PHP應用
namespace woo\base;
//基類
abstract class Registry {
  abstract protected function get($key);
  abstract protected function set($key,$val);
}
//請求級別,他的生存周期通常為從用戶發起一個請求到后臺程序回復這個請求為止
class RequestRegistry extends Registry{
  private $values = array();
  private static $instance;
  
  private function __construct (){}
  static function instance(){　　　　// 單例,即這個類只有一個唯一的實例
    if(!isset(self::$instance)){
      self::$instance = new self();
    }
    return self::$instance;
  }
  
  protected function get($key){
    if(isset($this->values[$key]){
      return $this->values[$key];
    }
    return null;
  }
  
  protected function set($key,$val){
    $this->values[$key] = $val;
  }
  
  static function getRequest(){
    return self::instance()->get('request');
  }
  
  static function setRequest(\woo\controller\Request $request){　　　　　　//\woo\controller\Request 主要功能是處理用戶請求信息的一個類
    return self::instance()->set('request',$request);
  }
}
//會話級別,此示例中類的生存周期主要還是看SESSION的生存時間
class SessionRegistry extends Registry{
  private static $instance;
  private function __construct (){
    session_start();
  }
  
  static function instance(){
    if(!isset(self::$instance)){
      self::$instance = new self();
    }
    return self::$instance;
  }
  
  protected function get($key){
    if(isset($_SESSION[__CLASS__][$key])){
      return $_SESSION[__CLASS__][$key];
    }
    return null;
  }
  
  protected function set($key,$val){
    $_SESSION[__CLASS__][$key] = $val;
  }
  
  function setComplex(Complex $complex){
    self::instance()->set('complex',$complex);
  }
  
  function getComplex(){
    return self::instance()->get('complex');
  }
}
//應用程序級別,此示例中因相關的值是保存在文本文件中,所以只要文件存在,保存的值也就一直存在
 class ApplicationRegistry extends Registry{
  private Static $instance;
  private $freezedir = 'data';
  private $values = array();
  private $mtimes = array();
  private function __construct (){}
   
  static function instance(){
    if(!isset(self::$instance)){
      self::$instance = new self();    
    }
    return self::$instance;
  }
  
  protected function get($key){
    $path = $this->freezedir . DIRECTORY_SEPARATOR . $key; // 保存值的文件的路徑
    if(file_exists($path)){
      clearstatcache();   　　// 清除filemtime緩存的上次記錄的文件修改時間
      $mtime = filemtime($path);
      if(!isset($this->mtimes[$key])){
        $this->mtimes[$key] = 0;
      }
      if($mtime > $this->mtimes[$key]){　　　　// 文件內容假如被修改過,那么就要重新獲取里面的值
        $data = file_get_contents($path);
        $this->mtimes[$key] = $mtime;
        return ($this->values[$key] = unserialize($data));
      }
    }
    if(isset($this->values[$key])){
      return $this->values[$key];
    }
    return null;
  }
  
  protected function set ($key,$val){
    $this->values[$key] = $val;
    $path = $this->freezedir . DIRECTORY_SEPARATOR . $key;
    file_put_contents($path,serialize($val));
    $this->mtimes[$key] = time();
  }
  
  static function getDSN(){
    return self::instance()->get('dsn');
  }
  
  static function setDSN($dsn){
    return self::instance()->set('dsn',$dsn);
  }
   
 }