域名查询是否被注册的类PHP封装

前两天客户需要域名查询是否被注册的方法，我就封装了一个简单的类 因为时间匆忙，没有改善，希望朋友们看到了一块帮忙完善一下 谢谢大家现在放出源码;

//这是类方法
<?php
/**
 * 域名查询类
 *
 * @copyright      Copyright (c) 2012, Widuu, Inc.
 * @author         Porwered BY 肖伟
 * @link           http://yun.widuu.com
 */
class Domain{

	private $domain_last_all=array('com', 'cn', 'net'); //包含的后缀名
	private $domain_last;   //封装的后缀名
	private $name;
	
	function __construct($name=""){
		$this->domain_last=$this->get_domain_last($this->domain_last_all);
		$this->name=$name;
	}
	//对传过来的查询条件，进行循环查询
	private function query_domain($domain, $domain_last) {
    if ($domain != "" && isset($domain)) {
        foreach ($domain_last as $value) {
            //每次初始化为空值
            $domain_string="";
            $domain_string=$domain.$value;
            echo $domain;
            echo $value;
            $xml_arr=$this->query($domain_string);
            $this->show($xml_arr);
			}
		}
	}
	//查询接口
	private function query($domain) {
    $do = "http://panda.www.net.cn/cgi-bin/check.cgi?area_domain=" . $domain;
    $xml_data = file_get_contents($do);
    $xml_arr = (array) simplexml_load_string($xml_data);
    return $xml_arr;
	}
	//显示接口
	private function show($result_arr){
		$returncode=$result_arr['returncode'];
		$key=$result_arr['key'];
		$original=$result_arr['original'];
		$status=  substr($original,0,3);
		//申明返回值
		$result;
		if($status=="210"){
			echo "可以注册";
		}else if($status=="211"){
        echo "已经注册";
		}else if($status=="212"){
			echo "参数错误";
		}
	}
	//循环获取到的域名后缀经过判断后放入数组
	private function get_domain_last($domain_last_all){
		$post = $_POST;
		//循环预设域名后缀
		$domain_last = array();
		foreach ((array)$domain_last_all as $value) {
        //将非空的域名后缀放入数组$domain_last
		$domain = $post[$value];
        if ($domain != "") {
            $domain_last[] = $domain;
        }
    }
		return $domain_last;
	}	

	function domain(){
		$name=$this->name;
	    $domain=$_POST["{$this->name}"];
		if ($domain != "" && isset($domain)) {
		$domain_last = $this->get_domain_last($this->domain_last_all);
		$this->query_domain($domain,$domain_last);
		} else {
		echo '未输入域名！';
		}
	}
}
//实例化类调用类
<?php
header('content-type:text/html;charset=utf-8');
include ("Domian.class.php");
$domian=new Domain('domain');
$domian->domain();
?>
//前台界面
<form method="post" action="4.php">
<input type="text" name="domain">
<p>
    <label>
      <input type="checkbox" name="com" value=".com" >
      .com</label><br>
    <label>
      <input type="checkbox" name="cn" value=".cn" >
      .cn</label><br>
    <label>
      <input type="checkbox" name="net" value=".net">
      .net</label><br>
  </p>
<input type="submit" value="提交">
</form>