public synchronized String getListOfAllUsers(boolean online){
		StringBuilder userList= new StringBuilder();
		for (User userFound : _users.values()){
			String username= userFound.getUsername();
	        if ((online) && (userFound.isLoggedIn())){
	        	if (!username.equals("server"))
		        	userList.append(username).append(" ");
	        }
	        else
	        	if (!username.equals("server"))
		        	userList.append(username).append(" ");
		}
		System.out.println(userList.toString());
		return userList.toString();
	}