从异步方法返回 object 到 CompletableFuture<object> 列表？<div id="text_translate"><p> 我有一个要使用异步方法处理的对象列表（来自 model class 名称）。 异步方法将获取列表中的每个名称 object 并对其进行处理（检查它是否未被占用），我希望在所有名称都被异步方法处理后返回到isNameAvailable(LinkedHashSet<Name> nameList)方法</p><p>我的执行者配置</p><pre>@Configuration @ManagedResource public class ThreadConfig { @Bean(name = "nameAvailabilityExecutor") public Executor nameAvailabilityExecutor() { ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor(); executor.setCorePoolSize(100); executor.setMaxPoolSize(1200); executor.setQueueCapacity(10000); executor.setThreadNamePrefix("nameAvailabilityExecutor-"); executor.initialize(); return executor; } }</pre><p> 服务 class 将调用另一个 class 中的异步方法</p><pre>public LinkedHashSet<Name> isNameAvailable(LinkedHashSet<Name> nameList) { LinkedHashSet<Name> nameCheckedList = new LinkedHashSet<>(); for (Name nameObj: nameList) { Name nameCheckedObj = domainAvailabilityServiceThread.isNameAvailable(nameObj); nameCheckedList.add(nameCheckedObj); } return nameCheckedList; }</pre><p> 将进行处理的异步方法</p><pre>@Async("nameAvailabilityExecutor") public Name isNameAvailable(Name nameObj) { String name = nameObj.getName(); if (getByNameCheck(name)) { nameObj.setAvailable(true); } else { nameObj.setAvailable(false); } return nameObj; }</pre><p> 根据我的理解 CompletableFuture 是我需要在这里使用的吗？ 在这种情况下使用 CompletableFuture 的正确方法是什么？</p></div></object>

Question

I have a list of objects (from model class Name) that I want to process using an async method. The async method will take each Name object in the list and process it (check if it's not taken), I want to have a list of Names after they all get processed by the async method to get returned to the isNameAvailable(LinkedHashSet<Name> nameList) method

My executor config

@Configuration
@ManagedResource
public class ThreadConfig {
    @Bean(name = "nameAvailabilityExecutor")
    public Executor nameAvailabilityExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(100);
        executor.setMaxPoolSize(1200);
        executor.setQueueCapacity(10000);
        executor.setThreadNamePrefix("nameAvailabilityExecutor-");
        executor.initialize();
        return executor;
    }
}

Service class which will call the Async method in another class

public LinkedHashSet<Name> isNameAvailable(LinkedHashSet<Name> nameList) {
    LinkedHashSet<Name> nameCheckedList = new LinkedHashSet<>();

    for (Name nameObj : nameList) {
        Name nameCheckedObj = domainAvailabilityServiceThread.isNameAvailable(nameObj);
        nameCheckedList.add(nameCheckedObj);
    }

    return nameCheckedList;
}

The async method which will do the processing

@Async("nameAvailabilityExecutor")
public Name isNameAvailable(Name nameObj) {
    String name = nameObj.getName();

    if (getByNameCheck(name)) {
        nameObj.setAvailable(true);
    } else {
        nameObj.setAvailable(false);
    }

    return nameObj;
}

From my understanding CompletableFuture is what I need to use here? What is the correct way using CompletableFuture in this scenario?

Answer 1

You can simply make isNameAvailable(Name) return a CompletableFuture :

@Async("nameAvailabilityExecutor")
public CompletableFuture<Name> isNameAvailable(Name nameObj) {
    String name = nameObj.getName();

    if (getByNameCheck(name)) {
        nameObj.setAvailable(true);
    } else {
        nameObj.setAvailable(false);
    }

    return CompletableFuture.completedFuture(nameObj);
}

Spring @Async will deal with the asynchronous execution as you intended.

You will also need to change the return type of isNameAvailable(LinkedHashSet) to a simple List or something similar, since it does not really make sense to store CompletableFuture s in a Set :

public List<CompletableFuture<Name>> isNameAvailable(LinkedHashSet<Name> nameList) {
    List<CompletableFuture<Name>> nameCheckedList = new ArrayList<>();

    for (Name nameObj : nameList) {
        CompletableFuture<Name> nameCheckedObj = domainAvailabilityServiceThread.isNameAvailable(nameObj);
        nameCheckedList.add(nameCheckedObj);
    }

    return nameCheckedList;
}

Note that it is probably not a good idea to asynchronously modify the state of an object like you are doing here with Name , as it makes it more difficult to guarantee what state will be visible to the calling thread. It might be preferable to work with CompletableFuture<Boolean> :

@Async("nameAvailabilityExecutor")
public CompletableFuture<Boolean> isNameAvailable(Name nameObj) {
    String name = nameObj.getName();

    return CompletableFuture.completedFuture(getByNameCheck(name));
}

and return a Map<Name, CompletableFuture<Boolean>> :

public Map<Name, CompletableFuture<Boolean>> isNameAvailable(LinkedHashSet<Name> nameList) {
    Map<Name, CompletableFuture<Boolean>> nameCheckedList = new HashMap<>();

    for (Name nameObj : nameList) {
        CompletableFuture<Boolean>> nameCheckedObj = domainAvailabilityServiceThread.isNameAvailable(nameObj);
        nameCheckedList.put(nameObj, nameCheckedObj);
    }

    return nameCheckedList;
}

and let the calling thread do whatever is needed with that check.