public static function getInstance()
 {
     if (!self::$instance) {
         self::$instance = new ConnectionFactory();
     }
     return self::$instance;
 }
 /**
  * @return ConnectionFactory
  */
 public static function getInstance()
 {
     if (self::$instance === null) {
         self::$instance = new self();
     }
     return self::$instance;
 }
 /**
  * Retorna um objeto da classe ConnectionFactory
  * @return ConnectionFactory object
  */
 public static function getInstance()
 {
     if (!isset(self::$instance)) {
         $c = __CLASS__;
         self::$instance = new $c();
     }
     return self::$instance;
 }
 public static function getInstance()
 {
     if (!isset(self::$instance)) {
         try {
             self::$instance = new PDO('mysql:host=' . ConnectionProperty::getHost() . ';dbname=' . ConnectionProperty::getDatabase() . ';charset=utf8', ConnectionProperty::getUser(), ConnectionProperty::getPassword());
             self::$instance->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
             self::$instance->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_OBJ);
         } catch (PDOException $e) {
             echo $e->getMessage();
         }
     }
     return self::$instance;
 }