Carlisle's Jini Badge Locator Service (designed for him to understand Jini services)

Carlisle's Jini Badge Locator Service (designed for him to understand Jini services).
Thanks also to Jan Newmarch's Jini Tutorial for helping this understanding

Four machines were used in the experiment.

shop110ab.cse: This machine provided the lookup service. None of the code I wrote was placed on the machine by me. Lookup service gets and passes on a serialized stub object.

balmy.cse: This machine provided the web service. Part of startup of the programs specifies that this machine will serve the byte codes needed by clients.

Software placed on balmy was:

GetPut.class:

the interface shared by client and server

Service_Stub.class:

the RMI stub bytecode needed by the client

starthttpcommand:

the following script used to start the web server

java -jar /usr/local/jini/jini1_0/lib/tools.jar -port 8080 -dir /home/carlisle -verbose

bandy.cse: This machine was a client that knew the location of "carlisle" and told the Service that he was in "Dunstan" . Files on this machine were

TestGetPut1.class

the byte code for the first client

policy.all

the policy file for the RMI security manager

GetPut.class

the byte code for the shared interface

startclient1command

the following shell script to start the command.

java -cp /usr/local/jini/jini1_0/lib/jini-core.jar:/usr/local/jini/jini1_0/lib/jiniext.jar:

/usr/local/jini/jini1_0/lib/sun-util.jar:/home/carlisle

-Djava.security.policy=/usr/local/jini/jini1_0/example/lookup/policy.all TestGetPut1

(note that the policy.all file came from a different place but could have been local copy).

barre.cse: This machine was a client that wanted to know the location of carlisle and is told that he is in Dunstan. Files on this machine were

TestGetPut2.class policy.all GetPut.class client.bat startclient2command

balsa.cse: This machine had two purposes. One to start up the database service and the other to be the database service. Files on this machine are:

Server.class

this class starts up the database

Service_Stub.class

needed by the database service for RMI

GetPut.class

the interface

Service.class

the database service

startservicecommand

the following script starts the server which registers and starts the service

java -cp /usr/local/jini/jini1_0/lib/jini-core.jar:/usr/local/jini/jini1_0/lib/jini-ext.jar:

/usr/local/jini/jini1_0/lib/sun-util.jar:/home/carlisle

-Djava.security.policy=/usr/local/jini/jini1_0/example/lookup/policy.all

-Djava.rmi.server.codebase=http://balmy.cse:8080/ Server

OK….now for the code:

GetPut.java: the interface for client and service

//This file is compiled with the command: java GetPut.java


import java.lang.String;
import java.io.Serializable;
import java.rmi.Remote;
//probably should separate this interface for the two kinds of clients

public interface GetPut extends Serializable,Remote
{
  public void isAt(String person, String location)
                                   throws java.rmi.RemoteException;
  public String whereIs(String person)
                   throws java.rmi.RemoteException;
}

TestGetPut1.java the first client that knows where carlisle is

Client files were compiled with the command

javac -classpath /opt/jini/jini1_0/lib/jinicore.jar:

/opt/jini/jini1_0/lib/jini-ext.jar:

/opt/jini/jini1_0/lib/sun-util.jar:/home/carlisle TestGetPut1.java TestGetPut2.java


import net.jini.discovery.*;
import net.jini.core.lookup.*;
import java.rmi.RemoteException;
import java.rmi.RMISecurityManager;

public class TestGetPut1 implements DiscoveryListener {
    protected ServiceTemplate template;
    protected LookupDiscovery disco;
    
    public static void main(String[] argv) {
	   new TestGetPut1();
	   try {
	     Thread.currentThread().sleep(100000L);
           }
	   catch(java.lang.InterruptedException e) {}
	}
    public TestGetPut1() {
	    System.setSecurityManager(new RMISecurityManager());
     	    LookupDiscovery discover = null;
	    try {
		  
                  // debug
                  System.out.println("Constructor ");
                  //end debug


               discover = new LookupDiscovery(
		            LookupDiscovery.ALL_GROUPS);
	    }
	    catch(Exception e) 
	        { System.err.println(""+e);
		  System.exit(1);
		}
	
            discover.addDiscoveryListener(this);
     }
		 
     public void discovered(DiscoveryEvent ev) {
         ServiceRegistrar[] newregs = ev.getRegistrars();
         // debug
          System.out.println("entered discovered ");
         // end debug
         Class [] classes = new Class[]{GetPut.class};
		 GetPut o = null;
		 ServiceTemplate template = 
		    new ServiceTemplate(null, classes, null);
		 for (int i=0 ; i<newregs.length ; i++) {
		    ServiceRegistrar r = newregs[i];
		    try {
			  o = (GetPut) r.lookup(template);
		    }
	  	    catch(java.rmi.RemoteException e) {
			   e.printStackTrace();
			   System.exit(2);
		    }
		    if(o == null) {
                       //debug
                       System.out.println("Continuing search ");
                       continue;
                       }
		    try {
			   o.isAt("Carlisle", "Dunstan");
                    }
		    catch(java.rmi.RemoteException e) {
			    System.err.println(""+e);
		    }
		  }
        }
        public void discarded(DiscoveryEvent ev) {}
    }

