VTU Distributed Computing Lab

RMI

Problem statement:

Design and implement client server application using RMI (Remote Method Invocation) to invoke a service to calculate the income tax.

Start NetBean IDE

Create new project:

File-> New Project  

Select Java project and Click on next:

Provide the Project Name: (it-rmi-server)

And Click on Finish

Expand your project:

Right click on package (it.rmi.server) Create new interface

Provide name for the interface: (ItTaxCal)

Click on Finish

After removing comments in  ItTaxCal interface looks:

package it.rmi.server;

import java.rmi.Remote;

public interface ItTaxCal extends Remote{

   

}

Add the method to ItTaxCal interface as shown bellow:

package it.rmi.server;

import java.rmi.Remote;

import java.rmi.RemoteException;

public interface ItTaxCal extends Remote{

     

       public double getTaxAmount(double income,double deductions)throws RemoteException;

}

Right Click on package and create new Class ( ItTaxCalImp)

Click on Finish

Note: Auto generate comments has been removed  

Add the following code to the ItTaxCalImp class

package it.rmi.server;

import java.rmi.RemoteException;

import java.rmi.server.UnicastRemoteObject;

public class ItTaxCalImp extends UnicastRemoteObject implements ItTaxCal {

   public ItTaxCalImp() throws RemoteException {

   }

   @Override

   public double getTaxAmount(double income, double deductions) throws RemoteException {

       

//Write your Business Logic

       double taxAmount = 0.0d;

        if (income > deductions) {

            taxAmount = (income - deductions) * .3;

        }

        return taxAmount;

   }

 }

Open ItRmiServer  calss add the following code

package it.rmi.server;

import java.rmi.AlreadyBoundException;

import java.rmi.RemoteException;

import java.rmi.registry.LocateRegistry;

import java.rmi.registry.Registry;

public class ItRmiServer {

  public static void main(String[] args) {

       try{

           Registry registry=LocateRegistry.createRegistry(1099);

           ItTaxCal obj=new ItTaxCalImp();

           registry.bind("taxcal", obj);

           System.out.println("RMI Server is started......");

       }catch(RemoteException | AlreadyBoundException e){

           System.out.println(e);

       }

   }

}

With this we have done with the RMI server application

Creating client project:

Select Java Project and click on Next:

Provide project name and click on finish

To add Remote interface, right click on it-rmi-client project and select the Properties

Then the following window appears

Select the Libraries 

Select Add Project Tab, then select it-rmi-server project click on Add Project JAR Files

Then the following screen appears:

Open the ItRmiClient calss and add following code:

package it.rmi.client;

import it.rmi.server.ItTaxCal;

import java.rmi.NotBoundException;

import java.rmi.RemoteException;

import java.rmi.registry.LocateRegistry;

import java.rmi.registry.Registry;

import java.util.Scanner;

public class ItRmiClient {

   public static void main(String[] args) {

       try{

           Registry registry=LocateRegistry.getRegistry("localhost",1099);

           ItTaxCal obj=(ItTaxCal)registry.lookup("taxcal");

           Scanner sc=new Scanner(System.in);

           System.out.println("Enter your name:");

           String name=sc.nextLine();

           System.out.println("Enter Income :");

           double income=sc.nextDouble();

           System.out.println("Enter Deductions");

           double deductions=sc.nextDouble();

           

           double taxamt=obj.getTaxAmount(income, deductions);

          

           System.out.println("\n Hi, "+name +" your tax details :");

           System.out.println("Income     :"+income);

           System.out.println("Deductions :"+deductions);

           System.out.println("Tax Amount :"+taxamt);

           

       }catch(RemoteException | NotBoundException e){

           System.out.println(e);

       }

   }

   

}

We are done with ItRmiClient class:

To Run the application:

First run the ItRmiServer Program (Open ItRmiServer)

Right click and RunFile

On console,  RMI server is started…….

Now RMI server is running successfully. To access RMI Service we we should run client class

Open ItRmiClient class, Riht click and click on Run file

Provide valid inputs:  

Based on your inputs tax calculation will be calculated and displayed on console.