Question 5

(a) It is required to have total two threads, both capable of acting as a produce as well as a consumer. If first thread acts as a producer then, the second thread becomes the consumer and vice-versa. They communicate with each other through a buffer, storing one integer number. One of the threads initiates the communication by sending 1 to the other thread. The second thread, on receiving 1 sends 2 to the first thread. On receiving 2, the first thread sends three integer numbers, one by one to the second thread. The second thread consumes the numbers by displaying them. Both threads terminate after that. Note that both threads must be capable of initiating the communication. Write complete multi-threaded program to meet above requirements.

class CI
{
	int n;
	boolean valueSet = false;
	synchronized int recieve()
	{
		while(!valueSet)
			try
			{
				wait();
			}
			catch(InterruptedException e)
			{
				System.out.println("InterruptedException caught");
			}	
		System.out.println("Recieve : " + n);
		valueSet = false;
		notify();
		return n;
	}
	synchronized void send(int n)
	{
		while(valueSet)
			try
			{
				wait();
			}
			catch(InterruptedException e)
			{
				System.out.println("InterruptedException caught");
			}
		this.n = n;
		valueSet = true;
		System.out.println("Send : "+n);
		notify();
	}
}
class Producer implements Runnable
{
	CI ci;
	Producer(CI ci)
	{
		this.ci = ci;
		new Thread(this,"Producer").start();
	}
	public void run()
	{
		int i=0;
		while(true)
		{
			ci.send(i++);
		}
	}
}
class Consumer implements Runnable
{
	CI ci;
	Consumer(CI ci)
	{
		this.ci = ci;
		new Thread(this,"Consumer").start();
	}
	public void run()
	{
		while(true)
		{
			ci.recieve();
		}
	}
}
class multithreadedProgramProducerConsumerExampleH2E
{
	public static void main(String args[])
	{
		CI ci = new CI();
		new Producer(ci);
		new Consumer(ci);
		System.out.println("Press Control-C to Stop.");
	}
}

(b) Explain utility class Hashtable and instanceof operator by giving examples.

// utility class Hashtable Example


import java.io.*;
import java.util.*;
class utilityClassHashtableExampleH2E
{
	public static void main(String args[]) throws IOException
	{
		Hashtable<String,Integer> ht = new Hashtable<String,Integer>();
		ht.put("Jaydip",88);
		ht.put("Arpan",89);
		ht.put("Praik",90);
		System.out.println("The Students names : ");
		Enumeration e = ht.keys();
		while(e.hasMoreElements())
			System.out.println(e.nextElement());	
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		System.out.println("Enter Student Name : ");
		String name = br.readLine();
		name = name.trim();
		Integer mark = ht.get(name);
		if(mark != null)
		{
			int mv = mark.intValue();
			System.out.println(name + " mark : "+mv);
		}
		else
			System.out.println("Student Not Found");
	}
}

// Instanceof Operator Example


class A
{
	int i,j;
}
class B
{
	int i,j;
}
class C extends A
{
	int k;
}
class D extends A
{
	int k;
}
class instanceofOperatorExampleH2E
{
		public static void main(String args[])
		{
			A a = new A();
			B b = new B();
			C c = new C();
			D d = new D();
			if(a instanceof A)
				System.out.println("a is instance of A");
			if(b instanceof B)
				System.out.println("b is instance of B");
			if(c instanceof C)
				System.out.println("c is instance of C");
			if(d instanceof D)
				System.out.println("d is instance of D");
			System.out.println();
			A ob;		
			ob = d;
			System.out.println("ob is now refers to d");
			System.out.println();
			if(ob instanceof D)
				System.out.println("ob is instance of D");
			ob = c;
			System.out.println();
			System.out.println("ob is now refers to C");
			System.out.println();
			if(ob instanceof D)
				System.out.println("ob can cast to D");
			else
				System.out.println("ob can not cast to D");	
		}
}

Question 5

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