PHP code to recursively delete all files in a directory and multi-level subdirectories

/**
 desc: recursively delete files in the directory
 link: bbs.it-home.org
 date: 2013/2/24
*/
class cacheClearFile{

 var $dir = '111cn.Net';

 function __construct()
 {
 $this ->listFils();
 }

 function listFiles()
 {
 if(is_dir($this->dir))
 {
 if($dir_file=opendir($ this->dir))
 {
 while(($dir_list=readdir($dir_file))!==false)
 {
 if($dir_list!="." && $dir_list!="..")
 {
 if( is_file($dir_list)
 {
 unlink($dir_list);
 }
 else
 {
 $this->dir =$dir_list;
 listFils();
 }
 }
 }
 }else{
 echo("The directory cannot be opened");
 }
 }
 else
 {
 echo("Not a directory");
 }
 }
}
//Calling example
$files = new cacheClearFile();
$files->listFiles();
?>