Module: ActsAsListAR::InstanceMethods

Defined in:
lib/acts_as_list_ar.rb,
lib/acts_as_list_ar/rails2.rb,
lib/acts_as_list_ar/rails3.rb

Overview

All the methods available to a record that has had acts_as_list specified. Each method works by assuming the object to be the item in the list, so chapter.move_lower would move that chapter lower in the list of all chapters. Likewise, chapter.first? would return true if that chapter is the first in the list of all chapters.

Instance Method Summary collapse

Instance Method Details

#decrement_position ⇒ Object

Decrease the position of this item without adjusting the rest of the list.



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# File 'lib/acts_as_list_ar.rb', line 151

def decrement_position
  # return unless in_list?
  update_attribute position_column, self.send(position_column).to_i - 1
end

#first? ⇒ Boolean

Return true if this object is the first in the list.

Returns:

  • (Boolean) 


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# File 'lib/acts_as_list_ar.rb', line 157

def first?
  # return false unless in_list?
  self.send(position_column) == 1
end

#higher_item ⇒ Object

Return the next higher item in the list.



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# File 'lib/acts_as_list_ar.rb', line 169

def higher_item
  # return nil unless in_list?  # http://github.com/brightspark3/acts_as_list/commit/8e55352aaa437d23a1ebdeabd5276c6dd5aad6a1      
  acts_as_list_class.find(:first, :conditions =>
    "#{scope_condition} AND #{position_column} < #{send(position_column).to_s}", :order => "#{position_column} DESC"
  )                           
end

#in_list? ⇒ Boolean

Test if this record is in a list

Returns:

  • (Boolean) 


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# File 'lib/acts_as_list_ar.rb', line 185

def in_list?
  !send(position_column).nil?
end

#increment_position ⇒ Object

Increase the position of this item without adjusting the rest of the list.



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# File 'lib/acts_as_list_ar.rb', line 145

def increment_position
  # return unless in_list?
  update_attribute position_column, self.send(position_column).to_i + 1
end

#insert_at(position = 1) ⇒ Object

Insert the item at the given position (defaults to the top position of 1).



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# File 'lib/acts_as_list_ar.rb', line 61

def insert_at(position = 1)
  insert_at_position(position)
end

#insert_at_bottom ⇒ Object

Inserts the item at the bottom of the list



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# File 'lib/acts_as_list_ar.rb', line 66

def insert_at_bottom
  assume_bottom_position
end

#insert_into(list, options = {}) ⇒ Object 



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# File 'lib/acts_as_list_ar.rb', line 70

def insert_into(list, options = {})
  position = options.delete(:position) || list.size
  options.each { |attr, value| self.send "#{attr}=", value }

  list.insert(position, self)
  list.each_with_index { |item, index| item.update_attribute(:position, index + 1) }
end

#last? ⇒ Boolean

Return true if this object is the last in the list.

Returns:

  • (Boolean) 


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# File 'lib/acts_as_list_ar.rb', line 163

def last?
  # return false unless in_list?
  self.send(position_column) == bottom_position_in_list
end

#lower_item ⇒ Object

Return the next lower item in the list.



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# File 'lib/acts_as_list_ar.rb', line 177

def lower_item
  # return nil unless in_list?
  acts_as_list_class.find(:first, :conditions => 
    "#{scope_condition} AND #{position_column} > #{send(position_column).to_s}", :order => "#{position_column} ASC"
  )
end

#move_higher ⇒ Object

Swap positions with the next higher item, if one exists.



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# File 'lib/acts_as_list_ar.rb', line 103

def move_higher
  higher = higher_item
  return unless higher
  acts_as_list_class.transaction do
    self.update_attribute(position_column, higher.send(position_column))
    higher.increment_position
  end
end

#move_lower ⇒ Object

Swap positions with the next lower item, if one exists.



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# File 'lib/acts_as_list_ar.rb', line 93

def move_lower
  lower = lower_item
  return unless lower
  acts_as_list_class.transaction do
    self.update_attribute(position_column, lower.send(position_column))
    lower.decrement_position
  end
end

#move_to(position = 1) ⇒ Object 



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# File 'lib/acts_as_list_ar.rb', line 78

def move_to(position = 1)
  move_to_position(position)
end

#move_to_bottom ⇒ Object

Move to the bottom of the list. If the item is already in the list, the items below it have their position adjusted accordingly.



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# File 'lib/acts_as_list_ar.rb', line 114

def move_to_bottom
  # return unless in_list?
  acts_as_list_class.transaction do
    decrement_positions_on_lower_items if in_list?
    assume_bottom_position
  end
end

#move_to_top ⇒ Object

Move to the top of the list. If the item is already in the list, the items above it have their position adjusted accordingly.



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# File 'lib/acts_as_list_ar.rb', line 124

def move_to_top
  # return unless in_list?
  acts_as_list_class.transaction do
    # increment_positions_on_higher_items
    in_list? ? increment_positions_on_higher_items : increment_positions_on_all_items
    assume_top_position
  end
end

#remove_from(list, options = {}) ⇒ Object 



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# File 'lib/acts_as_list_ar.rb', line 82

def remove_from(list, options = {})
  if in_list?
    decrement_positions_on_lower_items

    self.send "#{position_column}=", nil
    options.each { |attr, value| self.send "#{attr}=", value }
    list.delete self
  end
end

#remove_from_list ⇒ Object

Removes the item from the list.



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# File 'lib/acts_as_list_ar.rb', line 134

def remove_from_list
  # if in_list?
  #   decrement_positions_on_lower_items
  #   update_attribute position_column, nil
  # end            
  return unless in_list?
  decrement_positions_on_lower_items
  update_attribute position_column, nil        
end