/**
  * Dispatched from execute();
  */
 private function processParameter($sParameter)
 {
     try {
         $this->oRequestedTitle = Title::newFromText($sParameter);
         /*if( !$this->oRequestedTitle->exists() && $this->oRequestedTitle->getNamespace() != NS_SPECIAL ) { //!$this->mRequestedTitle->isSpecialPage() does not work in MW 1.13
         			throw new Exception( 'error-requested-title-does-not-exist' );
         		}*/
         //Get relevant page props
         $dbr = wfGetDB(DB_SLAVE);
         $res = $dbr->selectField('page_props', 'pp_value', array('pp_propname' => 'bs-universalexport-params', 'pp_page' => $this->oRequestedTitle->getArticleID()));
         if ($res != false) {
             $res = FormatJson::decode($res, true);
             if (is_array($res)) {
                 $this->aParams = array_merge($this->aParams, $res);
             }
         }
         BsUniversalExportHelper::getParamsFromQueryString($this->aParams);
         //Title::userCan always returns false on special pages (exept for createaccount action)
         if ($this->oRequestedTitle->getNamespace() === NS_SPECIAL) {
             if ($this->getUser()->isAllowed('universalexport-export') !== true) {
                 throw new Exception('bs-universalexport-error-permission');
             }
         } elseif ($this->oRequestedTitle->userCan('universalexport-export') === false) {
             throw new Exception('bs-universalexport-error-permission');
         }
         // TODO RBV (24.01.11 17:37): array_intersect(), may be better?
         $aCategoryNames = BsUniversalExportHelper::getCategoriesForTitle($this->oRequestedTitle);
         foreach ($aCategoryNames as $sCategoryName) {
             if (in_array($sCategoryName, $this->aCategoryBlacklist)) {
                 throw new Exception('bs-universalexport-error-requested-title-in-category-blacklist');
             }
         }
         BsUniversalExportHelper::checkPermissionForTitle($this->oRequestedTitle, $this->aParams);
         //Throws Exception
         $sModuleKey = $this->aParams['module'];
         if (!isset($this->aModules[$sModuleKey]) || !$this->aModules[$sModuleKey] instanceof BsUniversalExportModule) {
             throw new Exception('bs-universalexport-error-requested-export-module-not-found');
         }
         $oExportModule = $this->aModules[$sModuleKey];
         $aFile = $oExportModule->createExportFile($this);
         $this->returnFile($aFile);
     } catch (Exception $oException) {
         //Display Exception-Message and Stacktrace
         $this->oOutputPage->setPageTitle(wfMessage('bs-universalexport-page-title-on-error')->text());
         $oExceptionView = new ViewException($oException);
         $this->oOutputPage->addHtml($oExceptionView->execute());
     }
 }