package com.company;

import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.function.Supplier;

public class Main {

    public static abstract class AbstractAdder {
        long res = 0;

        public void add(String toAdd) {
            runWithSync(() -> res += 1);
        }

        protected abstract void runWithSync(Supplier<?> dd);
    }

    public static class SyncAdder extends AbstractAdder{

        @Override
        protected void runWithSync(Supplier<?> dd) {
            synchronized (this) {
                dd.get();
            }
        }
    }

    public static class LockAdder extends AbstractAdder {

        private final Lock lock = new ReentrantLock();

        @Override
        protected void runWithSync(Supplier<?> dd) {
            lock.lock();
            try {
                dd.get();
            } finally {
                lock.unlock();
            }
        }
    }

    public static void main(String[] args) throws ExecutionException, InterruptedException {
        AbstractAdder sync = new SyncAdder();
        AbstractAdder lock = new LockAdder();

        runAdder(sync, "sync");
        runAdder(lock, "lock");
        System.out.println();
        runAdder(sync, "sync");
        runAdder(lock, "lock");
        System.out.println();
        runAdder(sync, "sync");
        runAdder(lock, "lock");
        System.out.println();
        runAdder(sync, "sync");
        runAdder(lock, "lock");
        System.out.println();
        runAdder(sync, "sync");
        runAdder(lock, "lock");
        System.out.println();
        runAdder(sync, "sync");
        runAdder(lock, "lock");
        System.out.println();
        runAdder(sync, "sync");
        runAdder(lock, "lock");
    }

    private static void runAdder(AbstractAdder adder, String name) throws ExecutionException, InterruptedException {
        int executors = 10;
        int adds = 10000000;

        long l = System.currentTimeMillis();
        ExecutorService executorService = Executors.newFixedThreadPool(executors);
        Future[] futures = new Future[executors];
        for (int i = 0; i < executors; i++) {
            Future<Void> future = executorService.submit(() -> {
                for (int j = 0; j < adds; j++) {
                    adder.add("d");
                }
                return null;
            });
            futures[i] = future;
        }
        for (Future future : futures) {
            future.get();
        }
        executorService.shutdown();
        System.out.println(name + " spent " + (System.currentTimeMillis() - l) + " and got " + adder.res);
    }
}