Test select return value. Java code example - Click here to copy ->>>

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Code:



 



package com.ronsoft.books.nio.channels;



import java.nio.ByteBuffer;

import java.nio.channels.ServerSocketChannel;

import java.nio.channels.SocketChannel;

import java.nio.channels.Selector;

import java.nio.channels.SelectionKey;

import java.nio.channels.SelectableChannel;



import java.net.Socket;

import java.net.ServerSocket;

import java.net.InetSocketAddress;

import java.util.Iterator;



/**

 * Test select return value.

 * Start this server, then connect to port 1234.  The incoming

 * connection will be registered with the selector but never read.

 * Type something on the conection, the selector will see the channel

 * ready but the channel is never serviced in the loop.  Select will

 * return 1 forever after.

 *

 * @author Ron Hitchens (ron@ronsoft.com)

 * @version $Id: SelectTest.java,v 1.1 2002/05/20 07:24:29 ron Exp $

 */

public class SelectTest

{

   public static int PORT_NUMBER = 1234;



   public static void main (String [] argv)

      throws Exception

   {

      ServerSocketChannel ssc = ServerSocketChannel.open();

      Selector selector = Selector.open();



      ssc.socket().bind (new InetSocketAddress (PORT_NUMBER));

      ssc.configureBlocking (false);

      ssc.register (selector, SelectionKey.OP_ACCEPT);



      while (true) {

         int n = selector.select (1000);



         System.out.println ("selector returns: " + n);



         Iterator it = selector.selectedKeys().iterator();



         while (it.hasNext()) {

            SelectionKey key = (SelectionKey) it.next();



            // Is a new connection coming in?

            if (key.isAcceptable()) {

               ServerSocketChannel server =

                  (ServerSocketChannel) key.channel();

               SocketChannel channel = server.accept();



               // set the new channel non-blocking

               channel.configureBlocking (false);



               // register it with the selector

               channel.register (selector,

                  SelectionKey.OP_READ);



               it.remove();

            }



            // is there data to read on this channel?

            if (key.isReadable()) {

               System.out.println ("Channel is readable");

               // don't actually do anything

            }



            // it.remove();

         }

      }

   }

}