My last (hopefully) socket question...

Question

Hi,
thanks to the people who helped me get my sockets up and running. I got pointed in the right direction (when I was convinced something else was the problem) and now I fixed my bug. So, now when I receive things over the socket, I always receive the same thing. On the sender side I am printing out what I am sending. The receiver prints out what it receives. The receiver is always printing out the first thing it received, even though the sender has claimed to send something newer. This goes on and on. The sender always prints out that it is sending something new, yet what the receiver prints out is what it read the first time.
Is there some flushing of the object input stream that I need to do? I tried setting ois.enableResolveObject(true) but my compiler tells me that method has protected access, so I must not be able to call it.
For reference, here is my receiver code:
ArrayList remoteEvents = null;
while (running) {
        remoteEvents = null;
        remoteEvents = (ArrayList)ois.readObject();
        while (remoteEvents == null) {
          remoteEvents = (ArrayList)ois.readObject();
        for(int index=0; index < remoteEvents.size(); index++) {
          System.out.println("receiving event " + ((SimEvent)remoteEvents.get(index)));
        addRemoteEvents(remoteEvents);
}Any ideas?
Thanks.

Answer 1

Ok, here is some more of the code. I tried clearing the ArrayList each time before calling readObject() and now I am thoroughly confused again. If I clear the ArrayList then nothing is received over the socket, i.e. the ArrayList received has size() == 0. If I don't clear the ArrayList then I continually receive the same thing that was sent the first time. Here's the code:
ArrayList remoteEvents = new ArrayList();
while (running) {
        remoteEvents.clear();  //causes empty ArrayList to be received
        remoteEvents = null;
        remoteEvents = (ArrayList)ois.readObject();
        while (remoteEvents == null) {
          remoteEvents = (ArrayList)ois.readObject();
        for(int index=0; index < remoteEvents.size(); index++) {
          System.out.println("receiving event " + (SimEvent)remoteEvents.get(index));
        addRemoteEvents(remoteEvents);
}Just for reference, here is the sender code:
for(int index=0; index < msg_queue.size(); index++) {
        System.out.println("sending event " + (SimEvent)msg_queue.get(index));
      //now send msg_queue over the socket
      ConnectionObject co = (ConnectionObject)peerSockets.get(machine);
      try {
        co.oos.writeObject(msg_queue);
        co.oos.flush();
      } catch (Exception e) {
        System.err.println("error writing messages to machine " + machine);
        System.err.println(e.getMessage());
        e.printStackTrace();
        System.exit(-1);
}Any hints on why the clear() on the ArrayList would cause such a difference in behavior would be appreciated.
Thanks.