php适配器模式

   适配器的使用将一个类的接口转换成客户希望的另外一个接口,使用原本不兼容的而不能在一起工作的那些类可以在一起工作，主要应用在第三方api的适配和多个类库的选择适配到我们的应用的接口规则。

例子 

/**
 * 普通媒体接口
 */

interface MediaInterface
{
  public function play($file='');
}


/**
 * 音频设备实体
 */
class AudioPlayer implements MediaInterface
{
  public function play($file='', $type='')
  {
    switch ($type) {
      case 'mp3':
        echo 'playing file: ' . $file . ".mp3\n";
        break;
      case 'mp4':
        $adapter = new Adapter($type);
        $adapter->play($file);
        break;
      case 'wma':
        $adapter = new Adapter($type);
        $adapter->play($file);
        break;

      default:
        throw new Exception("$type is not supported", 400);
        break;
    }

  }
}



/**
 * 高级媒体接口
 */
interface MediaAdvanceInterface
{
  public function playMp4($file='');
  public function playWma($file='');
}



/**
 * mp4高级播放器实体
 */
class AdvanceMp4Player implements MediaAdvanceInterface
{
  public function playMp4($file='')
  {
      echo 'AdvanceMp4Player driver playing file: ' . $file . ".mp4\n";
  }

  public function playWma($file='')
  {
      //do nothing
  }
}

/**
 * wma高级播放器实体
 */
class AdvanceWmaPlayer implements MediaAdvanceInterface
{
  public function playMp4($file='')
  {
      //do nothing
  }

  public function playWma($file='')
  {
      echo 'AdvanceWmaPlayer driver playing file: ' . $file . ".wma\n";
  }
}

/**
 * 高级播放器适配器
 */
class Adapter
{
  private $_advancePlayerInstance;

  private $_type = '';

  public function __construct($type='')
  {
    switch ($type) {
      case 'mp4':
        $this->_advancePlayerInstance = new AdvanceMp4Player();
        break;
      case 'wma':
        $this->_advancePlayerInstance = new AdvanceWmaPlayer();
        break;

      default:
        throw new Exception("$type is not supported", 400);
        break;
    }
    $this->_type = $type;
  }

  public function play($file='')
  {
    switch ($this->_type) {
      case 'mp4':
        $this->_advancePlayerInstance->playMp4($file);
        break;
      case 'wma':
        $this->_advancePlayerInstance->playWma($file);
        break;
      default:
        break;
    }
  }
}