Java + Corba Help

Creamy Goodness

hey, i have to do an assignment to create a chat server with clients using corba objects and i'm completely lost. i have some sample code but it may as well be in dutch to me.

i've left this really late, and the fact that i missed a view vital classes doesn't help me either and was hoping for someone to give me a quick overview of what's happening here.

here's some sample code i have.

Client.java

import java.util.Properties;
import org.omg.CORBA.ORB;
import org.omg.PortableServer.POA;
import org.omg.PortableServer.POAHelper;
import org.omg.CosNaming.NameComponent;
import org.omg.CosNaming.NamingContext;
import org.omg.CosNaming.NamingContextHelper;

public class Client {

    public static void main(String[] args) {
	try {

            //initialize orb
            Properties props = System.getProperties();
            props.put("org.omg.CORBA.ORBInitialPort", "1050");
            //Replace MyHost with the name of the host on which you are running the server
            props.put("org.omg.CORBA.ORBInitialHost", "localhost");
            ORB orb = ORB.init(args, props);
	    	System.out.println("Initialized ORB");

            //Instantiate Servant and create reference
	    	POA rootPOA = POAHelper.narrow(

			orb.resolve_initial_references("RootPOA"));
            ListenerImpl listener  = new ListenerImpl();
            rootPOA.activate_object(listener);
	    	Listener ref = ListenerHelper.narrow(rootPOA.servant_to_reference(listener));

            //Resolve MessageServer
	    	MessageServer msgServer = MessageServerHelper.narrow(orb.string_to_object("corbaname:iiop:1.2@localhost:1050#MessageServer"));

            //Register listener reference (callback object) with MessageServer
            msgServer.register(ref);
            System.out.println("Listener registered with MessageServer");

	    	//Activate rootpoa
            rootPOA.the_POAManager().activate();

            //Wait for messages
            System.out.println("Wait for incoming messages");
            orb.run();

		} 
		catch (Exception e) {
	    	e.printStackTrace();
		}
    }
}

ListenerImpl.java

public class ListenerImpl extends ListenerPOA {

    public void message(String msg) {
	System.out.println("Message from server : " + msg);
    }
}

MessageServerImpl.java

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Vector;
import java.util.Iterator;

public class MessageServerImpl extends MessageServerPOA {

    private Vector clients = new Vector();
    private ReadThread rt = null;

    public MessageServerImpl() {
	rt = new ReadThread(this);
    }

    public void register(Listener lt) {
	clients.add(lt);
    }

    public void startReadThread() {
        rt.start();
    }

    public void message(String msg) {
	Iterator it = clients.iterator();
	while (it.hasNext()) {
	    Listener lt = (Listener) it.next();
	    lt.message(msg);
	    //FOR THE SIMPLER EXAMPLE, ADD A SIMPLE
	    //MESSAGE TO BE CALLED BACK, FOR EXAMPLE,
	    //SLEEP FOR 30 SECONDS, THEN SEND THE TIME
	}
    }
}

//EXCLUDE THIS CLASS FOR THE SIMPLER EXAMPLE
class ReadThread extends Thread {

    MessageServerImpl msImpl = null;

    public ReadThread(MessageServerImpl msImpl) {
	this.msImpl = msImpl;
    }

    public void run() {
	BufferedReader br = new BufferedReader(
	    new InputStreamReader(System.in));

        try {
	    for (;;) {
                System.out.print("message > ");
		String msg = br.readLine();
		msImpl.message(msg);
	    }
	} catch (Exception e) {
	    e.printStackTrace();
	}
    }
}

Server.java

import org.omg.CORBA.ORB;
import org.omg.PortableServer.POA;
import org.omg.PortableServer.POAHelper;
import org.omg.CosNaming.NameComponent;
import org.omg.CosNaming.NamingContext;
import org.omg.CosNaming.NamingContextHelper;
import java.util.Properties;

public class Server {

    public static void main(String[] args) {
	try {
            //create and initialize the ORB
            Properties props = System.getProperties();
            props.put("org.omg.CORBA.ORBInitialPort", "1050");
            //Replace MyHost with the name of the host on which you are running the server
            props.put("org.omg.CORBA.ORBInitialHost", "localhost");
            ORB orb = ORB.init(args, props);
	    	System.out.println("Initialized ORB");

            //Instantiate Servant and create reference
	    	POA rootPOA = POAHelper.narrow(
			orb.resolve_initial_references("RootPOA"));
	    	MessageServerImpl msImpl = new MessageServerImpl();
	    	rootPOA.activate_object(msImpl);
	    	MessageServer msRef = MessageServerHelper.narrow(
			rootPOA.servant_to_reference(msImpl));

            //Bind reference with NameService
	    	NamingContext namingContext = NamingContextHelper.narrow(
			orb.resolve_initial_references("NameService"));
            System.out.println("Resolved NameService");
            NameComponent[] nc = { new NameComponent("MessageServer", "") };
	    	namingContext.rebind(nc, msRef);

	    	//Activate rootpoa
            rootPOA.the_POAManager().activate();

            //Start readthread and wait for incoming requests
            System.out.println("Server ready and running ....");

            //REMOVE THE NEXT LINE FOR THE SIMPLER EXAMPLE
            msImpl.startReadThread();

            orb.run();

	} catch (Exception e) {
	    e.printStackTrace();
	}
    }
}

callback.idl

interface Listener {
	void message(in string msg);
};

interface MessageServer {
	void register(in Listener lt);
};

i compile it using the following.

mkdir classes
idlj -fall -td ./classes callback.idl
javac -classpath ./classes -d ./classes *.java
javac -classpath ./classes *.java

in terminal 1
orbd -ORBInitialPort 1050 -ORBInitialHost localhost &

in terminal 2
java -classpath ./classes Server -ORBInitialPort 1050

in terminal 3
java -classpath ./classes Client -ORBInitialPort 1050

how hard would it be to re-jig this example into making the client send the message to the server and the server then sending it out to the other clients.