/**
* Start listening for changes in document
*/
public function listen()
{
$revisionsCollection = $this->getRevisionsCollection();
$document = $this->document;
$createRevisionCallback = function () use($revisionsCollection, $document) {
// create new revision
$revisionsCollection->createDocument()->setDocumentData($document->getOriginalData())->save();
};
$this->document->onBeforeUpdate($createRevisionCallback, PHP_INT_MAX);
$this->document->onBeforeDelete($createRevisionCallback, PHP_INT_MAX);
}
