Taking a quick look at the proposal and have a few thoughts ...
1. Can I get some more explanation about the connection between jdo and
jpa? Why do we need implementations of both?
2. I'm not sure I understand this data mapper strategy. I thought the
purpose of the XXXManager classes is already to do this work, I'm not
sure I see why we need another layer of abstraction here. Basically you
are now saying that to query for something you need to call a Manager,
which calls a DataMapper, which calls your ORM solution, which does the sql?
It also feels a little bit like reinventing the wheel since based on the
example code I saw there will be a new query convention for using the
data mapper. So now I need to do extra work because I need to
understand how to use this custom data mapper language with
"getByPingTarget&&website", and I still need a data mapper
implementation which parses the data mapper queries and translates them
into queries in my ORM tool.
I haven't used this pattern before so I'm sure I don't fully understand
how it's supposed to work, but I'm not seeing the benefit so far.
-- Allen
Dave Johnson wrote:
Adding Craig to the CC list.
- Dave
On 6/29/06, Dave Johnson <[EMAIL PROTECTED]> wrote:
Craig Russell has updated his JDO backend proposal to use a data
mapper and named query architecture instead of developing a query API.
I think the proposal looks really good:
<http://rollerweblogger.org/wiki/Wiki.jsp?page=Proposal_JDOBackend>
It is my understanding that this new architecture will:
1) Make it easy to develop side-by-side implementations of the Roller
backend using JDO and JPA/EJB3.
2) Allow us to specify queries as externalized meta-data, making it
easy for database administrators to review our queries without having
Java source code access.
3) Leave our existing Hibernate impementation in-place, i.e. Craig is
not proposing that we rewrite our Hibernate implemetation using this
datamapper/named-query approach.
Craig has already started implementation, but he wants to get some
review and consensus befoe he goes much further. So please review the
proposal and respond here on the list.
I'd like to propose that Craig do this work in the sandbox of the
Roller 3.0 branch so he can keep in sync with on-going development
going on there.
- Dave
