public void deleteAnswer(SocialUser loginUser, Long questionId, Long answerId) {
Assert.notNull(loginUser, "loginUser should be not null!");
Assert.notNull(questionId, "questionId should be not null!");
Assert.notNull(answerId, "answerId should be not null!");
Answer answer = answerRepository.findOne(answerId);
if (!answer.isWritedBy(loginUser)) {
throw new AccessDeniedException(loginUser + " is not owner!");
}
answerRepository.delete(answer);
Question question = questionRepository.findOne(questionId);
question.deAnswered();
}
