public FSDataInputStream(InputStream in) throws IOException 
{
    super(in);
    if( !(in instanceof Seekable) || !(in instanceof PositionedReadable) ) {
      throw new IllegalArgumentException(
          "In is not an instance of Seekable or PositionedReadable");
    }
}

 public long getPos() throws IOException 
{
    return ((Seekable)in).getPos();
}

 public int read(long position,
    byte[] buffer,
    int offset,
    int length) throws IOException 
{
    return ((PositionedReadable)in).read(position, buffer, offset, length);
}

 public  void readFully(long position,
    byte[] buffer) throws IOException 
{
    ((PositionedReadable)in).readFully(position, buffer, 0, buffer.length);
}

 public  void readFully(long position,
    byte[] buffer,
    int offset,
    int length) throws IOException 
{
    ((PositionedReadable)in).readFully(position, buffer, offset, length);
}

 public synchronized  void seek(long desired) throws IOException 
{
    ((Seekable)in).seek(desired);
}

 public boolean seekToNewSource(long targetPos) throws IOException 
{
    return ((Seekable)in).seekToNewSource(targetPos);
}