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import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
class Horse implements Runnable{
private static int counter = 0;
private final int id = counter++;
private int strides = 0;
private static Random rand = new Random(47);
private static CyclicBarrier barrier;
public Horse(CyclicBarrier b) {
this.barrier = b;
}
public synchronized int getStrides() {
return strides;
}
@Override
public void run() {
try {
while(!Thread.interrupted()){
synchronized (this) {
strides += rand.nextInt(3);
}
barrier.await();//循环等待
}
} catch (InterruptedException e) {
// TODO: handle InterruptedException
} catch (BrokenBarrierException e) {
throw new RuntimeException(e);
}
}
@Override
public String toString() {
return "Horse " + id + " ";
}
public String tracks(){
StringBuilder s = new StringBuilder();
for (int i = 0; i < getStrides(); i++) {
s.append("*");
}
s.append(id);
return s.toString();
}
}
public class HorseRace {
static final int FINISH_LINE = 75;
private List<Horse> horses = new ArrayList<Horse>();
private ExecutorService exec = Executors.newCachedThreadPool();
private CyclicBarrier barrier;
public HorseRace(int nHorses,final int pause) {
barrier = new CyclicBarrier(nHorses,new Runnable() {
@Override
public void run() {
StringBuilder s = new StringBuilder();
for (int i = 0; i < FINISH_LINE; i++) {
s.append("=");
}
System.out.println(s);
for (Horse horse : horses) {
System.out.println(horse.tracks());
}
for (Horse horse : horses) {
if(horse.getStrides() >= FINISH_LINE){
System.out.println(horse + "won!");
exec.shutdownNow();
return;
}
}
try {
//可以睡眠,显示出效果,否则复很快执行完,看不出明显的效果
TimeUnit.MILLISECONDS.sleep(pause);
} catch (InterruptedException e) {
System.out.println("屏障—行为 sleep interrupted");
}
}
});
for (int i = 0; i < nHorses; i++) {
Horse horse = new Horse(barrier);
horses.add(horse);
exec.execute(horse);
}
}
public static void main(String[] args) {
int nHorses = 7;
int pause = 200;
if(args.length > 0){
int n = new Integer(args[0]);
nHorses = n > 0 ? n : nHorses;
}
if(args.length > 1){
int p = new Integer(args[1]);
pause = p > 1 ? p : pause;
}
new HorseRace(nHorses, pause);
}
}
效果图:
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原文地址:http://www.cnblogs.com/wangjun2016/p/wangjun20160913.html