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From Rick McGuire <>
Subject Re: [AsyncHttpClient] order of Future completion and callback invocation
Date Wed, 16 Jan 2008 10:28:14 GMT
Sangjin Lee wrote:
> Currently the callback methods from AsyncHttpClientCallback get called 
> *after* the response future object is completed.  I think this causes 
> a subtle bug that may prevent the callback methods from being 
> completed if one uses both the callback and the future.
> For example, consider the following case:
> ResponseFuture future = client.invoke(..., callback); // callback is 
> not null
> HttpResponseMessage response = future.get(); // this blocks until 
> future is complete
> Since the future is completed before the callback is invoked, the 
> caller thread in this case gets unblocked before the callback is 
> called.  If the caller thread goes away, then there is possibility 
> that the callback may not be completed or may not even be called, 
> depending on the timing.
> This strikes me as a bug...  I propose we invoke the callback first 
> and then complete the future so the callbacks are guaranteed to be 
> completed even if future is used.  What do you think?  I'll open a 
> JIRA issue if you guys agree this is a bug.
Yes, I agree.  If the callback is used, then we should ensure that it 
gets called appropriately. 

> Thanks,
> Sangjin

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