function setConfig( $config, $value ) {
    switch( strtoupper( $config )) {
      case 'ALLOWEMPTY':
        $this->allowEmpty = $value;
        break;
      case 'FORMAT':
        $value   = trim( $value );
        $this->format = $value;
        break;
      case 'LANGUAGE':
         // set language for calendar component as defined in [RFC 1766]
        $value   = trim( $value );
        $this->language = $value;
        break;
      case 'NL':
        $this->nl = $value;
        break;
      case 'UNIQUE_ID':
        $value   = trim( $value );
        $this->unique_id = $value;
        break;
    }
  }