清理GWT / Java中的方法来等待多个异步事件完成 [英] Clean way in GWT/Java to wait for multiple asynchronous events to finish

问题描述

在继续之前，等待多个异步回调函数以Java完成的最佳方式是什么？具体来说，我使用GWT与AsyncCallback，但我认为这是一个通用的问题。这是我现在拥有的，但肯定有更清晰的方式...

  AjaxLoader.loadApi（books，0 ，new Runnable（）{
 public void run（）{
 bookAPIAvailable = true; 
 ready（）; 
}}，null）; 
 ajaxLoader.loadApi（search，1，new Runnable（）{
 public void run（）{
 searchAPIAvailable = true; 
 ready（）; 
}}，null）; 
 
 $ b loginService.login（GWT.getHostPageBaseURL（），new AsyncCallback< LoginInfo>（）{
 public void onSuccess（LoginInfo result）{
 appLoaded = true; 
 ready（）; 
} 
}）; 
 $ b private void ready（）{
 if（bookAPIAvailable&&& searchAPIAvailable&& appLoaded）{
 //所有加载的
} 
 } 
  

解决方案

项目。基本上，每个回调都会向父级注册。父级等待每个子回调完成，然后触发它自己的handleSuccess（）。

客户端代码如下所示：

  
  public void someGwtClientSideMethod（）{
 SomeServiceAsync someService = GWT.create（SomeService.class）; 
 ParallelCallback fooCallback = new ParallelCallback（）; 
 ParallelCallback barCallback = new ParallelCallback（）; 
 ParentCallback parent = new ParentCallback（fooCallback，barCallback）{
 public void handleSuccess（）{
 doSomething（getCallbackData（1），getCallbackData（2））; 
} 
}; 
 someService.foo（fooCallback）; 
 someService.bar（barCallback）; 
} 
  
 

我在这里写了一篇文章解释它： GWT中的并行异步调用。这两个类的实现是从该帖子链接的（对不起，因为我是一个新手用户，所以不能在这里给出链接 - 没有足够的业力包含多个链接！）。

What is the best way to wait for multiple asynchronous callback functions to finish in Java before continuing. Specifically I'm using GWT with AsyncCallback, but I think this is a generic problem. Here's what I have now, but surely there is cleaner way...

    AjaxLoader.loadApi("books", "0", new Runnable(){
        public void run() {
            bookAPIAvailable = true;
            ready();
        }}, null);
    AjaxLoader.loadApi("search", "1", new Runnable(){
        public void run() {
            searchAPIAvailable = true;
            ready();
        }}, null);


    loginService.login(GWT.getHostPageBaseURL(), new AsyncCallback<LoginInfo>() {
        public void onSuccess(LoginInfo result) {
            appLoaded  = true;
            ready();
        }
    });

private void ready() {
    if(bookAPIAvailable && searchAPIAvailable && appLoaded) {
                // Everything loaded
    }
}

解决方案

I wrote two classes that solve this problem on my project. Basically, each individual callback registers with a parent. The parent waits for each child callback to complete, then fires off it's own handleSuccess().

The client code looks like this:

public void someGwtClientSideMethod() {
    SomeServiceAsync someService = GWT.create(SomeService.class);
    ParallelCallback fooCallback = new ParallelCallback();
    ParallelCallback barCallback = new ParallelCallback();
    ParentCallback parent = new ParentCallback(fooCallback, barCallback) {
        public void handleSuccess() {
            doSomething(getCallbackData(1), getCallbackData(2));
        }
    };
    someService.foo(fooCallback);
    someService.bar(barCallback);
}

I wrote a post explaining it here: Parallel Asynchronous Calls in GWT. The implementation for these two classes is linked from that post (sorry, can't give links here because I'm a newbie user - not enough karma to include more than one link!).

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