// Add server
//
// Server for simple example application which computes the sum of two integers
// if the sequence number of the call (seqnum) matches the expected value;
// otherwise, add() will return 0.
//
// The sequence of seqnum is established by the SecureRandom
// seed during the initial authentication of the RMI connection.
//
// R. Perry, July 1998

import java.io.*;
import java.rmi.server.*;

public class AddServer
  extends UnicastRemoteObject
  implements Add
{
  private LoginServer L;

  public AddServer( LoginServer L)
    throws java.rmi.RemoteException
  {
    super();
    this.L = L;
  }

  public int add( int x, int y, long seqnum)
    throws java.rmi.RemoteException, java.rmi.server.ServerNotActiveException
  {
    System.out.println( "AddServer: add(): called from " + this.getClientHost());

    if( !L.verify( seqnum))	// client is unauthenticated or used bad sequence number
      return 0;

    return x + y;
  }
}