OUser fromUser = UserService.getOUserByUsername(from);
if (fromUser == null){
throw new UserNotFoundException("User "+from+" does not exists");
}
if (!UserService.exists(to)){
throw new UserToFollowNotExistsException("User "+to+" does not exists");
}
String friendshipName = RoleDao.FRIENDS_OF_ROLE+to;
boolean areFriends = RoleService.hasRole(fromUser.getName(),friendshipName);
if (areFriends) {
UserService.removeUserFromRole(fromUser.getName(),friendshipName);