Doesn't seem right.

What about:

``` php
$queryParameters = array(
    'data_in' => isset($params[self::GRID_PARAM_DATA_IN]) ? $params[self::GRID_PARAM_DATA_IN] : array(),
    'data_not_in' => isset($params[self::GRID_PARAM_DATA_NOT_IN]) ? $params[self::GRID_PARAM_DATA_NOT_IN] : array(),
);
```