Question

Can you show an example of a java program that reads in a large data set from a file using thread pools, callables and futures, adding the values to a list?

Answer 1

import java.util.Random;
import java.util.concurrent.Callable;
import java.util.concurrent.FutureTask;
import java.io.*;
class CallableExample implements Callable
{
   public Object call() throws Exception
   {
       Random generator = new Random();
       File f = new File("a.txt");
       BufferedReader br = new BufferedReader(new FileReader(f));
       String s;
       while ((s = br.readLine()) != null)
       System.out.println(s);
       Thread.sleep(1000);
       return s;
   }
}

class A
{
   public static void main(String[] args) throws Exception
   {
       FutureTask[] randomNumberTasks = new FutureTask[5];
       for (int i = 0; i < 5; i++)
       {
           Callable callable = new CallableExample();
           randomNumberTasks[i] = new FutureTask(callable);
           Thread t = new Thread(randomNumberTasks[i]);
           t.start();
       }
   }
}