switch theme class for wordpress plugin

switchTheme.php

<?php
class switchTheme {

    private $name = null;
    private $dir  = null;
    private $url  = null;

    function __construct($name = null, $dir = null, $url = null)
    {
        $this->name = $name;
        $this->dir  = $dir;
        $this->url  = $url;
        add_filter("show_admin_bar", "__return_false");
        add_filter("stylesheet", array(&$this, "template"));
        add_filter("template", array(&$this, "template"));
        add_filter("theme_root", array(&$this, "theme_root"));
        add_filter("theme_root_uri", array(&$this, "theme_root_uri"));
    }

    public function template($name)
    {
        if ($this->name) {
            return $this->name;
        } else {
            return $name;
        }
    }

    public function theme_root($dir)
    {
        if ($this->dir) {
            return $this->dir;
        } else {
            return $dir;
        }
    }

    public function theme_root_uri($url)
    {
        if ($this->url) {
            return $this->url;
        } else {
            return $url;
        }
    }
}

?>

詳細は以下のページで。
http://firegoby.theta.ne.jp/archives/2251