// model: Category
// table: category
------------------------------
id
name
type

// model: CategoryCategory
// table: category_category
------------------------------
id
categoryId [references: category.id]
parentId [references: category.id]

protected function _sortNodes($nodes)
{
    $sorted = array();
    foreach ($nodes as $node) {
        
        $tmp = array(
            'id'       =>    $node->id,
            'name'  =>    $node->name,
            'childs'   =>    array()
        );
			
        $category = new Category();
        $select = $category->select();
        $where = $select->where("type = $this->type");
		
        $childs = $node->findManyToManyRowset('Category', 'CategoryCategory', 'Childs', null, $where);
		 	
        if ($childs->count() > 0) {
			
            $tmp['childs'] = $this->_sortNodes($childs);
 				
        }
 			
        $sorted[] = $tmp;
 			
    }	  

    return $sorted;
}