On Sat, May 30, 2009 at 1:31 PM, Gavin King <
gavin.king@gmail.com> wrote:
> On Sat, May 30, 2009 at 12:43 PM, Gavin King <
gavin.king@gmail.com> wrote:
>
>>> Looking at the Conversation public API I don't see any programmatic
>>> way to restore a conversation. Perhaps we should add such an API?
>>
>> Ugh, I really didn't want to go there in this release, though it
>> would, very clearly, be a very useful feature.
>>
>> If we were going to go there, the way I would do it is to say that the
>> conversation context is defined for all servlet requests, but it is by
>> default transient. The container would be required to call back to
>> Extensions to obtain a conversation id.
>
> Actually, upon reflection, I think we need to do this :-/
>
> Because even in JSF, we want a way to customize the mechanism for
> conversation propagation.
>
> So we could say that an Extension may optionally implement this interface:
>
> public interface ConversationExtension {
> String getConversationId(HttpServletRequest request,
> ServletContext context);
> }
>
> And say that before any Filter is called, the container calls all
> ConversationExtensions looking for a conversation id, and if it finds
> one, restores the conversation.
>
> Alternatively, we could say that the conversation is only restored
> *after* all ServletFilters have been called, and say that the
> container looks in a specially-named request attribute, for example
> "javax.contexts.spi.conversationId". Then we would not need a special
> interface, and any servlet filter could do conversation management.
> This seems more elegant, but means you don't get a conversation
> context in your filters.
>