sivaramaiah - Record 3

Record 3:Calculator:
Create a remote server that implements a calculator with basic functionalities like addition, subtraction, division, multiplication and client, which uses the remote calculator.

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Program 1: Interface program calc.java

import java.rmi.*;

public interface calc extends Remote
{
   float add(float a,float b) throws RemoteException;
   float sub(float a,float b) throws RemoteException;
   float mul(float a,float b) throws RemoteException;
   float div(float a,float b) throws RemoteException;
   double power(float base,float power) throws RemoteException;
}

Program 2: Implementation program calcImp.java

import java.rmi.*;
import java.rmi.server.*;
import java.lang.Math.*;

public class calcImp extends UnicastRemoteObject implements calc
{
   public calcImp() throws RemoteException
   {
       super();
   }

   public float add(float a,float b) throws RemoteException
   {
       float result=a+b;
       return result;
   }

   public float sub(float a,float b) throws RemoteException
   {
       float result=(float)a-b;
       return result;

   }

   public float mul(float a,float b) throws RemoteException
   {
       float result=(float)a*b;
       return result;

   }

   public float div(float a,float b) throws RemoteException
   {
   //if(b==0) return 0;
       float result=(float)a/b;
       return result;

   }

   public double power(float base,float power) throws RemoteException
   {
       double result= (double)Math.pow(base,power);
       return result;

   }

}

Program 3: Server program calcServer.java

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

public class calcServer
{
   public static void main(String[] args)
   {
       try
       {
       System.out.print("Constructing Server Implementation...");
       calcImp calc1 = new calcImp();

       System.out.print("Done!nBinding Server Implementation...");

       Naming.rebind("RMICalc",calc1);

       System.out.print("Done!nWaiting for Invocations from client...n");
       }
       catch(Exception e)
       { System.out.print("nError Generated in calcServer : "+e.toString()+"n");
       }
   }
}

Program 4: Client program calcTClient.java

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

public class calcClient
{
   public static void main(String[] args)
   {
   float o1,o2;
   int choice=0;
   System.setSecurityManager(new RMISecurityManager());

       try
       {
       System.out.print("Naming.lookup for Bindings...");
       calc calcu = (calc) Naming.lookup("RMICalc");

       System.out.print("Done!n");

       DataInputStream dis = new DataInputStream(System.in);


           while(choice!=6)
           {
           System.out.println("n1. Addn2. Subtractn3. Multiplyn4. Dividen5. Powern6. Exit");
           System.out.print("Enter your choice : ");
           choice = Integer.parseInt(dis.readLine());
           if(choice==6) break;

           System.out.print("Enter first Number : ");
           o1 = Float.parseFloat(dis.readLine());
           System.out.print("Enter second Number : ");
           o2 = Float.parseFloat(dis.readLine());

           switch(choice)
           {
               case 1: System.out.println(o1+"+"+o2+"="+calcu.add(o1,o2)); break;
               case 2: System.out.println(o1+"-"+o2+"="+calcu.sub(o1,o2)); break;
               case 3: System.out.println(o1+"*"+o2+"="+calcu.mul(o1,o2)); break;
               case 4: System.out.println(o1+"/"+o2+"="+calcu.div(o1,o2)); break;
               case 5: System.out.println(o1+"^"+o2+"="+calcu.power(o1,o2)); break;
               default: System.out.println("Invalid Choice");
           }

           }

       }
       catch(Exception e)
       { System.out.print("Error Generated in commServer : "+e.toString()+"n");
       }
   System.exit(0);
   }
}

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Program 5: Show Bindings showBingings.java

import java.rmi.*;

import java.rmi.server.*;

public class showBindings

{

public static void main(String[] args)

{

try

{

String[] bindings = Naming.list("");

for(int i=0;i<bindings.length;i++)

System.out.println("Binding ["+(i+1)+"] => "+bindings[i]);

}

catch(Exception e)

{ System.out.println("Error in showBindings : "+e.toString()); }

}

Program 6: clinet.policy clinet.policy

grant

{

permission java.net.SocketPermission

"*:1024-65335","connect";

};

How to run the program

1. compile all java files

javac *.java

2. use RMICompiler to create stubs & skeletons of Implementations

rmic calcImp

3. run rmiregistry

start rmiregistry

4. create policy file with following contents

client.policy

~~~~~~~~~~~~~

grant

{

permission java.net.SocketPermission

"*:1024-65335","connect";

};

5. run server

java calcServer

6. run client with policy created in step 4.

java -Djava.security.policy=client.policy calcClient