Re: [Geotools-devel] JAXB annotations on metadata module?

[Justin D. <jde...@op...>]

I was not aware that jaxb was bundled with jdk6. Geotools is a java5 so
that is what i use to build it. I only run with java6 in production.

Correct me if i am wrong but even with a dummy module for java 5 there
is a still a dependency on jaxb from the core of the library. If we can
move this dummy module out into a plugin then i would have no problem
with it.

Martin Desruisseaux wrote:
> Justin Deoliveira a écrit :
>> I am not sure adding a dependency on jaxb from a core module like
>> metadata is such good idea. Others may feel differently about this but i
>> would prefer that dependencies such as this are not added to the very
>> core of the library unless its absolutely necessary. Is there any way
>> you can achieve your goals in a separate module?
> 
> My strategy is driven by the fact that JAXB 2.0 is builden in Java 6, so for
> Java 6 users there is no new dependencies at all. For Java 5, we can erase this
> dependency totally.
> 
> There is my strategy. Would it be acceptable?
> 
> 1) Creates a dummy module that declares some JAXB annotations (only the
>    one we use) with @Retention(RetentionPolicy.SOURCE) policy.
> 
> 2) When building with Java 5, add the above module in the dependencies
>    with <scope>provided</scope>. When building with Java 6, do not add
>    any dependency at all.
> 
> The result is:
> 
> * When building with Java 6, the build-in JAXB is used.
>   Absolutly no new dependency.
> 
> * When building with Java 5, the effect of @Retention(RetentionPolicy.SOURCE)
>   is that annotations are totally discarted by the compiler. The result will
>   be as if we never wrote those annotations. Because the module has been
>   declared in Maven pom.xml with "provided" scope, it will not appears in the
>   JAR dependencies neither. So again the result is: absolutly no new dependency.
> 
> 
> So as you see, I can manage the build in such a way that there is really no
> dependency added, at the cost of a dummy module for Java 5 only which is not
> retained in the final dependencies.
> 
> 
>> The upgrade to jaxb 2.0 will be a problem for the xsd module, which
>> depends on metadata. I tried before and it led to problems. I would have
>> to look into it again to see what exactly they are.
> 
> But Java 6 is bundled with JAXB 2.0. Wouldn't be JAXB 1.3 a risk of conflict for
> Java 6 users?
> 
> 
>> It also seems that we are adding another xml serialization technology to
>> the mix... sigh. That brings us up to 5:
>>
>> * raw sax
>> * raw dom
>> * xdo
>> * xsd
>> * jaxb
> 
> I must admit that I'm not familiar with all those technology, and I don't know
> the pros and cons of each of them. My motivation was partially based on my wish
> to leverage technologies bundled in JDK when we can. Having JAXB annotation
> would not force users to use JAXB, but they can if they wish.
> 
>     Martin
> 
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-- 
Justin Deoliveira
The Open Planning Project
http://topp.openplans.org