IssueGalleyForm::validate PHP Méthode

    function validate($request)
    {
        // Check if public galley ID is already being used
        $journal = $request->getJournal();
        $journalDao = DAORegistry::getDAO('JournalDAO');
        /* @var $journalDao JournalDAO */
        $publicGalleyId = $this->getData('publicGalleyId');
        if ($publicGalleyId) {
            if (is_numeric($publicGalleyId)) {
                $this->addError('publicGalleyId', __('editor.publicIdentificationNumericNotAllowed', array('publicIdentifier' => $publicGalleyId)));
                $this->addErrorField('publicGalleyId');
            } elseif ($journalDao->anyPubIdExists($journal->getId(), 'publisher-id', $publicGalleyId, ASSOC_TYPE_ISSUE_GALLEY, $this->_issueGalley ? $this->_issueGalley->getId() : null, true)) {
                $this->addError('publicGalleyId', __('editor.publicIdentificationExistsForTheSameType', array('publicIdentifier' => $publicGalleyId)));
                $this->addErrorField('publicGalleyId');
            }
        }
        return parent::validate();
    }

 /**
  * Update a issue
  * @param $args array
  * @param $request PKPRequest
  * @return JSONMessage JSON object
  */
 function update($args, $request)
 {
     $issue = $this->getAuthorizedContextObject(ASSOC_TYPE_ISSUE);
     $issueGalley = $this->getAuthorizedContextObject(ASSOC_TYPE_ISSUE_GALLEY);
     import('controllers.grid.issues.form.IssueGalleyForm');
     $issueGalleyForm = new IssueGalleyForm($request, $issue, $issueGalley);
     $issueGalleyForm->readInputData();
     if ($issueGalleyForm->validate($request)) {
         $issueId = $issueGalleyForm->execute($request);
         return DAO::getDataChangedEvent($issueId);
     } else {
         return new JSONMessage(false);
     }
 }