/**
  * Initializes the persistence manager
  *
  * @return void
  * @throws \TYPO3\Flow\Persistence\Generic\Exception\MissingBackendException
  */
 public function initialize()
 {
     if (!$this->backend instanceof \TYPO3\Flow\Persistence\Generic\Backend\BackendInterface) {
         throw new \TYPO3\Flow\Persistence\Generic\Exception\MissingBackendException('A persistence backend must be set prior to initializing the persistence manager.', 1215508456);
     }
     $this->backend->setPersistenceManager($this);
     $this->backend->initialize($this->settings['backendOptions']);
 }