场景题之最快返回结果

场景题之最快返回结果

问题描述

输入中文，最快从百度翻译、谷歌翻译、有道翻译获取结果返回。

代码实现

思路：采用CompletableFuture实现，多个CompletableFuture可以串行执行，也可以并行执行。其中anyOf()方法只要任意一个返回结果，就完成操作。

import java.util.concurrent.CompletableFuture;
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.ThreadPoolExecutor.CallerRunsPolicy;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;

public class FastestResult {

    public static void main(String[] args) {
        String zh = "中国";
        System.out.println(getResult(zh));
    }

    private static Object getResult(String zh) {
        AtomicReference<Object> res = new AtomicReference<>("");
        // 从三处获取结果
        CompletableFuture<String> baidu = CompletableFuture.supplyAsync(() -> getFromBaidu(zh));
        CompletableFuture<String> google = CompletableFuture.supplyAsync(() -> getFromGoogle(zh));
        CompletableFuture<String> youdao = CompletableFuture.supplyAsync(() -> getFromYoudao(zh));

		// 只要任意一个返回结果，就完成操作
        CompletableFuture<Object> result = CompletableFuture.anyOf(baidu, google, youdao);
        result.thenAccept(res::set);
        // 阻塞获取结果，否则主线程关闭，CompletableFuture默认使用的线程池会立刻关闭
        result.join();
        return res.get();
    }

    static String getFromBaidu(String zh) {
        try {
            Thread.sleep((long) (Math.random() * 1000));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return "baidu: " + zh;
    }

    static String getFromGoogle(String zh) {
        try {
            Thread.sleep((long) (Math.random() * 1000));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return "google: " + zh;
    }

    static String getFromYoudao(String zh) {
        try {
            Thread.sleep((long) (Math.random() * 1000));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return "youdao: " + zh;
    }

}