NETWORK OPERATING SYSTEMS

AIM:

            To write a java program for network operating systems

ALGORITHM:

Step 1:         Start the program

Interface program

Step 2:         Create an interface ReceiveMessageInterface which extends Remote class

Step 3:         Declare method receiveMessage inside interface

Server Program

Step 4:         Create class RmiServer which extends UnicastRemoteObject which again extends the ReceiveMessageInterface

Step 5:         Define the method receiveMessage which get parameter x

Step 6:         Declare a Random object which is used to get random integers

Step 7:         Using the value of x get the Random number one by one and store it in val[i]

Step 8:         Define a constructor RmiServer in that get the local address of the Server by using InetAddress.getLocalHost()

Step 9:         Declare a port and register it in the registry object

Step 10:     Using Rebind method we register the port and a string “rmiserver” into the rmiregistry table

Step 11:     Create a object using RmiServer so that the Constructor will be initialized automatically

Client program

Step 12:     Create class RmiClient

Step 13:     Declare an object rmiServer for ReceiveMessageInterface

Step 14:     Get the server’s local address and the port in command line arguments

Step 15:     Locate the registry object using the server port

Step 16:     Using registry object call the method lookup of the server string “rmiserver” by casting the interface which is already defined

Step 17:     Now using the rmiServer object call the method receiveMessage and receive all random number one by one from the server

Step 18:     End of programs

PROGRAM:-

ReceiveMessageInterface:

import java.rmi.*;

public interface ReceiveMessageInterface extends Remote

{

   public int [] receiveMessage(int x) throws RemoteException;

}

RmiClient.java:

import java.io.*;

import java.rmi.*;

import java.rmi.registry.*;

import java.net.*;

public class RmiClient

{

    static public void main(String args[])throws IOException

    {

       ReceiveMessageInterface rmiServer;

       Registry registry;

       String serverAddress=args[0];

       String serverPort=args[1];

       int no;

       no=Integer.parseInt(args[2]);

       int rval[]=new int[no];

       System.out.println("sending "+no+" to "+serverAddress+":"+serverPort);

       try{

           registry=LocateRegistry.getRegistry(serverAddress,(new Integer(serverPort)).intValue());

           rmiServer=(ReceiveMessageInterface)(registry.lookup("rmiServer"));

           rval=rmiServer.receiveMessage(no);

           for(int i=0;i<no;i++)

           System.out.println(rval[i]);

          }

       catch(RemoteException e)

       {

            e.printStackTrace();

       }

       catch(NotBoundException e)

       {

        e.printStackTrace();

       }

    }

}

RmiServer.java:

import java.util.*;

import java.rmi.*;

import java.rmi.registry.*;

import java.rmi.server.*;

import java.net.*;

public class RmiServer extends java.rmi.server.UnicastRemoteObject

implements ReceiveMessageInterface

{

    int      thisPort;

    String   thisAddress;

    Registry registry;

    public int[] receiveMessage(int x) throws RemoteException

    {

        System.out.println(x);

          Random r=new Random();

        int val[] = new int[x];

          for(int i=0;i<x;i++)

          {

          val[i]=r.nextInt(25);

          }

        return val;

    }

    public RmiServer() throws RemoteException

    {

              try

            {

               thisAddress= (InetAddress.getLocalHost()).toString();

              }

              catch(Exception e)

            {

            throw new RemoteException("can't get inet address.");

            }

            thisPort=3232;

            System.out.println("this address="+thisAddress+",port="+thisPort);

            try

              {

            registry = LocateRegistry.createRegistry( thisPort );

            registry.rebind("rmiServer", this);

            }

        catch(RemoteException e)

        {

           throw e;

        }

    }

         

    static public void main(String args[])

    {

        try

        {

           RmiServer s=new RmiServer();

          }

          catch (Exception e)

        {

          e.printStackTrace();

          System.exit(1);

          }

     }

}

Output:

U:\OS_Lab\EX5\RMI>javac RmiServer.java

U:\OS_Lab\EX5\RMI>java RmiServer

this address=rdl30/180.100.102.30,port=3232

U:\OS_Lab\EX5\RMI>javac RmiClient.java

U:\OS_Lab\EX5\RMI>java RmiClient 180.100.102.30 3232 4

sending 4 to 180.100.102.30:3232

6

7

10

24