Non Blocking Server - 100% CPU Usage without OP_WRITE

From:
"rajatag" <rjsoftwares@gmail.com>
Newsgroups:
comp.lang.java.programmer
Date:
25 Aug 2006 02:06:21 -0700
Message-ID:
<1156496781.196762.114130@74g2000cwt.googlegroups.com>
Hi Everyone,

I have a non blocking server which accepts new connections as per the
acceptConnections() method below.

Connections are closed by calling channel.socket().close();

The server works fine, however after sometime we notice that the CPU
usage becomes 100% even though the server continues to function
normally.

I assume that this is due to the channels not being closed after being
registered for an OP_WRITE. However, I am not sure why that would
occur.

If someone can help it would be great!

Thanks!
Rajat

=======================

public void acceptConnections() throws IOException,
InterruptedException {

    SelectionKey acceptKey =
this.selectableChannel.register(this.selector,SelectionKey.OP_ACCEPT);

    while ((this.keysAdded = acceptKey.selector().select()) > 0) {
        Set readyKeys = this.selector.selectedKeys();
        Iterator i = readyKeys.iterator();

        while (i.hasNext()) {
            try {
                SelectionKey key = (SelectionKey) i.next();
                i.remove();
                if (key.isAcceptable()) {
                    ServerSocketChannel nextReady = (ServerSocketChannel) key
                            .channel();

                    SocketChannel channel = nextReady.accept();

                    if (db.checkIPBanning(channel.socket().getInetAddress()
                            .toString())) {
                        channel.configureBlocking(false);
                        SelectionKey readKey = channel.register(
                                this.selector, SelectionKey.OP_READ);

                        readKey.attach(new ClientConnection(this, channel,
                                "" + channel.socket().getPort()
                                        + channel.socket().getInetAddress()
                                        + ran.nextInt()));
                    } else {
                        channel.socket().close();
                        System.out.println("Banned IP ... "
                                + channel.socket().getInetAddress()
                                        .toString());
                    }

                } else if (key.isReadable()) {
                    try {
                        this.readMessage((ClientConnection) key
                                .attachment());
                    } catch (Exception e) {
                        key.channel().close();
                    }
                }
            } catch (Exception e) {
            }
        }

    }
}

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