Module: Sequel::Plugins::List::InstanceMethods

The model object at the given position in the list containing this instance.

    # File lib/sequel/plugins/list.rb, line 89
89:         def at_position(p)
90:           list_dataset.first(position_field => p)
91:         end

last_position()

Find the last position in the list containing this instance.

[Source]

    # File lib/sequel/plugins/list.rb, line 94
94:         def last_position
95:           list_dataset.max(position_field).to_i
96:         end

list_dataset()

A dataset that represents the list containing this instance.

[Source]

     # File lib/sequel/plugins/list.rb, line 99
 99:         def list_dataset
100:           model.scope_proc ? model.scope_proc.call(self) : model.dataset
101:         end

move_down(n = 1)

Move this instance down the given number of places in the list, or 1 place if no argument is specified.

[Source]

     # File lib/sequel/plugins/list.rb, line 105
105:         def move_down(n = 1)
106:           move_to(position_value + n)
107:         end

move_to(target, lp = nil)

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.

[Source]

     # File lib/sequel/plugins/list.rb, line 111
111:         def move_to(target, lp = nil)
112:           current = position_value
113:           if target != current
114:             checked_transaction do
115:               ds = list_dataset
116:               op, ds = if target < current
117:                 raise(Sequel::Error, "Moving too far up (target = #{target})") if target < 1
118:                 [:+, ds.filter(position_field=>target...current)]
119:               else
120:                 lp ||= last_position
121:                 raise(Sequel::Error, "Moving too far down (target = #{target}, last_position = #{lp})") if target > lp
122:                 [:-, ds.filter(position_field=>(current + 1)..target)]
123:               end
124:               ds.update(position_field => Sequel::SQL::NumericExpression.new(op, position_field, 1))
125:               update(position_field => target)
126:             end
127:           end
128:           self
129:         end

move_to_bottom()

Move this instance to the bottom (last position) of the list.

[Source]

     # File lib/sequel/plugins/list.rb, line 132
132:         def move_to_bottom
133:           lp = last_position 
134:           move_to(lp, lp)
135:         end

move_to_top()

Move this instance to the top (first position, position 1) of the list.

[Source]

     # File lib/sequel/plugins/list.rb, line 138
138:         def move_to_top
139:           move_to(1)
140:         end

move_up(n = 1)

Move this instance the given number of places up in the list, or 1 place if no argument is specified.

[Source]

     # File lib/sequel/plugins/list.rb, line 144
144:         def move_up(n = 1)
145:           move_to(position_value - n) 
146:         end

next(n = 1)

The model instance the given number of places below this model instance in the list, or 1 place below if no argument is given.

[Source]

     # File lib/sequel/plugins/list.rb, line 150
150:         def next(n = 1)
151:           n == 0 ? self : at_position(position_value + n)
152:         end

position_value()

The value of the model‘s position field for this instance.

[Source]

     # File lib/sequel/plugins/list.rb, line 155
155:         def position_value
156:           send(position_field)
157:         end

prev(n = 1)

The model instance the given number of places below this model instance in the list, or 1 place below if no argument is given.

[Source]

     # File lib/sequel/plugins/list.rb, line 161
161:         def prev(n = 1)
162:           self.next(n * -1)
163:         end

Methods

Public Instance methods