package com.gf.demo10;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
/**
* 编写一个程序，开启 3 个线程，这三个线程的ID 分别为A、B、C,每个线程将自己的ID 在屏幕上打印 10 遍 ，要求输出结果必须按顺序显示。
* 如：ABCABCABC …… 依次递归
*
*/
public class TestABCCAlternate {
public static void main(String[] args) {
AlternateDemo ad = new AlternateDemo();
new Thread(new Runnable() {
@Override
public void run() {
for (int i = 1; i <= 20; i++) {
ad.loopA(i);
}
}
}, "A").start();
new Thread(new Runnable() {
@Override
public void run() {
for (int i = 1; i <= 20; i++) {
ad.loopB(i);
}
}
}, "B").start();
new Thread(new Runnable() {
@Override
public void run() {
for (int i = 1; i <= 20; i++) {
ad.loopC(i);
System.out.println("---------------------------------");
}
}
}, "C").start();
}
}
class AlternateDemo {
private int number = 1; // 当前正在执行线程的标记
private Lock lock = new ReentrantLock();
private Condition condition1 = lock.newCondition();
private Condition condition2 = lock.newCondition();
private Condition condition3 = lock.newCondition();
/**
* @param totalLoop
* ：循环第几轮
*/
public void loopA(int totalLoop) {
lock.lock();
try {
// 1. 判断
if (1 != number) {
condition1.await();
}
// 2. 打印
for (int i = 1; i <= 5; i++) {
System.out.println(Thread.currentThread().getName() + " " + i + " " + totalLoop);
}
// 3. 唤醒
number = 2;
condition2.signal();
} catch (Exception e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
public void loopB(int totalLoop) {
lock.lock();
try {
// 1. 判断
if (2 != number) {
condition2.await();
}
// 2. 打印
for (int i = 1; i <= 5; i++) {
System.out.println(Thread.currentThread().getName() + " " + i + " " + totalLoop);
}
// 3. 唤醒
number = 3;
condition3.signal();
} catch (Exception e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
public void loopC(int totalLoop) {
lock.lock();
try {
// 1. 判断
if (3 != number) {
condition3.await();
}
// 2. 打印
for (int i = 1; i <= 5; i++) {
System.out.println(Thread.currentThread().getName() + " " + i + " " + totalLoop);
}
// 3. 唤醒
number = 1;
condition1.signal();
} catch (Exception e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
}
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