Module: RailsExtensions::HabtmList::AssociationListMethods

Defined in:
lib/webpulser-habtm_list.rb

Instance Method Summary collapse

Instance Method Details

#add_to_list_bottom(item) ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 181

def add_to_list_bottom(item)
  item.save! if item.id.nil? # Rails 2.0.2 - Callbacks don't save first on association.create()
  list_item_class.transaction do
    assume_bottom_position(item)
  end
  resort_array
end

#add_to_list_top(item) ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 189

def add_to_list_top(item)
  list_item_class.transaction do
    increment_positions_on_all_items
    assume_top_position(item)
  end
  resort_array
end

#assume_bottom_position(item) ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 251

def assume_bottom_position(item)
  set_position(item, self.length - 1)
end

#assume_top_position(item) ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 255

def assume_top_position(item)
  set_position(item, 0)
end

#decrement_position(item) ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 275

def decrement_position(item)
  increment_position_by(item, -1)
end

#decrement_positions_on_higher_items(position) ⇒ Object

This has the effect of moving all the higher items up one.



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# File 'lib/webpulser-habtm_list.rb', line 280

def decrement_positions_on_higher_items(position)
  connection.update(
    "UPDATE #{join_table} SET #{position_column} = (#{position_column} - 1) " +
    "WHERE #{foreign_key} = #{owner.id} AND #{position_column} <= #{position}"
  )
  target.each { |obj|
    obj[position_column] = obj[position_column].to_i - 1 if in_list?(obj) && obj[position_column].to_i <= position
  } if target
end

#decrement_positions_on_lower_items(item) ⇒ Object

This has the effect of moving all the lower items up one.



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# File 'lib/webpulser-habtm_list.rb', line 85

def decrement_positions_on_lower_items(item)
  return unless in_list?(item)
  position = list_position(item)
  connection.update(
    "UPDATE #{join_table} SET #{position_column} = (#{position_column} - 1) " +
    "WHERE #{foreign_key} = #{owner.id} AND #{position_column} > #{position}"
  )
  target.each { |obj|
    obj[position_column] = obj[position_column].to_i - 1 if in_list?(obj) && obj[position_column].to_i > position
  } if target
end

#first?(item) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/webpulser-habtm_list.rb', line 159

def first?(item)
  item == self.first
end

#foreign_key ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 239

def foreign_key
  proxy_association.reflection.primary_key_name
end

#higher_item(item) ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 167

def higher_item(item)
  return nil unless in_list?(item)
  self.find(:first, :conditions => "#{position_column} = #{(list_position(item) - 1).to_s}")
end

#in_list?(item) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/webpulser-habtm_list.rb', line 177

def in_list?(item)
  self.include?(item)
end

#increment_position(item) ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 271

def increment_position(item)
  increment_position_by(item, 1)
end

#increment_position_by(item, increment) ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 259

def increment_position_by(item, increment)
  return unless in_list?(item)
  connection.update(
    "UPDATE #{join_table} SET #{position_column} = #{position_column} + (#{increment}) " +
    "WHERE #{foreign_key} = #{owner.id} AND #{list_item_foreign_key} = #{item.id}"
  )
  if target
    obj = target.find {|obj| obj.id == item.id}
    obj[position_column] = obj[position_column].to_i + increment if obj
  end
end

#increment_positions_on_all_items ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 301

def increment_positions_on_all_items
  connection.update(
    "UPDATE #{join_table} SET #{position_column} = (#{position_column} + 1) " +
    "WHERE #{foreign_key} = #{owner.id}"
  )
  target.each { |obj|
    obj[position_column] = obj[position_column].to_i + 1 if in_list?(obj)
  } if target
end

#increment_positions_on_higher_items(item) ⇒ Object

This has the effect of moving all the higher items down one.



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# File 'lib/webpulser-habtm_list.rb', line 98

def increment_positions_on_higher_items(item)
  return unless in_list?(item)
  position = list_position(item)
  connection.update(
    "UPDATE #{join_table} SET #{position_column} = (#{position_column} + 1) " +
    "WHERE #{foreign_key} = #{owner.id} AND #{position_column} < #{position}"
  )
  target.each { |obj|
    obj[position_column] = obj[position_column].to_i + 1 if in_list?(obj) && obj[position_column].to_i < position
  } if target
end

#increment_positions_on_lower_items(position) ⇒ Object

This has the effect of moving all the lower items down one.



