Question

1. Create two directories from a DOS or Unix prompt. Name one directory 'RMILabServer' and the other directory 'RMILabClient'.

2. Within the server directory, save the following three classes.

//************************************************************

// Calculator.java Interface for a Calculator import java.rmi.*;

public interface Calculator extends Remote {

// this method will be called from remote clients int add (int x, int y) throws RemoteException;

}

//*************************************************************

// CalculatorServant.java

// A Remote object class that implements Calculator.

import java.rmi.*;

import java.rmi.server.UnicastRemoteObject;

public class CalculatorServant extends UnicastRemoteObject implements Calculator {

public CalculatorServant() throws RemoteException { }

public int add(int x, int y) throws RemoteException {

System.out.println("Got request to add " + x + " and " + y);

return x + y; } }

//**************************************************************

// CalculatorServer.java Serve remote Calculator

// Creates a calculator object and gives

// it a name in the registry.

import java.rmi.*;

public class CalculatorServer {

public static void main(String args[]){

System.out.println("Calculator Server Running");

try{

// create the servant

Calculator c = new CalculatorServant();

System.out.println("Created Calculator object");

System.out.println("Placing in registry");

// publish to registry

Naming.rebind("CoolCalculator", c);

System.out.println("CalculatorServant object ready");

}catch(Exception e) {

System.out.println("CalculatorServer error main " + e.getMessage());

} } }

Compile all the code with the command "javac *.*". Run RMIC on the servant class with the command "rmic -v1.2 CalculatorServant". Copy the interface Calculator.java and the stub class to the client. The stub will be called CalculatorServant_Stub.class. Within the server directory, start the rmiregistry with the command "rmiregistry &" (Unix) or "start rmiregistry (DOS)". Run the server with the command "java CalculatorServer".

3. In the client directory, enter the following program:

//*******************************************************

// CalculatorClient.java

// This client gets a remote reference from the rmiregistry

// that is listening on the default port of 1099.

// It allows the client to quit with a "!".

// Otherwise, it computes the sum of two integers

// using the remote calculator.

import java.rmi.*;

import java.rmi.server.*;

import java.io.*;

import java.util.StringTokenizer;

public class CalculatorClient {

public static void main(String args[]) throws Exception {

BufferedReader in = new BufferedReader( new InputStreamReader(System.in));

// connect to the rmiregistry and get a remote reference to the Calculator

// object.

Calculator c = (Calculator) Naming.lookup("//localhost/CoolCalculator");

System.out.println("Found calculator. Enter ! to quit");

while(true) { try {

// prompt the user

System.out.print("client>");

// get a line

String line = in.readLine();

// if a "!" is entered just exit

if(line.equals("!")) System.exit(0);

// if it's not a return get the two integers and call add

// on the remote calculator.

if(!line.equals("")) {

StringTokenizer st = new StringTokenizer(line);

String v1 = st.nextToken();

String v2 = st.nextToken();

int i = Integer.parseInt(v1);

int j = Integer.parseInt(v2);

int sum = c.add(i,j);

System.out.println(sum);

} } catch(RemoteException e)

{

System.out.println("allComments: " + e.getMessage());

} } } }

Compile the code on the client and run with the command "java CalculatorClient". Study what you have and then begin the main exersise of this lab. ===============================================================================

Answer 1

To Make two directories named as RMILabServer,RMILabClient
-----------------------------------------------------------------
mkdir -p /home/user/{RMILabServer,RMILabClient}

---------------------
Calculator.java
---------------------

import java.rmi.*;
public interface Calculator extends Remote {
public int add(int a,int b) throws RemoteException;
public int sub(int a,int b) throws RemoteException;
public int mul(int a,int b) throws RemoteException;
public int div(int a,int b) throws RemoteException;
}

-------------------------------

CalculatorServant.java
-------------------------------
import java.rmi.*;
import java.rmi.server.*;
public class CalculatorServant extends UnicastRemoteObject implements Calculator{
public CalculatorServant() throws RemoteException{
super();
}
public int sub(int a,int b)
{
int sub;
sub=a-b;
return sub;
}
public int mul(int a,int b)
{
int m;
m=a*b;
return m;
}
public int div(int a,int b)
{
int d;
d=a/b;
return d;
}
public int add(int a,int b)
{
int add;
add=a+b;
return add;
}
}

-----------------------------

CalculatorServer.java
-----------------------------

import java.rmi.*;
public class CalculatorServer{
public CalculatorServer() {}

public static void main(String args[]) throws Exception{
CalculatorServant robj=new CalculatorServant();
Naming.rebind("rmi://localhost:1099/CalculatorService",robj);
}
}

----------------------------

CalculatorClient.java
----------------------------

import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.rmi.registry.*;   
import java.util.Scanner;
import java.rmi.*;
public class CalculatorClient{
public static void main(String[] args) throws Exception{
Calculator stub=(Calculator)Naming.lookup("rmi://localhost:1099/CalculatorService");
Scanner sc = new Scanner(System.in);
System.out.println("Enter 1st Number : ");
int a=sc.nextInt();
System.out.println("Enter 2nd Number : ");
int b=sc.nextInt();
int a=stub.add(a,b);
int s=stub.sub(a,b);
int mu=stub.mul(a,b);
int di=stub.div(a,b);
System.out.println("Addition : "+a);
System.out.println("Subtraction : "+s);
System.out.println("Multiplication : "+mu);
System.out.println("Divition : "+di);
}
}

Note:Could you please consider my effort on this work and give up vote. Thank you :)