return null;
String language = refframe.getContentLanguage();
String encoding = refframe.getContentEncoding();
String charset = refframe.getCharset();
MimeType mtype = refframe.getContentType();
HTTPFrame itsframe = null;
for (int i = num; i < variants.length; i++) {
try {
resource = (FramedResource)variants[i].unsafeLock();
itsframe = (HTTPFrame)
resource.unsafeGetFrame(httpFrameClass);
if (language != null) {
if (!language.equals(itsframe.getContentLanguage())) {
b_language = true;
}
} else {
if (itsframe.getContentLanguage() != null) {
b_language = true;
}
}
if (encoding != null) {
if (!encoding.equals(itsframe.getContentEncoding())) {
b_encoding = true;
}
} else {
if (itsframe.getContentEncoding() != null) {
b_encoding = true;
}
}
if (charset != null) {
if (!charset.equals(itsframe.getCharset())) {
b_charset = true;
}
} else {
if (itsframe.getCharset() != null) {
b_charset = true;
}
}
if (mtype != null) {
MimeType o_type = itsframe.getContentType();
if ((o_type != null) && (mtype.match(o_type) !=
MimeType.MATCH_SPECIFIC_SUBTYPE)) {
b_type = true;
}
} else {