Check for running tasks in ThreadPoolExecutor java

check-for-running-tasks-in-thread-pool-executor.java

public class CalculationExecutor {

    private final ThreadPoolExecutor executor;

    public CalculationExecutor() {
        executor = createThreadPool(1);
    }

    public void execute(Runnable runnable) {
        executor.execute(runnable);
    }

    public boolean hasRunningCalculations() {
        return executor.getActiveCount() > 0;
    }

    private static ThreadPoolExecutor createThreadPool(int threads) {
        return new ThreadPoolExecutor(threads, threads,
                0L, TimeUnit.MILLISECONDS,
                new LinkedBlockingQueue<>());
    }

    public static void main(String[] args) throws InterruptedException {
        CalculationExecutor calculationExecutor = new CalculationExecutor();
        System.out.println(calculationExecutor.hasRunningCalculations()); // false
        calculationExecutor.execute(() -> {
            try {
                Thread.sleep(100);
            }
            catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
        });
        System.out.println(calculationExecutor.hasRunningCalculations()); // true
        Thread.sleep(101);
        System.out.println(calculationExecutor.hasRunningCalculations()); // false

    }
}