root/trunk/app/models/node_link.rb @ 1

class NodeLink < AbstractModel

        property :node_id, "Node"
        property :target_node_id, "Node"
        property :position, "Integer"
        
  belongs_to :node
  belongs_to :target_node, :class_name => "Node", :foreign_key => "target_node_id"
  acts_as_list :scope => 'node_id = <#{SemanticRecord::Base::SR_NAMESPACE}#{node_id}> and type = <#{SemanticRecord::Base::SR_NAMESPACE}#{type_attr}>'
  
  def before_destroy() remove_from_list end
  
  def self.find_all_by_node(node_id, type = nil)
    if type.nil?
      find_all ["node_id = ?", node_id]
    else
      find_all ["node_id = ? and type = ?", node_id, to_uri(type)]
                end      
  end
  
  def self.destroy_by_values(node_id, target_node_id = nil, type = nil)
    if target_node_id && type
      destroy_all ["node_id = ? and target_node_id = ? and type = ?", node_id, target_node_id, to_uri(type)]
    else
      if type.nil?
        destroy_all ["node_id = ? and target_node_id = ?", node_id, target_node_id]
      elsif target_node_id.nil?
        destroy_all ["node_id = ? and type = ?", node_id, to_uri(type)]
      else
        destroy_all ["node_id = ?", node_id]
                end
        end      
        end

        def self.find_by_values(node_id, target_node_id, type)
          NodeLink.find_first [ "node_id = ? AND target_node_id = ? AND type = ?", node_id, target_node_id, type.to_uri ]
        end

        def after_save
          treat_inverse { |nl, inverse_link|
            if nl.nil?
              klass = Object.const_get(inverse_link.name) rescue nil
              klass.create("node_id" => target_node_id, "target_node_id" => node_id) if klass             
                        end
                }
        end

        def after_destroy
          treat_inverse { |nl, inverse_link| nl.destroy if nl }
        end
        
        def treat_inverse
          link = Link.find_by_name(type)
          if link.inverse_link
            nl = NodeLink.find_by_values target_node_id, node_id, link.inverse_link.name                          
            yield(nl, link.inverse_link)
                end
        end
end