Re: JSR311: Response isn't adequate

From: Marc Hadley <Marc.Hadley_at_Sun.COM>
Date: Fri, 29 Feb 2008 13:39:59 -0500

On Feb 29, 2008, at 1:20 PM, Bill Burke wrote:
> Marc Hadley wrote:
>> On Feb 28, 2008, at 12:10 PM, Bill Burke wrote:
>>> And I've already told you that this just not cut it for specific
>>> use cases (Blobs). It is going to make EJB integration(really
>>> anybody that uses JTA) unusable in those cases. I don't think
>>> Lobs are an unreasonable use case to support.
>>>> - In a servlet container you can inject HttpServletResponse and
>>>> use the OutputStream from that but you'll have to set any headers
>>>> yourself before you commence writing.
>>> So, anything that doesn't fit the @Provider model, we'll have to
>>> escape to Servlet API or worse, have our own vendor specific
>>> extension for? Hmmmm...All because we can't inject an OutputStream.
>> I'm not I understand why blobs don't fit the provider model ? If
>> the provider runs in the same connection+transaction scope as the
>> resource method and can be injected with all the same stuff what
>> doesn't work ? Sorry if I'm being dense here.
> That's the thing, the provider has to run in the same transaction
> scope as the resource. Every container I know that does
> transactions usually ends the transaction before a response is sent
> back to the client. (a.k.a EJB TransAttribute.REQUIRED). You
> basically wouldn't be able to use container managed transactions.
> Are you following me? I don't know if I'm being clear.
So how would you stream back a blob in servlet, if reading the data
requires an open transaction but the container closes it before
sending the response ?


>> Injecting an OutputStream is only half the work, if you still want
>> to be able to use Response to specify headers then you'd either
>> have to call that first and somehow pass that to the runtime then
>> start writing to the output stream or we'd have to buffer the
>> output waiting for the method to complete and return the response.
>> Again, sorry if I missed something, I'm still catching up from a
>> few days vacation.
> Don't want the buffering. That could be done in the current model.
> I want the ability to stream LOBs and again, some DBs require a
> connection to be open while you're reading a LOB.
> --
> Bill Burke
> JBoss, a division of Red Hat
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Marc Hadley <marc.hadley at>
CTO Office, Sun Microsystems.