package com.zetcode;

import java.util.Random;

import java.util.concurrent.ExecutionException;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

import java.util.concurrent.Future;

public class FutureCancelEx {

public static void main(String[] args) throws InterruptedException, ExecutionException {

int delay = new Random().nextInt(6) + 1;

ExecutorService executorService = Executors.newSingleThreadExecutor();

long startTime = System.nanoTime();

Future<String> future = executorService.submit(() -> {

Thread.sleep(2000);

return "message from callable";

});

while (!future.isDone()) {

System.out.println("working on task ...");

Thread.sleep(400);

double elapsedTimeInSec = (System.nanoTime() - startTime) / 1000000000.0;

if (elapsedTimeInSec > delay) {

future.cancel(true);

}

}

if (!future.isCancelled()) {

System.out.println("task completed");

String result = future.get();

System.out.println(result);

} else {

System.out.println("task cancelled");

}

executorService.shutdown();

}

}