How to add query string to JControllerForm auto redirects

From Joomla! Documentation

Here is the example of how you can adding query string to JControllerForm/Admin auto redirects that caused by sub-controllers of joomla 1.6+.

In this example my query string that I want to add is "example=test"

protected function getRedirectToItemAppend($recordId = null, $urlVar = 'id') {
	$append = parent::getRedirectToItemAppend($recordId,$urlVar);
	return $append.'&example=test';