public FileDesc getFileDescForUrn(URN urn) {
if (urn.toString().equals(FileDescStub.DEFAULT_URN)) return fdStub;
else if (urn.equals(_notHave)) return null;
else if (_urns.containsKey(urn)) return (FileDesc) _urns.get(urn);
else return new FileDescStub("other.txt");
}
/** @see similar(RemoteFileDesc, RemoteFileDesc) */
static boolean same(String name1, long size1, URN hash1, String name2, long size2, URN hash2) {
// Either they have the same hashes...
if (hash1 != null && hash2 != null) return hash1.equals(hash2);
// ..or same name and size and no conflicting hashes.
else return size1 == size2 && name1.equals(name2);
}