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# File 'lib/webpulser-habtm_list.rb', line 291

def increment_positions_on_lower_items(position)
  connection.update(
    "UPDATE #{join_table} SET #{position_column} = (#{position_column} + 1) " +
    "WHERE #{foreign_key} = #{owner.id} AND #{position_column} >= #{position}"
  )
  target.each { |obj|
    obj[position_column] = obj[position_column].to_i + 1 if in_list?(obj) && obj[position_column].to_i >= position
  } if target
end

#insert_at_position(item, position) ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 79

def insert_at_position(item, position)
  increment_positions_on_lower_items(position)
  set_position(item, position)
end

#join_table ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 235

def join_table
  proxy_association.reflection.options[:join_table]
end

#last?(item) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/webpulser-habtm_list.rb', line 163

def last?(item)
  item == self.last
end

#list_item_class ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 223

def list_item_class
  proxy_association.reflection.klass
end

#list_item_foreign_key ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 243

def list_item_foreign_key
  proxy_association.reflection.association_foreign_key
end

#list_position(item) ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 247

def list_position(item)
  self.index(item)
end

#lower_item(item) ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 172

def lower_item(item)
  return nil unless in_list?(item)
  self.find(:first, :conditions => "#{position_column} = #{(list_position(item) + 1).to_s}")
end

#move_higher(item) ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 131

def move_higher(item)
  list_item_class.transaction do
    higher = higher_item(item)
    return unless higher
    increment_position(higher)
    decrement_position(item)
  end
  resort_array
end

#move_lower(item) ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 121

def move_lower(item)
  list_item_class.transaction do
    lower = lower_item(item)
    return unless lower
    decrement_position(lower)
    increment_position(item)
  end
  resort_array
end

#move_to_bottom(item) ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 141

def move_to_bottom(item)
  return unless in_list?(item)
  list_item_class.transaction do
    decrement_positions_on_lower_items(item)
    assume_bottom_position(item)
  end
  resort_array
end

#move_to_position(item, position) ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 64

def move_to_position(item, position)
  #return if !in_list?(item) || position.to_i == list_position(item)
  list_item_class.transaction do
    remove_from_list(item)
    decrement_positions_on_lower_items(item)
    insert_at_position(item, position)
  end
  resort_array
end

#move_to_top(item) ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 150

def move_to_top(item)
  return unless in_list?(item)
  list_item_class.transaction do
    increment_positions_on_higher_items(item)
    assume_top_position(item)
  end
  resort_array
end

#owner ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 227

def owner
  proxy_association.owner
end

#position_column ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 219

def position_column
  proxy_association.reflection.options[:order] || 'position'
end

#remove_from_list(item) ⇒ Object

should only be called externally from the before_remove callback



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# File 'lib/webpulser-habtm_list.rb', line 75

def remove_from_list(item)
  item[position_column] = nil
end

#reset_positions ⇒ Object

“First aid” method in case someone shifts the array around outside these methods, or the positions in the joins table go totally out of whack. Don’t use it for simple ordering because it’s inefficient.



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# File 'lib/webpulser-habtm_list.rb', line 200

def reset_positions
  self.each_index do |i|
    item = self[i]
    connection.update(
      "UPDATE #{join_table} SET #{position_column} = #{i} " +
      "WHERE #{foreign_key} = #{owner.id} AND #{list_item_foreign_key} = #{item.id}"
    )
  end
end

#reset_positions_by_ids(ids = self.collect(&:id)) ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 210

def reset_positions_by_ids(ids = self.collect(&:id))
  ids.each_with_index do |id, i|
    connection.update(
      "UPDATE #{join_table} SET #{position_column} = #{i} " +
      "WHERE #{foreign_key} = #{owner.id} AND #{list_item_foreign_key} = #{id}"
    ) if id.to_i != 0
  end
end

#resort_array ⇒ Object

called after changing position values so the array reflects the updated ordering



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# File 'lib/webpulser-habtm_list.rb', line 312

def resort_array
  target.sort! {|x,y| x[position_column].to_i <=> y[position_column].to_i} if target
end

#set_position(item, position) ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 110

def set_position(item, position)
  connection.update(
    "UPDATE #{join_table} SET #{position_column} = #{position} " +
    "WHERE #{foreign_key} = #{owner.id} AND #{list_item_foreign_key} = #{item.id}"
  ) if owner.id
  if target
    obj = target.find {|obj| obj.id == item.id}
    obj[position_column] = position if obj
  end
end

#target ⇒ Object 



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# File 'lib/webpulser-habtm_list.rb', line 231

def target
  proxy_association.target
end