简单好用的PHP无限分类

/**
* author: askie
* blog: http://www.pkphp.com
* 版权： 随便用
* 无限分类
*/
class Tree
{
        public $data=array();
        public $cateArray=array();
       
        function Tree()
        {
              
        }
        function setNode ($id, $parent, $value)
    {
        $parent = $parent?$parent:0;
        $this->data[$id]                = $value;
        $this->cateArray[$id]        = $parent;
    }
    function getChildsTree($id=0)
    {
            $childs=array();
            foreach ($this->cateArray as $child=>$parent)
            {
                    if ($parent==$id)
                    {
                            $childs[$child]=$this->getChildsTree($child);
                    }
                   
            }
            return $childs;
    }
    function getChilds($id=0)
    {
            $childArray=array();
            $childs=$this->getChild($id);
            foreach ($childs as $child)
            {
                    $childArray[]=$child;
                    $childArray=array_merge($childArray,$this->getChilds($child));
            }
            return $childArray;
    }
    function getChild($id)
    {
            $childs=array();
            foreach ($this->cateArray as $child=>$parent)
            {
                    if ($parent==$id)
                    {
                            $childs[$child]=$child;
                    }
            }
            return $childs;
    }
    //单线获取父节点
    function getNodeLever($id)
    {
            $parents=array();
            if (key_exists($this->cateArray[$id],$this->cateArray))
            {
                    $parents[]=$this->cateArray[$id];
                    $parents=array_merge($parents,$this->getNodeLever($this->cateArray[$id]));
            }
            return $parents;
    }
    function getLayer($id,$preStr='|-')
    {
            return str_repeat($preStr,count($this->getNodeLever($id)));
    }
    function getValue ($id)
    {
        return $this->data[$id];
    } // end func
}

/*$Tree = new Tree("请选择分类");
//setNode(目录ID,上级ID，目录名字);
$Tree->setNode(1, 0, '目录1');
$Tree->setNode(2, 1, '目录2');
$Tree->setNode(5, 3, '目录5');
$Tree->setNode(3, 0, '目录3');
$Tree->setNode(4, 2, '目录4');
$Tree->setNode(9, 4, '目录9');
$Tree->setNode(6, 2, '目录6');
$Tree->setNode(7, 2, '目录7');
$Tree->setNode(8, 3, '目录8');

//print_r($Tree->getChildsTree(0));
//print_r($Tree->getChild(0));
//print_r($Tree->getLayer(2));

$category = $Tree->getChilds();

//遍历输出
foreach ($category as $key=>$id)
{
    echo $id.$Tree->getLayer($id, '|-').$Tree->getValue($id)."\n";
}*/

?>