我需要创建 2 个类,Class Player
和Class Referee
其中implement Runnable
接口(interface)(基本上,创建线程)。
线程执行的顺序是
裁判 玩家 1 或 2 裁判 玩家 1 或 2 等等..
这是我想出的解决方案,但是,订单似乎没有发生。在裁判完成检查之前,选手们仍在继续比赛。
``
public class a {
public static synchronized void main(String[] args) throws InterruptedException {
ready = false;
finish = false;
ExecutorService executorService = Executors.newCachedThreadPool();
executorService.execute(new Referee());
executorService.execute(new Player(1));
executorService.execute(new Player(2));
Thread.sleep(1000);
executorService.shutdown();
executorService.awaitTermination(1, TimeUnit.MINUTES);
}
/*....FOLLOWED BY GETTER AND SETTER METHODS
*
*
*/
}
class Player implements Runnable{
public synchronized void play() throws InterruptedException{
//continue playing unless game is over
while(true)
{
while( (a.getReady()) != true){
wait();
}
/***
*
*
*
execute some code to play
**/
//Change the value of the condition variable for the referee to start executing
a.putReady(false);
}
}
@Override
public void run() {
try {
play();
} catch (InterruptedException ex) {
Logger.getLogger(Player.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
class Referee implements Runnable{
public synchronized void check() throws InterruptedException {
while(true)
{
/****INITIALIZING THE GAME***/
while(a.getReady())
wait();
//If some player has won, releasing locks and exiting the threads
if(winner != 0)
{
a.putReady(true);
a.putFinish(true);
return;
}
//If the boards are full and ends in a draw
else if(count_plays >= 42)
{
System.out.print("\n Board is full. Its a draw!!\n");
a.putReady(true);
a.putFinish(true);
return;
}
//If there is more space on the board to play
else
{
System.out.print("\nNo player has won, let the play resume!!\n");
//Thread.sleep((long)100);
}
/* Code for checking if there has been a winner
*
*
*/
a.putReady(true);
notify();
}
}
@Override
public void run(){
try {
check();
}
catch (InterruptedException ex) {
Logger.getLogger(Player.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
`
我知道不同对象的线程无法同步,并且序列化同步下的代码是没有意义的。这是我被分配的任务。在上面的代码中,即使提供了一组条件变量,玩家也会同时进行比赛,并且不允许裁判线程在每次比赛时检查获胜者。
请给我一个使用同步方法、notify() 和 wait() 提供此类输出的代码概要。
最佳答案
这是允许的,但很少有意义,并且在您的情况下没有意义。两个线程将在不同的对象上同步,这不会产生任何影响。同步方法的目的是防止两个线程同时访问同一个对象。如果两个玩家需要访问某个公共(public)对象,但您不希望访问重叠,则应该在该对象上同步或同步该对象的方法之一。您应该只在同步块(synchronized block)或方法中停留尽可能短的时间。不必要的同步可能会导致性能不佳或死锁。
对我来说最有意义的是:
一个
public static class a {
static boolean finish = false;
public static void main(String[] args) throws InterruptedException {
finish = false;
ExecutorService executorService = Executors.newCachedThreadPool();
executorService.execute(new Referee());
executorService.execute(new Player(1));
executorService.execute(new Player(2));
// wait for user to press enter, just for testing
new Scanner(System.in).nextLine();
executorService.shutdown();
executorService.awaitTermination(1, TimeUnit.MINUTES);
}
}
玩家
public class Player implements Runnable {
final int playernum;
public Player(int playernum) {
this.playernum = playernum;
}
@Override
public void run() {
try {
while (!a.finish) {
synchronized (a.class) {
for (int i = 0; i < 5; i++) {
Thread.sleep(1000);
System.out.println("player " + playernum + " does step " + i);
}
}
Thread.sleep(1000);
}
} catch (InterruptedException interruptedException) {
}
}
}
裁判
public class Referee implements Runnable {
@Override
public void run() {
try {
while (!a.finish) {
synchronized (a.class) {
System.out.println("Check for winner.");
}
Thread.sleep(1000);
}
} catch (InterruptedException interruptedException) {
}
}
}
请注意,仅在内部 block 期间,它在整个运行期间不同步。
它应该产生这样的结果:
Check for winner.
player 1 does step 0
player 1 does step 1
player 1 does step 2
player 1 does step 3
player 1 does step 4
Check for winner.
player 2 does step 0
player 2 does step 1
player 2 does step 2
player 2 does step 3
player 2 does step 4
如果没有同步,您将无法看到每个玩家的全部 5 个步骤,而没有其他玩家的干预检查或步骤。
关于java - 如何序列化正在同步的代码?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/34099174/