public function import ( ImportStream $stream, ImportContext $context ) {
        $datasourceName = $context->get('datasourceName');
        if (!$datasourceName) {
            throw new \Exception('Missing required datasource name.');
        }
        gd_datasource_set_active($datasourceName);

        foreach ( $this->handlers as $h ) {
            $handler = new $h['class']();
            $handler->import($stream,$context);
        }
    }
 public function import(ImportStream $stream, ImportContext $context) {
     $operation = $context->get('operation');
     switch ($operation) {
         case 'create' :
             $this->create($stream,$context);
             break;
         case 'update' :
             $this->update($stream,$context);
             break;
         default:
             throw new UnsupportedImportOperationException('Unsupported import operation "'.$operation.'" requested.');
             break;
     }
 }