Module: OrderedTree

Defined in:
lib/ordered_tree.rb,
lib/ordered_tree/version.rb,
lib/ordered_tree/class_methods.rb,
lib/ordered_tree/instance_methods.rb,
lib/ordered_tree/instance_methods/list.rb,
lib/ordered_tree/instance_methods/misc.rb,
lib/ordered_tree/instance_methods/tree.rb,
lib/ordered_tree/instance_methods/destroy.rb

Overview

:nodoc:

Defined Under Namespace

Modules: ClassMethods, InstanceMethods

Constant Summary collapse

VERSION = 
"1.0.0"

Instance Method Summary collapse

Instance Method Details

#ordered_tree(options = {}) ⇒ Object

Configuration:

class Person < ActiveRecord::Base
  ordered_tree :foreign_key   => :parent_id,
               :order         => :position
end

class CreatePeople < ActiveRecord::Migration
  def self.up
    create_table :people do |t|
      t.column :parent_id ,:integer ,:null => false ,:default => 0
      t.column :position  ,:integer
    end
    add_index(:people, :parent_id)
  end
end



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# File 'lib/ordered_tree.rb', line 22

def ordered_tree(options = {})
  cattr_accessor :ordered_tree_config
  self.ordered_tree_config ||= {}
  self.ordered_tree_config[:foreign_key] ||= :parent_id
  self.ordered_tree_config[:order] ||= :position
  self.ordered_tree_config[:primary_key] ||= :id
  self.ordered_tree_config.update(options) if options.is_a?(Hash)

  belongs_to(
    :parent_node,
    lambda { |instance| where(instance.send(:scope_condition)) },
    :class_name  => self.name,
    :foreign_key => ordered_tree_config[:foreign_key],
    :primary_key => ordered_tree_config[:primary_key],
  )
  has_many(
    :child_nodes,
    lambda { |instance|
      where(instance.send(:scope_condition)).
        order(ordered_tree_config[:order])
    },
    :class_name  => self.name,
    :foreign_key => ordered_tree_config[:foreign_key],
    :primary_key => ordered_tree_config[:primary_key]
  )
  scope :roots, lambda { |*args|
    column = "#{self.table_name}.#{self.ordered_tree_config[:foreign_key].to_sym}"
    scope_condition = args[0]
    where(scope_condition).
      where("#{column} = 0 OR #{column} IS NULL").
      order(self.ordered_tree_config[:order])
  }

  include OrderedTree::ClassMethods
  include OrderedTree::InstanceMethods
end