I have a good opinion about Tapestry IoC approach in general
(including the now defunct Hivemind), and I wanted to investigate Guice.
There's some conflicting requirements to address here - we don't want
to write/maintain our own IoC container, yet, we don't want to embed a
huge third-party engine, of which we'll use only a subset of features.
I'd like it to work standalone, as well as be able to integrate (or at
least play well) with popular IoC containers (how many containers in
one app is too many?). Then there's a matter of modeler support, which
is adverse to annotations, and favors XML or other config files...
All in all, I think assembling a core of Cayenne stack via such a
container should open some interesting possibilities, beyond
organizing current configuration.
Andrus
On Jun 2, 2009, at 6:53 PM, Robert Zeigler wrote:
If you're really considering going the 3rd party ioc route, I highly
recommend T5IOC.
Note that configuration is (typically) done via code in T5IOC, but I
find it extremely flexible & powerful, while still being simple to
use (and small! :).
If not that, then guice. I'd even go for pico (though preferably
not). Anything but the monster that spring has become. ;)
Robert
On Jun 2, 2009, at 6/29:02 AM , Andrus Adamchik wrote:
On Jun 2, 2009, at 4:38 PM, Andrus Adamchik wrote:
Modeler support will be covered by setting class name of strategy
I am afraid this approach will be rather arbitrary to the end
user, so I suggest we discuss it some more before putting it in
Cayenne. Marking an entity to use "soft delete" based on some
criteria is a clear and understandable feature. Setting a "delete
strategy" is not, and will contribute to confusion. This is
totally be ok as a backend extension point, but I will hate to see
that as a general use feature.
In this context let me mention one idea for Cayenne 3.0 + N, that
I've been thinking about for some time. I am taking this to a
separate thread to avoid distraction from the soft delete
discussion, which has only tangential relevance.
Since we already have a bunch of extension points throughout the
stack, some exposed via the Modeler (misplaced like cache JGroups
config, or justified like Adapter config), and some are available
only via the code, we need a way to reign them in. The standard way
of doing that is via an IoC container.
No, I don't want to bundle Spring with Cayenne, besides it has to
integrate with the larger app ecosystem, so we still need to figure
the technical details. But the point is that we will be able to
provide a single place to configure all extension points, separate
from the mapping. As unlike the mapping those parameters are often
different for the same project, depending on the environment where
it is deployed.
Right now this place is cayenne.xml (and it might as well stay this
way in the future), just that unlike say Spring config files, it
has a rigid structure and is not generic enough to handle arbitrary
extensions and dependencies. It was ok for the early versions of
Cayenne, since there was only a few things you could change (data
source factory and adapter I believe). But now something more
powerful and clean is desirable.
Just some raw thoughts.
Andrus
