import java.util.Vector;
import java.rmi.*;
import java.rmi.server.*;

/**
  * Implementation for the Remote interface PopupServerInterface
  */
public class PopupServerImpl  extends UnicastRemoteObject implements PopupServerInterface{

/**
  *Constructor that calls the super.
  *Create and export a new UnicastRemoteObject object using an anonymous port.
  */
PopupServerImpl() throws RemoteException {
super();
}


Vector v= new Vector();  // Vector to hold the references to the individual clients


/**
  *Method to add a user on the server. 
  *Basically regiseters a client with the server
  *@param userId, the remote interface representing the client object
  */
public void addUser(PopupClientInterface userId)  throws RemoteException{
	v.addElement(userId);
}

/**
  *Method to remove a registerd user onthe server.
  *Called by the client in its destroy before going down.
  *@param userId, the remote interface representing the client object
  */
public void removeUser(PopupClientInterface userId)  throws RemoteException {
 v.removeElement(userId);
 }

/**
  *Returns a listing of all the registerd users at any point of time.
  *@return The vector containing all the references to the clients
  */
public Vector getUsers()  throws RemoteException {
	v.trimToSize();
	return v;
}

/**
  *Sends a message to all the registerd  clients.
  *@param String containing the message to be brodcast.
  */
public void sendMessage(String message) throws RemoteException {
	v.trimToSize();
	for ( int i=0; i <v.size();i++){
	PopupClientInterface client=(PopupClientInterface)v.elementAt(i);
	client.showPopup(message);
	}

  }

}