code: public void loadConfig(String config)
          throws IOException
      {
          Properties properties = new Properties();
          Resource resource=Resource.newResource(config);
          properties.load(resource.getInputStream());
          
          _jdbcDriver = properties.getProperty("jdbcdriver");
          _url = properties.getProperty("url");
          _userName = properties.getProperty("username");
          _password = properties.getProperty("password");
          _userTable = properties.getProperty("usertable");
          _userTableKey = properties.getProperty("usertablekey");
          _userTableUserField = properties.getProperty("usertableuserfield");
          _userTablePasswordField = properties.getProperty("usertablepasswordfield");
          _roleTable = properties.getProperty("roletable");
          _roleTableKey = properties.getProperty("roletablekey");
          _roleTableRoleField = properties.getProperty("roletablerolefield");
          _userRoleTable = properties.getProperty("userroletable");
          _userRoleTableUserKey = properties.getProperty("userroletableuserkey");
          _userRoleTableRoleKey = properties.getProperty("userroletablerolekey");
          _cacheTime = new Integer(properties.getProperty("cachetime")).intValue();
          
          if (_jdbcDriver == null || _jdbcDriver.equals("")
              || _url == null || _url.equals("")
              || _userName == null || _userName.equals("")
              || _password == null
              || _cacheTime < 0)
          {
              if(log.isDebugEnabled())log.debug("UserRealm " + getName()
                          + " has not been properly configured");
          }
          _cacheTime *= 1000;
          _lastHashPurge = 0;
          _userSql = "select " + _userTableKey + ","
              + _userTablePasswordField + " from "
              + _userTable + " where "
              + _userTableUserField + " = ?";
          _roleSql = "select r." + _roleTableRoleField
              + " from " + _roleTable + " r, "
              + _userRoleTable + " u where u."
              + _userRoleTableUserKey + " = ?"
              + " and r." + _roleTableKey + " = u."
              + _userRoleTableRoleKey;
      }
docs: Load JDBC connection configuration from properties file.
  
  @param config Filename or url of user properties file.
  @exception IOException