享元模式

/**
* flyweight模式
*
* 运用享元技术有效的支持大量细粒度的对象
*/
    class CD
    {
        private $_title = null;
        private $_artist = null;
        
        public function setTitle($title)
        {
            $this->_title =$title;
        }
        
        public function getTitle()
        {
            return $this->_title;
        }
        
        public function setArtist($artist)
        {
            $this->_artist =$artist;
        }
        
        public function getArtist($artist)
        {
            return $this->_artist;
        }
    }
    
    class Artist
    {
        private $_name;
        public function __construct($name)
        {
            echo "construct " . $name . "
";
            $this->_name =$name;
        }
        
        public function getName()
        {
            return $this->_name;
        }
    }
    
    class ArtistFactory
    {
        private $_artists = array();
        public function getArtist($name)
        {
            if (isset($this->_artists[$name])) {
                return $this->_artists[$name];
            } else {
                $objArtist = new Artist($name);
                $this->_artists[$name] = $objArtist;
                return $objArtist;
            }
        }
    }
    
$objArtistFactory=new ArtistFactory();
$objCD1=new CD();
$objCD1->setTitle("title1");
$objCD1->setArtist($objArtistFactory->getArtist('artist1'));

$objCD2=new CD();
$objCD2->setTitle("title2");
$objCD2->setArtist($objArtistFactory->getArtist('artist2'));

$objCD3=new CD();
$objCD3->setTitle("title3");
$objCD3->setArtist($objArtistFactory->getArtist('artist1'));

参考文章 https://wenku.baidu.com/view/b4c78b4702768e9951e738fb.html