!7

import java.nio.*;

import java.nio.channels.*;

static long timeout = 30000+10000; // idle time + latency

static ConnectedInstances cI;

static ReliableSingleThread rst = new(r update);

static int theNumber;

static int port = 6000;

static Set<AsynchronousSocketChannel> channels = synchroSet();

sclass State {

  S computerID;

  int countSeen = -1;

}

p {

  cI = new ConnectedInstances;

  cI.connected2.onChange(rst);

  InetSocketAddress sockAddr = new InetSocketAddress(port);

  AsynchronousServerSocketChannel serverSock =  AsynchronousServerSocketChannel.open().bind(sockAddr);

  //start to accept the connection from client

  serverSock.accept(serverSock, new CompletionHandler<AsynchronousSocketChannel,AsynchronousServerSocketChannel>() {

    public void completed(AsynchronousSocketChannel sockChannel, AsynchronousServerSocketChannel serverSock) {

      //a connection is accepted, start to accept next connection

      serverSock.accept(serverSock, this);

      channels.add(channel);

      //start to read message from the client

      startRead( sockChannel );

    }

    public void failed(Throwable exc, AsynchronousServerSocketChannel serverSock) {

      print("fail to accept a connection");

    }

  });

}

static void startRead( AsynchronousSocketChannel sockChannel) {

  final ByteBuffer buf = ByteBuffer.allocate(2048);

  //read message from client

  sockChannel.read(buf, sockChannel, new CompletionHandler<Int, AsynchronousSocketChannel>() {

    @Override

    public void completed(Int result, AsynchronousSocketChannel channel) {

      buf.flip();

      // echo the message

      startWrite(channel, buf);

      // start to read next message again

      startRead(channel);

    }

    @Override

    public void failed(Throwable exc, AsynchronousSocketChannel channel) {

      print( "fail to read message from client");

    }

  });

}

static void startWrite(AsynchronousSocketChannel sockChannel, final ByteBuffer buf) {

  sockChannel.write(buf, sockChannel, new CompletionHandler<Integer, AsynchronousSocketChannel >() {

    @Override

    public void completed(Int result, AsynchronousSocketChannel channel) {                 

      // finish to write message to client, nothing to do

      // (close socket?)

    }

    @Override

    public void failed(Throwable exc, AsynchronousSocketChannel channel) {

      print("Fail to write message to client");

    }

  });

}

html { ret "Use port " + port; }

svoid sendNumber(O ws) {

  State s = wsToState.get(ws);

  if (s != null && theNumber != s.countSeen) {

    s.countSeen = theNumber;

    print("Sending number to " + s.computerID + ": " + theNumber);

    call(ws, 'send, str(theNumber));

  }

}

svoid update {

  print("OS Instances update");

  if (webSocketManager.isEmpty()) ret;

  int value = cI.value();

  //if (value == theNumber) ret;

  theNumber = value;

  for (O ws : webSocketManager.webSockets()) pcall {

    sendNumber(ws);

  }

  print("OS Instances update done");

}