To me i seems strange that the same API method both takes a callback and
returns a Furure. It should be either or, not both.
On Thu, Jan 22, 2015 at 7:48 PM, Robert DiFalco <robert.difalco_at_gmail.com>
wrote:
> Marek, the issue I had is that the behavior of getting a Future<Response>
> with a callback is indeterminate. There seems to be a race condition with
> readEntity such that even if you request the entity to be buffered it can
> still end up as malformed in either the Future#get or the
> InvocationCallback#completed.
>
> On Thu, Jan 22, 2015 at 9:34 AM, Mikael Ståldal <
> mikael.staldal_at_appearnetworks.com> wrote:
>
>> > 1. InvocationCallback<Order> is run from some other thread (i.e.
>> asynchronously) that has issued the request
>>
>> Yes, so far so good. But then I cannot access the response metadata (HTTP
>> status, response headers).
>>
>> > 2. The callback is only invoked AFTER the
>> Response.readEntity(Order.class) has completed. So having an
>> InvocationCallback<Response> and invoking Response.readEntity(..) inside is
>> not making things worse.
>>
>> So if I do like this:
>>
>> Invocation invocation = client.target(someURL).request().buildGet();
>> invocation.submit(new InvocationCallback<Response> {
>> public void completed(Response response) {
>> int statusCode = response.getStatus();
>>
>> Order order = response.readEntity(Order.class); // blocking? process(statusCode, order);
>> }
>> public void failed(Throwable throwable) {
>> error();
>> }
>> });
>>
>>
>> It will not block on I/O when invoking response.readEntity(Order.class)?
>> If so, my understanding of how it works was wrong, and the issue is
>> invalid.
>>
>> > Perhaps you are looking for a non-blocking I/O API support
>>
>> I am, but this particular issue is not really about that.
>>
>> > Something like Response.readEntity(Order.class, order -> { … }) ?
>>
>> If it works the way you say (Response.readEntity is non-blocking since it
>> just return something which has already been read, parsed and buffered in
>> memory), that shouldn't be necessary.
>>
>> > Btw. do you know that you can easily check the response code from a
>> JAX-RS ClientResponseFilter
>> <https://jax-rs-spec.java.net/nonav/2.0-rev-a/apidocs/javax/ws/rs/client/ClientResponseFilter.html>
>> ?
>>
>> To me, it seems quite clumsy if I would have to use a filter in this use
>> case.
>>
>>
>> On Thu, Jan 22, 2015 at 1:42 PM, Marek Potociar <
>> marek.potociar_at_oracle.com> wrote:
>>
>>> Hi Mikael,
>>>
>>> Please see inline.
>>>
>>> On 12 Jan 2015, at 11:29, Mikael Ståldal <
>>> mikael.staldal_at_appearnetworks.com> wrote:
>>>
>>> No, I did not get any answer to this. And neither to the JIRA issues I
>>> have filed:
>>>
>>> https://java.net/jira/browse/JERSEY-2682
>>>
>>>
>>> C&Ping my comment from the issue:
>>>
>>> I have looked at the issue and I’m not sure I understand the problem you
>>> are pointing out:
>>>
>>> 1. InvocationCallback<Order> is run from some other thread (i.e.
>>> asynchronously) that has issued the request
>>> 2. The callback is only invoked AFTER the
>>> Response.readEntity(Order.class) has completed. So having an
>>> InvocationCallback<Response> and invoking Response.readEntity(..) inside is
>>> not making things worse.
>>>
>>> Perhaps you are looking for a non-blocking I/O API support, which is
>>> planned for the next release of JAX-RS
>>> <https://jcp.org/en/jsr/detail?id=370>? Something like
>>> Response.readEntity(Order.class, order -> { … }) ?
>>> Btw. do you know that you can easily check the response code from a
>>> JAX-RS ClientResponseFilter
>>> <https://jax-rs-spec.java.net/nonav/2.0-rev-a/apidocs/javax/ws/rs/client/ClientResponseFilter.html>
>>> ?
>>>
>>>
>>> To me, it seems like the async part of the JAX-RS 2.0 client API is
>>> flawed (not to mention the default implementation in Jeresy:
>>> https://java.net/jira/browse/JERSEY-2058).
>>>
>>>
>>> The primary problem is in lack of NIO support in the current JAX-RS API.
>>> We’re looking into fixing it for the next JAX-RS release, as noted above.
>>> Obviously, we will first try to make it work in Jersey, so Jersey users
>>> should have a working solution long before JAX-RS.next is released. I do
>>> not have any ETA at this point though.
>>>
>>>
>>> It's a pity, since the synchronous client API in JAX-RS 2.0 (and its
>>> implementation in Jersey) is really nice.
>>>
>>> I am considering using something else for async REST client, such as
>>> https://github.com/AsyncHttpClient/async-http-client or Jetty client.
>>>
>>>
>>> FWIW, our grizzly connector is actually wrapped into async HTTP client
>>> API. But again, current lack of NIO support in JAX-RS APIs is making it
>>> difficult to come up with a good async client solution. That said, we’re
>>> already trying, stay tuned.
>>>
>>> Marek
>>>
>>>
>>> On Wed, Dec 31, 2014 at 9:06 PM, Robert DiFalco <
>>> robert.difalco_at_gmail.com> wrote:
>>>
>>>> Did you ever get an answer to this?
>>>>
>>>> On Mon, Oct 6, 2014 at 7:45 AM, Mikael Ståldal <
>>>> mikael.staldal_at_appearnetworks.com> wrote:
>>>>
>>>>> Consider using Jersey client in async mode with an
>>>>> InvocationCallback<Response>, and then use readEntity() on the Response.
>>>>> Order is a custom domain object for which we have a MessageBodyReader
>>>>> available.
>>>>>
>>>>> Invocation invocation = client.target(someURL).request().buildGet();
>>>>> invocation.submit(new InvocationCallback<Response> {
>>>>> public void completed(Response response) {
>>>>> int status = response.getStatus();
>>>>> if (status == 200) {
>>>>> Order order = response.readEntity(Order.class); //
>>>>> blocking ?
>>>>> process(order);
>>>>> } else {
>>>>> error();
>>>>> }
>>>>> }
>>>>> public void failed(Throwable throwable) {
>>>>> error();
>>>>> }
>>>>> });
>>>>>
>>>>> Is the response.readEntity() call blocking? Is it I/O bound if the
>>>>> response is large? Or is the whole response read from network before the
>>>>> completed() callback is invoked?
>>>>>
>>>>> Will the asynchronicity be improved if I do InvocationCallback<Order>
>>>>> instead? What if I want to get other information from the Response?
>>>>>
>>>>> --
>>>>> Mikael Ståldal
>>>>> Chief Software Architect
>>>>> *Appear*
>>>>> Phone: +46 8 545 91 572
>>>>> Email: mikael.staldal_at_appearnetworks.com
>>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>> Mikael Ståldal
>>> Chief Software Architect
>>> *Appear*
>>> Phone: +46 8 545 91 572
>>> Email: mikael.staldal_at_appearnetworks.com
>>>
>>>
>>>
>>
>>
>> --
>> Mikael Ståldal
>> Chief Software Architect
>> *Appear*
>> Phone: +46 8 545 91 572
>> Email: mikael.staldal_at_appearnetworks.com
>>
>
>
--
Mikael Ståldal
Chief Software Architect
*Appear*
Phone: +46 8 545 91 572
Email: mikael.staldal_at_appearnetworks.com