import java.util.Random;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
class Player implements Runnable{
private String name;
private CyclicBarrier barrier;
private Player next;//下壹棒
private int time;//用時
private boolean run;//第壹棒
public Player(String name, CyclicBarrier barrier, boolean run) {
super();
this.name = name;
this.setBarrier(barrier);
this.run = run;
}
public void run() {
try {
synchronized (this) {
while(!run){//等待隊員
wait();
}
}
Random r = new Random();
TimeUnit.MILLISECONDS.sleep(r.nextInt(2000));
next(next,11 + r.nextInt(2));
} catch (InterruptedException e) {
e.printStackTrace();
}
}
private void next(Player next, int time) {
System.out.println(name + " 用時：" + time + ",交接棒");
if(next != null){
next.setTime(this.time + time);
synchronized (next) {
next.setRun(true);
next.notify();
}
}else{
System.out.println("跑完，總用時：" + (this.time + time));
}
}
public void setTime(int time) {
this.time = time;
}
public int getTime(){
return this.time;
}
public void setNext(Player next) {
this.next = next;
}
public void setRun(boolean run) {
this.run = run;
}
public void setBarrier(CyclicBarrier barrier) {
this.barrier = barrier;
}
public CyclicBarrier getBarrier() {
return barrier;
}
}
public class RelayRace {
public static void main(String[] args) throws InterruptedException {
final Player[] players = new Player[4];
ExecutorService exec = Executors.newCachedThreadPool();
CyclicBarrier barrier = new CyclicBarrier(4, new Runnable() {
public void run() {
System.out.println("結束，總用時：" + players[3].getTime());
}
});
for(int i = 0; i < 4; i++){
players[i] = new Player("隊員" + ( i + 1), barrier, i == 0);
}
for(int i = 0; i < 4; i++){
if( i < 3){
players[i].setNext(players[i + 1]);
exec.execute(players[i]);
}else{
exec.execute(players[3]);
break;
}
}
}
}