Hello Arjan,

On 03/12/14 19:44, arjan tijms wrote:

Hi,

On Wednesday, December 3, 2014, Pavel Bucek <pavel.bucek@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.

Okay, so in a more broader application than just WebSocket it could be defined somewhere lower in the spec hierarchy. If it's specific to HTTP upgrades as you mention, then Servlet may be the next candidate to consider.

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.

But some of these may not actually belong there. They may have been put there originally since as a new spec that had yet to be proven, CDI could not right away ask other specs to support it.

There are discussions going on to move some of the Servlet things from CDI to Servlet.

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.

There are plenty of other reasons too ;) For Servlet I expect the dependencies to be optional. Servlet in a EE environment will then provide scope X & Y, and producers for types Q & R, but it will continue to run standalone without needing any CDI. In short, it would provides things for CDI then but in its core wouldn't need CDI.