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

Defined in:
lib/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 



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# File 'lib/active_record/acts/list.rb', line 125

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

#first? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/acts/list.rb', line 130

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

#higher_item ⇒ Object 



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# File 'lib/active_record/acts/list.rb', line 140

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

#in_list? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/acts/list.rb', line 154

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

#increment_position ⇒ Object 



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# File 'lib/active_record/acts/list.rb', line 120

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

#insert_at(position = 1) ⇒ Object 



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# File 'lib/active_record/acts/list.rb', line 78

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

#last? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/acts/list.rb', line 135

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

#lower_item ⇒ Object 



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# File 'lib/active_record/acts/list.rb', line 147

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

#move_higher ⇒ Object 



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

def move_higher
  return unless higher_item

  acts_as_list_class.transaction do
    higher_item.increment_position
    decrement_position
  end
end

#move_lower ⇒ Object 



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# File 'lib/active_record/acts/list.rb', line 82

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 



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# File 'lib/active_record/acts/list.rb', line 100

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 



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# File 'lib/active_record/acts/list.rb', line 108

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

#remove_from_list ⇒ Object 



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# File 'lib/active_record/acts/list.rb', line 116

def remove_from_list
  decrement_positions_on_lower_items if in_list?
end