/**
* @see Filter::process()
* @param $input MetadataDescription the NLM meta-data description
* to be transformed
* @return string the rendered citation output
*/
function &process(&$input)
{
// Check whether the incoming publication type is supported by this
// output filter.
$supportedPublicationTypes = $this->getSupportedPublicationTypes();
$inputPublicationType = $input->getStatement('[@publication-type]');
if (!in_array($inputPublicationType, $supportedPublicationTypes)) {
$this->addError(__('submission.citations.filter.unsupportedPublicationType'));
$emptyResult = '';
return $emptyResult;
}
return parent::process($input);
}