code: protected boolean userAlreadyExists(String username) {
  
          if (m_user != null) {
              return false;
          }
          CmsUser user = null;
          try {
              user = m_cms.readUser(m_ou.getValue() + username);
          } catch (CmsException e) {
              return false;
          }
  
          return user != null;
  
      }
docs: Checks if given user exists.<p>
  
  @param username to check
  @return boolean