private void writeCollectionElement(Object o) throws IOException
    {
        if (o == null)
        {
            _out.write("null");
        }
        else if (o instanceof Boolean || o instanceof Long || o instanceof Double)
        {
            _out.write(o.toString());
        }
        else if (o instanceof String)
        {
            writeJsonUtf8String((String) o, _out);
        }
        else
        {
            writeImpl(o, true);
        }
    }