html">OutputFilter:</A> Filters characters written to a Sink
    <LI><A HREF="../concepts/bidirectional_filter.html">BidirectionalFilter:</A> Filters two separate character sequences, one read from a Sink and the other written to a Sink.
    <LI><A HREF="../concepts/seekable_filter.html">SeekableFilter:</A> Filters a single characters sequence, controlled by a SeekableDevice, 
    providing filtered input, output and random access with a single repositionable read/write head
</UL>

<A NAME="optional_behavio