class JpUnstructuredHeader extends Swift_Mime_Headers_UnstructuredHeader
{
  public function getFieldBody()
  {
    if (!$this->getCachedValue()) {
      if (strcasecmp($this->getCharset(), 'iso-2022-jp') === 0) {
        $this->setCachedValue($this->getValue());
      }
      else {
        parent::getFieldBody();
      }
    }
    return $this->getCachedValue();
  }
}