java promise

java 模拟javascripe的promise 

必须通过Callable接口,通过主线程阻塞监听 futures[j].get(); 来保证任务执行完毕. 示例代码

public class TestV {

    public static List<Integer> list = Collections.synchronizedList(new ArrayList<>());

    public static void main(String[] args) {
        Future<Boolean>[] futures=new Future[10000];
        for(int i=0; i<10000; i++) {
            BatchCall c = new BatchCall(i);
            futures[i] = ThreadPoolUtil.executor.submit(c);
        }
        for(int j=0; j<10000; j++) {
            try{
                futures[j].get();
            }catch (Exception e) {
                System.out.println(futures.length);
                e.printStackTrace();
            }
        }
        System.out.println(list.size());
    }

}

class BatchCall implements Callable {
    private int i;
    public BatchCall() {
    }

    public BatchCall(int i) {
        this.i = i;
    }

    @Override
    public Object call() throws Exception {
        TestV.list.add(1);
        Thread.sleep(2);
        System.out.println(this.i);
        return true;
    }
}