Here's the client that tries to find carlisle


 

import net.jini.discovery.*;

import net.jini.core.lookup.*;
import java.rmi.RemoteException;
import java.rmi.RMISecurityManager;

public class TestGetPut2 implements DiscoveryListener {
    protected ServiceTemplate template;
    protected LookupDiscovery disco;
    
    public static void main(String[] argv) {
	   new TestGetPut2();
	   try {
	     Thread.currentThread().sleep(100000L);
           }
	   catch(java.lang.InterruptedException e) {}
	}
    public TestGetPut2() {
	    System.setSecurityManager(new RMISecurityManager());
     	    LookupDiscovery discover = null;
	    try {
		  
                  // debug
                  System.out.println("Constructor2 ");
                  //end debug

               discover = new LookupDiscovery(
		            LookupDiscovery.ALL_GROUPS);
	    }
	    catch(Exception e) 
	        { System.err.println(""+e);
		  System.exit(1);}
	
            discover.addDiscoveryListener(this);
     }
		 
     public void discovered(DiscoveryEvent ev) {
         ServiceRegistrar[] newregs = ev.getRegistrars();
         // debug
          System.out.println("entered discovered ");
         // end debug
         Class [] classes = new Class[]{GetPut.class};
		 GetPut o = null;
		 ServiceTemplate template = 
		    new ServiceTemplate(null, classes, null);
		 for (int i=0 ; i<newregs.length ; i++) {
		    ServiceRegistrar r = newregs[i];
		    try {
			  o = (GetPut) r.lookup(template);
		    }
	  	    catch(java.rmi.RemoteException e) {
			   e.printStackTrace();
			   System.exit(2);
		    }
		    if(o == null) {
                       //debug
                       System.out.println("Continuing search ");
                       continue;
                       }
		    try {
			   String t = o.whereIs("Carlisle");
			   System.out.println(t);
                    }
		    catch(java.rmi.RemoteException e) {
			    System.err.println(""+e);
		    }
		  }
        }
        public void discarded(DiscoveryEvent ev) {}
    }

The following file is the databases Service.java and was compiled with the command

javac -classpath /opt/jini/jini1_0/lib/jini-core.jar:/opt/jini/jini1_0/lib/jini-ext.jar:/opt/jini/jini1_0/lib/sun-util.jar:/home/carlisle Service.java

import java.util.Hashtable;


import java.lang.String;
import java.rmi.server.UnicastRemoteObject;

class Service extends UnicastRemoteObject
   implements GetPut
   
 {   protected Hashtable d;
    public Service() throws java.rmi.RemoteException {
       d = new Hashtable();
       }
     public void isAt(String person, String location)
        throws java.rmi.RemoteException { d.put(person,location);}
     public String whereIs(String person)
        throws java.rmi.RemoteException { return (String)d.get(person);}
  }

additionally the RMI stub is generated from this compiled class with the command

rmic –v1.2 –d /home/carlisle Service

The file Server.java follows. This program starts the service and registers it.

It is compiled with the command

javac -classpath /opt/jini/jini1_0/lib/jini- core.jar:/opt/jini/jini1_0/lib/jini-ext.jar:

/opt/jini/jini1_0/lib/sun-util.jar:/home/carlisle Server.java


import net.jini.discovery.*;
import net.jini.core.lookup.*;
import java.util.Hashtable;
import java.io.IOException;
import java.rmi.RMISecurityManager;
import com.sun.jini.lease.*;
import net.jini.core.lease.Lease;
 
public class Server implements 
       DiscoveryListener, LeaseListener {
    protected Service service;    
    protected LeaseRenewalManager leaseManager =
	                new LeaseRenewalManager(); 
	protected ServiceID serviceID = null;
	
	public static void main(String args[]) {
	    new Server();
	     
    }
    	public Server() {
	     try {
		   service = new Service();
		 }
		 catch(Exception e) {
		   System.err.println(""+e);
		   System.exit(1);
		 }
		 System.setSecurityManager(
		      new RMISecurityManager());
         LookupDiscovery discover = null;
		 try {
		   discover = new LookupDiscovery(
		      LookupDiscovery.ALL_GROUPS);
	     }
		 catch(Exception e) {
		    System.err.println(""+e);
			System.exit(1);
		}
		discover.addDiscoveryListener(this);
	}
		      
	public void discovered(DiscoveryEvent evt) {
        ServiceRegistrar[] registrars = evt.getRegistrars();
		 
        for (int n=0 ; n<registrars.length ; n++) {
          ServiceRegistrar registrar = registrars[n];
		  ServiceItem item = new ServiceItem(
		      null, service, null);
    //debug
                  System.out.println("registered " + service.getClass().getName());
    //enddebug
		  ServiceRegistration reg = null;
		  try {
		    reg = registrar.register(item,Lease.FOREVER);
            }
		  catch(java.rmi.RemoteException e) {
		     System.err.println("" + e);
			 continue;
             }
		  leaseManager.renewUntil(reg.getLease(),
		          Lease.FOREVER,this);
		 }
	}
	public void discarded(DiscoveryEvent evt) {}
		     
    public void notify(LeaseRenewalEvent evt) {
	   System.out.println("LeaseExpired " + evt); }
}