Module: ActiveRecord::Acts::List::InstanceMethods

Defined in:
lib/acts_as_list/active_record/acts/list.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/active_record/acts/list.rb', line 150

def decrement_position
  return unless in_list?
  update_attributes! position_column => self.send(position_column).to_i - 1
end

#default_position ⇒ Object 



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# File 'lib/acts_as_list/active_record/acts/list.rb', line 192

def default_position
  acts_as_list_class.columns_hash[position_column.to_s].default
end

#default_position? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/acts_as_list/active_record/acts/list.rb', line 196

def default_position?
  default_position == send(position_column)
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/active_record/acts/list.rb', line 156

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

#higher_item ⇒ Object

Return the next higher item in the list.



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# File 'lib/acts_as_list/active_record/acts/list.rb', line 168

def higher_item
  return nil unless in_list?
  acts_as_list_class.unscoped.find(:first, :conditions =>
    "#{scope_condition} AND #{position_column} = #{(send(position_column).to_i - 1).to_s}"
  )
end

#in_list? ⇒ Boolean

Test if this record is in a list

Returns:

  • (Boolean) 


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# File 'lib/acts_as_list/active_record/acts/list.rb', line 184

def in_list?
  !not_in_list?
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/active_record/acts/list.rb', line 144

def increment_position
  return unless in_list?
  update_attributes! position_column => self.send(position_column).to_i + 1
end

#insert_at(position = acts_as_list_top) ⇒ Object

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



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# File 'lib/acts_as_list/active_record/acts/list.rb', line 91

def insert_at(position = acts_as_list_top)
  insert_at_position(position)
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/active_record/acts/list.rb', line 162

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/active_record/acts/list.rb', line 176

def lower_item
  return nil unless in_list?
  acts_as_list_class.unscoped.find(:first, :conditions =>
    "#{scope_condition} AND #{position_column} = #{(send(position_column).to_i + 1).to_s}"
  )
end

#move_higher ⇒ Object

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



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# File 'lib/acts_as_list/active_record/acts/list.rb', line 106

def move_higher
  return unless higher_item

  acts_as_list_class.transaction do
    higher_item.increment_position
    decrement_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/active_record/acts/list.rb', line 96

def move_lower
  return unless lower_item

  acts_as_list_class.transaction do
    lower_item.decrement_position
    increment_position
  end
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/active_record/acts/list.rb', line 117

def move_to_bottom
  return unless in_list?
  acts_as_list_class.transaction do
    decrement_positions_on_lower_items
    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/active_record/acts/list.rb', line 127

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

#not_in_list? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/acts_as_list/active_record/acts/list.rb', line 188

def not_in_list?
  send(position_column).nil?
end

#remove_from_list ⇒ Object

Removes the item from the list.



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# File 'lib/acts_as_list/active_record/acts/list.rb', line 136

def remove_from_list
  if in_list?
    decrement_positions_on_lower_items
    update_attributes! position_column => nil
  end
end