Module ActiveRecord::Acts::NestedSet::InstanceMethods
In: vendor/rails/activerecord/lib/active_record/acts/nested_set.rb

Methods

Public Instance methods

Adds a child to this object in the tree. If this object hasn‘t been initialized, it gets set up as a root node. Otherwise, this method will update all of the other elements in the tree and shift them to the right, keeping everything balanced.

[Source]

     # File vendor/rails/activerecord/lib/active_record/acts/nested_set.rb, line 142
142:         def add_child( child )     
143:           self.reload
144:           child.reload
145: 
146:           if child.root?
147:             raise "Adding sub-tree isn\'t currently supported"
148:           else
149:             if ( (self[left_col_name] == nil) || (self[right_col_name] == nil) )
150:               # Looks like we're now the root node!  Woo
151:               self[left_col_name] = 1
152:               self[right_col_name] = 4
153:               
154:               # What do to do about validation?
155:               return nil unless self.save
156:               
157:               child[parent_column] = self.id
158:               child[left_col_name] = 2
159:               child[right_col_name]= 3
160:               return child.save
161:             else
162:               # OK, we need to add and shift everything else to the right
163:               child[parent_column] = self.id
164:               right_bound = self[right_col_name]
165:               child[left_col_name] = right_bound
166:               child[right_col_name] = right_bound + 1
167:               self[right_col_name] += 2
168:               self.class.transaction {
169:                 self.class.update_all( "#{left_col_name} = (#{left_col_name} + 2)",  "#{scope_condition} AND #{left_col_name} >= #{right_bound}" )
170:                 self.class.update_all( "#{right_col_name} = (#{right_col_name} + 2)",  "#{scope_condition} AND #{right_col_name} >= #{right_bound}" )
171:                 self.save
172:                 child.save
173:               }
174:             end
175:           end                                   
176:         end

Returns a set of all of its children and nested children

[Source]

     # File vendor/rails/activerecord/lib/active_record/acts/nested_set.rb, line 189
189:         def all_children
190:           self.class.find(:all, :conditions => "#{scope_condition} AND (#{left_col_name} > #{self[left_col_name]}) and (#{right_col_name} < #{self[right_col_name]})" )
191:         end

Prunes a branch off of the tree, shifting all of the elements on the right back to the left so the counts still work.

[Source]

     # File vendor/rails/activerecord/lib/active_record/acts/nested_set.rb, line 200
200:         def before_destroy
201:           return if self[right_col_name].nil? || self[left_col_name].nil?
202:           dif = self[right_col_name] - self[left_col_name] + 1
203: 
204:           self.class.transaction {
205:             self.class.delete_all( "#{scope_condition} and #{left_col_name} > #{self[left_col_name]} and #{right_col_name} < #{self[right_col_name]}" )
206:             self.class.update_all( "#{left_col_name} = (#{left_col_name} - #{dif})",  "#{scope_condition} AND #{left_col_name} >= #{self[right_col_name]}" )
207:             self.class.update_all( "#{right_col_name} = (#{right_col_name} - #{dif} )",  "#{scope_condition} AND #{right_col_name} >= #{self[right_col_name]}" )
208:           }
209:         end

Returns true is this is a child node

[Source]

     # File vendor/rails/activerecord/lib/active_record/acts/nested_set.rb, line 127
127:         def child?                          
128:           parent_id = self[parent_column]
129:           !(parent_id == 0 || parent_id.nil?) && (self[left_col_name] > 1) && (self[right_col_name] > self[left_col_name])
130:         end

Returns the number of nested children of this object.

[Source]

     # File vendor/rails/activerecord/lib/active_record/acts/nested_set.rb, line 179
179:         def children_count
180:           return (self[right_col_name] - self[left_col_name] - 1)/2
181:         end

Returns a set of only this entry‘s immediate children

[Source]

     # File vendor/rails/activerecord/lib/active_record/acts/nested_set.rb, line 194
194:         def direct_children
195:           self.class.find(:all, :conditions => "#{scope_condition} and #{parent_column} = #{self.id}")
196:         end

Returns a set of itself and all of its nested children

[Source]

     # File vendor/rails/activerecord/lib/active_record/acts/nested_set.rb, line 184
184:         def full_set
185:           self.class.find(:all, :conditions => "#{scope_condition} AND (#{left_col_name} BETWEEN #{self[left_col_name]} and #{self[right_col_name]})" )
186:         end

Returns true is this is a root node.

[Source]

     # File vendor/rails/activerecord/lib/active_record/acts/nested_set.rb, line 121
121:         def root?
122:           parent_id = self[parent_column]
123:           (parent_id == 0 || parent_id.nil?) && (self[left_col_name] == 1) && (self[right_col_name] > self[left_col_name])
124:         end

Returns true if we have no idea what this is

[Source]

     # File vendor/rails/activerecord/lib/active_record/acts/nested_set.rb, line 133
133:         def unknown?
134:           !root? && !child?
135:         end

[Validate]