Java多线程循环打印ABC 10次，可能是东半球最美解决方案了

Java多线程循环打印ABC 10次

package com.dragon.hqw;

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;

/**
* @author hanquanwei2010@gmail.com
* @date 2016.1.19
* @desc
* Java多线程循环打印ABC，9次
*/
public class PrintABC {

<span style="font-family: Arial, Helvetica, sans-serif;">
</span>

<span style="font-family: Arial, Helvetica, sans-serif;">//control & lock 机制</span>

private static final class CountingLock extends ReentrantLock {
private static final long serialVersionUID = -4489011051093305026L;
private int mNum = 0;
private final int total;

private final Condition a;
private final Condition b;
private final Condition c;

private CountingLock(int total) {
this.total = total * 3;
a = this.newCondition();
b = this.newCondition();
c = this.newCondition();
}

private boolean isA() {
return mNum % 3 == 0;
}

private boolean isB() {
return mNum % 3 == 1;
}

private boolean isC() {
return mNum % 3 == 2;
}

private boolean increase() {
mNum++;
if (mNum > total - 3) {
return true;//任务循环的退出机制
}
return false;
}

private Condition getA() {
return a;
}

private Condition getB() {
return b;
}

private Condition getC() {
return c;
}
}

private static final class A extends Thread {

private CountingLock mCountingLock;

private A(final CountingLock countingLock) {
this.mCountingLock = countingLock;
}

public void run() {

while (true) {
mCountingLock.lock();
try {
if (mCountingLock.isA()) {
printA();
boolean end = mCountingLock.increase();
mCountingLock.getA().signal();
if (end) {
break;
}
} else {
try {
mCountingLock.getC().await();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
} finally {
mCountingLock.unlock();
}
}
}

private void printA() {
System.out.print("A \t");
}
}

private static final class B extends Thread {

private CountingLock mCountingLock;

private B(final CountingLock countingLock) {
this.mCountingLock = countingLock;
}

@Override
public void run() {
while (true) {
mCountingLock.lock();
try {
if (mCountingLock.isB()) {
printB();
boolean end = mCountingLock.increase();
mCountingLock.getB().signal();
if (end) {
break;
}
} else {
try {
mCountingLock.getA().await();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
} finally {
mCountingLock.unlock();
}
}
}

private void printB() {
System.out.print("B \t");
}
}

private static final class C extends Thread {

private CountingLock mCountingLock;

private C(final CountingLock countingLock) {
this.mCountingLock = countingLock;
}

@Override
public void run() {
while (true) {
mCountingLock.lock();
try {
if (mCountingLock.isC()) {
printC();
boolean end = mCountingLock.increase();
mCountingLock.getC().signal();
if (end) {
break;
}
} else {
try {
mCountingLock.getB().await();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
} finally {
mCountingLock.unlock();
}
}
}

private void printC() {
System.out.print("C \t");
}
}

public static void main(String[] args) {
CountingLock lock = new CountingLock(9);
A a = new A(lock);
B b = new B(lock);
C c = new C(lock);
a.start();
b.start();
c.start();
}
}