php设计模式之委托模式

<?php
/**
 * 原来的程序写法
 * @var playlist
 */
$playlist = new playlist();
$playlist->addSong(‘/home/aaron/music/aa.mp3‘, ‘Brr‘);
$playlist->addSong(‘/home/aaron/music/bb.mp3‘, ‘GoodBye‘);
if ($extType == ‘pls‘) {
    $playlistContent = $playlist->getPLS();
} else {
    $playlistContent = $playlist->getM3U();
}

/**
* 委托模式的类
*/
class newPlaylist
{
    private $__songs;
    private $__typeObject;
    public function __construct($type)
    {
        $this->__songs = array();
        $object = "{$type}Playlist";
        $this->__typeObject = new $object;
    }

    public function addSong($location, $title)
    {
        $song = array(‘location‘ => $location, ‘title‘=>$title);
        $this->__songs[] = $song;
    }

    public function getPlaylist()
    {
        $playlist = $this->__typeObject->getPlaylist($this->__songs);
        return $playlist;
    }
}

/**
* m3u   Delegate
*/
class m3uPlaylistDelegate
{
    
    public function getPlaylist($songs)
    {
        $m3u = "#EXTM3U\n\n";
    }

    /*
    other function
     */
}
/**
* pls    Delegate
*/
class plsPlaylistDelegare
{
    
    function getPlaylist($songs)
    {
        $pls=" ";
    }
}

/**
 * 如何使用
 */
$extType = ‘pls‘;//$extTyle = ‘m3u‘;
$playlist = new newPlaylist($extType);
$playlistContent = $playlist->getPlaylist();