The Line Oriented Talker: Registry version 2

Registry.java

import java.lang.*;
import java.util.*;

public class TalkerRegistry
{
    public static synchronized boolean register(Handler handler)
    {
        if (vTalkers == null)
        {
            vTalkers = new Vector();
        }
        
        boolean bReturn = handler.register(vTalkers);
        
        if (bReturn)
            System.out.println(vTalkers.size());
        
        return bReturn;
    }
    
    public static synchronized void unregister(Handler handler)
    {
        if (vTalkers == null)
        {
            vTalkers = new Vector();
        }
        
        handler.unregister(vTalkers);
    }
    
    public static synchronized boolean isRegistered(Handler handler)
    {
        if (vTalkers == null)
        {
            vTalkers = new Vector();
        }
        
        if (vTalkers.indexOf(handler) != -1)
        {
            return true;
        }
        else
        {
            return false;
        }
    }
    
    public static void postMessage(Handler handler, String strMessage)
    {
        if (vTalkers == null)
        {
            vTalkers = new Vector();
        }
        
        Object obj;
        Telnet tObj, tHandler;
        
        for (Enumeration enHandlers = vTalkers.elements(); enHandlers.hasMoreElements(); )
        {
            obj = enHandlers.nextElement();
            
            if (handler instanceof Telnet)
            {
                tHandler = (Telnet)handler;

                if (obj instanceof Telnet)
                {
                    tObj = (Telnet)obj;
                    tObj.postMessage(new Message(new String("["+tHandler.getUserName()+"] "+strMessage+"\n")));
                }
            }
            // no other cases defined
        }
    }
    
    public static String getWelcomeMessage()
    {
        return "Welcome to the Talker\nAfter you're logged in, you can use @QUIT to quit.\n";
    }
    
    public static String getLoginMessage()
    {
        return "Please enter your name.\n";
    }
        
    
    private static Vector vTalkers;
}