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

When destroying an instance, move all entries after the instance down one position, so that there aren‘t any gaps

    # File lib/sequel/plugins/list.rb, line 94
94:         def after_destroy
95:           super
96: 
97:           f = Sequel[position_field]
98:           list_dataset.where(f > position_value).update(f => f - 1)
99:         end

at_position(p)

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

[Source]

    # File lib/sequel/plugins/list.rb, line 88
88:         def at_position(p)
89:           list_dataset.first(position_field => p)
90:         end

before_validation()

Set the value of the position_field to the maximum value plus 1 unless the position field already has a value.

[Source]

     # File lib/sequel/plugins/list.rb, line 175
175:         def before_validation
176:           unless get_column_value(position_field)
177:             set_column_value("#{position_field}=", list_dataset.max(position_field).to_i+1)
178:           end
179:           super
180:         end

last_position()

Find the last position in the list containing this instance.

[Source]

     # File lib/sequel/plugins/list.rb, line 102
102:         def last_position
103:           list_dataset.max(position_field).to_i
104:         end

list_dataset()

A dataset that represents the list containing this instance.

[Source]

     # File lib/sequel/plugins/list.rb, line 107
107:         def list_dataset
108:           model.scope_proc ? model.scope_proc.call(self) : model.dataset
109:         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 113
113:         def move_down(n = 1)
114:           move_to(position_value + n)
115:         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 119
119:         def move_to(target, lp = nil)
120:           current = position_value
121:           if target != current
122:             checked_transaction do
123:               ds = list_dataset
124:               op, ds = if target < current
125:                 target = 1 if target < 1
126:                 [:+, ds.where(position_field=>target...current)]
127:               else
128:                 lp ||= last_position
129:                 target = lp if target > lp
130:                 [:-, ds.where(position_field=>(current + 1)..target)]
131:               end
132:               ds.update(position_field => Sequel::SQL::NumericExpression.new(op, position_field, 1))
133:               update(position_field => target)
134:             end
135:           end
136:           self
137:         end

move_to_bottom()

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

[Source]

     # File lib/sequel/plugins/list.rb, line 140
140:         def move_to_bottom
141:           lp = last_position 
142:           move_to(lp, lp)
143:         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 146
146:         def move_to_top
147:           move_to(1)
148:         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 152
152:         def move_up(n = 1)
153:           move_to(position_value - n) 
154:         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 158
158:         def next(n = 1)
159:           n == 0 ? self : at_position(position_value + n)
160:         end

position_value()

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

[Source]

     # File lib/sequel/plugins/list.rb, line 163
163:         def position_value
164:           get_column_value(position_field)
165:         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 169
169:         def prev(n = 1)
170:           self.next(n * -1)
171:         end

Methods

Public Instance methods