code: private static boolean areTokensValid(Token... tokens)
      {
          for (Token token : tokens)
          {
              if (!isTokenValid(token))
                  return false;
          }
          return true;
      }
docs: Checks if the specified tokens are valid.
  
  @param tokens the tokens to check
  @return <code>true</code> if all the specified tokens are valid ones, <code>false</code> otherwise.