Module: ActiveRecord::Acts::List::ClassMethods
- Defined in:
- lib/acts_as_list/active_record/acts/list.rb
Overview
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
Instance Method Summary collapse
-
#acts_as_list(options = {}) ⇒ Object
Configuration options are:.
Instance Method Details
#acts_as_list(options = {}) ⇒ Object
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 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:acts_as_list :scope => 'todo_list_id = #{todo_list_id} AND completed = 0'
-
top_of_list
- defines the integer used for the top of the list. Defaults to 1. Use 0 to make the collection act more like an array in its indexing. -
add_new_at
- specifies whether objects get added to the :top or :bottom of the list. (default:bottom
)
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# File 'lib/acts_as_list/active_record/acts/list.rb', line 36 def acts_as_list( = {}) configuration = { :column => "position", :scope => "1 = 1", :top_of_list => 1, :add_new_at => :bottom} configuration.update() if .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 self.class.send(:sanitize_sql_hash_for_conditions, { :#{configuration[:scope].to_s} => send(:#{configuration[:scope].to_s}) }) end ) elsif configuration[:scope].is_a?(Array) scope_condition_method = %( def scope_condition attrs = %w(#{configuration[:scope].join(" ")}).inject({}) do |memo,column| memo[column.intern] = send(column.intern); memo end self.class.send(:sanitize_sql_hash_for_conditions, attrs) end ) else scope_condition_method = "def scope_condition() \"#{configuration[:scope]}\" end" end class_eval <<-EOV include ::ActiveRecord::Acts::List::InstanceMethods def acts_as_list_top #{configuration[:top_of_list]}.to_i end def acts_as_list_class ::#{self.name} end def position_column '#{configuration[:column]}' end #{scope_condition_method} after_destroy :decrement_positions_on_lower_items before_create :add_to_list_#{configuration[:add_new_at]} after_update :update_positions EOV end |