package com.itbac.cas;

import java.util.concurrent.atomic.AtomicLong;

import java.util.concurrent.atomic.LongAdder;

// 测试用例： 同时运行2秒，检查谁的次数最多

public class LongAdderDemo {

    // synchronized 方式

    private long count = 0;

    // Atomic方式

    private AtomicLong acount = new AtomicLong(0L);

    // LongAdder 方式  （jdk1.8,新计数器）

    private LongAdder lacount = new LongAdder();

    // 运行时间，毫秒数

    private  int time=2000;

    // 同步代码块的方式

    public void testSync() throws InterruptedException {

        for (int i = 0; i < 3; i++) {

            new Thread(() -> {

                long starttime = System.currentTimeMillis();

                while (System.currentTimeMillis() - starttime < time) { // 运行两秒

                    synchronized (this) {

                        ++count;

                    }

                }

                long endtime = System.currentTimeMillis();

                System.out.println("SyncThread spend:" + (endtime - starttime) + "ms" + " v:" + count);

            }).start();

        }

    }

    public void testAtomic() throws InterruptedException {

        for (int i = 0; i < 3; i++) {

            new Thread(() -> {

                long starttime = System.currentTimeMillis();

                while (System.currentTimeMillis() - starttime < time) { // 运行两秒

                    acount.incrementAndGet(); // acount++;

                }

                long endtime = System.currentTimeMillis();

                System.out.println("AtomicThread spend:" + (endtime - starttime) + "ms" + " v:" + acount.incrementAndGet());

            }).start();

        }

    }

    public void testLongAdder() throws InterruptedException {

        for (int i = 0; i < 3; i++) {

            new Thread(() -> {

                long starttime = System.currentTimeMillis();

                while (System.currentTimeMillis() - starttime < time) { // 运行两秒

                    lacount.increment();

                }

                long endtime = System.currentTimeMillis();

                System.out.println("LongAdderThread spend:" + (endtime - starttime) + "ms" + " v:" + lacount.sum());

            }).start();

        }

    }

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

        LongAdderDemo demo = new LongAdderDemo();

        demo.testSync();

        demo.testAtomic();

        demo.testLongAdder();

    }

}

SyncThread spend:2000ms v:25458554

SyncThread spend:2000ms v:25458554

SyncThread spend:2000ms v:25458554

AtomicThread spend:2000ms v:78489760

AtomicThread spend:2000ms v:78489759

AtomicThread spend:2000ms v:78489758

LongAdderThread spend:2000ms v:141154988

LongAdderThread spend:2000ms v:141154988

LongAdderThread spend:2000ms v:141352859

* @since 1.5

* @author Doug Lea

AtomicLong

* @since 1.8

* @author Doug Lea

LongAdder