[xwiki-devs] [Proposal] Introduce new Execution Context module

Hi, I've been thinking a lot about the Container component I introduced and while writing unit tests for some of the new rendering classes I realized there was something not right: it's not normal that the HTML exporter or the rendering module depend on the Container object, and especially on the Request. Thus I'd like to introduce the notion of Execution Context (EC in short). The idea is that the xwiki entry points depend on the environment (Servlet, Portlet, etc) but those entry points create an Execution Context which is then used by the core components, independently of the environment. For example the VelocityContext is now put in the EC and not in the Request object. The Container objects still exist and can be used where required but it's expected that they should not be used since that makes the code dependent on the environment. This solves issue I had with code that don't have a request. I have it done on my machine. WDYT? Ok to commit? Thanks -Vincent PS: BTW this makes it very similar to the current XWikiContext (which is good) with the exception that the Container objects are not located inside the EC but as separate threadsafe variables.