//file: Consumer.java
import java.util.Vector;

public class Consumer extends Thread {
    Producer producer;

    Consumer(Producer p) {
        producer = p;
    }

    public void run(  ) {
        try {
            while ( true ) {
                String message = producer.getMessage(  );
                System.out.println("Got message: " + message);
                sleep( 2000 );
            }
        }
        catch( InterruptedException e ) { }
    }

    public static void main(String args[]) {
        Producer producer = new Producer(  );

        producer.start(  );
        new Consumer( producer ).start(  );
    }
}
//import java.util.*;

class Producer extends Thread {
    static final int MAXQUEUE = 5;
    private Vector messages = new Vector(  );

    public void run(  ) {
        try {
            while ( true ) {
                putMessage(  );
                sleep( 1000 );
            }
        }
        catch( InterruptedException e ) { }
    }

    private synchronized void putMessage(  )
      throws InterruptedException {

        while ( messages.size(  ) == MAXQUEUE ) {
            System.out.println("Producer queue full");
            wait(  );
//            System.out.println("post wait()");
	}

        messages.addElement( new java.util.Date().toString(  ) );

        notify(  );
    }

    // called by Consumer
    public synchronized String getMessage(  )
      throws InterruptedException {

		// not necessary if clause, but it's a better practice
//		if (messages.size() == 0)
  	      notifyAll(  );
//        	System.out.println("Post notify");

        while ( messages.size(  ) == 0 )
            wait(  );

        String message = (String)messages.firstElement(  );
        messages.removeElement( message );

        return message;
    }
}  // end of class Producer