InvokeAll: Batch Execution with time out

<T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit) throws InterruptedException
Executes the given tasks, returning a list of Futures holding their status and results when all complete or the timeout expires. Upon return, tasks that have not completed are cancelled.

import java.util.concurrent.*;
import java.util.*;

public class CallableTask<String> implements Callable<String>{
 String name;

 CallableTask(String name){
  this.name = name;
 }

 public String call(){
  try{
   Thread.sleep(1000);
   System.out.println(name +" Finishes Execution");
  }
  catch(Exception e){
   System.out.println(name + " Interrupted " + e);
  }
  return (String)(new Date() + " :: " + name);
 }
}

  

import java.util.concurrent.*;
import java.util.*;

class SimpleThreadPool{
 public static void main(String args[])throws Exception{
  ExecutorService exec = new ThreadPoolExecutor(3, 3, 0L, TimeUnit.MILLISECONDS, new LinkedBlockingQueue<Runnable>());

  List<CallableTask<String>> l1 = new ArrayList<> ();
  List<Future<String>> f1;

  /* Create 5 Callable Tasks */
  CallableTask<String> task1 = new CallableTask<> ("Task1");
  CallableTask<String> task2 = new CallableTask<> ("Task2");
  CallableTask<String> task3 = new CallableTask<> ("Task3");
  CallableTask<String> task4 = new CallableTask<> ("Task4");
  CallableTask<String> task5 = new CallableTask<> ("Task5");

  /* Adding the tasks to the list of type Callable */
  l1.add(task1);
  l1.add(task2);
  l1.add(task3);
  l1.add(task4);
  l1.add(task5);

  /*Submitting all the tasks in the list l1 to the Thread pool */
  try{
   f1 = exec.invokeAll(l1, 2000, TimeUnit.MILLISECONDS);
   exec.awaitTermination(3, TimeUnit.SECONDS);

   /* Priniting the resultes returned by the tasks */
   System.out.println("Are the tasks completed");
   for(Future obj : f1)
    System.out.println(obj.get() + "\t" +obj.isDone());
  }
  catch(Exception e){
   System.out.println("Exception is " +e);
  }
  exec.shutdown();
 }
}

   

Sample Output

Task1 Finishes Execution
Task3 Finishes Execution
Task2 Finishes Execution
Task5 Interrupted java.lang.InterruptedException: sleep interrupted
Task4 Interrupted java.lang.InterruptedException: sleep interrupted
Are the tasks completed
Sun Mar 09 20:50:31 IST 2014 :: Task1 true
Sun Mar 09 20:50:31 IST 2014 :: Task2 true
Sun Mar 09 20:50:31 IST 2014 :: Task3 true
Exception is java.util.concurrent.CancellationException

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