public ConversationID getConversationAt(HttpUrl url, int index) {
public ConversationID getConversationAt(int index) {
    public ConversationID getConversationAt(HttpUrl url, int index) {        try {            _model.readLock().acquire();            ArrayList filtered = (ArrayList) _filtered.get(url);            if (filtered == null)                filtered = updateFiltered(url);            return (ConversationID) filtered.get(index);        } catch (InterruptedException ie) {            // _logger.warning("Interrupted waiting for the read lock! " + ie.getMessage());            return null;        } finally {            _model.readLock().release();        }    }