objectbridge-developers

[OJB-developers] weekly status update

[Thomas M. <tho...@ho...>]

Hi all,

here is the second edition of the weekly OJB status update.
See the attached html file to see the status of your bug and feature
requests.

In the last week I used the JDK 1.3 dynamic Proxy concept to build an
improvement of the OJB virtual proxy concept. Now you don't have to
implement the proxy classes yourself, but can declare the usage of
dynamic proxies in the the XML repository.

This works great and avoids a lot of non-productive work from for
app-developers using OJB.

There is only one problem: this feature requires JDK 1.3 or later.

I see 2 option to deal with this situation:
1. just say OJB needs JDK 1.3 or later. Period.
2. try to support a JDK 1.2 compliant version without this feature.

Of course 1.) will save me a lot of work. But maybe some of you still
rely on JDK 1.2 in certain production environments ? Please tell me if
you need OJB running under JDK 1.2.

The easiest way to provide a JDK 1.2 compliant version would be to use
compiler switches in the code. Unfortunately Java does not have a
preprocessor.
What is the best solution in Java to provide this kind of preprocessing?
Can we use ANT for this  work? Any hints are most welcome.

regards,

--Thomas

[OJB-developers] weekly status update

[Thomas M. <tho...@ho...>]

Hi all,

attached you'll find the weekly update.

Colin Sampaleanu provided me with a cool link:

http://staff.develop.com/halloway/code/jcfe.html

this project developed a JDK1.2 based implementation of the JDK1.3
Dynamic Proxy classes.
By using this library it is possible to compile OJB under JDK1.2 without
any sourcecode modification!

Thanks again Colin for this smart solution.

Currently I'm working mostly on minor bug fixes and the third tutorial.
I hope to finish it during the next week. Once it is finished it's time
for a new release!

--Thomas

[OJB-developers] weekly status update

[Thomas M. <tho...@ho...>]

Hi all,

Please see the attached todo-list to see what's going on.
I've prepared a prerelease of the upcoming 0.7 release:
http://prdownloads.sourceforge.net/objectbridge/ojb-0.7.207-src.tgz

The API is complete but still a lot of things won't work in
client/server mode.
Once everything is working I will call it OJB 0.7.
The new features are mainly related to SQL based queries and accessing
the metadata layer via the PersistenceBroker.
When this is finished the persistence kernel API is complete! (Things
like M:N mapping, adding support for Joins, etc. can be done without
touching the API)
I'm planning to invite developers from the SourceForge community to
collaborate on a JDO implementation based on the OJB 0.7 API.

I'm on a short trip, so please don't expect quick replies in the next
few days...

--Thomas

Re: [OJB-developers] weekly status update

[David F. <dw...@la...>]

At 12:20 AM 1/1/1997 +0100, Thomas Mahler wrote:
>Hi all,
>
>here is the second edition of the weekly OJB status update.
>See the attached html file to see the status of your bug and feature
>requests.
>
>In the last week I used the JDK 1.3 dynamic Proxy concept to build an
>improvement of the OJB virtual proxy concept. Now you don't have to
>implement the proxy classes yourself, but can declare the usage of
>dynamic proxies in the the XML repository.
>
>This works great and avoids a lot of non-productive work from for
>app-developers using OJB.
>
>There is only one problem: this feature requires JDK 1.3 or later.
>
>I see 2 option to deal with this situation:
>1. just say OJB needs JDK 1.3 or later. Period.
>2. try to support a JDK 1.2 compliant version without this feature.
>
>Of course 1.) will save me a lot of work. But maybe some of you still
>rely on JDK 1.2 in certain production environments ? Please tell me if
>you need OJB running under JDK 1.2.
>
>The easiest way to provide a JDK 1.2 compliant version would be to use
>compiler switches in the code. Unfortunately Java does not have a
>preprocessor.
>What is the best solution in Java to provide this kind of preprocessing?
>Can we use ANT for this  work? Any hints are most welcome.

We could live with the JDK1.3 requirement, since we have other reasons
to require this already.   However, I think you can do conditional compiles
on classes with Ant by checking to see if certain classes exist.  That is
how we handle optional module support in OpenEMed now.  For example,
if the right POET classes don't exist, we don't compile POET support.
This is totally transparent.  You need to be careful how you handle 
constructors in
in this approach, but it is quite workable.

