Do you mean multiple DataDomains?
I don't have all the details yet, but the container API will be
extended as needed to fit our needs. For now I am thinking that all
cases where we need to access objects by name, will be delegated to
Configuration and other objects outside container. The container may
store maps of all names, and Configuration will be a frontend to read
from those maps.
But if we find that extending the container is beneficial, we can do
that too. E.g. I am planning something similar to Tapestry
configurations for the users to register/override ExtendedTypes, so
that the users don't have to redefine all types if they need to add
just one extra object.
Also to ensure we are on the same page, I am not planning app-facing
injection, just internal injection of Cayenne classes between
themselves. I.e. we won't inject anything in an app class that is
calling an ObjectContext (unless it is an override for the standard
service).
And finally, unrelated, but since DataDomains were mentioned... I've
been thinking to do away with multiple DataDomains. They are really
independent stacks, so why bother keeping them together in one
project. The users can start multiple Cayenne stacks instead.
Andrus
On Nov 16, 2009, at 4:28 PM, Michael Gentry wrote:
How are you envisioning injecting an ObjectContext for different
DataNodes, etc?
Thanks,
mrg
On Sun, Nov 15, 2009 at 4:57 PM, Andrus Adamchik <[email protected]
> wrote:
Just for kicks wrote a simple DI container for Cayenne. I checked
it in
partially to sanbdox folder until the ASF SVN repo went down
(http://monitoring.apache.org/), so I'll commit the rest on Monday,
or
whenever SVN becomes available.
This no-frills DI container took me only a couple of hours to write
(it
borrows some Guice API, but implementation is all mine). It supports
* annotation-based field dependency injection
* binding interfaces to implementation classes via fluent API
* binding interfaces to "provider" (same as "factory") classes
* merging multiple DI "modules".
The whole thing is only 14K after compilation (so it beats all full
featured
DI containers in size). Of course that's because it doesn't have
all the
fancy stuff (of which we'll add at least a few more things) such as
constructor injection, dependency cycle resolving, dynamic interface
proxies, bound object lifecycle, integration with Spring, etc.
Since we are
not planning a general purpose container, we might survive without
most of
those.
Here is how the current Configuration class might look like when it
is based
on DI:
public class Configuration {
private Injector injector;
public Configuration() {
this(new CayenneModule());
}
public Configuration(Module... modules) {
this.injector = DIBootstrap.createInjector(modules);
}
public DataChannel getDataChannel() {
return injector.getInstance(DataChannel.class);
}
public ObjectContext getNewContext() {
return injector.getInstance(ObjectContext.class);
}
// we may create getters for other "services" if we need to
}
And the actual configuration class (aka "module") used above:
public class CayenneModule implements Module {
public void configure(Binder binder) {
binder.bind(EventManager.class).to(EventManagerImpl.class);
binder.bind(DataChannel.class).to(DataDomain.class);
binder.bind(QueryCache.class).toProvider(LRUCacheFactory.class);
binder.bind(QueryLogger.class).toProvider(FancyLogger.class);
// an so on...
}
}
"CayenneModule" is what users can override (e.g. simply subclass),
providing
alternative implementations for some services.
The next step in this prototype would be an attempt to define the
current
Cayenne stack in terms of DI.
Andrus
On Oct 27, 2009, at 11:01 PM, Kevin Menard wrote:
On Sun, Oct 25, 2009 at 5:05 PM, Andrus Adamchik <[email protected]
>
wrote:
And I just discovered that both Spring (3.0RC1) and Juice (trunk)
support
the annotations from this JSR. So it could make sense for us to
use these
annotations internally as well. Couldn't dig any info on the
Tapestry IoC
support for this JSR, but they are on the JSR "support group", so
at
least
they are watching it.
Thiago, the Tapestry member on the support group, just learned
that it
had been approved. Howard didn't even know the JSR existed.
There's
no discussion on adding in the annotation support to Tapestry IoC
and
I suspect it will happen, but Tapestry is behind the ball on that
one.
--
Kevin
