Incrémentation d'un compteur par plusieurs threads en utilisant AtomicLong

atomic-long-counter.java

/// usr/bin/env jbang "$0" "$@" ; exit $?
// A exécuter avec JBang : jbang atomic-long-counter.java

import java.time.Duration;
import java.util.concurrent.atomic.AtomicLong;

interface LongCounter {
    String name();
    void increment();
    long value();
}

class AtomicLongCounter implements LongCounter {

    private final AtomicLong counter;
    private final String name;

    public AtomicLongCounter(String name) {
        this.counter = new AtomicLong(0);
        this.name = name;
    }

    @Override
    public String name() {
        return name;
    }

    @Override
    public void increment() {
        this.counter.incrementAndGet();
    }

    @Override
    public long value() {
        return counter.longValue();
    }
}

class IncrementerWorker implements Runnable {

    private final LongCounter counter;

    public IncrementerWorker(LongCounter counter){
        this.counter = counter;
    }

    @Override
    public void run(){
        for(int i=0; i < 100; i++) {
            counter.increment();
            try {
                Thread.sleep(Duration.ofMillis(10));
            }
            catch(InterruptedException ie) {
                ie.printStackTrace();
            }
        }
    }
}

class Main {

    public static void main(String... args) throws InterruptedException {
        System.out.println("Code examples with updated counter in concurrent environment");
        LongCounter atomicLongCounter = new AtomicLongCounter("AtomicLongCounter");
        updateCounterFromThreads(atomicLongCounter);
    }

    public static void updateCounterFromThreads(LongCounter longCounter) throws InterruptedException {
        System.out.println(longCounter.name() + " initial value : " + longCounter.value());
        Thread t1 = new Thread(new IncrementerWorker(longCounter));
        Thread t2 = new Thread(new IncrementerWorker(longCounter));
        Thread t3 = new Thread(new IncrementerWorker(longCounter));
        //Starting the threads
        t1.start();
        t2.start();
        t3.start();
        //Waiting for the end of the work done by the threads
        t1.join();
        t2.join();
        t3.join();
        System.out.println(longCounter.name() + " value after counting with workers ends : " + longCounter.value());
        System.out.println("\n---------------------\n");
    }
}