Handling of EE apis and other multiple implementations
 

----- Original Message -----
> From: "Stanislav Ochotnicky" <sochotnicky@redhat.com>
> To: "Fedora Java Development" <java-devel@lists.fedoraproject.org>
> Sent: Thursday, May 10, 2012 5:31:58 PM
> Subject: [fedora-java] Handling of EE apis and other multiple implementations
>
> Hi all,
>
> we have been having long-standing issues with multiple
> implementations
> of the same APIs (javax.servlet, javax.servlet.jsp, etc). Namely we
> don't handle them at all. They work in Maven through our dependency
> mapping, but are not really usable during runtime.
>
> What I mean is for example several packages requiring javax.servlet
> implementation, but in reality they have to pick one of several RPMs
> we
> have. This inevitably leads to bloated installations when users
> inevitably end up with more than one implementation installed (and
> their
> deps).
>
> There has always been a solution for this, which is using
> alternatives
> system[1]. We haven't used it, mostly because relatively complicated
> nature. So I went looking into simplifying it with rpm macros. Long
> story short...this didn't turn out well mostly due to different
> implementations needing different things on classpath.
>
> Ergo: I would like to propose a standardization on naming and use of
> java EE APIs.
>
> There are several aspects of this:
> 1. We need to chose 1 implementation to serve as "THE"
> implementation
> for each API.

I propose this being to be the implementation of the latest version with smallest number of dependencies - both runtime and build time. This should work pretty well as the packages that can work with whatever implementation are easy to port to new version too.

> 2. That package will get to "Provides: EEAPI". Other packages can
> stop
> pretenting to provide any EE api :-) They can of course be used
> directly if a package requires something specific.
> 3. Since packages will be using "Requires: EEAPI" we can switch
> implementations easily if the need arises (dead project, new
> major
> version etc.)
>
> Now, I would like to standardize EEAPI naming as well. We have
> several
> versions of this. For example from tomcat.spec:
>
> Provides: jsp = %{jspspec}
> Provides: jsp22
> ... # other package
> Provides: el_1_0_api = %{epoch}:%{version}-%{release}
> Provides: el_api = %{elspec}
> ... # other package
> Provides: servlet = %{servletspec}
> Provides: servlet6
> Provides: servlet3
>
> So it looks like we are not consistent and I would like to fix that.
> My
> first idea was to have:
>
> Provides: javax.xml
> ...
> %files
> %{_javadir}/javax.xml.jar # this is symlink
>
> Then I realized JSP is "javax.servlet.jsp", and Servlet API is a
> superset so first 2 parts of package name would not be enough there.
> We
> could still have:
>
> Provides: javax.servlet # in servlet impl
> and:
> Provides: javax.servlet.jsp # in jsp impl
>
> To be clear: I want the names to be simple to deduce without going
> through spec files, searching with yum (much) etc. The simpler the
> better. I would hope Java devs chime in here. What would be the first
> thing that came to your mind here?

This proposal pretty much matches the osgi bundle names see http://download.eclipse.org/tools/orbit/downloads/drops/R20120119162704/
javax.activation
javax.annotation
javax.el
javax.inject
javax.jws
javax.mail
javax.management
javax.management.remote
javax.persistence
javax.security.auth.message
javax.servlet
javax.servlet.jsp
javax.servlet.jsp.jstl
javax.transaction
javax.ws.rs
javax.wsdl
javax.xml
javax.xml.bind
javax.xml.rpc
javax.xml.soap
javax.xml.stream
javax.xml.ws

So sticking close to each other would be even better.

>
> As for versioning APIs, I am not sure that would be needed. We
> usually
> try to keep packages up to date with latest APIs and packages not
> supporting current API can be moved to an older implementation.

No versions needed for the default. Every package that doesn't stick to the default should pick implementation on its own or ask for help to get ported.

