Module: OpenStax::Utilities::ActsAsNumberable

Included in:
ActiveRecord::Base
Defined in:
lib/openstax/utilities/acts_as_numberable.rb

Defined Under Namespace

Modules: BasicInstanceMethods, ContainerInstanceMethods

Instance Method Summary collapse

Instance Method Details

#acts_as_numberable(options = {}) ⇒ Object

Adds code to an ActiveRecord object so that it can be sorted.

Examples:

Model is ordered globally using a ‘number’ field

class MyModel < ActiveRecord::Base
  acts_as_numberable

Model is ordered globally using a ‘position’ field

class MyModel < ActiveRecord::Base
  acts_as_numberable :number_field => :position

Model is ordered within a container class using a position field

class MyModel < ActiveRecord::Base
  belongs_to :other_model
  acts_as_numberable :container => :other_model,
                     :number_field => :position

Parameters:

  • :container —

    The relationship that contains this model in an order. Note that this code assumes the foreign key for this container is found by appending “_id” onto the container name, which might not always be the case.

  • :number_field —

    The column to use as the sorting number, given either as a string or a symbol. The default is ‘number’

  • :table_class —

    By default this code assumes that the database table name to use for this model can be derived from the model’s class name; in some cases (e.g. STI) this is not the case and this parameter can be used to manually specify the class from which to derive the database table name.



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# File 'lib/openstax/utilities/acts_as_numberable.rb', line 32

def acts_as_numberable(options={})
  configuration = {}
  configuration.update(options) if options.is_a?(Hash)
 
  container_column = nil
  container_column_symbol = nil

  # When calling assign_number below, you normally want to run a query against
  # self.class to figure out what the next available number is; however, if the 
  # class acting as numberable is using STI, self.class will return the child class
  # which is likely not what we want.  In these cases, we can specify the base
  # class here (the class that has the same name as the DB table) so that it is used
  # instead.
  table_class = configuration[:table_class]

  number_field = (configuration[:number_field] || 'number').to_s
  
  if !configuration[:container].nil?
    container_column = configuration[:container].to_s + "_id"
    container_column_symbol = configuration[:container].to_sym
  end
  
  uniqueness_scope_string = container_column.nil? ? "" : ":scope => :#{container_column},"
 
  class_eval "    include ActsAsNumberable::BasicInstanceMethods\n  \n    before_validation :assign_number, :on => :create\n    \n    validates :\#{number_field}, :uniqueness => { \#{uniqueness_scope_string}\n                                                 :allow_nil => true},\n                                :numericality => { :only_integer => true, \n                                                   :greater_than_or_equal_to => 0,\n                                                   :allow_nil => true }    \n\n    \n    after_destroy :mark_as_destroyed\n    \n    attr_accessor :destroyed\n    attr_accessor :changed_sets\n\n    attr_protected :\#{number_field}\n  \n    scope :ordered, order('\#{number_field} ASC')\n    scope :reverse_ordered, order('\#{number_field} DESC')\n    \n    def self.sort!(sorted_ids)\n      return if sorted_ids.blank?\n      items = []\n      ActiveRecord::Base.transaction do\n        items = find_in_specified_order(sorted_ids)\n        \n        items.each do |item|\n          item.send('\#{number_field}=', nil)\n          item.save!\n        end\n        \n        items.each_with_index do |item, ii| \n          item.send('\#{number_field}=', ii)\n          item.save!\n        end\n      end\n      items\n    end\n\n    def table_class\n      \#{table_class}\n    end\n\n    def number_field\n      '\#{number_field}'\n    end\n  EOV\n \n \n  if !configuration[:container].nil?\n    class_eval <<-EOV\n      include ActsAsNumberable::ContainerInstanceMethods\n    \n      # When we had nested acts_as_numberables, there were cases where the\n      # objects were having their numbers changed (as their peers were being\n      # removed from the container), but then when it came time to delete those \n      # objects they still had their old number.  So just reload before\n      # destroy.\n      before_destroy(prepend: true) {self.reload}\n    \n      after_destroy :remove_from_container!\n    \n      def container_column\n        '\#{container_column}'\n      end\n\n      def container\n        '\#{configuration[:container]}'\n      end\n\n      def table_class\n        \#{table_class}\n      end\n    \n    EOV\n    \n  end\n     \nend\n"