package yn.ngems.cn;
import java.util.concurrent.Callable;
import java.util.concurrent.FutureTask;
public class ThreadDemo{
    public static void main(String[] args) throws Exception{
        MyThread thread = new MyThread();
        FutureTask<String> ftA = new FutureTask<String>(thread);
        FutureTask<String> ftB = new FutureTask<String>(thread);
        FutureTask<String> ftC = new FutureTask<String>(thread);
        new Thread(ftA,"執行緒A").start();
        new Thread(ftB,"執行緒B").start();
        new Thread(ftC,"執行緒C").start();
        System.out.println(ftA.get());
        System.out.println(ftB.get());
        System.out.println(ftC.get());
    }
}
class MyThread implements Callable<String>{
    private boolean flag = false;
    @Override
    public String call() throws Exception {
        Thread.sleep(1000);
        synchronized (this) {
            if(this.flag == false) {
                this.flag = true;
                return Thread.currentThread().getName() + "搶答成功！";
            }else {
                return Thread.currentThread().getName() + "搶答失敗！";
            }
        }
    }
}

同步鎖機制，搶答開關，同時需要一個返回值