[slf4j-dev] using slf4j, nlog4j in Eclipse RCP

[Ceki Gülcü]

Hello John,

You are obviously a few steps ahead of me. I'll try to answer when I can, 
and ask questions otherwise.

More in line.

At 09:07 PM 11/22/2005, John Franey wrote:
>Hi,
>
>I've created a logging prototype in the Eclipse rich client platform using 
>slf4j and nlog4j.  I've written an article about it which is in its final 
>draft.  I'm about to submit it to the editors of EclipseZone 
>(http:www.eclipsezone.com), but there are some questions I'd like to ask 
>your development team.

I hope they accept your submission. However, regardless of their decision, 
I suggest that you ask to keep the copyright so that you can publish its 
contents elsewhere. In my experience, the publicity spurt that an article 
in a magazine brings is not worth the steady diffusion power of the article 
published on the web-pages of your project. Most magazine editors (but not 
book editors) will let you keep the copyright. In short, you license your 
article to the magazine but keep the copyright.

>In the article, Eclipse plug-ins for the slf4j class libraries are created 
>and introduced; one plug-in for each slf4j variant.  These plug-ins are 
>interchangeable and so allows seperation between the application and 
>logging framework.  Also, because slf4j contains a JCL implementation, the 
>slf4j plug-ins can support other plug-ins that use JCL.  Way cool.  Thanks 
>for the library.

I am not familiar with Eclipse plug-ins (except as an Eclipse user). What 
advantages does the plug-in form SLF4J have compared to the stand-alone 
form? I apologize if this may seem like a stupid question.

>First question: The name of the plug-ins incorporate the name of your 
>organization: org.slf4j.  Is this OK?  Its a naming convention in Eclipse 
>plug-ins; to name a plug-in after the java package that it 
>implements.   For example, a plug-in for LOG4J logging would be called 
>org.apache.log4j.   Also, 99.9% of the code in the plug-in originates from 
>slf4j, not any other entity.  The only code that I provide are entries to 
>a jar's MANIFEST.MF file.

The SLF4J is distributed under the X11 license (see 
http://www.slf4j.org/license.html ) which is quite permissive. In short, 
provided that:

  the copyright notice(s) and this permission notice appear in all copies of
  the  Software and  that both  the above  copyright notice(s)  and this
  permission notice appear in supporting documentation.

You should be fine.

>Second question:  Its very easy for you to build and distribute your 
>library as Eclipse plug-ins, incorporating the modifications detailed in 
>the article.  It requires only OSGi entries in the jar file's 
>MANIFEST.MF.  Would you be interested in doing this?

Why not? However, as mentioned above, the advantages of distributing SLF4J 
as Eclipse plug-ins are not entirely obvious to me :-).

>Third question:  I created a plug-in for an slf4j Logger implementation 
>over the Eclipse RCP logging framework.  I used org.slf4j in the name of 
>the plug-in only to keep it consistent with the other plug-in names in the 
>article.  Is that OK?  Only the Logger, LoggerFactory and binding classes 
>are contributed by me, the rest of the code is all yours and I'd like to 
>maintain that credit belongs to you.

Although you do not have to, you could license the code to slf4j.org so 
that it could distribute your code. Alternatively, you could chose to 
distribute your code on your own.

>Fourth question:  Could I contribute the slf4j on Eclipse logging to your 
>project?  One objection you may have is that there are build time 
>dependencies on the Eclipse RCP libraries.

The Eclipse RCP library dependency is not a problem. In principle, each 
binding already depends on some underlying library, e.g. log4j. 
Dependencies on logging systems is what SLF4J is all about.

Let me contact you offline for details about creating an account for you, 
commit rights etc on the slf4j.org server.

>Thanks,
>John

-- 
Ceki Gülcü

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