T3Flow-1

# Action 

/**
 * Shows a list of books
 *
 * @return void
 */
public function booksAction() {
	$genre = $this->getQueryStringVar('genre');
	
	$this->view->assign('books', $this->bookRepository->findAll($genre));
	$this->view->assign('settings', $this->settings);
}



# Gets query var

/**
 * Finds a get var from the query string.
 *
 * @param string $queryVar The name of the query var.
 * @param string $queryVarElement The name of the element in the query var.
 * @return mixed $queryVarValue Returns the get var or FALSE.
 */
protected function getQueryStringVar($queryVar, $queryVarElement = '') {
	$queryVarValue = FALSE;
	
	if (is_string($queryVar) && !empty($queryVar)) {
		$queryStringVars = $this->request->getArguments();
		
		if (isset($queryStringVars[$queryVar])) {
			if (is_string($queryVarElement) && !empty($queryVarElement)) {
				$queryVarValue = $queryStringVars[$queryVar][$queryVarElement];
				
				if (is_string($queryVarValue)) {
					$queryVarValue = trim($queryVarValue);
				}
				
			} else {
				$queryVarValue = $queryStringVars[$queryVar];
				
				if (is_string($queryVarValue)) {
					$queryVarValue = trim($queryVarValue);
				}
			}
		}
	}

	return $queryVarValue;
}


# Repo method
/**
 * Finds all unhidden & published books.
 *
 * @param mixed $genre The genre to filter by (an array), or FALSE if there is no filter genre.
 * @return \TYPO3\Flow\Persistence\QueryResultInterface The query result
 */
public function findAll($genre = FALSE) {
	$query = $this->createQuery();
	
	if ($genre !== FALSE) {
		$query->matching(
			$query->logicalAnd(
				$query->equals('hidden', 0),
				$query->equals('published', 1),
				$query->contains('genres', $genre)
			)
		);
		
	} else {
		$query->matching(
			$query->logicalAnd(
				$query->equals('hidden', 0),
				$query->equals('published', 1)
			)
		);
	}
	
	$query->setOrderings(
		array('title' => \TYPO3\Flow\Persistence\QueryInterface::ORDER_ASCENDING)
	);
	
	return $query->execute();
}

make it

<?php
/**
 * Shows a list of books
 *
 * @param \Vendor\Package\Domain\Model\Genre $genre
 * @return void
 */
public function booksAction(\Vendor\Package\Domain\Model\Genre $genre = NULL)