Selector thread in JSSE with NIO works nor parallely?

Question

Hi,
I am now studying JSSE with NIO. Most of the codes are that I looked, used the Selectable Non blocking IO model. Selector thread contains many keys(keys == client sockets nearly)
The Selector object maintains a set of selected keys and just one key is processed at a given time in a server program. So, there is no parallel work. I wonder why this keys are not processed parallely, not in batch process model in one thread?

Answer 1

wow, this reply enlightens me.I have a question for you.
here is a samle run method of runnable selector class.
public void run() {
    while (true) {
      doPendingTasks();
      if (closeRequested) {
        return;
      int selectedKeys = 0;
      try {
        selectedKeys = selector.select();
      } catch (IOException ioe) {      
        ioe.printStackTrace();
        continue;
      if (selectedKeys == 0) {
        continue;
      Iterator it = selector.selectedKeys().iterator();
      while (it.hasNext()) {
        SelectionKey sk = (SelectionKey)it.next();
        it.remove();
        try {
          int readyOps = sk.readyOps();
          sk.interestOps(sk.interestOps() & ~readyOps);
          SelectorHandler handler =
             (SelectorHandler) sk.attachment();         
          if (sk.isAcceptable()) {
            ((AcceptSelectorHandler)handler).handleAccept();
          } else if (sk.isConnectable()) {     
            ((ConnectorSelectorHandler)handler).handleConnect();           
          } else {
            ReadWriteSelectorHandler rwHandler =
              (ReadWriteSelectorHandler)handler;              
            if (sk.isReadable()) {               
              rwHandler.handleRead();             
            if (sk.isValid() && sk.isWritable()) {
              rwHandler.handleWrite();                             
        } catch (Throwable t) {
          Shutdown();
          t.printStackTrace();
          return;
  }in this code every operation is managed by handler named "handleXXX".for example "handleRead" does reading job and also informs the side(client or server) for the data read.
public void handleRead() {
    try {     
      int readBytes = channel.read(inBuffer);     
      if (readBytes == -1) {
        // Closing channel...
        close();
        side.socketDisconnected(this);
        return;
      inBuffer.flip();
      processInBuffer(); //if there is parts that belongs to more than one packet, seperate them and inform side(client/server)
    } catch (IOException ex) {
      side.socketException(this, ex);
      close();
  }Finally my question is if this approach is wrong.if not ,it takes more than zero time,doesn't it?
If it is wrong , what approach do you suggest about handling operations?
Thanks.