php simple factory pattern

//抽象产品类TV
interface TV {
	public function play();
}
//具体产品类HaierTv
class HaierTV implements TV 
{
	public function play() {
		echo '海尔电视机播放中...<br>';
	}
}

//具体产品类HisenseTV
class HisenseTV implements TV 
{
	public function play() {
		echo '海信电视播放中...<br>';
	}
}
class TVFactory
{
	public static function produceTV($name) {
		switch ($name)
		{
			case 'Haier': echo '电视机工厂生产海尔电视机<br>';return new HaierTV();
			case 'Hisense': echo '电视机工厂生产海信电视机<br>';return new HisenseTV();
			default: echo '不能生产该电视机<br>';break;
		}
	}
}

$factory = new TVFactory();
$tvstring = simplexml_load_file('configTV.xml'); 


foreach ($tvstring as $tv ) {
$tmp = $factory->produceTV($tv->name);
if ($tmp != NULL) {
$tmp->play();
}
}

<?xml version="1.0" encoding="UTF-8"?>  
  <TV>  
	  <HaierTV>  
		  <name>Haier</name>   
	  </HaierTV>  
	  <HisenseTV>  
		  <name>Hisense</name>  
	  </HisenseTV> 	  
  </TV>