provides the capabilities for sorting and reordering a number of objects in a 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 <tt>_id</tt>
|
|
|
|
# (if it hasn't already been added) 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: <tt>acts_as_list :scope => 'todo_list_id = #{todo_list_id} AND completed = 0'</tt>
|
|
|
|
def acts_as_list(options = {})
|
|
|
|
configuration = { :column => "position", :scope => "1 = 1" }
|
|
|
|
configuration.update(options) if options.is_a?(Hash)
|
|
|
|
|
|
|
|
configuration[:scope] = "#{configuration[:scope]}_id".intern if configuration[:scope].is_a?(Symbol) && configuration[:scope].to_s !~ /_id$/
|
|
|
|
|
|
|
|
if configuration[:scope].is_a?(Symbol)
|
|
|
|
scope_condition_method = %(
|
|
|
|
def scope_condition
|
|
|
|
if #{configuration[:scope].to_s}.nil?
|
|
|
|
"#{configuration[:scope].to_s} IS NULL"
|
|
|
|
else
|
|
|
|
"#{configuration[:scope].to_s} = \#{#{configuration[:scope].to_s}}"
|
|
|
|
end
|
|
|
|
end
|
|
|
|
)
|
|
|
|
else
|
|
|
|
scope_condition_method = "def scope_condition() \"#{configuration[:scope]}\" end"
|
|
|
|
end
|
|
|
|
|
|
|
|
class_eval <<-EOV
|
|
|
|
include ActiveRecord::Acts::List::InstanceMethods
|
|
|
|
|
|
|
|
def acts_as_list_class
|
|
|
|
::#{self.name}
|
|
|
|
end
|
|
|
|
|
|
|
|
def position_column
|
|
|
|
'#{configuration[:column]}'
|
|
|
|
end
|
|
|
|
|
|
|
|
#{scope_condition_method}
|
|
|
|
|
|
|
|
before_destroy :remove_from_list
|
|
|
|
before_create :add_to_list_bottom
|
|
|
|
EOV
|
|
|
|
end
|
|
|
|
end
|
|
|
|
|
|
|
|
# All the methods available to a record that has had <tt>acts_as_list</tt> specified. Each method works
|
|
|
|
# by assuming the object to be the item in the list, so <tt>chapter.move_lower</tt> would move that chapter
|
|
|
|
# lower in the list of all chapters. Likewise, <tt>chapter.first?</tt> would return +true+ if that chapter is
|
|
|
|
# the first in the list of all chapters.
|
|
|
|
module InstanceMethods
|
|
|
|
# Insert the item at the given position (defaults to the top position of 1).
|
|
|
|
def insert_at(position = 1)
|
|
|
|
insert_at_position(position)
|
|
|
|
end
|
|
|
|
|
|
|
|
# Swap positions with the next lower item, if one exists.
|
|
|
|
def move_lower
|
|
|
|
return unless lower_item
|
|
|
|
|
|
|
|
acts_as_list_class.transaction do
|
|
|
|
lower_item.decrement_position
|
|
|
|
increment_position
|
|
|
|
end
|
|
|
|
end
|
|
|
|
|
|
|
|
# Swap positions with the next higher item, if one exists.
|
|
|
|
def move_higher
|
|
|
|
return unless higher_item
|
|
|
|
|
|
|
|
acts_as_list_class.transaction do
|
|
|
|
higher_item.increment_position
|
|
|
|
decrement_position
|
|
|
|
end
|
|
|
|
end
|
|
|
|
|
|
|
|
# Move to the bottom of the list. If the item is already in the list, the items below it have their
|
|
|
|
# position adjusted accordingly.
|
|
|
|
def move_to_bottom
|
|
|
|
return unless in_list?
|
|
|
|
acts_as_list_class.transaction do
|
|
|
|
decrement_positions_on_lower_items
|
|
|
|
assume_bottom_position
|
|
|
|
end
|
|
|
|
end
|
|
|
|
|
|
|
|
# Move to the top of the list. If the item is already in the list, the items above it have their
|
|
|
|
# position adjusted accordingly.
|
|
|
|
def move_to_top
|
|
|
|
return unless in_list?
|
|
|
|
acts_as_list_class.transaction do
|
|
|
|
increment_positions_on_higher_items
|
|
|
|
assume_top_position
|
|
|
|
end
|
|
|
|
end
|
2009-02-26 12:21:41 +03:00
|
|
|
|
|
|
|
# Move to the given position
|
|
|
|
def move_to=(pos)
|
|
|
|
case pos.to_s
|
|
|
|
when 'highest'
|
|
|
|
move_to_top
|
|
|
|
when 'higher'
|
|
|
|
move_higher
|
|
|
|
when 'lower'
|
|
|
|
move_lower
|
|
|
|
when 'lowest'
|
|
|
|
move_to_bottom
|
|
|
|
end
|
|
|
|
end
|
2007-12-10 20:58:07 +03:00
|
|
|
|
|
|
|
# Removes the item from the list.
|
|
|
|
def remove_from_list
|
|
|
|
if in_list?
|
|
|
|
decrement_positions_on_lower_items
|
|
|
|
update_attribute position_column, nil
|
|
|
|
end
|
|
|
|
end
|
|
|
|
|
|
|
|
# Increase the position of this item without adjusting the rest of the list.
|
|
|
|
def increment_position
|
|
|
|
return unless in_list?
|
|
|
|
update_attribute position_column, self.send(position_column).to_i + 1
|
|
|
|
end
|
|
|
|
|
|
|
|
# Decrease the position of this item without adjusting the rest of the list.
|
|
|
|
def decrement_position
|
|
|
|
return unless in_list?
