Module: CollectiveIdea::Acts::NestedSet::Model::Movable

Defined in:
lib/awesome_nested_set/model/movable.rb

Instance Method Summary collapse

Instance Method Details

#find_left_neighbor(parent, order_attribute, ascending) ⇒ Object

Find the node immediately to the left of this node.


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# File 'lib/awesome_nested_set/model/movable.rb', line 87

def find_left_neighbor(parent, order_attribute, ascending)
  left = nil
  parent.children.each do |n|
    if ascending
      left = n if n.send(order_attribute) < self.send(order_attribute)
    else
      left = n if n.send(order_attribute) > self.send(order_attribute)
    end
  end
  left
end

#move_leftObject

Shorthand method for finding the left sibling and moving to the left of it.


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# File 'lib/awesome_nested_set/model/movable.rb', line 18

def move_left
  move_to_left_of left_sibling
end

#move_possible?(target) ⇒ Boolean

Returns:

  • (Boolean)

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# File 'lib/awesome_nested_set/model/movable.rb', line 9

def move_possible?(target)
  self != target && # Can't target self
    same_scope?(target) && # can't be in different scopes
    # detect impossible move
    within_bounds?(target.left, target.left) &&
    within_bounds?(target.right, target.right)
end

#move_rightObject

Shorthand method for finding the right sibling and moving to the right of it.


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# File 'lib/awesome_nested_set/model/movable.rb', line 23

def move_right
  move_to_right_of right_sibling
end

#move_to(target, position) ⇒ Object


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# File 'lib/awesome_nested_set/model/movable.rb', line 99

def move_to(target, position)
  prevent_unpersisted_move

  run_callbacks :move do
    in_tenacious_transaction do
      target = reload_target(target, position)
      self.reload_nested_set

      Move.new(target, position, self).move
      update_counter_cache
    end
    after_move_to(target, position)
  end
end

#move_to_child_of(node) ⇒ Object

Move the node to the child of another node


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# File 'lib/awesome_nested_set/model/movable.rb', line 38

def move_to_child_of(node)
  move_to node, :child
end

#move_to_child_with_index(node, index) ⇒ Object

Move the node to the child of another node with specify index


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# File 'lib/awesome_nested_set/model/movable.rb', line 43

def move_to_child_with_index(node, index)
  if node.children.empty?
    move_to_child_of(node)
  elsif node.children.count == index
    move_to_right_of(node.children.last)
  else
    my_position = node.children.to_a.index(self)
    if my_position && my_position < index
      # e.g. if self is at position 0 and we want to move self to position 1 then self
      # needs to move to the *right* of the node at position 1. That's because the node
      # that is currently at position 1 will be at position 0 after the move completes.
      move_to_right_of(node.children[index])
    elsif my_position && my_position == index
      # do nothing. already there.
    else
      move_to_left_of(node.children[index])
    end
  end
end

#move_to_left_of(node) ⇒ Object

Move the node to the left of another node


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# File 'lib/awesome_nested_set/model/movable.rb', line 28

def move_to_left_of(node)
  move_to node, :left
end

#move_to_ordered_child_of(parent, order_attribute, ascending = true) ⇒ Object

Order children in a nested set by an attribute Can order by any attribute class that uses the Comparable mixin, for example a string or integer Usage example when sorting categories alphabetically: @new_category.move_to_ordered_child_of(@root, “name”)


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# File 'lib/awesome_nested_set/model/movable.rb', line 71

def move_to_ordered_child_of(parent, order_attribute, ascending = true)
  self.move_to_root and return unless parent

  left_neighbor = find_left_neighbor(parent, order_attribute, ascending)
  self.move_to_child_of(parent)

  return unless parent.children.many?

  if left_neighbor
    self.move_to_right_of(left_neighbor)
  else # Self is the left most node.
    self.move_to_left_of(parent.children[0])
  end
end

#move_to_right_of(node) ⇒ Object

Move the node to the right of another node


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# File 'lib/awesome_nested_set/model/movable.rb', line 33

def move_to_right_of(node)
  move_to node, :right
end

#move_to_rootObject

Move the node to root nodes


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# File 'lib/awesome_nested_set/model/movable.rb', line 64

def move_to_root
  move_to self, :root
end