I really like the proposal.
Alex

>
> How does this sound to you all?
>
>
> [1] http://fedoraproject.org/wiki/Packaging:Alternatives
>
>
> --
> Stanislav Ochotnicky <sochotnicky@redhat.com>
> Software Engineer - Base Operating Systems Brno
>
> PGP: 7B087241
> Red Hat Inc. http://cz.redhat.com
> --
> java-devel mailing list
> java-devel@lists.fedoraproject.org
> https://admin.fedoraproject.org/mailman/listinfo/java-devel
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Handling of EE apis and other multiple implementations
 

Quoting Aleksandar Kurtakov (2012-05-10 16:55:14)
> > Ergo: I would like to propose a standardization on naming and use of
> > java EE APIs.
> >
> > There are several aspects of this:
> > 1. We need to chose 1 implementation to serve as "THE"
> > implementation
> > for each API.
>
> I propose this being to be the implementation of the latest version with smallest number of dependencies - both runtime and build time. This should work pretty well as the packages that can work with whatever implementation are easy to port to new version too.
>

Agreed there. Minimal dependencies are a major selling point for me as
well. Unless of course there is some deficiency in the implementation.

> > So it looks like we are not consistent and I would like to fix that.
> > My
> > first idea was to have:
> >
> > Provides: javax.xml
> > ...
> > %files
> > %{_javadir}/javax.xml.jar # this is symlink
> >
> > Then I realized JSP is "javax.servlet.jsp", and Servlet API is a
> > superset so first 2 parts of package name would not be enough there.
> > We
> > could still have:
> >
> > Provides: javax.servlet # in servlet impl
> > and:
> > Provides: javax.servlet.jsp # in jsp impl
> >
> > To be clear: I want the names to be simple to deduce without going
> > through spec files, searching with yum (much) etc. The simpler the
> > better. I would hope Java devs chime in here. What would be the first
> > thing that came to your mind here?
>
> This proposal pretty much matches the osgi bundle names see http://download.eclipse.org/tools/orbit/downloads/drops/R20120119162704/
> javax.activation
> javax.annotation
> javax.el
> javax.inject
> javax.jws
> javax.mail
> javax.management
> javax.management.remote
> javax.persistence
> javax.security.auth.message
> javax.servlet
> javax.servlet.jsp
> javax.servlet.jsp.jstl
> javax.transaction
> javax.ws.rs
> javax.wsdl
> javax.xml
> javax.xml.bind
> javax.xml.rpc
> javax.xml.soap
> javax.xml.stream
> javax.xml.ws
>
> So sticking close to each other would be even better.

Note to all, that we have a working draft[1] for new guidelines. There are
a few improvements (better explanation of %add_maven_depmap macro, few
more hints here and there), removal of old guideline cruft (mostly
maven2 related) and now I've added an initial EE api packaging
guideline.

See [2] for a diff against current guidelines. Feel free to tweak, add,
improve. We can review/fix/revert whatever changes come in later before
putting it to a vote during our overdue SIG meeting.

One thing I wonder about adding is that each javax.XX providing package
should also install additional file which would basically constitute
needed classpath to run the implementation (i.e. arguments for
build-classpath). For example "glassfish-jsp-api" would need
"glassfish-jsp" on the classpath so it would install let's say:
%{_javadir}/javax.servlet.jsp.classpath (just an idea)
and this would contain:
glassfish-jsp

> > As for versioning APIs, I am not sure that would be needed. We
> > usually
> > try to keep packages up to date with latest APIs and packages not
> > supporting current API can be moved to an older implementation.
>
> No versions needed for the default. Every package that doesn't stick to the default should pick implementation on its own or ask for help to get ported.
>
> I really like the proposal.


[1] https://fedoraproject.org/wiki/User:Akurtakov/JavaPackagingDraftUpdate
[2] http://goo.gl/GYrOf

--
Stanislav Ochotnicky <sochotnicky@redhat.com>
Software Engineer - Base Operating Systems Brno

PGP: 7B087241
Red Hat Inc. http://cz.redhat.com
--
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Handling of EE apis and other multiple implementations
 

On 05/11/2012 11:53 AM, Stanislav Ochotnicky wrote:

Quoting Aleksandar Kurtakov (2012-05-10 16:55:14)

Ergo: I would like to propose a standardization on naming and use of
java EE APIs.

There are several aspects of this:
1. We need to chose 1 implementation to serve as "THE"
implementation
for each API.

I propose this being to be the implementation of the latest version with smallest number of dependencies - both runtime and build time. This should work pretty well as the packages that can work with whatever implementation are easy to port to new version too.