|
|
|
|
update_attribute position_column, self.send(position_column).to_i - 1
|
|
|
|
end
|
|
|
|
|
|
|
|
# Return +true+ if this object is the first in the list.
|
|
|
|
def first?
|
|
|
|
return false unless in_list?
|
|
|
|
self.send(position_column) == 1
|
|
|
|
end
|
|
|
|
|
|
|
|
# Return +true+ if this object is the last in the list.
|
|
|
|
def last?
|
|
|
|
return false unless in_list?
|
|
|
|
self.send(position_column) == bottom_position_in_list
|
|
|
|
end
|
|
|
|
|
|
|
|
# Return the next higher item in the list.
|
|
|
|
def higher_item
|
|
|
|
return nil unless in_list?
|
|
|
|
acts_as_list_class.find(:first, :conditions =>
|
|
|
|
"#{scope_condition} AND #{position_column} = #{(send(position_column).to_i - 1).to_s}"
|
|
|
|
)
|
|
|
|
end
|
|
|
|
|
|
|
|
# Return the next lower item in the list.
|
|
|
|
def lower_item
|
|
|
|
return nil unless in_list?
|
|
|
|
acts_as_list_class.find(:first, :conditions =>
|
|
|
|
"#{scope_condition} AND #{position_column} = #{(send(position_column).to_i + 1).to_s}"
|
|
|
|
)
|
|
|
|
end
|
|
|
|
|
|
|
|
# Test if this record is in a list
|
|
|
|
def in_list?
|
|
|
|
!send(position_column).nil?
|
|
|
|
end
|
|
|
|
|
|
|
|
private
|
|
|
|
def add_to_list_top
|
|
|
|
increment_positions_on_all_items
|
|
|
|
end
|
|
|
|
|
|
|
|
def add_to_list_bottom
|
|
|
|
self[position_column] = bottom_position_in_list.to_i + 1
|
|
|
|
end
|
|
|
|
|
|
|
|
# Overwrite this method to define the scope of the list changes
|
|
|
|
def scope_condition() "1" end
|
|
|
|
|
|
|
|
# Returns the bottom position number in the list.
|
|
|
|
# bottom_position_in_list # => 2
|
|
|
|
def bottom_position_in_list(except = nil)
|
|
|
|
item = bottom_item(except)
|
|
|
|
item ? item.send(position_column) : 0
|
|
|
|
end
|
|
|
|
|
|
|
|
# Returns the bottom item
|
|
|
|
def bottom_item(except = nil)
|
|
|
|
conditions = scope_condition
|
|
|
|
conditions = "#{conditions} AND #{self.class.primary_key} != #{except.id}" if except
|
|
|
|
acts_as_list_class.find(:first, :conditions => conditions, :order => "#{position_column} DESC")
|
|
|
|
end
|
|
|
|
|
|
|
|
# Forces item to assume the bottom position in the list.
|
|
|
|
def assume_bottom_position
|
|
|
|
update_attribute(position_column, bottom_position_in_list(self).to_i + 1)
|
|
|
|
end
|
|
|
|
|
|
|
|
# Forces item to assume the top position in the list.
|
|
|
|
def assume_top_position
|
|
|
|
update_attribute(position_column, 1)
|
|
|
|
end
|
|
|
|
|
|
|
|
# This has the effect of moving all the higher items up one.
|
|
|
|
def decrement_positions_on_higher_items(position)
|
|
|
|
acts_as_list_class.update_all(
|
|
|
|
"#{position_column} = (#{position_column} - 1)", "#{scope_condition} AND #{position_column} <= #{position}"
|
|
|
|
)
|
|
|
|
end
|
|
|
|
|
|
|
|
# This has the effect of moving all the lower items up one.
|
|
|
|
def decrement_positions_on_lower_items
|
|
|
|
return unless in_list?
|
|
|
|
acts_as_list_class.update_all(
|
|
|
|
"#{position_column} = (#{position_column} - 1)", "#{scope_condition} AND #{position_column} > #{send(position_column).to_i}"
|
|
|
|
)
|
|
|
|
end
|
|
|
|
|
|
|
|
# This has the effect of moving all the higher items down one.
|
|
|
|
def increment_positions_on_higher_items
|
|
|
|
return unless in_list?
|
|
|
|
acts_as_list_class.update_all(
|
|
|
|
"#{position_column} = (#{position_column} + 1)", "#{scope_condition} AND #{position_column} < #{send(position_column).to_i}"
|
|
|
|
)
|
|
|
|
end
|
|
|
|
|
|
|
|
# This has the effect of moving all the lower items down one.
|
|
|
|
def increment_positions_on_lower_items(position)
|
|
|
|
acts_as_list_class.update_all(
|
|
|
|
"#{position_column} = (#{position_column} + 1)", "#{scope_condition} AND #{position_column} >= #{position}"
|
|
|
|
)
|
|
|
|
end
|
|
|
|
|
|
|
|
# Increments position (<tt>position_column</tt>) of all items in the list.
|
|
|
|
def increment_positions_on_all_items
|
|
|
|
acts_as_list_class.update_all(
|
|
|
|
"#{position_column} = (#{position_column} + 1)", "#{scope_condition}"
|
|
|
|
)
|
|
|
|
end
|
|
|
|
|
|
|
|
def insert_at_position(position)
|
|
|
|
remove_from_list
|
|
|
|
increment_positions_on_lower_items(position)
|
|
|
|
self.update_attribute(position_column, position)
|
|
|
|
end
|
|
|
|
end
|
|
|
|
end
|
|
|
|
end
|
|
|
|
end
|