Module: Mongoid::Acts::NestedSet::Base

Defined in:
lib/mongoid_nested_set/base.rb

Instance Method Summary collapse

Instance Method Details

#acts_as_nested_set(options = {}) ⇒ Object

Configuration options are:

  • :parent_field - field name to use for keeping the parent id (default: parent_id)

  • :left_field - field name for left boundary data, default ‘lft’

  • :right_field - field name for right boundary data, default ‘rgt’

  • :outline_number_field - field name for the number field, default nil. If set, the value will be used as a field name to keep track of each node’s “outline number” (e.g. 1.2.5).

  • :scope - restricts what is to be considered a list. Given a symbol, it’ll attach “_id” (if it hasn’t been already) and use that as the foreign key restriction. You can also pass an array to scope by multiple attributes

  • :dependent - behavior for cascading destroy. If set to :destroy, all the child objects are destroyed alongside this object by calling their destroy method. If set to :delete_all (default), all the child objects are deleted without calling their destroy method.

  • :klass - class to use for queries (defaults to self)

See Mongoid::Acts::NestedSet::ClassMethods for a list of class methods and Mongoid::Acts::NestedSet::InstanceMethods for a list of instance methods added to acts_as_nested_set models



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# File 'lib/mongoid_nested_set/base.rb', line 25

def acts_as_nested_set(options = {})
  options = {
    :parent_field => 'parent_id',
    :left_field => 'lft',
    :right_field => 'rgt',
    :outline_number_field => nil,
    :dependent => :delete_all, # or :destroy
    :klass => self,
  }.merge(options)

  if options[:scope].is_a?(Symbol) && options[:scope].to_s !~ /_id$/
    options[:scope] = "#{options[:scope]}_id".intern
  end

  class_attribute :acts_as_nested_set_options, :instance_writer => false
  self.acts_as_nested_set_options = options

  unless self.is_a?(Document::ClassMethods)
    include Document
    include OutlineNumber if outline_number_field_name

    field left_field_name, :type => Integer
    field right_field_name, :type => Integer
    field outline_number_field_name, :type => String if outline_number_field_name
    field :depth, :type => Integer

    has_many   :children, :class_name => self.name, :foreign_key => parent_field_name, :inverse_of => :parent, :order => left_field_name.to_sym.asc
    belongs_to :parent,   :class_name => self.name, :foreign_key => parent_field_name

    attr_accessor :skip_before_destroy

    if accessible_attributes.blank?
      attr_protected left_field_name.intern, right_field_name.intern
    end

    define_callbacks :move, :terminator => "result == false"

    before_create  :set_default_left_and_right
    before_save    :store_new_parent
    after_save     :move_to_new_parent
    before_destroy :destroy_descendants

    # no assignment to structure fields
    [left_field_name, right_field_name].each do |field|
      module_eval <<-"end_eval", __FILE__, __LINE__
              def #{field}=(x)
                raise NameError, "Unauthorized assignment to #{field}: it's an internal field handled by acts_as_nested_set code, use move_to_* methods instead.", "#{field}"
              end
      end_eval
    end

    scope :roots, lambda {
      where(parent_field_name => nil).asc(left_field_name)
    }
    scope :leaves, lambda {
      where("this.#{quoted_right_field_name} - this.#{quoted_left_field_name} == 1").asc(left_field_name)
    }
    scope :with_depth, lambda { |level|
      where(:depth => level).asc(left_field_name)
    }

  end
end