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如何避免在等待未来完成时循环?

vert.x future quarkus redis java

Jan Kück · 技术社区 · 1 年前

我对java future和处理程序函数有问题。代码示例:

public HealthCheckResponse call() {

  String redisHost = this.configuration.getRedisHost();
  log.info("connect to redis host: {}", redisHost);
  
  Future<RedisConnection> redisConnectionFuture = Redis.createClient(Vertx.vertx(), redisHost).connect();
        while (!redisConnectionFuture.isComplete()) {
            log.debug("waiting for redis connection future complete: ({})", redisConnectionFuture.isComplete());
        }
        log.info("redis connection future completed, {} and succeded {}", redisConnectionFuture.isComplete(), redisConnectionFuture.succeeded());
        if (redisConnectionFuture.isComplete() && redisConnectionFuture.succeeded()) {
            return HealthCheckResponse.up("RedisCustomHealthCheck");
        }
        log.info("sending down RedisCustomHealthCheck");
        return HealthCheckResponse.down("RedisCustomHealthCheck");
    }

所以我的问题是我必须检查redis连接。这是一个异步函数,所以我可以设置onSuccess并编写我的逻辑。在那里我无法返回健康检查响应。问题,我不想等待while循环。这个问题的可能解决方案是什么?

1 回复 | 直到 1 年前

Pendula 1 年前

如果您没有在vertx事件循环线程上执行此操作,则可以安全地使用 java.util.concurrent.CountDownLatch

以下是您的用例的一个快速示例:

public HealthCheckResponse call() {
    Future<RedisConnection> redisConnectionFuture = Redis.createClient(Vertx.vertx(), redisHost).connect();
    CountDownLatch countDownLatch = new CountDownLatch(1);

    redisConnectionFuture.onComplete(x -> countDownLatch.countDown());

    try {
      countDownLatch.await();
    } catch (InterruptedException e) {
      throw new RuntimeException(e);
    }

    if (redisConnectionFuture.succeeded()) {
      return HealthCheckResponse.up("RedisCustomHealthCheck");
    } else {
      return HealthCheckResponse.down("RedisCustomHealthCheck");
    }
  }

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