Module: Mongoid::Traversable

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

Overview

Provides behavior around traversing the document graph.

Defined Under Namespace

Modules: ClassMethods, DiscriminatorAssignment, DiscriminatorRetrieval

Instance Method Summary collapse

Instance Method Details

#_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.

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 127

def _children
  @__children ||= collect_children
end

#_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.

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 141

def _descendants
  @__descendants ||= collect_descendants
end

#_parent ⇒ Object 



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# File 'lib/mongoid/traversable.rb', line 11

def _parent
  @__parent ||= nil
end

#_parent=(p) ⇒ Object 



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# File 'lib/mongoid/traversable.rb', line 15

def _parent=(p)
  @__parent = p
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 266

def _reset_memoized_descendants!
  _parent._reset_memoized_descendants! if _parent
  @__children = nil
  @__descendants = nil
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 279

def _root
  object = self
  while (object._parent) do object = object._parent; end
  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 291

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 150

def collect_children
  children = []
  embedded_relations.each_pair do |name, association|
    without_autobuild do
      child = send(name)
      if child
        children += Array.wrap(child)
      end
    end
  end
  children
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 168

def collect_descendants
  children = []
  to_expand = []
  expanded = {}
  embedded_relations.each_pair do |name, association|
    without_autobuild do
      child = send(name)
      if child
        to_expand += Array.wrap(child)
      end
    end
  end
  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 199

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 211

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 224

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 237

def remove_child(child)
  name = child.association_name
  if child.embedded_one?
    self.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 252

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