Module: Mongoid::Traversable::ClassMethods

Defined in:
lib/mongoid/traversable.rb

Overview

Class-level methods for the Traversable behavior.

Instance Method Summary collapse

Instance Method Details

#hereditary? ⇒ true | false

Determines if the document is a subclass of another document.

Examples:

Check if the document is a subclass.

Square.hereditary?

Returns:

  • (true | false) —

    True if hereditary, false if not.



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# File 'lib/mongoid/traversable.rb', line 20

def hereditary?
  !!(superclass < Mongoid::Document)
end

#inherited(subclass) ⇒ Object

When inheriting, we want to copy the fields from the parent class and set the on the child to start, mimicking the behavior of the old class_inheritable_accessor that was deprecated in Rails edge.

rubocop:disable Metrics/AbcSize

Examples:

Inherit from this class.

Person.inherited(Doctor)

Parameters:

  • subclass (Class) —

    The inheriting class.



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# File 'lib/mongoid/traversable.rb', line 34

def inherited(subclass)
  super

  # Register the new subclass with the resolver subsystem
  Mongoid::ModelResolver.register(subclass)

  @_type = nil
  subclass.aliased_fields = aliased_fields.dup
  subclass.localized_fields = localized_fields.dup
  subclass.fields = fields.dup
  subclass.pre_processed_defaults = pre_processed_defaults.dup
  subclass.post_processed_defaults = post_processed_defaults.dup
  subclass._declared_scopes = Hash.new { |_hash, key| _declared_scopes[key] }
  subclass.discriminator_value = subclass.name

  # We need to do this here because the discriminator_value method is
  # overridden in the subclass above.
  subclass.include DiscriminatorRetrieval

  # We only need the _type field if inheritance is in play, but need to
  # add to the root class as well for backwards compatibility.
  return if fields.key?(discriminator_key)

  default_proc = -> { self.class.discriminator_value }
  field(discriminator_key, default: default_proc, type: String)
end