/** Return the archive file type corresponding to the MIME type, or null if none. */
 public String getFromMime(String contentType) {
   String mimeType = HeaderUtil.getMimeTypeFromContentType(contentType);
   if (mimeType == null) {
     return null;
   }
   return getExtMimeMap().get(mimeType.toLowerCase());
 }
  protected FilterRule constructFilterRule(String contentType) {
    String mimeType = HeaderUtil.getMimeTypeFromContentType(contentType);

    Object filter_el =
        definitionMap.getMapElement(mimeType + DefinableArchivalUnit.SUFFIX_FILTER_RULE);

    if (filter_el instanceof String) {
      log.debug("Loading filter " + filter_el);
      return (FilterRule) newAuxClass((String) filter_el, FilterRule.class);
    } else if (filter_el instanceof List) {
      if (((List) filter_el).size() > 0) {
        return new DefinableFilterRule((List) filter_el);
      }
    }
    return super.constructFilterRule(mimeType);
  }