PHP-SplDoublyLinkedList

<?php
/**
 * @package a doubly linked list test
 * @author  zhaoyingnan<zhaoyn@bbtree.com>
 * @copyright
 * @version
 * @since
 **/

/* SplDoublyLinkedList
 * 方法
 SplDoublyLinkedList implements Iterator , ArrayAccess , Countable
 {
     public __construct ( void )
         public void add ( mixed $index , mixed $newval ) 在指定的索引位置插入值
         public mixed bottom ( void ) 查看开始位置的节点
         public mixed top ( void ) 查看结束位置的节点
         public int count ( void ) 返回所有的元素的数量
         public void rewind ( void ) 倒回迭代器的开始
         public mixed current ( void ) 返回当前节点的信息
         public mixed key ( void ) 返回当前节点的索引
         public void setIteratorMode ( int $mode ) 设置迭代的模式
         public int getIteratorMode ( void ) 返回迭代的模式
         public bool isEmpty ( void ) 检查该双向列表是否是空的
         public void next ( void ) 移动到下一个节点
         public void prev ( void ) 移动到上一个节点
         public bool offsetExists ( mixed $index )
         public mixed offsetGet ( mixed $index )
         public void offsetSet ( mixed $index , mixed $newval )
         public void offsetUnset ( mixed $index )
         public mixed pop ( void ) 从双向列表的末尾弹出一个节点
         public void push ( mixed $value ) 向双向列表的末尾推入一个元素
         public mixed shift ( void ) 从双向列表的头部弹出一个节点
         public void unshift ( mixed $value ) 向双向列表的头部插入一个元素
         public string serialize ( void )
         public void unserialize ( string $serialized )
         public bool valid ( void ) 检查双向列表是否有更多的节点
}
 */
$SplDoublyLinkedList = new SplDoublyLinkedList();
$mysqli = new mysqli('114.55.104.117', 'db_writer', 'ka_32^%*ko', 'db_community');
if($mysqli->connect_errno)
    exit('Mysql connect error ' . $mysqli->connect_error);
$query  = "show tables like '%zhs_user_timeline_%'";
$result = $mysqli->query($query);
if(!$result)
    exit('error ' . $mysqli->error);
while($row = $result->fetch_row())
{
    //list($arData[]) = array_values($row);
    $SplDoublyLinkedList->push($row[0]);
}
$result->close();
$mysqli->close();

echo count($SplDoublyLinkedList), PHP_EOL;
$SplDoublyLinkedList->rewind();
while($SplDoublyLinkedList->valid())
{
    var_export($SplDoublyLinkedList->shift());
    echo PHP_EOL;
    echo count($SplDoublyLinkedList), PHP_EOL;
    $SplDoublyLinkedList->next();
}
echo count($SplDoublyLinkedList);
?>