Re: Switching from Non-Blocking to Blocking IO

From:

"Mike Schilling" <mscottschilling@hotmail.com>

Newsgroups:

comp.lang.java.programmer

Date:

Fri, 30 Nov 2007 17:44:36 GMT

Message-ID:

<8_X3j.48595$eY.15305@newssvr13.news.prodigy.net>

Christian wrote:

Hello

I have just tried using non-Blocking IO in a JavaSE program.
My problem is that at one point I have to switch during the the
running protocol to blocking-io as some compressed data arrives and
my gzip implementation only allows decompressing from a blocking
stream.

so what I tried was this

@Override
public ByteChannel retrieveChannel() throws IOException {

   SocketChannel sc = (SocketChannel)key.channel();
   key.cancel();

   sc.configureBlocking(true);
   sc.socket().setSoTimeout(20000);
   return sc;
}

the problem with this code is that after calling retrieveChannel()
some data arrvies on the channel and is immediately read by the
thread that uses the selector to get all non-blocking io..

Now what have I done wrong?
It smells like a synchronization problem ..

Any hints for me? Or better solutions to the problem?

If you can buffer the entire gzip file in memory, do that, and point a
ByteArrayInputStream at the result. If not, create an InputStream subclass
that returns data from the socket and blocks when none is available. The
second is more complicated, of course, since it requires multiple threads
and some synchronization between them.