/**
* @param Message $message
* @param Shared\StoryId $storyId
* @throws Exception\Story
* @return ChapterNumber
*/
private function assertAndGetChapterNumberFromMessage(Message $message, StoryId $storyId)
{
$chapterNumber = Metadata::getChapterNumberFromMessage($message);
if (!$storyId->equals($chapterNumber->storyId())) {
throw Exception\Story::receivedMessageForDifferentStory($message, $storyId, $chapterNumber->storyId());
}
return $chapterNumber;
}
