private boolean isMediaTypeString(String string) {
      // IANA doesn't specify a pattern for the subtype of example content
      // types but other subtypes seem to be one or more groups of
      // alphanumerics characters, the groups being separated by a single
      // period (.), hyphen (-) or plus (+) character
      //
      // Valid examples:
      //
      // "example/foo"
      // "example/foo.bar"
      // "example/foo-bar+baz"
      // "example/foo1.2006-bar"
      //
      // Invalid examples:
      //
      // "example/foo$bar"              ($ isn't a valid separator)
      // "example/foo."                 (can't end with a separator)
      //
      if (m_recognizeExampleMediaType &&
          string.matches(Holder.EXAMPLE_MIME_MEDIA_TYPE_PATTERN)) {
        return true;
      }
      return Holder.mimeTypes.contains(string);
    }
private boolean isMediaTypeString(String string)