Module: Mongoid::Traversable

Extended by:
ActiveSupport::Concern
Included in:
Composable
Defined in:
lib/mongoid/traversable.rb

Overview

Mixin module included in Mongoid::Document to provide behavior around traversing the document graph.

Defined Under Namespace

Modules: ClassMethods, DiscriminatorAssignment, DiscriminatorRetrieval

Instance Method Summary collapse

Instance Method Details

#_children(reset: false) ⇒ Array<Document>

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Get all child Documents to this Document

Returns:

  • (Array<Document>) —

    All child documents in the hierarchy.



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# File 'lib/mongoid/traversable.rb', line 207

def _children(reset: false)
  # See discussion above for the `_parent` method, as to why the variable
  # here needs to have two underscores.
  #
  # rubocop:disable Naming/MemoizedInstanceVariableName
  if reset
    @__children = nil
  else
    @__children ||= collect_children
  end
  # rubocop:enable Naming/MemoizedInstanceVariableName
end

#_descendants(reset: false) ⇒ Array<Document>

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Get all descendant Documents of this Document recursively. This is used when calling update persistence operations from the root document, where changes in the entire tree need to be determined. Note that persistence from the embedded documents will always be preferred, since they are optimized calls… This operation can get expensive in domains with large hierarchies.

Returns:

  • (Array<Document>) —

    All descendant documents in the hierarchy.



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# File 'lib/mongoid/traversable.rb', line 230

def _descendants(reset: false)
  # See discussion above for the `_parent` method, as to why the variable
  # here needs to have two underscores.
  #
  # rubocop:disable Naming/MemoizedInstanceVariableName
  if reset
    @__descendants = nil
  else
    @__descendants ||= collect_descendants
  end
  # rubocop:enable Naming/MemoizedInstanceVariableName
end

#_parent ⇒ Mongoid::Document | nil

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Retrieves the parent document of this document.

Returns:



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# File 'lib/mongoid/traversable.rb', line 74

def _parent
  @__parent || nil
end

#_parent=(document) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Sets the parent document of this document.

Parameters:



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# File 'lib/mongoid/traversable.rb', line 86

def _parent=(document)
  @__parent = document
end

#_reset_memoized_descendants! ⇒ nil

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Resets the memoized descendants on the object. Called internally when an embedded array changes size.

Returns:

  • (nil) —

    nil.



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# File 'lib/mongoid/traversable.rb', line 357

def _reset_memoized_descendants!
  _parent&._reset_memoized_descendants!
  _children reset: true
  _descendants reset: true
end

#_root ⇒ Document

Return the root document in the object graph. If the current document is the root object in the graph it will return self.

Examples:

Get the root document in the hierarchy.

document._root

Returns:

  • (Document) —

    The root document in the hierarchy.



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# File 'lib/mongoid/traversable.rb', line 370

def _root
  object = self
  object = object._parent while object._parent
  object
end

#_root? ⇒ true | false

Is this document the root document of the hierarchy?

Examples:

Is the document the root?

document._root?

Returns:

  • (true | false) —

    If the document is the root.



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# File 'lib/mongoid/traversable.rb', line 382

def _root?
  _parent ? false : true
end

#collect_children ⇒ Array<Document>

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Collect all the children of this document.

Returns:



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# File 'lib/mongoid/traversable.rb', line 248

def collect_children
  [].tap do |children|
    embedded_relations.each_pair do |name, _association|
      without_autobuild do
        child = send(name)
        children.concat(Array.wrap(child)) if child
      end
    end
  end
end

#collect_descendants ⇒ Array<Document>

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Collect all the descendants of this document.

Returns:

  • (Array<Document>) —

    The descendants.



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# File 'lib/mongoid/traversable.rb', line 264

def collect_descendants
  children = []
  to_expand = _children
  expanded = {}

  until to_expand.empty?
    expanding = to_expand
    to_expand = []
    expanding.each do |child|
      next if expanded[child]

      # Don't mark expanded if _id is nil, since documents are compared by
      # their _ids, multiple embedded documents with nil ids will compare
      # equally, and some documents will not be expanded.
      expanded[child] = true if child._id
      children << child
      to_expand += child._children
    end
  end

  children
end

#flag_descendants_persisted ⇒ Array<Document>

Marks all descendants as being persisted.

Returns:

  • (Array<Document>) —

    The flagged descendants.



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# File 'lib/mongoid/traversable.rb', line 290

def flag_descendants_persisted
  _descendants.each do |child|
    child.new_record = false
  end
end

#hereditary? ⇒ true | false

Determines if the document is a subclass of another document.

Examples:

Check if the document is a subclass

Square.new.hereditary?

Returns:

  • (true | false) —

    True if hereditary, false if not.



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# File 'lib/mongoid/traversable.rb', line 302

def hereditary?
  self.class.hereditary?
end

#parentize(document) ⇒ Document

Sets up a child/parent association. This is used for newly created objects so they can be properly added to the graph.

Examples:

Set the parent document.

document.parentize(parent)

Parameters:

  • document (Document) —

    The parent document.

Returns:



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# File 'lib/mongoid/traversable.rb', line 315

def parentize(document)
  self._parent = document
end

#remove_child(child) ⇒ Object

Remove a child document from this parent. If an embeds one then set to nil, otherwise remove from the embeds many.

This is called from the RemoveEmbedded persistence command.

Examples:

Remove the child.

document.remove_child(child)

Parameters:

  • child (Document) —

    The child (embedded) document to remove.



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# File 'lib/mongoid/traversable.rb', line 328

def remove_child(child)
  name = child.association_name
  if child.embedded_one?
    attributes.delete(child._association.store_as)
    remove_ivar(name)
  else
    relation = send(name)
    relation._remove(child)
  end
end

#reset_persisted_descendants ⇒ Array<Document>

After descendants are persisted we can call this to move all their changes and flag them as persisted in one call.

Returns:

  • (Array<Document>) —

    The descendants.



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# File 'lib/mongoid/traversable.rb', line 343

def reset_persisted_descendants
  _descendants.each do |child|
    child.move_changes
    child.new_record = false
  end
  _reset_memoized_descendants!
end