Module | Sequel::Plugins::List::InstanceMethods |
In: |
lib/sequel/plugins/list.rb
|
The model object at the given position in the list containing this instance.
# File lib/sequel/plugins/list.rb, line 86 86: def at_position(p) 87: list_dataset.first(position_field => p) 88: end
Set the value of the position_field to the maximum value plus 1 unless the position field already has a value.
# File lib/sequel/plugins/list.rb, line 92 92: def before_create 93: unless send(position_field) 94: send("#{position_field}=", list_dataset.max(position_field).to_i+1) 95: end 96: super 97: end
Find the last position in the list containing this instance.
# File lib/sequel/plugins/list.rb, line 100 100: def last_position 101: list_dataset.max(position_field).to_i 102: end
A dataset that represents the list containing this instance.
# File lib/sequel/plugins/list.rb, line 105 105: def list_dataset 106: model.scope_proc ? model.scope_proc.call(self) : model.dataset 107: end
Move this instance down the given number of places in the list, or 1 place if no argument is specified.
# File lib/sequel/plugins/list.rb, line 111 111: def move_down(n = 1) 112: move_to(position_value + n) 113: end
Move this instance to the given place in the list. Raises an exception if target is less than 1 or greater than the last position in the list.
# File lib/sequel/plugins/list.rb, line 117 117: def move_to(target, lp = nil) 118: current = position_value 119: if target != current 120: checked_transaction do 121: ds = list_dataset 122: op, ds = if target < current 123: raise(Sequel::Error, "Moving too far up (target = #{target})") if target < 1 124: [:+, ds.filter(position_field=>target...current)] 125: else 126: lp ||= last_position 127: raise(Sequel::Error, "Moving too far down (target = #{target}, last_position = #{lp})") if target > lp 128: [:-, ds.filter(position_field=>(current + 1)..target)] 129: end 130: ds.update(position_field => Sequel::SQL::NumericExpression.new(op, position_field, 1)) 131: update(position_field => target) 132: end 133: end 134: self 135: end
Move this instance to the bottom (last position) of the list.
# File lib/sequel/plugins/list.rb, line 138 138: def move_to_bottom 139: lp = last_position 140: move_to(lp, lp) 141: end
Move this instance to the top (first position, position 1) of the list.
# File lib/sequel/plugins/list.rb, line 144 144: def move_to_top 145: move_to(1) 146: end
Move this instance the given number of places up in the list, or 1 place if no argument is specified.
# File lib/sequel/plugins/list.rb, line 150 150: def move_up(n = 1) 151: move_to(position_value - n) 152: end
The model instance the given number of places below this model instance in the list, or 1 place below if no argument is given.
# File lib/sequel/plugins/list.rb, line 156 156: def next(n = 1) 157: n == 0 ? self : at_position(position_value + n) 158: end
The value of the model‘s position field for this instance.
# File lib/sequel/plugins/list.rb, line 161 161: def position_value 162: send(position_field) 163: end