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From Andrus Adamchik <and...@objectstyle.org>
Subject Re: Creating a new ServerRuntime from an existing ServerRuntime
Date Fri, 27 Sep 2013 16:37:32 GMT
ServerRuntime encapsulates a full Cayenne stack (which includes injector). How you create and
manage it is left up to the app. Here is for instance how I usually encapsulate it in a Tapestry
application:

  https://github.com/andrus/wowodc13/blob/master/services/src/main/java/demo/services/cayenne/CayenneService.java

CayenneService in this example is both a factory (defining custom modules among other things)
and a holder of a reference to ServerRuntime. CayenneService itself is a singleton injectable
via Tapestry to pages and other services. Your version of CayenneService can store multiple
runtimes if needed. As to where to put CayenneService, you may use something like Spring or
put it in ServletContext. In other words just follow the patterns for managing app singletons
that you are using already. Cayenne is intentionally made agnostic to that.

Andrus



On Sep 27, 2013, at 6:46 PM, Mike Kienenberger <mkienenb@gmail.com> wrote:
> The idea of creating a new ServerRuntime is good, but the
> implementation leaves  me with a few questions.    My ServerRuntime is
> created in the context of the web app.
> 
> Is it reasonable to try to create it using the information in the
> existing ServerRuntime?   Can I pull the injector and modules out of
> the existing Runtime and reuse them to create a new runtime, or do I
> need to create copies of the existing modules and injector?   My guess
> is that each runtime needs unique injector and modules objects, but I
> want to minimize the work I need to do.
> 
> It looks like I have to pull my configurationLocation out of the
> ServerModule, which doesn't really provide it.
> 
> I'm not seeing an easy way to create a new ServerRuntime from scratch
> without having access to data which was only available back when the
> web application started up, short of storing that information
> somewhere globally and reusing it.
> 
> On Tue, Sep 24, 2013 at 2:04 PM, Andrus Adamchik <andrus@objectstyle.org> wrote:
>>> The "special DataContext" case where the qualifier should be ignored can probably
be handled by starting a separate ServerRuntime, where you can strip off the qualifiers. For
whatever overhead it creates (ideally not much), this has an advantage of cleanly separating
"spaces" with different ORM rules.
>> 
>> Elaborating on this a bit… The old Configuration allowed multiple DataDomains,
each of those requiring its own DataMap(s) saved in the project upfront. Good idea, but hard
to use in practice.
>> 
>> ServerRuntime (with single DD each) is more user-friendly. By starting multiple independent
runtimes you to easily reuse a single mapping project, tweaking each in-memory copy local
to each Runtime (as well as tweaking other parameters like cache). 2 Runtimes can reuse a
single DataSource (JNDI, or otherwise), etc.
>> 
>> Andrus
>> 
> 


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