Ojs\JournalBundle\Entity\Journal::getPublisher PHP Method

    public function getPublisher()
    {
        return $this->publisher;
    }

 /**
  * @param SitemapPopulateEvent $event
  * @param Journal $journal
  * @return SitemapPopulateEvent
  */
 private function generateIssueLinks(SitemapPopulateEvent $event, Journal $journal)
 {
     $issues = $journal->getIssues();
     /** @var Issue $issue */
     foreach ($issues as $issue) {
         $event->getGenerator()->addUrl(new UrlConcrete($this->router->generate('ojs_issue_page', ['publisher' => $journal->getPublisher()->getSlug(), 'journal_slug' => $journal->getSlug(), 'id' => $issue->getId()], true), new \DateTime(), UrlConcrete::CHANGEFREQ_WEEKLY, 1), 'journals-' . $journal->getSlug());
         $event = $this->generateArticleLinks($event, $issue);
     }
     return $event;
 }