java.util.concurrent.atomic.AtomicBoolean;
java.util.concurrent.atomic.AtomicInteger;
java.util.concurrent.atomic.AtomicLong;
java.util.concurrent.atomic.AtomicReference;

package test.java;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicInteger;

import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;

/**
 * 測試AtomicInteger與普通int值在多線程下的遞增操作
 */
public class TestAtomic {

 // 原子Integer遞增對象
 public static AtomicInteger counter_integer;// = new AtomicInteger(0);
 // 一個int類型的變量
 public static int count_int = 0;

 @Before
 public void setUp() {
 // 所有測試開始之前執(zhí)行初始設(shè)置工作
 counter_integer = new AtomicInteger(0);
 }

 @Test
 public void testAtomic() throws InterruptedException {
 // 創(chuàng)建的線程數(shù)量
 int threadCount = 100;
 // 其他附屬線程內(nèi)部循環(huán)多少次
 int loopCount = 10000600;
 // 控制附屬線程的輔助對象;(其他await的線程先等著主線程喊開始)
 CountDownLatch latch_1 = new CountDownLatch(1);
 // 控制主線程的輔助對象;(主線程等著所有附屬線程都運行完畢再繼續(xù))
 CountDownLatch latch_n = new CountDownLatch(threadCount);
 // 創(chuàng)建并啟動其他附屬線程
 for (int i = 0; i < threadCount; i++) {
  Thread thread = new AtomicIntegerThread(latch_1, latch_n, loopCount);
  thread.start();
 }
 long startNano = System.nanoTime();
 // 讓其他等待的線程統(tǒng)一開始
 latch_1.countDown();
 // 等待其他線程執(zhí)行完
 latch_n.await();
 //

 long endNano = System.nanoTime();
 int sum = counter_integer.get();
 //
 Assert.assertEquals("sum 不等于 threadCount * loopCount,測試失敗",
  sum, threadCount * loopCount);
 System.out.println("--------testAtomic(); 預(yù)期兩者相等------------");
 System.out.println("耗時: " + ((endNano - startNano) / (1000 * 1000)) + "ms");
 System.out.println("threadCount = " + (threadCount) + ";");
 System.out.println("loopCount = " + (loopCount) + ";");
 System.out.println("sum = " + (sum) + ";");
 }

 @Test
 public void testIntAdd() throws InterruptedException {
 // 創(chuàng)建的線程數(shù)量
 int threadCount = 100;
 // 其他附屬線程內(nèi)部循環(huán)多少次
 int loopCount = 10000600;
 // 控制附屬線程的輔助對象;(其他await的線程先等著主線程喊開始)
 CountDownLatch latch_1 = new CountDownLatch(1);
 // 控制主線程的輔助對象;(主線程等著所有附屬線程都運行完畢再繼續(xù))
 CountDownLatch latch_n = new CountDownLatch(threadCount);
 // 創(chuàng)建并啟動其他附屬線程
 for (int i = 0; i < threadCount; i++) {
  Thread thread = new IntegerThread(latch_1, latch_n, loopCount);
  thread.start();
 }
 long startNano = System.nanoTime();
 // 讓其他等待的線程統(tǒng)一開始
 latch_1.countDown();
 // 等待其他線程執(zhí)行完
 latch_n.await();
 //
 long endNano = System.nanoTime();
 int sum = count_int;
 //
 Assert.assertNotEquals(
  "sum 等于 threadCount * loopCount,testIntAdd()測試失敗", 
  sum, threadCount * loopCount);
 System.out.println("-------testIntAdd(); 預(yù)期兩者不相等---------");
 System.out.println("耗時: " + ((endNano - startNano) / (1000*1000))+ "ms");
 System.out.println("threadCount = " + (threadCount) + ";");
 System.out.println("loopCount = " + (loopCount) + ";");
 System.out.println("sum = " + (sum) + ";");
 }

 // 線程
 class AtomicIntegerThread extends Thread {
 private CountDownLatch latch = null;
 private CountDownLatch latchdown = null;
 private int loopCount;

 public AtomicIntegerThread(CountDownLatch latch,
  CountDownLatch latchdown, int loopCount) {
  this.latch = latch;
  this.latchdown = latchdown;
  this.loopCount = loopCount;
 }

 @Override
 public void run() {
  // 等待信號同步
  try {
  this.latch.await();
  } catch (InterruptedException e) {
  e.printStackTrace();
  }
  //
  for (int i = 0; i < loopCount; i++) {
  counter_integer.getAndIncrement();
  }
  // 通知遞減1次
  latchdown.countDown();
 }
 }

 // 線程
 class IntegerThread extends Thread {
 private CountDownLatch latch = null;
 private CountDownLatch latchdown = null;
 private int loopCount;

 public IntegerThread(CountDownLatch latch, 
  CountDownLatch latchdown, int loopCount) {
  this.latch = latch;
  this.latchdown = latchdown;
  this.loopCount = loopCount;
 }

 @Override
 public void run() {
  // 等待信號同步
  try {
  this.latch.await();
  } catch (InterruptedException e) {
  e.printStackTrace();
  }
  //
  for (int i = 0; i < loopCount; i++) {
  count_int++;
  }
  // 通知遞減1次
  latchdown.countDown();
 }
 }
}

--------------testAtomic(); 預(yù)期兩者相等-------------------
耗時: 85366ms
threadCount = 100;
loopCount = 10000600;
sum = 1000060000;
--------------testIntAdd(); 預(yù)期兩者不相等-------------------
耗時: 1406ms
threadCount = 100;
loopCount = 10000600;
sum = 119428988;