Using CyclicBarrier

[Bob Matthews]

Here is my first attempt at RMI code

Don't know whether it is part of my particular solution I am seeking ?

Writing the RMI interface

import java.rmi.*;

//
// OptimizedTrades Interface
//
// Interface for an RMI service that optimizes a list of Prospective Trades
//

public interface OptimizedTrades extends java.rmi.Remote
{
	// Calculate the list of optimized trades
	public OptimizedTrades optimize ( String ProspectiveTrades )
		throws RemoteException;

}

Server code:-

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

//
// OptimizedTradesServer
//
// Server for a RMI service that optimizes a list of Prospective Trades
//

public class OptimizedTradesServer extends UnicastRemoteObject
implements OptimizedTrades
{
    public OptimizedTrades () throws RemoteException
    {
        super();
    }

// Calculate the list of optimized trades
** TODO **
   return (OptimizedTrades);

// Assign a security manager, in the event that dynamic
// classes are loaded
if (System.getSecurityManager() == null)
    System.setSecurityManager ( new RMISecurityManager() );

// Create an instance of our Optimized Trades service server ...
    OptimizedTradesServer svr = new OptimizedTradesServer();

// ... and bind it with the RMI Registry
    Naming.bind ("OptimizedTrades", svr);

    System.out.println ("Service bound....");
}

Client code:

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

//
// OptimizedTradesServer
//
// Server for a RMI service that optimizes a list of Prospective Trades
//

public class OptimizedTradesServer extends UnicastRemoteObject
implements OptimizedTrades
{
    public OptimizedTradeServer () throws RemoteException
    {
        super();
    }

 // Calculate the list of optimized trades
** TODO **
   return (OptimizedTrades);

// Assign a security manager, in the event that dynamic
// classes are loaded
if (System.getSecurityManager() == null)
     System.setSecurityManager ( new RMISecurityManager() );

// Create an instance of our optimized trades server ...
     OptimizedTradesServer svr = new OptimizedTradesServer();

// ... and bind it with the RMI Registry
     Naming.bind ("OptimizedTrades", svr);

     System.out.println ("Service bound....");
 }


import java.rmi.*;
import java.rmi.Naming;
import java.io.*;

//
//
// OptimizedTradesClient
//
//

public class OptimizedTradesClient 
{
// Check for hostname argument
	if (args.length != 1)
	{
		System.out.println
		("Syntax - OptimizedTradesClient host");
		System.exit(1);
	}

// Assign security manager
	if (System.getSecurityManager() == null)
	{
		System.setSecurityManager
		(new RMISecurityManager());
	}

// Call registry for OptimizedTrades
	OptimizedTrades service = (OptimizedTrades) Naming.lookup
		("rmi://" + args[0] + "/OptimizedTrades");

	DataInputStream din = new 
		DataInputStream (System.in);

	for (;;)
	{
		System.out.println 
		  ("1 - Calculate list of optimized trades");
		System.out.println 
		  ("2 - Exit"); System.out.println();
		System.out.print ("Choice : ");

		String line = din.readLine();
		Integer choice = new Integer(line);
			
		int value = choice.intValue();

		switch (value)
		{
		case 1:
		  System.out.print ("List of optimized trades: ");
		  line = din.readLine();
		  System.out.println();
		  choice = new String (line);
		  value  = choice.intValue();
				
// Call remote method
		  System.out.println 
		  ("Answer : " + service.OptimizedTrades);
				
		  break;
		  case 2:
		  System.exit(0);
		  default :
		  System.out.println ("Invalid option");
		 break;
		}
	}
}

[Bob Matthews]

Can I modify the following example code for my first of two 'waits' where MAXQUEUE = no. of subscribed clients, each of which will send a message to the server with a prospective trade ?

import java.util.Vector;
 
class Producer extends Thread {
 
    static final int MAXQUEUE = 5;
    private Vector messages = new Vector();
 
    @Override
    public void run() {
        try {
            while (true) {
                putMessage();
                //sleep(5000);
            }
        } catch (InterruptedException e) {
        }
    }
 
    private synchronized void putMessage() throws InterruptedException {
        while (messages.size() == MAXQUEUE) {
            wait();
        }
        messages.addElement(new java.util.Date().toString());
        System.out.println("put message");
        notify();
        //Later, when the necessary event happens, the thread that is running it calls notify() from a block synchronized on the same object.
    }
 
    // Called by Consumer
    public synchronized String getMessage() throws InterruptedException {
        notify();
        while (messages.size() == 0) {
            wait();//By executing wait() from a synchronized block, a thread gives up its hold on the lock and goes to sleep.
        }
        String message = (String) messages.firstElement();
        messages.removeElement(message);
        return message;
    }
}
 
class Consumer extends Thread {
 
    Producer producer;
 
    Consumer(Producer p) {
        producer = p;
    }
 
    @Override
    public void run() {
        try {
            while (true) {
                String message = producer.getMessage();
                System.out.println("Got message: " + message);
                //sleep(200);
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
 
    public static void main(String args[]) {
        Producer producer = new Producer();
        producer.start();
        new Consumer(producer).start();
    }
}