Java NIO 与 基于reactor设计模式的事件处理模型

package reactor.section3;

import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set;

public class NBTest1 {
    
    

    private static void printKeyInfo(SelectionKey sk) {
        String s = new String();
        s += "Att: " + (sk.attachment() == null ? "no" : "yes");
        s += ", Read: " + sk.isReadable();
        s += ", Acpt: " + sk.isAcceptable();
        s += ", Cnct: " + sk.isConnectable();
        s += ", Wrt: " + sk.isWritable();
        s += ", Valid: " + sk.isValid();
        s += ", Ops: " + sk.interestOps();
        debug(s);
    }
    private static void debug(String s) {
        System.out.println(s);
    }
    public static void main(String args[]) {
        NBTest1 nbTest = new NBTest1();
        try {
            nbTest.startServer();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    
    private void startServer()  throws Exception{
        int channels = 0;
        int nKeys = 0;
        int currentSelector = 0;

        //使用Selector
        Selector selector = Selector.open();

        //建立Channel 并绑定到9000端口
        ServerSocketChannel ssc = ServerSocketChannel.open();
        InetSocketAddress address = new InetSocketAddress(InetAddress.getLocalHost(),9000); 
        ssc.socket().bind(address);

        //使设定non-blocking的方式。
        ssc.configureBlocking(false);

        //向Selector注册Channel及我们有兴趣的事件
        SelectionKey s = ssc.register(selector, SelectionKey.OP_ACCEPT);
        printKeyInfo(s);
        while(true) //不断的轮询
        {
            
            debug("NBTest: Starting select");
            //Selector通过select方法通知我们我们感兴趣的事件发生了。
            nKeys = selector.select();
            //如果有我们注册的事情发生了，它的传回值就会大于0
            if(nKeys > 0){
                debug("NBTest: Number of keys after select operation: " +nKeys);
                
                Set selectedKeys = selector.selectedKeys();
                Iterator i = selectedKeys.iterator();
                while(i.hasNext()){
                    
                    s = (SelectionKey) i.next();
                    printKeyInfo(s);
                    debug("NBTest: Nr Keys in selector: " +selector.keys().size());
                    //一个key被处理完成后，就都被从就绪关键字（ready keys）列表中除去
                    i.remove();
                    if(s.isAcceptable()){
                        // 从channel()中取得我们刚刚注册的channel。
                        Socket socket = ((ServerSocketChannel)s.channel()).accept().socket();
                        SocketChannel sc = socket.getChannel();
                        sc.configureBlocking(false);
                        sc.register(selector, SelectionKey.OP_READ |SelectionKey.OP_WRITE);
                        System.out.println(++channels);
                    }else{
                        debug("NBTest: Channel not acceptable");
                    }
                }
                
                
                
            }else{
                debug("NBTest: Select finished without any keys.");
            }

        }
        
    }
}