[cdi-dev] New Servlet related scope - @UpgradeScoped (?)

Antonio Goncalves antonio.goncalves at gmail.com
Thu Dec 4 04:17:48 EST 2014


FYI we are hoping to have no Servlet related topics in the CDI 2.0
specification. The idea is for other specifications to use CDI to create
their own scope (@ViewScoped/@FlowScoped in JSF, but also
@TransactionScoped in JTA). Following this logic, the @UpgradeScoped would
make sense in the WebSocket spec.


On Thu, Dec 4, 2014 at 9:28 AM, Pavel Bucek <pavel.bucek at oracle.com> wrote:

>  Hello Arjan,
> On 03/12/14 19:44, arjan tijms wrote:
> Hi,
> On Wednesday, December 3, 2014, Pavel Bucek <pavel.bucek at oracle.com>
> wrote:
>> Hi all,
>> I'm trying to figure out how to solve issue in JSR 356 - Java API for
>> WebSocket, related to CDI scope usable from WebSocket endpoints. Problem
>> is, that "standard" scopes do not apply, because there is no
>> @RequestScoped (http response is already sent), HttpSession does not
>> need to be created and the rest does not seem to be applicable, ...
>> I believe that CDI specification should define @UpgradeScoped, which
>> would cover usages of HttpUpgradeHandler from Servlet API. (Similarly as
>> it does for @RequestScoped, @SessionScoped, ... )
>  Wouldn't it be a better option to have WebSocket define that scope, using
> CDI to implement it?
> That is one possibility, but @UpgradeScoped would be more general than
> just for WebSocket - it would apply for all HTTP/1.1+ Upgrade applications.
> In my eyes, it is something which was forgotten to do in Java EE 7 release,
> since HttpUpgradeHandler was introduced in it.
> Also please note, that other Servlet related scopes are already in CDI
> spec, so it seems like it belongs there more than anywhere else. This might
> have multiple reasons - for example, you can easily define relationship
> between @UpgradeScoped and others, already existing ones. In this sense,
> CDI specification now depends on Servlet API (it references some of the
> classes defined in it), but Servlet does not do that for CDI. I don't think
> that Servlet spec should introduce similar dependency just because of new
> scope.
> Thanks,
> Pavel
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Antonio Goncalves
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