owncloud / core

	 * @param string $appId

	 * @throws \Exception

	 */

	public function enableApp($appId) {

		if($this->getAppPath($appId) === false) {

			throw new \Exception("$appId can't be enabled since it is not installed.");

		}

		$this->canEnableTheme($appId);

		$this->installedAppsCache[$appId] = 'yes';

		$this->appConfig->setValue($appId, 'enabled', 'yes');

		$this->dispatcher->dispatch(ManagerEvent::EVENT_APP_ENABLE, new ManagerEvent(

			ManagerEvent::EVENT_APP_ENABLE, $appId

		));

		$this->clearAppsCache();

	}

	/**

	 * Do not allow more than one active app-theme

	 * @param string $appId

	 * @throws \Exception if app can't be disabled

	 */

	public function disableApp($appId) {

		if ($this->isAlwaysEnabled($appId)) {

			throw new \Exception("$appId can't be disabled.");

		}

		unset($this->installedAppsCache[$appId]);

		$this->appConfig->setValue($appId, 'enabled', 'no');

		$this->dispatcher->dispatch(ManagerEvent::EVENT_APP_DISABLE, new ManagerEvent(

			ManagerEvent::EVENT_APP_DISABLE, $appId

		));

		$this->clearAppsCache();

	}

	/**

	 * Clear the cached list of apps when enabling/disabling an app