[PHP5] database abstraction ..........

[whisher]

Ciao che ne pensate di un approccio del genere

<?php
class InvalidArgException extends Exception{
       public function __construct($message, $code = 0){
      parent::__construct($message, $code);
      }
    public function __toString(){
       return __CLASS__ . " Line : [{$this->line}] Code : [{$this->code}] Msg : {$this->message}\n";
       }
}
class DbException extends Exception{
       public function __construct($message, $code = 0){
      parent::__construct($message, $code);
      }
    public function __toString(){
       return __CLASS__ . " Line : [{$this->line}] Code : [{$this->code}] Msg : {$this->message}\n";
       }
}
class DBFactory{
    private static $instance = null;
    public static function createDB($db,$options){
        if($db!='MySQL'&&$db!='SQLite'){
           throw new Exception('Invalid type of database class');
         }
        return self::getInstance($db,$options);
    }
    private static function getInstance($db,$options){
        if(is_null(self::$instance)){
            self::$instance = new $db($options);
        }
        return self::$instance;
    }
}
abstract class DBConnector{
       abstract private function connect();
    abstract public function close();
}
class MySQL extends DBConnector{
    private $host=''; 
    private $user=''; 
    private $password=''; 
    private $database='';
    public $mysqli=null;
    public function __construct($options=array()){
        if(count($options)<4){
            throw new InvalidArgException('Invalid options number in class ['.__CLASS__.']');
        }
        foreach($options as $parameter => $value){
            if(empty($value)){
                throw new InvalidArgException('Invalid parameter.Parameter ['.$parameter.'] is empty in class ['.__CLASS__.']');
            }
            $this->{$parameter}=$value;
        }
        $this->connect();
    }
    private function connect(){
        $this->mysqli = @new mysqli($this->host,$this->user,$this->password,$this->database);
        if(mysqli_connect_errno()){
            throw new DbException('Connect failed: '.mysqli_connect_error());
        }
    }
    public function close(){
        $this->mysqli->close();
        $this->__destruct();
    }
    final public function __destruct(){
        unset($this->_host);
        unset($this->_user);
        unset($this->_password);
        unset($this->_database);
    }
}//
class MySQL_query{
    private $mysqli=null;
    public function __construct(MySQL $msql){
        $this->mysqli=$msql;
    }
    public function query($query){    
        if(!$this->result=$this->mysqli->mysqli->query($query)){
            throw new DbException('Error query : ['.$query.']');
        }
        if($this->result instanceof mysqli_result){
            return new Result($this->result);
        }
    }
}
class Result{
    private $result;
    public function __construct(mysqli_result $mysqliResult){
        $this->result = $mysqliResult;
    }
    public function fetchObject(){
        return $this->result->fetch_object();
    }
}
try {
$options=array('host'=>'localhost','user'=>'','password'=>'','database'=>'');
$db= DBFactory::createDB('MySQL',$options);
$query= new MySQL_query($db);
$result= $query->query('SELECT * FROM users');
while($obj=$result->fetchObject()){
 echo $obj->username;
}
$db->close();
}
catch (InvalidArgException $e) {
    echo $e;
    error_log($e->getMessage()."\n", 3, $root."/log/error.log");
    exit();
}
catch (DbException $e) {
    echo $e;
    error_log($e->getMessage()."\n", 3, $root."/log/error.log");
    exit();
}
?>