I agree with this general direction of separating the persistence behavior from
the data holder beans; let pojos be pojos.
Putting the logic in managers does necessitate the need always to know about the association between the class and its manager. In
methods that deal with multiple different classes of objects we do persist, that can become an issue.
However, if we decide we want to be able to deal with instances that know how to save themselves, or determining if the current user
can save them, etc, that behavior should really be in classes that derive from or wrap/delegate to the pojo data holders, not the
other way around as it is now.
So Allen, +1 to this idea
--a.
----- Original Message -----
From: "David M Johnson" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Friday, July 01, 2005 7:09 AM
Subject: Re: velocity context cleanup
+1!!!
I'm guilty of moving methods like save(), remove(), etc. into the POJOs. I think everything you've outlined below is basically a
good idea, but I'd like to hold off on it until we merge 2.0 back in.
- Dave
On Jun 30, 2005, at 10:50 AM, Allen Gilliland wrote:
Okay, so it sounds like a few other people have given this a little thought and think that it may be beneficial to make some
changes to the way the Pojos and PersistentObjects work. I think it would help to add a little more detail to the discussion so
we know what we are talking about. Here's my stab at what changes I would think about making ...
- move PersistentObject.save() into Manager classes only
- move PersistentObject.remove() into Manager classes only
I think those 2 changes would go a long ways toward making it less dangerous to make Pojos directly available to users via the
velocity context. I am in partial agreement that we may not need the PersistentObject class at all. Right now I would also
consider doing ...
- remove PersistentObject.get/setId() (these are not necessarily part of all
objects)
- remove PersistentObject.setData() (this can easily be done elsewhere)
- remove PersistentObject.canSave() (i don't fully understand how this is used, but i believe this logic can be in the Manager
classes save/remove methods)
If we also want to do those last few items then the PersistentObject class would basically be useless. I think the first 2 are
pretty important, but the last 3 are optional. Personally I would probably go ahead and ditch the PersistentObject class just
because I don't think we really need it.
what do others think?
Remember, we are just talking about this right now so please speak up and voice your opinion. We aren't going to make any
changes right away, especially with the fact that Dave has a lot of data model work going on for the 2.0 release and we don't
want to mess with what he has done so far. Once we get a bit more consenus then I will formalize a Proposal that can be reviewed
again.
-- Allen
On Thu, 2005-06-30 at 10:12, Rudman Max wrote:
I just wanted to chime in that I really dislike persistence methods
being in POJOs also and would be willing to pitch in with moving
those out to the appropriate manager classes. In fact, I would even
like to see PersistenceObject go as having to extend data objects
from it pretty much negates one of the key benefits of Hibernate --
its non-intrusiveness into the object model.
Max
On Jun 30, 2005, at 11:53 AM, Anil Gangolli wrote:
The remove() method is used in several cases to do some of the
cascading needed to maintain consistency properties. Just make
sure to preserve that logic; if you take out the remove() methods,
this logic needs to be moved into the corresponding manager methods.
--a.
----- Original Message ----- From: "Lance Lavandowska"
<[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Thursday, June 30, 2005 8:24 AM
Subject: Re: velocity context cleanup
On 6/29/05, Allen Gilliland <[EMAIL PROTECTED]> wrote:
*Data.remove() is available to users (try $website.remove() in a
template)
This method should probably be removed from the classes. While I
think even POJOs should contain some business logic, I don't feel
that
persistence-related methods are appropriate. Because this is only my
personal gut-check, I've never objected.
PageHelper.evaluateString() is available to users (this one
actually bit us in the ass already and a user caught themself in
a recursive loop which killed the server)
I'm the one guilty of creating that monstrosity, and I say "get
rid of
it". I doubt it is in my real use - but you may break a few pages by
removing it. Perhaps change it to print "THIS MACRO HAS BEEN
REMOVED"? Note: this is a misguided macro, not a Context value.
Some of these may be a simple case of updating the public,
protected, private access levels on methods, but some cases may
mean removing objects from the Context and/or removing methods
from objects that are part of the Context.
All of the objects placed into the Context are done so to achieve an
objective in the *.vm templates or the Page templates. As I implied
above, let's look at what is being exposed by these objects that may
be 'dangerous' instead.
Lance
