Question

Make a Java, program with two processes, a producer and a consumer.

The producer process consists of a loop that writes the loop count (a value from 0 to 4) into a variable that it shares with the consumer process (this variable is to be initialized to 100). On each pass through the loop, before the producer writes into the shared variable, it does a random wait of from one to three seconds (compute a new random wait value on each pass through the loop). The loop is to be executed five times.

The consumer process consists of a loop that reads the variable it shares with the producer five times and computes the sum of the values it has read. On each pass through the loop before it reads the shared variable, it does a random wait of from one to three seconds (compute a new random value on each pass through the loop). When the loop finishes, the program is to write the sum into a file.

You must run the program twice. Note that the output from the runs will almost certainly be different if you have written your program correctly. (Mine is only output the same number all time)

This program must output to a data file like "output.txt"

The contents of the output file should look something like this (where ### is your computed sum).

Jack Smith

Assignment X

The sum is ###

Answer 1

Hey, please follow below, i have added comments where ever required.

App.java

import java.util.Random;

public class App {

private int count;

private int sum;

public static void main(String[] args) {

App app = new App();

Thread producer = new Thread(new Runnable() {

@Override

public void run() {

for (int i = 0; i <= 4; i++) {

// lock will be attained by producer first

synchronized (this) {

app.count = 100;

int nextWait = new Random().nextInt(4) + 1;

try {

wait(nextWait * 1000); // releases the lock

} catch (InterruptedException e) {

e.printStackTrace();

}

}

}

}

});

Thread consumer = new Thread(new Runnable() {

@Override

public void run() {

// adding sleep of 100 milli seconds as we want the lock to be

// acquired by the producer thread first

try {

Thread.sleep(100);

} catch (InterruptedException e1) {

e1.printStackTrace();

}

for (int i = 0; i <= 4; i++) {

synchronized (this) {

app.sum += app.count; // calculates the sum

notify(); // notifies waiting producer thread

} // releases the lock at this point

}

}

});

producer.start();

consumer.start();

// stopping the main thread, as we want the producer and consumer thread

// to complete their work

try {

producer.join();

consumer.join();

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

System.out.println("Sum is : " + app.sum);

}

}

Thanks !!!