PHP 工厂模式

/**
  * 工厂模式
  */
 //产品必须实现的接口
 interface  Animal{
   public function designation();
  }
 
 class Dog implements Animal
 {
   
   
   public function designation()
   {
      echo "Dog";
   }
 }
 
 class Cat implements Animal
 {
   
  
   public function designation()
   {
      echo "Cat";
   }
 }
 /**
  * 工厂类制造动物
  */
 
 class AnimalFactory 
 {
   static public function factory($animal_name){
        return new $animal_name();
    }
 }
 $animal_one=AnimalFactory::factory('Dog');
 $animal_one->designation();
 $animal_two=AnimalFactory::factory('Cat');
 $animal_two->designation();