Tuesday, March 22, 2011

.WAP for Thread pool Scenario .Make a class diagram for thread-pool. Also discuss how to allocate threads for different calls Read WIKIpedia for this

import java.util.LinkedList;

class ThreadTask extends Thread {
private ThreadPool pool;

public ThreadTask(ThreadPool thePool) {
pool = thePool;
}

public void run() {
while (true) {
// blocks until job
Runnable job = pool.getNext();
try {
job.run();
} catch (Exception e) {
// Ignore exceptions thrown from jobs
System.err.println("Job exception: " + e);
}
}
}
}

public class ThreadPool {
private LinkedList tasks = new LinkedList();

public ThreadPool(int size) {
for (int i = 0; i < size; i++) {
Thread thread = new ThreadTask(this);
thread.start();
}
}

public void run(Runnable task) {
synchronized (tasks) {
tasks.addLast(task);
tasks.notify();
}
}

public Runnable getNext() {
Runnable returnVal = null;
synchronized (tasks) {
while (tasks.isEmpty()) {
try {
tasks.wait();
} catch (InterruptedException ex) {
System.err.println("Interrupted");
}
}
returnVal = (Runnable) tasks.removeFirst();
}
return returnVal;
}

public static void main(String args[]) {
final String message[] = { "Java", "Source", "and", "Support" };
ThreadPool pool = new ThreadPool(message.length / 2);
for (int i = 0, n = message.length; i < n; i++) {
final int innerI = i;
Runnable runner = new Runnable() {
public void run() {
for (int j = 0; j < 25; j++) {
System.out.println("j: " + j + ": " + message[innerI]);
}
}
};
pool.run(runner);
}
}
}

1 comment :

Bhavesh Jogi said...

Hi, Its very helpful for me.

Can you solve this problem by Thread pools concept:

http://www.careercup.com/question?id=13582694

Thanks,
Bhavesh Jogi