Agreed there. Minimal dependencies are a major selling point for me as
well. Unless of course there is some deficiency in the implementation.


Not all implementations follow the same functionality. In some cases
defaults are provided within the implementation.


Carlo



So it looks like we are not consistent and I would like to fix that.
My
first idea was to have:

Provides: javax.xml
...
%files
%{_javadir}/javax.xml.jar # this is symlink

Then I realized JSP is "javax.servlet.jsp", and Servlet API is a
superset so first 2 parts of package name would not be enough there.
We
could still have:

Provides: javax.servlet # in servlet impl
and:
Provides: javax.servlet.jsp # in jsp impl

To be clear: I want the names to be simple to deduce without going
through spec files, searching with yum (much) etc. The simpler the
better. I would hope Java devs chime in here. What would be the first
thing that came to your mind here?

This proposal pretty much matches the osgi bundle names see http://download.eclipse.org/tools/orbit/downloads/drops/R20120119162704/
javax.activation
javax.annotation
javax.el
javax.inject
javax.jws
javax.mail
javax.management
javax.management.remote
javax.persistence
javax.security.auth.message
javax.servlet
javax.servlet.jsp
javax.servlet.jsp.jstl
javax.transaction
javax.ws.rs
javax.wsdl
javax.xml
javax.xml.bind
javax.xml.rpc
javax.xml.soap
javax.xml.stream
javax.xml.ws

So sticking close to each other would be even better.

Note to all, that we have a working draft[1] for new guidelines. There are
a few improvements (better explanation of %add_maven_depmap macro, few
more hints here and there), removal of old guideline cruft (mostly
maven2 related) and now I've added an initial EE api packaging
guideline.

See [2] for a diff against current guidelines. Feel free to tweak, add,
improve. We can review/fix/revert whatever changes come in later before
putting it to a vote during our overdue SIG meeting.

One thing I wonder about adding is that each javax.XX providing package
should also install additional file which would basically constitute
needed classpath to run the implementation (i.e. arguments for
build-classpath). For example "glassfish-jsp-api" would need
"glassfish-jsp" on the classpath so it would install let's say:
%{_javadir}/javax.servlet.jsp.classpath (just an idea)
and this would contain:
glassfish-jsp


As for versioning APIs, I am not sure that would be needed. We
usually
try to keep packages up to date with latest APIs and packages not
supporting current API can be moved to an older implementation.

No versions needed for the default. Every package that doesn't stick to the default should pick implementation on its own or ask for help to get ported.

I really like the proposal.


[1] https://fedoraproject.org/wiki/User:Akurtakov/JavaPackagingDraftUpdate
[2] http://goo.gl/GYrOf



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Handling of EE apis and other multiple implementations
 

Quoting Stanislav Ochotnicky (2012-05-11 11:53:40)
> One thing I wonder about adding is that each javax.XX providing package
> should also install additional file which would basically constitute
> needed classpath to run the implementation (i.e. arguments for
> build-classpath). For example "glassfish-jsp-api" would need
> "glassfish-jsp" on the classpath so it would install let's say:
> %{_javadir}/javax.servlet.jsp.classpath (just an idea)
> and this would contain:
> glassfish-jsp

Mikolaj's questions on the discussion page made me think of a better
solution (already in the draft):

* %{_javadir}/javax.XXX will be a directory
* this dir will contain all jars (symlinks) needed to use this API (api and impl)

This means things should work like this:

$ build-classpath javax.servlet.jsp
/usr/share/java/javax.servlet.jsp/glassfish-jsp-api.jar:/usr/share/java/javax.servlet.jsp/glassfish-jsp.jar

This is currently broken due to a bug in build-classpath script that
causes it to ignore symlinks to jar files. Possible issue here is that
other distributions taking our packages will be hitting weird bugs due
to this so we should get this into upstream. I don't see why they used
"-xtype f" in find instead of "-type f". Anyone knows?



--
Stanislav Ochotnicky <sochotnicky@redhat.com>
Software Engineer - Base Operating Systems Brno

PGP: 7B087241
Red Hat Inc. http://cz.redhat.com
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