CyclicBarrierDemo.java

package ca.bazlur.concurrency101;

import java.util.Random;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.TimeUnit;
import java.util.stream.IntStream;

public class CyclicBarrierDemo {
    public static void main(String[] args) throws InterruptedException {
        final int numberOfPortfolios = 3;
        Runnable barrierAction = ()
                -> System.out.println("All portfolios have completed the current step. " +
                "Proceeding to the next step.");

        var barrier = new CyclicBarrier(numberOfPortfolios, barrierAction);
        var random = new Random();
        IntStream.rangeClosed(1, numberOfPortfolios)
                .forEach(i -> Thread.startVirtualThread(
                        new PortfolioTask(("Portfolio " + i),
                                barrier, random.nextLong(1000))));

        TimeUnit.SECONDS.sleep(30);
        System.out.println("Hope by now all work is done!");
    }
}

record PortfolioTask(String portfolioName,
                     CyclicBarrier barrier, 
                     Long sleepTime) implements Runnable {
    @Override
    public void run() {
        try {
            System.out.println(portfolioName + " is gathering data...");
            TimeUnit.MILLISECONDS.sleep(sleepTime);
            barrier.await();

            System.out.println(portfolioName + " is calculating risk...");
            TimeUnit.MILLISECONDS.sleep(sleepTime);
            barrier.await();

            System.out.println(portfolioName + " is generating the report...");
            TimeUnit.MILLISECONDS.sleep(sleepTime);
            barrier.await();

            System.out.println(portfolioName + " risk assessment is complete.");
        } catch (Exception e) {
            Thread.currentThread().interrupt();
        }
    }
}