Module: EvenBetterNestedSet

Defined in:
lib/eb_nested_set.rb

Defined Under Namespace

Modules: NestedSet Classes: IllegalAssignmentError, NestedSetError

Instance Method Summary collapse

Instance Method Details

#acts_as_nested_set(options = {}) ⇒ Object

Declare this model as a nested set. Automatically adds all methods in EvenBetterNestedSet::NestedSet to the model, as well as parent and children associations.

Options

left [Symbol]

the name of the column that contains the left boundary [Defaults to left]

right [Symbol]

the name of the column that contains the right boundary [Defaults to right]

scope [Symbol]

the name of an association to scope this nested set to

Parameters:

  • options (Hash) (defaults to: {}) —

    a set of options



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# File 'lib/eb_nested_set.rb', line 18

def acts_as_nested_set(options={})
  options = { :left => :left, :right => :right }.merge!(options)
  options[:scope] = "#{options[:scope]}_id" if options[:scope]

  include NestedSet

  self.nested_set_options = options

  class_eval "    def \#{options[:left]}=(left)\n      raise EvenBetterNestedSet::IllegalAssignmentError, \"\#{options[:left]} is an internal attribute used by EvenBetterNestedSet, do not assign it directly as is may corrupt the data in your database\"\n    end\n\n    def \#{options[:right]}=(right)\n      raise EvenBetterNestedSet::IllegalAssignmentError, \"\#{options[:right]} is an internal attribute used by EvenBetterNestedSet, do not assign it directly as is may corrupt the data in your database\"\n    end\n  RUBY\n\n  named_scope :roots, :conditions => { :parent_id => nil }, :order => \"\#{nested_set_column(:left)} asc\"\n  has_many :children, :class_name => self.name, :foreign_key => :parent_id, :order => \"\#{nested_set_column(:left)} asc\"\n  belongs_to :parent, :class_name => self.name, :foreign_key => :parent_id\n\n  named_scope :descendants, lambda { |node|\n    left, right = find_boundaries(node.id)\n    { :conditions => [\"\#{nested_set_column(:left)} > ? and \#{nested_set_column(:right)} < ?\", left, right],\n      :order => \"\#{nested_set_column(:left)} asc\" }\n  }\n\n  before_create :append_node\n  before_update :move_node\n  before_destroy :reload\n  after_destroy :remove_node\n  validate_on_update :illegal_nesting\n  validate :validate_parent_is_within_scope\n\n  delegate :nested_set_column, :to => \"self.class\"\nend\n", __FILE__, __LINE__+1