Module: Mongoid::Tree::Ordering

Extended by:
ActiveSupport::Concern
Defined in:
lib/mongoid/tree/ordering.rb

Overview

Mongoid::Tree::Ordering

Mongoid::Tree doesn’t order the tree by default. To enable ordering of children include both Mongoid::Tree and Mongoid::Tree::Ordering into your document.

Utility methods

This module adds methods to get related siblings depending on their position:

node.lower_siblings
node.higher_siblings
node.first_sibling_in_list
node.last_sibling_in_list

There are several methods to move nodes around in the list:

node.move_up
node.move_down
node.move_to_top
node.move_to_bottom
node.move_above(other)
node.move_below(other)

Additionally there are some methods to check aspects of the document in the list of children:

node.at_top?
node.at_bottom?

Instance Method Summary collapse

Instance Method Details

#ancestors ⇒ Object

Returns a chainable criteria for this document’s ancestors



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# File 'lib/mongoid/tree/ordering.rb', line 47

def ancestors
  base_class.unscoped.where(:_id.in => parent_ids)
end

#at_bottom? ⇒ Boolean

Is this the lowest sibling?

Returns:

  • (Boolean) 


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# File 'lib/mongoid/tree/ordering.rb', line 85

def at_bottom?
  lower_siblings.empty?
end

#at_top? ⇒ Boolean

Is this the highest sibling?

Returns:

  • (Boolean) 


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# File 'lib/mongoid/tree/ordering.rb', line 79

def at_top?
  higher_siblings.empty?
end

#first_sibling_in_list ⇒ Object

Returns the highest sibling (could be self)



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# File 'lib/mongoid/tree/ordering.rb', line 73

def first_sibling_in_list
  siblings_and_self.first
end

#higher_siblings ⇒ Object

Returns siblings above the current document. Siblings with a position lower than this documents’s position.



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# File 'lib/mongoid/tree/ordering.rb', line 61

def higher_siblings
  self.siblings.where(:position.lt => self.position)
end

#last_sibling_in_list ⇒ Object

Returns the lowest sibling (could be self)



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# File 'lib/mongoid/tree/ordering.rb', line 67

def last_sibling_in_list
  siblings_and_self.last
end

#lower_siblings ⇒ Object

Returns siblings below the current document. Siblings with a position greater than this documents’s position.



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# File 'lib/mongoid/tree/ordering.rb', line 54

def lower_siblings
  self.siblings.where(:position.gt => self.position)
end

#move_above(other) ⇒ Object

Move this node above the specified node

This method changes the node’s parent if nescessary.



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# File 'lib/mongoid/tree/ordering.rb', line 123

def move_above(other)
  unless sibling_of?(other)
    self.parent_id = other.parent_id
    save!
  end

  if position > other.position
    new_position = other.position
    other.lower_siblings.where(:position.lt => self.position).each { |s| s.inc(:position, 1) }
    other.inc(:position, 1)
    self.position = new_position
    save!
  else
    new_position = other.position - 1
    other.higher_siblings.where(:position.gt => self.position).each { |s| s.inc(:position, -1) }
    self.position = new_position
    save!
  end
end

#move_below(other) ⇒ Object

Move this node below the specified node

This method changes the node’s parent if nescessary.



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# File 'lib/mongoid/tree/ordering.rb', line 147

def move_below(other)
  unless sibling_of?(other)
    self.parent_id = other.parent_id
    save!
  end

  if position > other.position
    new_position = other.position + 1
    other.lower_siblings.where(:position.lt => self.position).each { |s| s.inc(:position, 1) }
    self.position = new_position
    save!
  else
    new_position = other.position
    other.higher_siblings.where(:position.gt => self.position).each { |s| s.inc(:position, -1) }
    other.inc(:position, -1)
    self.position = new_position
    save!
  end
end

#move_down ⇒ Object

Move this node one position down



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# File 'lib/mongoid/tree/ordering.rb', line 113

def move_down
  return if at_bottom?
  siblings.where(:position => self.position + 1).first.inc(:position, -1)
  inc(:position, 1)
end

#move_to_bottom ⇒ Object

Move this node below all its siblings



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# File 'lib/mongoid/tree/ordering.rb', line 98

def move_to_bottom
  return true if at_bottom?
  move_below(last_sibling_in_list)
end

#move_to_top ⇒ Object

Move this node above all its siblings



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# File 'lib/mongoid/tree/ordering.rb', line 91

def move_to_top
  return true if at_top?
  move_above(first_sibling_in_list)
end

#move_up ⇒ Object

Move this node one position up



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# File 'lib/mongoid/tree/ordering.rb', line 105

def move_up
  return if at_top?
  siblings.where(:position => self.position - 1).first.inc(:position, 1)
  inc(:position, -1)
end