Greetings.  This is my first post to the list.

I would like to know about the code base itself.  There is not any
documentation that discusses the structure of the code itself and how
the software interacts with the data store.

Can any one tell me what source code files actually contain the code
that writes to the data store?

Thanks!

Richard Schilling

[ Post a follow-up to this message ]

Hi Richard,

Apache JDO is the home of the JDO API (the interface & class files of the
specification) & TCK (the code that tests whether a JDO implementation is
compliant with the specification); none of the code here actually writes to
a database*.  The reference implementation for JDO 2.0 is JPOX
(www.jpox.org) -- it is an implementation of the JDO 2.0 API.  There are
also many other implementations of JDO out there.

HTH,
Matthew

*:  There is a legacy reference implementation called FOStore (pronounced
like "foster") that was used as the JDO 1.0, but I don't think that's used
much anymore.  Others can comment on that.

-----Original Message-----
From: Richard Schilling [mailto:rschilling@cognitiongroup.biz]
Sent: Tuesday, July 31, 2007 10:22 AM
To: jdo-dev@db.apache.org
Subject: greetings and question about data stores

Greetings.  This is my first post to the list.

I would like to know about the code base itself.  There is not any
documentation that discusses the structure of the code itself and how
the software interacts with the data store.

Can any one tell me what source code files actually contain the code
that writes to the data store?

Thanks!

Richard Schilling

[ Post a follow-up to this message ]

I did realize that the JDO API and the model in the apache code was just
the implementation of the spec.  What I'm after is to make sure I
understand what parts of the API (which interfaces) are used by a
specific implementation to cause classes to be committed to the data
store.  It looks like the transactions defined in the spec serve this
purpose, but there's so much information I can't be sure.

Thanks ... still getting my head around the JDO spec - I've even read
the JDO book which I have.

Cheers.
Richard


Matthew T. Adams wrote:
> Hi Richard,
>
> Apache JDO is the home of the JDO API (the interface & class files of the
> specification) & TCK (the code that tests whether a JDO implementation is
> compliant with the specification); none of the code here actually writes t
o
> a database*.  The reference implementation for JDO 2.0 is JPOX
> (www.jpox.org) -- it is an implementation of the JDO 2.0 API.  There are
> also many other implementations of JDO out there.
>
> HTH,
> Matthew
>
> *:  There is a legacy reference implementation called FOStore (pronounced
> like "foster") that was used as the JDO 1.0, but I don't think that's used
> much anymore.  Others can comment on that.
>
> -----Original Message-----
> From: Richard Schilling [mailto:rschilling@cognitiongroup.biz]
> Sent: Tuesday, July 31, 2007 10:22 AM
> To: jdo-dev@db.apache.org
> Subject: greetings and question about data stores
>
> Greetings.  This is my first post to the list.
>
> I would like to know about the code base itself.  There is not any
> documentation that discusses the structure of the code itself and how
> the software interacts with the data store.
>
> Can any one tell me what source code files actually contain the code
> that writes to the data store?
>
> Thanks!
>
> Richard Schilling
>
>

[ Post a follow-up to this message ]

Richard,

If you are searching for the internals of a JDO implementation, you can read
 the
JPOX internals at
http://jpox.cvs.sourceforge.net/*ch...ore
.odp

Regards,

Quoting Richard Schilling <rschilling@cognitiongroup.biz>:

> I did realize that the JDO API and the model in the apache code was just
> the implementation of the spec.  What I'm after is to make sure I
> understand what parts of the API (which interfaces) are used by a
> specific implementation to cause classes to be committed to the data
> store.  It looks like the transactions defined in the spec serve this
> purpose, but there's so much information I can't be sure.
>
> Thanks ... still getting my head around the JDO spec - I've even read
> the JDO book which I have.
>
> Cheers.
> Richard
>
>
> Matthew T. Adams wrote: 
>
>

[ Post a follow-up to this message ]

[ Post a follow-up to this message ]

Erick

This is perfect.  Thanks - a must read.  I may be called upon to develop
a new datastore adapter soon, and this gives me a great place to start.

Richard

Erik Bengtson wrote:
> Richard,
>
> If you are searching for the internals of a JDO implementation, you can re
ad the
> JPOX internals at
> http://jpox.cvs.sourceforge.net/*ch...o
re.odp
>
> Regards,
>
> Quoting Richard Schilling <rschilling@cognitiongroup.biz>:
> 
>
>
>
>

[ Post a follow-up to this message ]

I was looking very carefully at fostore, and found myself going in
circles through the code without a good roadmap, like the one in the
presentation that Erik sent.

What I was really interested in doing, besides learning how a JDO
implementation uses a local store like fostore, was to learn how to use
fostore directly in my applications.  Found *no* information on that at
all - still can't.  So, I had hoped that by understanding the JDO
reference implementation use of fostore, I would be able to utilize
fostore directly.  After weeks of sifting through code though I gave up.

The closest I got was that the Netbeans b-tree library is used somehow,
but there is no documentation on that which I can find.

Cheers.

Richard


Craig L Russell wrote:
> Hi Richard,
>
> The fostore project at Apache JDO is an implementation that you could
> study for insights as to how the various components interact. There's a
> separation of an abstract StoreManager responsible for storing data to a
> specific datastore, a StateManager responsible for managing the state of
> individual instances, and a PersistenceManager whose API is pretty much
> defined in the JDO specification.
>
> Regards,
>
> Craig
>
> On Jul 31, 2007, at 3:23 PM, Richard Schilling wrote:
> 
>
> Craig Russell
> Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
> 408 276-5638 mailto:Craig.Russell@sun.com
> P.S. A good JDO? O, Gasp!
>

[ Post a follow-up to this message ]

Here is the posting I had way back in March of 2006, which didn't get
much response - if any at all:

http://www.webservertalk.com/archiv...-3-1437593.html

Never did find out the answers to these questions, but this explains
what I'm up to.

After just looking, I find this on the netbeans site:

http://mdr.netbeans.org/architecture.html#persistence

This explains MDR, the use of b-tree (which the JDO reference
implementation uses) in much more detail than I saw in the past.

FYI.

Cheers!

Richard Schilling




Craig L Russell wrote:
> Hi Richard,
>
> The fostore project at Apache JDO is an implementation that you could
> study for insights as to how the various components interact. There's a
> separation of an abstract StoreManager responsible for storing data to a
> specific datastore, a StateManager responsible for managing the state of
> individual instances, and a PersistenceManager whose API is pretty much
> defined in the JDO specification.
>
> Regards,
>
> Craig
>
> On Jul 31, 2007, at 3:23 PM, Richard Schilling wrote:
> 
>
> Craig Russell
> Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
> 408 276-5638 mailto:Craig.Russell@sun.com
> P.S. A good JDO? O, Gasp!
>

[ Post a follow-up to this message ]

[ Post a follow-up to this message ]

Looking some more this morning, I also found the source code repository
for netbeans b-tree implementation:

http://mdr.netbeans.org/source/brow...ag=release60_m4


And lo and behold, I also found an old CORBA module I didn't know
existed.  This is going to get interesting.... :-)

Richard


Craig L Russell wrote:
> Hi Richard,
>
> Sorry about that. The FOStore implementation had just a bit of
> documentation which I've tried to locate for you but can't seem to find
> just now. When I find it I'll post it on the JDO site and put a link here.
>
> Craig
>
> On Aug 3, 2007, at 11:07 PM, Richard Schilling wrote:
> 
>
> Craig Russell
> Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
> 408 276-5638 mailto:Craig.Russell@sun.com
> P.S. A good JDO? O, Gasp!
>

[ Post a follow-up to this message ]