/*  Implementation of the rmistack interface.  It is this file from which
we will use rmic on to generate code that automatically handles incomming
requests.
*/


import java.rmi.*;
import java.rmi.server.*;
import java.util.*;   // for arraylist data structure

// Every remote call to a method on a RemoteObject will spin off a new
// thread, which may need to be synchronized.  The distributed concurrency
// is thus mirrored by local thread-concurrency on the server.

public class stackimpl extends UnicastRemoteObject implements rmistack
{
    private ArrayList<String> St;

    // even the constructor must decalre exception
    public stackimpl() throws RemoteException
    {
	St = new ArrayList<String>();
    }

    public int size() throws RemoteException
    { return St.size(); }

    public void push(String s) throws RemoteException
    {
	St.add(s);
    }
    
    public String pop() throws RemoteException
    {
	int n = St.size();
	String response = null;
	if (n>0) 
	    {
	      response = St.get(n-1); // return last element of arraylist
	      St.remove(n-1);
	    }
	return response;
    }


    public String peek() throws RemoteException
    {
	int n = St.size();
	String response = null;
	if (n>0) 
	    {
	      response = St.get(n-1); // return last element of arraylist
	    }
	return response;
    }

    // main will register a stackimpl object with the local rmiregistry
    public static void main(String[] args) throws Exception
    {
	stackimpl stack0 = new stackimpl();
	stackimpl stack1 = new stackimpl();
	Naming.rebind("stack0",stack0); // register with local rmiregistry
	Naming.rebind("stack1",stack1); // register with local rmiregistry
    }

}//stackimpl

// Run this program after starting the rmiregistry on the local machine.