KTF

$driver = new XLSXExporter();
$exporter = new DataExporter($driver);

echo $exporter->getResult();

class DataExporter{
protected $driver;
function __construct(DriverExporterInterface $driver){
$this->driver = $driver;
}
function getResult(){
return $this->driver->process();
}
}
interface DriverExporterInterface{
public function process();
}

if( $format == 'XLSX' ) {
    $driver = new XLSXExporter();
    $driver->setColumnWidth( 0, 100 );
    $driver->setColumnWidth( 1, 30 );
    $driver->setColumnWidth( 2, 60 );
  }
else{
$driver = new EmptyExporter();
}

$exporter = new DataExporter($driver);
$exporter->setData( $data );

echo $exporter->getResult();