Dave

>regards,
>
>--Thomas

Re: [OJB-developers] weekly status update

[Dirk O. <di...@xa...>]

> There is only one problem: this feature requires JDK 1.3 or later.
> 
> I see 2 option to deal with this situation:
> 1. just say OJB needs JDK 1.3 or later. Period.
> 2. try to support a JDK 1.2 compliant version without this feature.
> 
> Of course 1.) will save me a lot of work. But maybe some of you still
> rely on JDK 1.2 in certain production environments ? Please tell me if
> you need OJB running under JDK 1.2.

From my experience, I would say don't bother with the 1.2 backward
compatability. If a package has to be *really* backwards compatible, you
would have to support JDK 1.1.x! So I guess the common case is that one
is either limited to a 1.1 VM or free to use the latest 1.3 one.

Just my 0.01 EUR,

-dirk

RE: [OJB-developers] weekly status update

[Colin S. <col...@ex...>]

> -----Original Message-----
> From: obj...@li...
> [mailto:obj...@li...]On Behalf Of
> Thomas Mahler
> Sent: Tuesday, December 31, 1996 6:20 PM
> To: objectbridge
> Subject: [OJB-developers] weekly status update
> ...
> In the last week I used the JDK 1.3 dynamic Proxy concept to build an
> improvement of the OJB virtual proxy concept. Now you don't have to
> implement the proxy classes yourself, but can declare the usage of
> dynamic proxies in the the XML repository.
>
> This works great and avoids a lot of non-productive work from for
> app-developers using OJB.
>
> There is only one problem: this feature requires JDK 1.3 or later.
>
> I see 2 option to deal with this situation:
> 1. just say OJB needs JDK 1.3 or later. Period.
> 2. try to support a JDK 1.2 compliant version without this feature.
>
> Of course 1.) will save me a lot of work. But maybe some of you still
> rely on JDK 1.2 in certain production environments ? Please tell me if
> you need OJB running under JDK 1.2.
>
> The easiest way to provide a JDK 1.2 compliant version would be to use
> compiler switches in the code. Unfortunately Java does not have a
> preprocessor.
> What is the best solution in Java to provide this kind of preprocessing?
> Can we use ANT for this  work? Any hints are most welcome.

Needing JDK/JRE 1.3 or higher is not that big a deal to me, but maybe you
could use this code for 1.2; it should be almost no extra work:
http://staff.develop.com/halloway/code/jcfe.html
The license does not appear to be an issue...

Regards,

RE: [OJB-developers] weekly status update

[<ll...@li...>]

Hi Thomas,

Sadly IBM doesn't support JDK 1.3 yet in its otherwise excellent
development environment VisualAge for Java.
Most IBM deployment environment also seems to suggest using JDK 1.2.

I didn't get a chance to try VAJ 4 yet. If that supports JDK 1.3 then I
think you can drop the JDK 1.2 support without further notice.
Otherwise there will be lots of JDK 1.2 users out there for a couple of
more years.

I saw that the JDOM project used ANT to replace the 1.2 collection
classes with the plug-in that came with 1.1. That might be possible in
this project also. I don't know if they dropped 1.1 support too by now,
but they were so kind as to support it at least until ibm came with VAJ
3.5

/Lazlo

(sorry if this is a repost)

-----Original Message-----
From: obj...@li...
[mailto:obj...@li...] On Behalf
Of Thomas Mahler
Sent: 1. januar 1997 00:20
To: objectbridge
Subject: [OJB-developers] weekly status update


Hi all,

here is the second edition of the weekly OJB status update.
See the attached html file to see the status of your bug and feature
requests.

In the last week I used the JDK 1.3 dynamic Proxy concept to build an
improvement of the OJB virtual proxy concept. Now you don't have to
implement the proxy classes yourself, but can declare the usage of
dynamic proxies in the the XML repository.

This works great and avoids a lot of non-productive work from for
app-developers using OJB.

There is only one problem: this feature requires JDK 1.3 or later.

I see 2 option to deal with this situation:
1. just say OJB needs JDK 1.3 or later. Period.
2. try to support a JDK 1.2 compliant version without this feature.

Of course 1.) will save me a lot of work. But maybe some of you still
rely on JDK 1.2 in certain production environments ? Please tell me if
you need OJB running under JDK 1.2.

The easiest way to provide a JDK 1.2 compliant version would be to use
compiler switches in the code. Unfortunately Java does not have a
preprocessor.
What is the best solution in Java to provide this kind of preprocessing?
Can we use ANT for this  work? Any hints are most welcome.

regards,

--Thomas