Description
Operating Systems 1
Through this assignment, you will learn how to use multiple threads in you Java
application programs. The assignment is to write a multithread Java program that
performs matrix multiplication. In the program, you need to calculate each element
in the result matrix in a separate thread. For the convenience of programming, two
sample matrices could be included in your code. However, your code should be
generic with regard to matrix size. The sizes of three matrices should be stored in
variable and used. The two operand matrices and the result matrix should be
printed.
You must submit Java files and screen shots that show how your program
works. Refer to the marking criteria at the end of this document.
Thread and Runnable classes
The following five sections are prepared to help you understand how to use Thread
and Runnable classes to implement multithread Java application programs.
1. Java thread states
ne
w
runnable
blocked
terminated
start()
sleep()
I/O
I/O is
available
exit()
2 Assignment 1
TRU Open Learning
2. Two approaches:
2.1 extends Thread
class Worker extends Thread
{
int id; // not shared among threads; instance variable for an
object, i.e., thread
Worker (int id) {
this.id = id;
}
// need to be implemented; starting point of threads, when
start() is called
public void run() {
System.out.println(“I am ” + id + “‘th worker thread”);
}
}
public class First
{
public static void main(String args[]) {
Worker runnerOne = new Worker(1); // create a thread
Worker runnerTwo = new Worker(2);
runnerOne.start(); // start the thread
runnerTwo.start();
System.out.println(“I am the main thread”);
}
}
COMP 3411: Operating Systems 3
TRU Open Learning
//——————————————————————————————————
public class Second extends Thread
{
int id;
Second (int id) {
this.id = id;
}
public void run() {
System.out.println(“I am ” + id + “‘th worker thread.”);
}
public static void main(String args[]) {
Second runnerOne = new Second(1);
Second runnerTwo = new Second(2);
runnerOne.start();
runnerTwo.start();
System.out.println(“I am the main thread.”);
}
}
Disadvantage
o Cannot extend other class
2.2 implements Runnable
Can extend other class
4 Assignment 1
TRU Open Learning
Sort of multiple inheritance
E.g., public class ThreadApplet extends Applet implements Runnable
class Worker implements Runnable
{
int id;
Worker (int id) {
this.id = id;
}
public void run() {
System.out.println(“I am ” + id + “‘th worker thread.”);
}
}
public class Third
{
public static void main(String args[]) {
Runnable worker = new Worker(1);
Thread runnerOne = new Thread(worker);
worker = new Worker(2);
Thread runnerTwo = new Thread(worker);
runnerOne.start();
runnerTwo.start();
System.out.println(“I am the main thread.”);
}
}
//————————————————————————————
public class Fourth implements Runnable
{
int id;
Fourth (int id) {
this.id = id;
COMP 3411: Operating Systems 5
TRU Open Learning
}
public void run() {
System.out.println(“I am ” + id + “‘th worker thread.”);
}
public static void main(String args[]) {
Runnable worker = new Fourth(1);
Thread runnerOne = new Thread(worker);
Thread runnerTwo = new Thread(new Fourth(2));
runnerOne.start();
runnerTwo.start();
System.out.println(“I am the main thread.”);
}
}
3. Joining threads
public class Fifth implements Runnable
{
int id;
Fifth (int id) {
this.id = id;
}
public void run() {
try { Thread.sleep(1000); } // sleep 1000 ms
catch (InterruptedException ie) {}
System.out.println(“I am ” + id + “‘th worker thread.”);
}
public static void main(String args[]) {
Runnable worker = new Fifth(1);
Thread runnerOne = new Thread(worker);
Thread runnerTwo = new Thread(new Fifth(2));
6 Assignment 1
TRU Open Learning
runnerOne.start();
runnerTwo.start();
try { runnerOne.join(); } // wait until runnerOne
terminates
catch(InterruptedException ie) {}
System.out.println(“The first worker done.”);
System.out.println(“I am the main thread.”);
}
}
4. Thread cancellation
public class Sixth implements Runnable
{
int id;
Sixth (int id) {
this.id = id;
}
public void run() {
while (true) {
try { Thread.sleep(1000); } // sleep 1000 ms
catch (InterruptedException ie) { // if interrupted
System.out.println(“I (” + id + “‘th worker) am
interrupted.”);
break;
}
System.out.println(“I am ” + id + “‘th worker
thread.”);
if (Thread.currentThread().isInterrupted()) { // if
interrupted
System.out.println(“I (” + id + “‘th worker) am
interrupted.”);
break;
}
COMP 3411: Operating Systems 7
TRU Open Learning
}
}
public static void main(String args[]) {
Runnable worker = new Sixth(1);
Thread runnerOne = new Thread(worker);
Thread runnerTwo = new Thread(new Sixth(2));
runnerOne.start();
runnerTwo.start();
runnerOne.stop(); // stop runnerOne; deprecated
try { runnerOne.join(); }
catch(InterruptedException ie) {}
System.out.println(“The first worker done.”);
runnerTwo.interrupt(); // interrupt runnerTwo
System.out.println(“I am the main thread.”);
}
}
5. Shared variable
public class Seventh implements Runnable
{
static int common; // shared among objects, i.e., threads
int id;
Seventh (int id) {
this.id = id;
common = id;
}
public void run() {
8 Assignment 1
TRU Open Learning
System.out.println(“I am ” + id + “‘th worker thread – ” +
common);
}
public static void main(String args[]) {
Thread runnerOne = new Thread(new Seventh(1));
Thread runnerTwo = new Thread(new Seventh(2));
runnerOne.start();
runnerTwo.start();
System.out.println(“I mm the main thread.”);
}
}
Assignment Marking Criteria Weighting
No syntax error: All requirements are fully implemented without syntax
errors. Submitted screen shots will be reviewed with source code. /5
Correct implementation: All requirements are correctly implemented
and produce correct results Submitted screen shots will be reviewed
with source code.
/5
Total /10
How to Submit your Assignment (PDF)
